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Of Dirt and Digger Bees

12/23/2019

 
One of my (many) entomological fixations is invertebrates in urban settings, so I’ve been getting better acquainted with native pollinators in my own urban garden in Portland, Oregon. While artificial nest sites like bee blocks and stem bundles are popular among home gardeners, my explorations have illustrated how essential open, undisturbed soil is for ground-nesting bees. I’ve monitored pollinators regularly for over two years, and I see something new each year. In 2019, it was my first local sighting of ground-nesting Bumble Bee-Mimic Digger Bees (Anthophora bomboides), which recently took up residence in a nearby park. In mid-June, while doing dragonfly surveys there, I paused to check out the soil-packed rootwad of a large tree placed several years ago during a stream restoration project. This rootwad is taller than I am and it’s been a hotbed of activity for Western Yellowjackets (Vespula pensylvanica), which I enjoy watching as they go about their daily business.
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Western Yellowjackets (Vespula pensylvanica) at nest entrance in rootwad, October 2017. Photo by C. A. Searles Mazzacano, all rights reserved.
This time I was greeted by a different sight—the rootwad was still a hotbed of activity, but each of the numerous nest holes was ornamented by a crooked little mud turret a few centimeters high, with a vertical slit along one side. Even more interesting was that the insects busily coming and going looked like smallish bumble bees…which in no way make nests like these. In a few seconds my brain clicked and I realized it was a different bee giving a great demonstration of its common name: Bumble-bee Mimic Digger Bees (Anthophora bomboides). This species isn’t uncommon, but it’s one I hadn’t observed before. 

Anthophora are among my favorite native bees; they have robust furry little bodies in attractive shades of grey, cream, orange, yellow, or red, and they zip around at manic speeds. They are equally manic when it comes to mating. Anthophora are protandrous, which means that when adults complete their development and emerge in spring, males emerge earlier than females. Anthophora males go about the business of reproduction with unseemly enthusiasm; a male Anthophora may attempt to mate once every three seconds, and newly-emerged females may find themselves the center of attention of a few dozen males all frantically trying to mate at once.
Anthophora bomboides (Bumblebee-mimic Digger Bee) nests in same rootwad, June 2019. Note female entering tunnel at upper right. Phtoos by C. A. Searles Mazzacano, all rights reserved.
The name Anthophora means “flower-bearer,” and these bees are super pollinators, for a variety of reasons. They are very good at shivering, which bees do to warm up their wing muscles, enabling them to fly and visit flowers when other bee species are too cold to be active (the flip side is that their furry bodies overheat more easily, so after a busy morning on a hot day they may retire to the shade). They are also one of the bee groups that does “buzz pollination,” whereby they hold onto a flower with their feet and vibrate their wing muscles to shake pollen out of the anthers (fun fact: non-native European Honey Bees (Apis mellifera can't buzz pollinate). Buzz pollination is critically important for plants such as tomatoes, peppers, eggplant, cranberry, and potato, whose anthers are akin to salt shakers, with small openings at the tip through which pollen must be shaken. Anthophora also have long tongues, which allow them to access nectar in deeper and more tubular flowers. 

The tribe that contains this genus (Anthophorini) has over 700 species in seven genera worldwide. We have just two genera in the US (Anthophora and Habropoda), but identification to species is often (and rightly) described as “fiendishly difficult” (and when it comes to bees, a notoriously troublesome group to ID, that’s saying something). There are about 50 Anthophora species in the US, most of which are western. The genus contains both generalist and specialist species, and specialists can be important pollinators of wildflowers such as beardtongues (Penstemon) and lupines. 
​

Like most of our native bees, almost all Anthophora nest in the ground, often in large aggregations, and several females may share the same nest entrance, though they maintain their own tunnels. Females use their forelegs and mandibles to loosen the soil and dig tunnels, shoveling loose dirt backwards; I’ve often been alerted to the presence of nesting females by puffs of dirt rising from the ground. Once a tunnel is complete, they excavate small chambers or cells, where a “loaf” of pollen and nectar is placed to provision the egg that is laid there. They line the nest with secretions from their Dufour’s gland, a specialized abdominal gland found in bees, wasps, and ants. In Anthophora, these secretions are rich in water-repellant triglycerides and hydrocarbons, to protect the nest and developing larvae from water and fungi. After nest provisioning and egg-laying is done, the tunnel opening is plugged with a circular bit of mud and the female flies away, dying not long afterwards.
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Female digger bee at the Oregon Coast, caught in the act of kicking excavated sand backwards out of her nest tunnel. Photo by C. A. Searles Mazzacano, all rights reserved.

Bumble-bee Mimic Digger Bees put their own twist on nest-building. They nest in banks and bluffs, generally not too far from a source of water, which they carry back to the nest in their crops to soften the soil for digging. My observations of the communal nest site in 2019 were almost exactly those of H.H. Nininger in 1920, who wrote, “Their burrows were placed close together and in an almost vertical position, and over the entrances of many of them were constructed very peculiar bent-over chimneys of clay…the warm sunshine kindled the vital spark in these insects to the greatest activity. They were scurrying in and out of their burrows…in what seemed to be feverish haste…” Nininger described the tunnels as 5-7 inches deep, with 2-5 oval egg chambers at the end. The “feverish haste” at my site included quite a few mis-identifications of the home tunnel, as many returning females shot into an opening and back out again just as quickly, occasionally with irritated help from the nest’s true owner. They use bits of wet soil from excavation to build their distinctive turrets, whose function isn’t completely known; hypotheses include deterring parasitism, preventing debris from entering the tunnel, serving as a sign for other females to nest, facilitating nest recognition, and protection from rain.

Bumble-bee Mimic Digger Bees are considered Batesian mimics (i.e., a palatable or harmless species assuming the appearance of a distasteful or dangerous one), as they are pretty docile even for a solitary bee; they may bite if handled roughly, but they aren’t big on stinging. They also provide habitat for an interesting array of other creatures. They have a strong association with nematode (roundworm) called Bursaphelenchus seani; in one study, the nematode was found in brood cells during all stages of larval and pupal development, and when adult bees emerged the juvenile nematodes moved into their reproductive tracts (which seems like a hell of a welcome to the world). Another paper described the nematode/bee relationship as phoretic, as they apparently hitch rides on adults so they can make their way to the protected nest cells made by female bees, where they feed on fungi (rather than on the nectar/pollen “bee bread”). Other studies note the presence in nests of a type of dermestid (carpet or skin beetle) in the genus Anthrenus, many of which are pollen-eaters and are known to scavenge the remains of pollen and dead bees in old nest cells, and a species of Medeus mite that feeds on pollen and fungi in host cells where young bees don’t develop successfully. 

There are several take-home messages here. The first is that native pollinators can survive and even thrive in urban settings—not all species, but certainly some. The second follows from that—setting out bee blocks and stem bundles for native bees is an increasingly popular pastime and it’s great fun to see mason or wool-carding bees move into them, but the fact is that over 70% of native bee species in North America nest in the ground. Undisturbed soil is hard to come by in urban settings, and ground-nesting bees tend to do worse in urban areas than crevice- or wood-nesting bees. Third, it isn’t just a diversity of bees we protect when we conserve and sustain patches of healthy habitat, it’s also all the other species that may rely on, associate with, benefit from, or opportunistically encounter bees and their nests. So this winter, when many of us are planning next year’s garden or restoration projects (and possibly buying “bee houses” as gifts for gardening friends), consider the simple expedient of also protecting areas of undisturbed soil. Come next spring and summer, you’ll be rewarded by the appearance of small round holes, and seeing the “vital spark” of native solitary ground-nesting bees “scurrying in and out of their burrows.”

Supporting literature

Brooks, R.W. 1983. Systematics and Bionomics of the Anthophora: the Bomboides group and species groups of the new world (Hymenoptera: Apoidea, Anthophoridae). University of California Publications in Entomology, Volume 98. 

Cane, J.H. 1981. Dufour’s gland secretion in the cell lining of bees (Hymenoptera: Apoidea). Journal of Chemical Ecology 7: 403-410.

Giblin, R.M. and H.K. Kaya. 1983. Field observations on the association of Anthophora bomboides standfordiana (Hymenoptera: Anthophoridae) with the nematode Bursaphelenchus seani (Aphelenchida: Aphelenchoididae). Annals of the Entomological Society of America 76(2): 228-231.

Nininger, H.H. 1920. Notes on the life-history of Anthophora stanfordiana, Psyche 27(6): 135-137. 

Norden BB, Batra SWT, Fales HM, Hefetz A, Shaw JC (1980) Anthophora bees; unusual glycerides from maternal Dufour’s glands serve as larval food and cell lining. Science 207: 1095–1097.

O’Connor, B.M. 1996. Two new mites (Acari: Acaridae) associated with long-tongued bees (Hymenoptera: Apidae) in North America. Journal of the Kansas Entomological Society 69(4) suppl.: 15-34.

Of stinking beetles, toxic millipedes, and questionable caterpillars

4/30/2018

 
This is a story of the connections between three very different kinds of arthropods, brought about by the annual Northwest Scientific Association meeting, which took place in Olympia, Washington. As usual when a bunch of biologists get together, the final day was a smorgasbord of field trips, and I opted for a jaunt to an acidic peatland. Washington ranks about 21st among US states in extent of peat soils; most of the state’s Sphagnum bogs are in the Puget Sound lowlands, so this seemed like an opportunity that shouldn’t be missed. It was too early in the year to expect much insect life, and the sunny weather that taunted us on indoor presentation days turned cloudy and drizzly, but I tromped out undeterred with bog boots, waterproof camera, and a mild feeling of hopefulness. 

I was busy chasing a Pardosa wolf spider across a puddle when one of my fellow attendees nudged me and held out his hand. Nestled on his palm was a shiny black beetle with preposterously huge, forward-projecting jaws. As I leaned in for a close shot, I also became aware of a substantial stink wafting from the beetle. I hadn’t seen this critter in the field before, but its general appearance was that of a ground beetle (Carabidae), and upon returning home I determined that it was in the genus Promecognathus.
(left) Acidic Sphagnum bog near Shelton, Washington (right) Promecognathus crassus, looking good and smelling bad. Photos by C.A. Searles Mazzacano, all rights reserved.
Promecognathines represent an old lineage that probably originated in Pangea; today they are found only in western North America (two species) and the Cape Province of South Africa (six species; [Bousquet, Y. 2012. Catalogue of Geadephaga (Coleoptera, Adephaga) of America, north of Mexico. ZooKeys 245: 1-1722]). The North American Promecognathus crassus and P. laevissimus look quite similar and Yves (2012) doubts they are separate species, but for now based on location I believe my specimen is P. crassus. 

Ground beetles are a large, diverse family composed mainly of predators. When threatened, some can also generate a potent shield of stink by secreting odoriferous and sometimes caustic compounds from glands near the anus. These organic cocktails of hydrocarbons, ketones, esters, acids, quinones, aldehydes, and phenols pack a startlingly powerful reek. Promecognathus is flightless, with reduced (brachypterous) hindwings, so the best defense for this earthbound beetle is apparently simply to be offensive. But what about those giant projecting jaws, the monstrous mandibles that give the genus its name (Promecognathus is derived from the Greek ‘promeces’, meaning advanced or in front of, and ‘gnathos’, meaning jaw)? 

​Most adult carabids are opportunistic predators, killing whatever they can catch, but some are specialists, concentrating on caterpillars, snails, or slugs. Promecognathus specializes in polydesmid millipedes. Our west coast Clown Millipede (Harpaphe haydeniana) is commonly encountered and easily recognized, with a large (up to 3 inch) chocolate-brown to black body studded along the sides with bright yellow dots. Clown Millipedes are important nutrient recyclers in forest ecology, munching on and breaking down tree leaves and needles, and they are abundant and slow-moving, so potentially a great snack for a predator. However, they have their own chemical weapon that ups the ante on bad-smelling beetles—they produce hydrogen cyanide (HCN) and benzaldehyde. HCN is a potent metabolic toxin that makes the millipedes extremely poisonous to small animals (but imparts a pleasant smell of almonds) and renders them almost immune to predation—except for Promecognathus. Using their long legs, adult beetles straddle a millipede and run up to its head, then sink those remarkable mandibles into its neck, severing the millipede’s ventral nerve cord and thus preventing it from using its cyanide defense spray.
(left) A mating pair of Clown Millipedes (Harpaphe haydeniana) in the California Redwoods (right) Parnassius clodius nectaring, Oregon Caves National Monument, Cave Junction, Oregon. Photos by C.A. Searles Mazzacano, all rights reserved.
This remarkable story of evolution and adaptation has an additional player—the butterfly Parnassius clodius (Clodius Parnassian). Parnassians are lovely butterflies with creamy white wings dotted with cranberry-red spots and ornamented by black bars and shading. P. clodius caterpillars aren’t showy but they do come in two color morphs; one is a gray or purplish-brown with light yellow spots along the sides that may merge to form a thin line, and thin black chevrons along the top; and the other is black, with a row of bright yellow spots along each side (McCorkle & Hammond, 1985, Observations on the Biology of Parnassius clodius (Papilionidae) in the Pacific Northwest, Journal of the Lepidopterists’ Society 39(3): 156-162). McCorkle & Hammond note that the grayish form is more abundant in alpine populations of P. clodius, where lighter coloration may help them blend into the rocks, while the yellow-spotted black form is more abundant in lowland populations—places where the Clown Millipede can also be found in large numbers. This suggests the caterpillars are mimicking the appearance of the toxic millipedes in the habitats where they co-exist. 

An edible mimic of a toxic model (a.k.a. Batesian mimicry) is only protected as long as predators are more likely to come into contact with the noxious model and have an unpleasant learning experience that results in future avoidance. Where edible mimics outnumber noxious models, Batesian mimicry can be a failure for the mimic, but the greater abundance and availability of millipedes vs. caterpillars works in favor of the caterpillar. There is also some question as to whether the caterpillars might themselves be distasteful, since this species uses Dicentra (bleeding heart, Dutchman’s Britches) as larval host plants. Dicentra contain toxic alkaloids (James & Nunnallee, 2011, Life Histories of Cascadia Butterflies, OSU Press), and a rather horrifying paper by Black & Kelly, published in 1930 when animal use standards were presumably different, describes in detail the death convulsions of multiple white mice injected with different concentrations of Dicentra extract (Toxicity of Bikukulla formosa, Western Bleedingheart, Journal of Agricultural Research, 40(10): 917-920). 

​Who knew that a peatbog Promecognathus would reveal such stirring biological drama?

Confessions of a formerly-uninterested caddisfly watcher

11/18/2017

 
Years ago I harbored something of a low-level grudge against caddisflies because I blamed them for my lack of knowledge about butterflies. Those two groups of insects might seem very different, but they actually share a close evolutionary relationship, as the orders Lepidoptera (moths and butterflies) and Trichoptera (caddisflies) are considered sister groups comprising a larger superorder called Amphiesmenoptera. Both are named for the appearance of their wings. Lepidoptera means “scale-wing”, referring to the minute overlapping scales that form colors and patterns on butterfly and moth wings. The tented wings of adult caddisflies have tiny hairs instead of scales, hence the name Trichoptera, meaning “hairy wing”. However, the excellent taxonomist who taught me in grad school specialized in caddisflies and had rather less use for Lepidoptera--which is unfortunately the one group that pretty much everyone expects an entomologist to reel off on sight.  Hence, my low-level grudge.

However, with time occasionally comes wisdom, and as I began to specialize in aquatic entomology (and do a lot of catch-up learning about butterflies and moths), I gained a better appreciation of this truly remarkable group of insects. Adult caddisflies are mostly dull-colored, with a passing resemblance to drab moths, but larvae are much more creatively attired. Like their caterpillar relatives, caddisfly larvae make silk, extruding it from a gland that opens at the base of the mouth. Some use silk to weave underwater shelters that double as fishing nets for organic debris, while others tie together bits of sand, gravel, leaves, fir needles, bark, or twigs to make intricate portable cases. This architectural adaptation is at the root of the name caddisfly: “cadas” is an Old French word meaning “floss silk” and “cadice” is a Middle English word for a strip of cloth, and itinerant cloth-sellers would pin bright “cadices” to themselves to advertise their wares from afar.
 (Left) Adult caddisflies resemble drab moths, but with hairy wings held rooflike over the body and long, forward-pointing antennae. They also lack the long tubular mouthpart (proboscis) that butterflies and moths use to sip nectar. (Right) Twig...or cased caddisfly larva???? Photos by C.A. Searles Mazzacano, all rights reserved.
Case-making larvae begin constructing their mobile shelters soon after hatching; their silk provides not only binding for the case materials, but also a lining for their clawed anal prolegs to cling to so the case stays with them as they crawl about. Material is added to the front of the case so it grows with them, and they can trim the back to keep it at a manageable length. Cases are roughly tubular but have an astonishing diversity of shapes and materials, from tiny spiraling coils of sand grains created by Snailcase Makers (Helicopsychidae)—such fine mimicry that they were originally classified as snails—to slender plant pieces stacked log cabin-style in square-sided homes of Humpless Case Makers (Brachycentridae), and weighty, tortoise-like gravel domes of Saddlecase Makers (Glossosomatidae). The propensity of mineral case-making caddisflies to use any materials of appropriate size has even led to novelty jewelry, with pendants and earrings made by larvae provided with chips of malachite, lapis, and amethyst.
Caddisfly larvae in Oregon's  Whychus Creek (left), Middle Fork John Day (center), and Sandy River (right). Photos by C.A. Searles Mazzacano, all rights reserved.
Small but mighty, caddisfly larvae have a big influence on aquatic ecosystems. Their value as fish food has given them an appreciation among fly fishers that dates back to at least 1653, when Izaak Walton’s Compleat Angler endorsed “cod-worms or caddis” as excellent bait, and today’s fly-fishers can use Sparkle Pupa Caddis, Floating Caddis Emerger, or Crunchy Caddis flies. Caddisfly larvae are eaten by a lot more than just fish, though; they are a solid meal for predatory stoneflies, diving beetles, and waterbirds, and the winged adults are eaten by terrestrial wildlife such as birds, dragonflies, spiders, and amphibians. Caddisflies have practical uses in stream ecology; many prefer running water, where they are one of “The Big Three” orders of insects (the others are mayflies and stoneflies) whose presence in biotic assessment studies indicates colder, cleaner, better-oxygenated waters (though some species prefer the warmer still waters of lakes and ponds). Caddisfly larvae are also ecosystem engineers, a term used to describe organisms that physically modify, create, or maintain habitat. Their silk is strong stuff—strong enough that an abundance of Net-spinning Caddisflies (Hydropsychidae) in a stream can actually help stabilize the gravels they colonize (see Cardinale et al., 2004; Johnson et al., 2010), and case-making caddis can fix tons of gravel and sand to the stream bed, helping to keep the substrate in place even during high flows.

So the next time you find yourself near a stream, pick up a few rocks, turn them over, and wait for some of the stony or twig-like adhesions to poke out a little caterpillar-like head and crawl around—and you too may be drawn further into the beguiling world of caddisflies.

Robber flies--killers on the wing

3/31/2017

 
When pressed to declare my favorite insects, I seem to have a strong predilection for predators, as my list is topped by dragonflies, mantids, and robber flies. The first two get a fair amount of press, but I feel that robber flies (Family Asilidae) often don’t receive the respect they deserve. Even the common name is a bit of an insult—who wouldn’t rather be characterized as a bold dragon than a skulking robber? The Latin root of the name for this family, asilus, is given by Webster’s Unabridged as meaning “gadfly or horsefly,” but given these insects’ propensity for hunting the very flies that trouble horses (while leaving the horses entirely alone), it appears that human confusion about the nature of robber flies is of long duration.

It’s a pity they aren’t better appreciated, because North America is home to about 1,000 of the more than 7,000 species known world-wide, so there are plenty of them to see—and they are well worth a closer look. They range from 0.1-2 inches (3-50 mm) in length, so admittedly some species can be pretty hard to find, and they like open, dry, sunny habitats. Like all true flies (Diptera), they have a single pair of wings, with the front wings used for flight and the rear pair reduced to small clublike balancing structures called halteres. One obvious feature of robber flies which is unique to this family, however, is their comically hairy faces, which give them the appearance of sporting a stylish ‘stache or bushy goatee. The official name for this fuzzy feature is the mystax, derived from the Greek mystakos meaning mustache or upper lip, and it is thought to protect their heads from the frantic movements of struggling prey. The top of their head is indented between widely separated compound eyes, and many have a stout thorax with a slender tapering abdomen. Some are wasp or bumble bee mimics, with striped and/or furry black and yellow bodies. “Raptor flies” might be a better name for this group, given their prodigious hunting abilities, but robber flies harbor no animosity towards humans and will not bite if handled gently. In fact, they land on people fairly readily, and most of my asilid photos have been taken when one landed on me to leisurely consume its large, recently-captured prey.
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Efferia robber fly on the lookout for lunch; Timpe Springs, UT. Photo by C.S. Searles Mazzacano, all rights reserved
Adults are generalist predators and eat any insect they can catch, which depending on the size of the robber fly ranges from tiny midges to robust dragonflies, and may include insects that have distasteful chemical defenses or stingers that would repel other predators. Their in-flight hunting is aided by large eyes with a binocular field of view, strong agile flight to dart out and snag passing prey, long spiny legs that can grasp struggling victims larger than their own bodies, and stout piercing-sucking mouthparts. They use these mouthparts to inject prey with a potent chemical cocktail of saliva, containing neurotoxins that immobilize the victim and proteolytic enzymes that digest its innards to a soup, which is then sucked up though the fly’s proboscis. One fly can eat thousands of prey in the weeks of its adult life, making these insects part of the suite of natural enemies that can help provide pest control in the farm and garden (although, in the interests of full entomological disclosure, some are also known to hang out next to beehives and capture workers as they come and go).

Robber flies are visual predators, but recent research shows just how amazing their vision is. A team of researchers  studied one of the smaller Asilidae, Holocephala fusca, which clocks in at a mere 6 mm long (Wardill et al. 2017, A novel interception strategy in a miniature robber fly with extreme visual acuity, Current Biology 27: 1-6). This tiny fly can spot potential prey more than 0.5 m away in less than half a second, which is about the same ratio as a human seeing a moving sandwich across a soccer field. Like all adult insects, robber flies have compound eyes made up of thousands of individual lenses called ommatidia. Robber flies have lenses in a range of different sizes, with larger lenses providing better vision; some lenses in the robber fly’s eyes are as large as those in the eyes of a dragonfly, an insect about 10 times larger. A dragonfly can have large lenses across its entire visual field, but a robber fly’s head simply isn’t big enough to accommodate the quantity of large lenses needed for this degree of visual acuity. In a neat evolutionary solution, the eyes of a robber fly are arranged with more of the larger lenses in the center of the field of vision and smaller lenses towards the outside of the eye, providing high acuity in a small space.

When a robber fly spots its prey, it takes off on a fast interception course using maximum acceleration. However, it is usually chasing a moving target that may alter its own speed and direction, so the hunter must be able to adjust course once it is in closer range to achieve a successful capture. In the studies on Holocephala, flies pursuing “prey” (a moving bead) used a constant approach speed when first zooming towards their target, but adjusted heading and speed once they were within about 29 cm (11.5 in.) of their target. The authors describe this as a “lock-on strategy”, and state that it has not been described in any other flying animal. They hypothesize that what flies lose in speed during this lock-on, they gain in increased likelihood of capture, making it an energetically worthwhile tradeoff. They further note that this strategy may be of future use in designing “bioinspired guidance systems” for miniature aerial vehicles, an area in which dragonflies have also provided inspiration.

If any of this has inspired you to find out more about the amazing robber fly, check out the web site of Asilidae biologist Fritz Geller-Grimm, which also has links to other researchers, some of whom have written regional field guides. As the British pathologist Edward Halford Ross wrote, “Each fly is king of his own country,” so the next time you see a robber fly zooming towards an intended victim, give it a small salute.
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Laphria bumble bee mimic with oil beetle (Meloidae) prey, Lewis River falls, WA. Photo by C.A. Searles Mazzacano, all rights reserved.
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Imposing-looking Promachus robber fly enjoying a warm day, South Padre Island, TX. Photo by C.A. Searles Mazzacano, all rights reserved.

This land is your land

1/6/2017

 
My favorite sight on the planet is the vista that opens up as you enter the Columbia River Gorge National Scenic Area, traveling east along the I-84 from Portland, Oregon. For the past nine years I have hiked, camped, kayaked, and surveyed and photographed insects throughout the Gorge. I have forced my aching calves up 2800 feet elevation gains, through mountainsides turned butter-yellow with extravagant blooms of balsamroot (Balsamorhiza), lifting my eyes from the busy scurryings of oil beetles (Meloe strigulosus) on the path to gaze out at the jagged snow-capped peaks of the Cascades. But each time my eyes sweep along the river floodplain, I am reminded by the patchwork of logged hillsides, farms, and homes, and the threads of interstate highway and railroad that run along the Columbia River in Washington and Oregon, of just how drastically altered this beautiful landscape is. As much as I love this place, I know that the sight that delights my eyes today would bring tears of grief and rage to the eyes of the First Nations peoples who lived along the river’s shores—much as it did to their descendants when multiple dams buried waterfalls and tribal fishing grounds in the 1900s. I was better able to appreciate just how much this landscape had changed in 2008, when "Wild Beauty" was published, a book that brought together over 130 images from early photographers of the Columbia River. Starting in 1867 and ending in 1957 (the year The Dalles Dam flooded Celilo Falls), these images showed facets of the river that are long gone, like broad swathes of sandy beaches and waters boiling with the thrashing bodies of salmon returning to spawn. 

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Columbia River Gorge on a misty morning.
Those of us who work in conservation face uncomfortable truths on a daily basis. No amount of restoration can return the habitats we love to some idealized, former state; in the U.S., benchmarks of “pre-European settlement” are often a goal, but truth be told, we usually don’t know exactly what those pristine historic conditions were, and the reality of humans on the landscape makes such a return improbable at best. Money poured into sustaining an endangered species may be futile if the larger, interconnected ecosystems on which that species relies are still being diminished and degraded. This is not to say that we should just throw up our hands in despair, however. People have been holding the line for decades, maintaining and improving what they can at the local and regional level, and much larger areas of land have been protected under federal designations as national parks or wild and scenic areas. The Clean Water Act has reduced point-source pollutant discharge into waters of the U.S., bringing life back to some waters that were not only lifeless but actually flammable (and incidentally making it possible for me to not just kayak but swim in Portland’s Willamette River, which would have been unthinkable and excessively unhealthy in the 1930s). The Endangered Species Act has helped prevent 99% of the species under its protection from going extinct and promoted recovery for over 100 species throughout the country (“A Wild Success”, Center for Biological Diversity, 2016), though speaking as an entomologist, I am compelled to say that insects continue to receive far less attention and protection overall than they should.
Sailing, wading, and kayaking  in Portland's Willamette River (left & center); restoration of Johnson Creek, a highly urban stream in Portland, has seen the return of spawning salmon (right)
These laws are hardly perfect; they had flaws when they were created, and since their establishment various corporate and political entities have continued to challenge and chip away at them, but they are the best we have to work with. And since the events of November 2016, many of us are feeling a deep sense of dread at the future of environmental protection in the United States. People with horrific environmental records are being tapped to lead federal departments that they have vowed in the past to dismantle, voices of scientists are being stifled, realities of climate change we can see with our own eyes today (and can still take actions to mitigate) are being denied, and bills are being introduced into the House and Senate that could open up millions of acres of federal public lands to mining, drilling, and logging. Many of us have become more proactive recently in calling and writing our representatives, upping donations to to environmental organizations, and signing petitions. All of that is necessary, important, and effective, but it can also feel removed from our daily lives, and perhaps like tilting at windmills. 

So I urge you to get involved with the natural resources where you live. Have you visited your public lands lately?  Take a trip to the nearest BLM, US Forest Service, or national wildlife refuge area and appreciate these places held in trust for everyone to hike, camp, bird watch, photograph, and, at appropriate times, hunt and fish—and if you have a friend or relative who’s never visited public lands before, take them with you. Many wildlife refuges as well as state and regional parks and natural areas have Friends groups—volunteer-based organizations that adopt an area and work together to restore habitat, educate the public, and advocate for their patch of ecosystem. If there’s a place you love to visit, ask if they have a Friends group you can join, and if they don’t, think about organizing one. Many places have natural resource programs such as Stream Team and Master Naturalist that offer environmental stewardship opportunities; explore the directory at the Alliance of Natural Resource Outreach and Service Programs to see if there are programs in your state. Contact your state, county, or city parks to see if they have programs for underserved youth (and advocate for such programs if they don’t), and be a volunteer to help create the next generation of conservationists. If your city or county parks have signs and interpretive materials only in English and you speak more than one language, contact the managers and ask if they’d like help with translation to make these sites more welcoming and accessible for everyone. If you are able to garden around your home, whether you rent or own, explore planting more native species and reducing or eliminating pesticides. Even small patches of habitat can make a big difference in the lives of native insect populations, and since these insects are a huge food base for songbirds and other animals, your yard or community garden plot can have a much wider impact—especially if you urge your friends and neighbors to do the same. 


​Aldo Leopold wrote “A handful of individuals have always taken care of the resources at their feet – not always because it was fashionable but because it was right.” With over 300 million people in the United States, if we all do whatever we can, in big efforts or small, to promote and engage in conservation and stewardship at the local as well as the state and national level, we can do a lot to ensure that we pass on the places we love today to the generations that follow.


American White Pelicans (Pelecanus erythrorhynchos) at Finley National Wildlife Refuge in OR (left); Sandhills National Wildlife Refuge, SC (center); Striped Meadowhawk (Sympetrum pallipes) at Tualatin National Wildlife Refuge in OR.

Nature's Clean-up Crew

9/5/2016

 
PictureNicrophorus beetle on dead mole. The pale oval specks on the beetle's body are mites. Note the fly maggot already present at center left.
Few among us are entirely comfortable talking about the business of mammalian effluvia. The beetle Scarabaeus sacer may have been sacred to the ancient Egyptians, who saw its dung-rolling behavior as a symbol of the god Khepri moving the sun across the sky, but the stock of decomposers has fallen sadly in modern times. In-depth discussions about feces or dead bodies aren’t likely to go over well at many parties, but were it not for the efforts of a group of insects often viewed with nose-wrinkled repugnance, we would be up to our collective hips in carcases and feces. This is a pity, because in addition to their tremendous usefulness, these managers of the planet’s garbage are beautiful animals with fascinating life histories.  
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Nature’s main insect garbage disposers are beetles and flies. Among the beetles, Silphidae are corpse specialists. Members of the genus Nicrophorus are known as burying or sexton beetles because they act as gravediggers, excavating the dirt below a corpse to make a crypt in which their food is protected from cadaver-minded competitors, such as flies. Flies are often the first to find a corpse, so carrion beetles may be faced with competition in the form of fly eggs or larvae, but carrion beetles also have a secret weapon—an entourage of predatory mites that travel on the beetles’ bodies. The strong-flying beetles provide the mites with transportation to the next available dead animal, where they disembark and prey on any fly eggs or larvae already infesting it, thereby reducing the competition to the beetles’ own offspring. Unlike most insects, not only do some male and female burying beetles remain together after mating, they even stick around long enough to care for their young, making little pockets in the corpse to house their offspring and feeding their larvae on well-chewed bits of cadaver. Necrophila, another silphid genus, do not bury their bodies but avoid competition from flies by specializing in cadavers too dry to be a good environment for maggots. Small, colorful, fuzzy-winged beetles in the family Dermestidae, known as skin or carpet beetles, also utilize drier corpses; this preference has made them both highly useful in museums (to convert bodies into clean skeletons) as well as a horrible nuisance (they can turn your painstakingly created insect collection into dust seemingly overnight).

Many flies (Diptera) also utilize corpses for their larvae (maggots), which basically liquefy bodies as they feed. Blow flies and bottle flies (Calliphoridae) are experts at finding fresh corpses on which to lay their eggs, while flesh flies (Sarcophagidae) arrive at the body a bit later but make up for lost time by depositing newly-hatched larvae instead of laying eggs. Some species of coffin fly (Phoridae) can even find and lay eggs in bodies buried six feet under. The rapidity with which carrion flies develop, going from egg to adult in as little as 10 days, once gave rise to the belief that these creatures spontaneously generated from rotting meat.  Today, the body of knowledge amassed about the diversity, host preferences, and developmental rates of many cadaver-exploiting flies has made them valuable forensic tools, enabling investigators to determine how long a body has been dead, whether a body was moved after death, and if victims had certain drugs or toxins in their blood when they expired.

Dead bodies need to be broken down, but live animals produce a prodigious quantity of waste that must also be recycled. A  staggering 100 billion tons of animals dung are deposited on the earth each day, and once again, insects come to the rescue. Dung beetles, a subgroup of the incredibly diverse scarab family (Scarabaeidae), are perhaps the best-known of these waste recyclers. Politely known as “coprophagous”, these beetles may bury the feces they find, or chew off chunks and roll it away to their burrows. This dung-rolling behavior usually looks a little less stately than its allegorical counterpart of the sun moving across the sky, and the undignified postures of beetles trying to move irregular balls of dung with their hind legs while simultaneously fighting off competitors has also given them the more whimsical name of “tumblebugs”.

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Dung beetles are an economically important part of livestock farming; in removing cow pies from the landscape, dung beetles recycle nitrogen into the soil, remove breeding grounds for pests and pathogens, and help keep the forage in pastures palatable to livestock. In the absence of dung beetles, the US cattle industry would have to spend almost $300 million annually to make up for the services these insects provide. Their importance to livestock production is illustrated by the Australian Dung Beetle Project (1966-1986), whose somewhat eyebrow-raising name is belied by the issue’s economic and environmental import. Australia’s marsupials produce understated little pellets of dry fibrous dung, and the beetles that evolved with them are adapted to this type of feces. When big grazing animals such as cattle were brought to Australia by European settlers, their large wet puddles of poop were unpalatable to the native dung beetles, and the country was literally being covered in cow pies. Dr. Gyorgy Ferenc Bornemissza, an entomologist who immigrated to Australia from Hungary, was quick to notice this disgusting landscape feature and suggested bringing in dung beetles from countries with large herbivores. Soon the imported Gazelle Scarab (Orthophagis gazella) was showing its mettle, removing in as little as one day dung pads that would otherwise take years to break down. Bornemissza’s “magnificent obsession” resulted in the release of 43 dung beetle species in Australia, 23 of which established successfully.

Many of the insects that recycle our planet’s waste are in trouble. The American Burying Beetle (Nicrophorus americanus), a handsome black-and-orange jacketed carrion beetle, has been on the Endangered Species List since 1989, when populations were so reduced that its prior U.S. range of 35 states fell to only four. The root of its precipitous decline has never been completely elucidated, though various hypotheses include habitat loss, disease, light pollution, fewer appropriately-sized host animals, or competition for carrion from greater numbers of vertebrate scavengers present due to the removal of large predators. A recent report in Mother Jones detailed the global plight of dung beetles, which are suffering broadly from habitat destruction, decreased dung quantities due to smaller populations of large animals such as rhinos and elephants, and the impacts of anti-worm medications used to treat humans and livestock, much of which ends up deposited in feces. Other types of beetles and flies also rely on carrion or dung, but their status and needs are less well known. Much has been made about the decline of pollinators and the potential impacts on our food system, but it’s time to start thinking too about the less palatable processes that insects mediate so well, and the impacts of human activities on Nature’s insect clean-up crew going quietly about its business beneath our feet. 

Ladybug, ladybug, fly away home

5/10/2016

 
PictureConvergent Lady Beetle
The word beetle comes from the Anglo-Saxon bitan, meaning to bite, and a sight of the sharp sickle-shaped mandibles of a tiger beetle (Cicindellidae) or the toothed pincer-like jaws of a ground beetle (Carabidae) easily reveals how that name came about. Beetles, formally known as Coleoptera (“shield-wing”, a reference to the glossy sheaths formed by their hardened forewings) outnumber us feeble mammals by a long shot. Current estimates say there are as many as 50 times more species of beetles than of mammals, and that gap widens each year as new beetle species are described. Such diversity—from minuscule (a 0.3 mm featherwing beetle) to huge (a 17 cm Hercules beetle); terrestrial to semi-aquatic and aquatic; plant chewers to meat-eaters; dung movers, corpse recyclers, and more—can lead to mixed feelings about beetles on the part of humans. However, there is one group of beetles that just about everyone loves—the lady beetles (Coccinellidae).  

If you live in the USA, you are more likely to refer to lady beetles as ladybugs, but the obsessive taxonomist that lurks within all entomologists compels us to spoil your fun and remind you that “all bugs are insects, but not all insects are bugs”. In the UK, the more whimsical common term of “ladybird” is used, though the mediaeval Christian symbology conferred onto ladybirds provided additional common names such as the evocative but perplexing “God’s little cow”. Lady beetles continue to have a strong hold on modern minds; as a child, I remember an obligation to recite the ditty “ladybug, ladybug, fly away home, your house is on fire, your children are gone”, which with the bloody-mindedness of youth I never questioned (though I did wonder why lady beetles above all others of their kin were so doomed to flaming immolation).

Lady beetles have an advantage in that they are undeniably cute—round and chubby, brightly colored and patterned, they seem hapless and charming as they doodle along in our gardens.  They are small enough not to be frightening, and if they do occasionally ooze odorous yellowish fluid from their leg joints upon being handled, what’s a little reflexive bleeding among friends? However, no amount of cuteness will get an insect very far if it isn’t accompanied by some sort of usefulness, and the lady beetle’s sweet appearance is really just a facade, as any aphid will tell you. North America is home to around 500 species of lady beetles, and most are voracious predators on aphids, mealybugs, scale insects, and other soft-bodied insects that plague gardeners and farmers. Lady beetle larvae, which emerge from small clusters of oval orange eggs laid on the undersides of leaves, appear startlingly different than the adults, looking more like tiny orange-and-black alligators covered with warts or branched spines. The larvae feed and grow through four stages (instars) before pupating on leaf surfaces and emerging as adults. Adults often hibernate through the winter in large aggregations in sheltered areas, and it’s not unusual for home gardeners to find a bright cluster of awakening lady beetles underneath a wad of leaf litter in spring.

The ability of lady beetle larvae and adults to consume large numbers of pest insects has given them an exalted status as biological control agents, but unfortunately, their appeal as beneficial insects has also led to the downfall of several of our native species. Many species from other countries have been imported for use as biocontrol agents against crop pests in North America. One of the best-known stories is that of the Vedalia Beetle (Rodolia cardinalis), a coccinellid brought in from Australia in the 1890s to control the cottony-cushion scale insect (Icerya purchasi) that was devastating California’s citrus crops. According to Marshall (2006), 179 species of lady beetle have been imported into North America as biological control agents, and several, along with additional unintentional imports, have become established. In my own garden, the native Convergent Lady Beetle (Hippodamia convergens), so-named for the angled white lines on the pronotum, is outnumbered by the Seven-Spotted Lady Beetle (Coccinella septempunctata), a European import; in the east, this species is thought to have largely ousted the native Nine-spotted Lady Beetle (C. novemnotata). And if there is one lady beetle that everyone loves to hate, it’s the imported Multicolored Asian Lady Beetle (Harmonia axyridis), which varies from pale orange to bight red, with many to no spots, but which can always be distinguished by the blotchy black “M” marking on its white pronotum. The Multicolored Asian Lady Beetle has an unfortunate tendency to invade people’s houses in the fall in search of hibernation sites, where the chemicals they secrete as a defense mechanism stain walls and furniture. During large outbreaks they may feed on and damage fruit crops such as grapes, a very un-lady(beetle)-like behavior, and when their secretions are left on grape skins they can cause an off-flavor in the resulting wine.
For my own part, when I am giving workshops about beneficial insects to home gardeners, I tell them to rely on the principles of conservation biocontrol, which can be summarized as “if you build it, they will come”, instead of purchasing insects from commercial sources. If you’ve already been noticing lady beetles in your area and would like to become involved in a nation-wide citizen science monitoring program, check out the Lost Ladybug Project . Started in 2000 by entomologists at Cornell University, this kid-friendly, National Science Foundation-funded project collects observations of Coccinellidae from around the country to determine where native and non-native species are found. Photos and information are submitted via an online form, and project scientists confirm (or correct) your species ID. The site features links to multiple identification aids and teaching tools, and you can view submitted records on a map and see what species have been reported near you. With spring well underway in most of the country, there’s no better time than now to get out there and meet the local lady beetles.

Bombus is back!

3/2/2016

 
PictureBumble bee on thistle
It’s human nature to be eager for the end of winter, no matter how much we enjoy it for a while, and everyone has their own talismans of reassurance that Spring is really on its way. For some, it’s the appearance of a particular migrating bird, or the first snowdrops to push their tough white flowers above the ice and mud. For myself, I can be sure that spring is safely on its way when I see the first bumblebee of the season. In my area, that’s usually the Black-tail Bumble Bee, known more formally as Bombus melanopygus.  

In the wake of Colony Collapse Disorder, the European honey bee (Apis mellifera) has become something of a household name, but the diverse array of native bees in North America has received shorter shrift. That’s a pity because most are lovely, charming, beneficial little insects, and none more so than the bumble bee (genus Bombus). The charm of the bumble bee is aptly reflected in the diverse array of common names attached to it, which include dusty miller, droner, humble bee, and, much to the delight of Harry Potter aficionados, dumbledore. Many of these names refer to the noise made by these big fuzzy bees; to “bumble” used to mean to drone or buzz, and the sight of a fluffy bumble bee is invariably accompanied by its loud droning hum. Even those who suffer from melissophobia (the official term for a fear of bees) can relax around bumble bees, as their mild dispositions live up to their teddy bear appearance. Bumble bees are social insects, like their imported honey bee cousins, but their colonies are small (ranging from ~50-800 bees) and only last one year. With no hive full of honey to protect, bumblebees are less territorial and aggressive than honey bees, and I have held many a bumble cupped in my palms with no fear of being stung (which is not to say a sting is impossible, especially if you wander unwittingly too near a colony while mowing the lawn or weed-whacking).  

Bumble bees are usually the first bees on the wing in spring and the last ones flying in the fall. Virgin queens mate at the end of summer, then spend the winter in hibernation. That new queen never needs to mate again; she will use the stored sperm to fertilize eggs that hatch into her daughters, and she will also lay some unfertilized eggs that develop into males. These young queens awaken in Spring, their fuzzy black-and-yellow or -orange coats providing insulation that enables them to be active on days that are too cold and damp for honey bees to forage. Once she finds a dry, sheltered cavity to serve as a home for her soon-to-be-growing family, she gets down to the business of provisioning the nest, making small wax pots which she fills with the nectar and pollen she gathers. She lays her first batch of eggs, and uses her own body to keep the temperature warm enough for the developing embryos. She continues her solitary maternal care of this brood, feeding and tending the larvae until they pupate and the first generation of daughters emerges and takes over in caring for subsequent batches of sisters. With just the queen to tend their needs, this first generation is usually smaller in size than their mother, but as the queen continues to lay fertilized eggs, there are more daughters to provide forage for the larvae that develop throughout the summer. This is no small task, as laboratory studies have found that a nest of 100 bumble bees can consume up to 2 g (0.07 oz) of pollen and 40 mL (1.4 oz) of sugar syrup daily!  At the end of summer, the old queen lays some eggs that develop into new young queens, as well as some unfertilized eggs that develop into males that quickly fly off to find mates of their own. The old queen dies and the new virgin queens make their mating flights and then hibernate through the winter, to await the following spring.

PictureBees enjoying an artichoke flower
Bumble bees are fun to watch and easy to observe because you can generally get up close and personal without risking being stung. I never harvest my artichokes because the bumbles (and other bees) love to forage in the huge purple flowers, and the rosemary and lavender that line my walkway form a backdrop for the ceaseless bee-thrum that to me is one of the integral sounds of summer. Their buzzing hum has practical applications as well; bumble bees are superior pollinators of some plants due to their ability to perform buzz pollination, which involves using their flight muscles to shake their entire body. The resulting vibrations help release the pollen from some plants, and it isn’t unusual while walking through one’s garden to be startled by a surprisingly loud “zzzzttt!” coming from a wildly shaking tomato or blueberry flower.

There are about 40 species of bumble bee in North America, but several have experienced serious declines due to pesticide use, habitat loss, and disease. Supporting your local bees isn’t that hard to do; just plant a patch of organically-maintained habitat that provides bloom from early spring through fall and watch how the bumbles and other native bees respond. And if you would like to contribute data from your own pollinator patch to larger studies on the status of bees in North America, check out the Great Sunflower Project (greatsunflower.org) to get involved in the Great Backyard Bee Count and find field guides (including guides to bumble bees of the eastern and western United States), image galleries, and information about the life history of bumble bees and other native bees.

Power of the People

1/6/2016

 
Several weeks ago I spent a typical Portland winter morning (i.e. grey, drizzling, and chilly) participating in a local Friends’ group volunteer event to pull weeds along a restored stretch of an urban stream.  Most of the weeds plaguing this site are non-native invasive species that either successfully resisted previous removal efforts or crept back after restoration.  Every state is cursed with its own particular rogue’s gallery of invasives, and the ones we fight here in Oregon include Himalayan blackberry (Rubus armeniacus), English ivy (Hedera spp.), English holly (Ilex aquifolium), and the plant that really puts the “noxious” into noxious weed, reed canarygrass (Phalaris arundinacea).
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Himalayan blackberry was introduced as a crop plant from Europe in the 19th century, and it certainly provides an abundance of tasty fruit, but it’s also armed with flesh-shredding thorns that make it a plant equivalent of the Wolverine, and it grows so quickly and in such impenetrable tangled mats that it out-competes every other plant in the understory.  English ivy is a regrettable ornamental with little habitat value that also escaped cultivation and spread rapidly as a habitat-choking groundcover and a vine that can cloak shrubs so throughly they may eventually die because sunlight can’t reach their leaves.  English holly, another European escapee, is beloved by birds for its bright red berries, which are also unfortunately carried into forests where they give rise to dense thickets that suppress germination and growth of native shrubs and trees.  Reed canarygrass, a perennial that grows 3-6 feet tall in crowded monocultures, is a major threat to northwestern wetland ecosystems that resists removal by heavy machinery (copious seeds and rhizomes simply grow back) and various herbicides (control is effective only for a few years, after which treated areas are re-invaded)
PictureHimalayan blackberry, scourge of the Northwest. Photo by C.A. Searles Mazzacano.
Controlling invasive species, especially in urban areas that experience continuing disturbance and high visitation by humans and pets that spread seeds and propagules, is an ongoing and often contentious issue.  Use herbicides as a necessary evil to knock back the invasives and hope the natives thrive? Go organic instead and find enough willing volunteers (which in Portland often includes goats, who eagerly consume Himalayan blackberry) to keep invasives under control long enough for newly-planted natives to gain a root-hold?  This dilemma drifted through my mind as I stood on the bank of a creek that just five years ago had a terribly degraded riparian zone, consisting of a few scattered cedar trees surrounded by a sea of reed canarygrass and ivy.  Now I gazed out on a vastly different scene, a functional riparian zone dominated by native plants, where tumbles of jewelweed edged banks shaded by red osier dogwood, willow, and alder.  Invasives persist, though in much lower numbers, primarily in patches where native plantings failed (or were chewed to nubs by urban beavers) or where restoration was not yet complete.  I went to work on one of these patches, standing in several inches of cold water while slamming a pickax into a clump of reed canarygrass clinging stubbornly to the bank.  After several minutes of vigorous pickax application I managed to hack loose a few square inches of the dense root mass, which repaid my efforts by spattering me thoroughly with icy mud as I heaved the startlingly heavy weight up onto the walkway for disposal.  

As I stood in the rain trying to recover enough feeling in my fingers to wipe the mud off my glasses, the head of the Friends group remarked that reed canarygrass had been awful originally, covering the banks and spilling into large mats in the stream itself.  When I asked what nuclear device had been deployed to knock the pestiferous plant back to its current low levels, she replied that it was done entirely by groups of volunteers who waded into the river with knives and axes, chopping the mats free and hauling them to shore for disposal.  I felt a little thunderstruck as I did some mental calculations to scale up the effort needed to remove a single chunk of this weed, and then I realized—this is why I volunteer.  Groundwater is being pumped dry, wetlands are being filled and degraded, rivers are being dammed and polluted, endemic insect species are going extinct as I type this, and in the course of my life, I can only only stem the tide of destruction for what feels like an increasingly and depressingly tiny proportion of the planet.  But “action is the antidote to despair”, as Joan Baez is credited with having said, and here and now in my own watershed, I can straighten my aching back, blink sweat and rain out of my eyes, and share some scones with a small group of people looking out contentedly on a patch of habitat that we made better for the wildlife and people who live here now, and for a generation to come.

Nature is where you find it

11/7/2015

 
PictureMt. St. Helen
After years of living all over the USA, I am fortunate to have fetched up in the Pacific Northwest. Every place has its beauties, of course, but the northwest is endlessly appealing, from the rich palette of the Painted Desert, the mossy cascades of the Columbia Gorge, and the murre-speckled sea stacks of the Pacific coast. But while I appreciate my proximity to breathtaking vistas and wild ocean shores, I also try to always be alert to the possibility of natural wonder in the city I live in.

Nature—the kind of nature to be conserved, restored, and marveled at—is often perceived as something far from one’s home, a place that requires a long drive with a carful of gear to get to.  But a visit to that type of “nature” may only happen a few times in someone’s life, if it occurs at all, and the daily view of nature for most of us has a lot more buildings and fewer mountain vistas. US Census data from 2010 showed over 80% of Americans living in urban areas; according to the World Health Organization, the urban population in 2014 accounted for 54.5% of the total global population, and is expected to grow 1.84% annually between 2015 and 2020. One of the many environmental challenges created by this continuing urbanization is finding ways to give people from all walks of life direct and meaningful interactions with nature on a regular basis.

As an entomologist, I find this task a little easier, because there are insects in pretty much every habitat you can imagine. I am a great believer in the role that urban habitats can play in providing refuge and connectivity for wildlife, and in the power of the public to enhance urban habitats and learn about biodiversity in the process. I have seen my own tiny backyard in Portland go from a lifeless expanse of sod (the legacy of previous owners) to a bird-rich haven of native shrubs where chickadees and goldfinches pick over sunflower heads while ground-based varied thrushes and juncos hunt for tidbits in the mulch and red-shafted flickers and cedar waxwings gobble an annual bounty of blue elderberries overhead. But even I fall into the trap of thinking that urban nature can get a little ho-hum, compared to the glories of a peat bog or mountain meadow, and the occasional wake-up call is needed.

My most recent “ah-hah!’ moment in this arena came last summer, when I volunteered to help with a bioblitz done to celebrate the grand opening of a new park in northeast Portland, in a neighborhood the city determined was lacking in green space. Named Kʰunamokwst, from a word in the Chinook Wawa language meaning “together”, this pocket park was created on a forgotten patch in the middle of a historically underserved and minority neighborhood with dense residential and commercial development. The “critter cruise”, as it was dubbed, featured naturalist-led walks for residents, with a strong focus on young children and their families. When I arrived in the morning and saw the small size of the park and the large number of surrounding houses, I confess my spirits sank a bit at the thought of filling three hours with observations of insects and other invertebrates. How on earth would I find enough to keep these kids interested?

As it turned out, my worries were unfounded, and I discovered two very important things that day. The first is that nature walks with children are terrific, because I didn’t have to do any work—I just turned the kids loose and they spent the whole time questing like beagles and running up to me with their finds. The second is that even the common is wondrous if it’s something you’ve never seen before. Mysterious monsters on a leaf brought to me by a small girl led to the discovery of lady beetle larvae, and a challenge to the group to see if they could find more lady beetle life stages. Within minutes I had a neat line-up of larvae, pupae, and adults, and a great jumping-off point for an impromptu teaching moment about metamorphosis as well as biological control. A boy showed me a round and lovely Cross Orb Weaver (Araneus diadematus) cupped in his palm, and I was able to compare and contrast his spider with a harvestman running around in another small participant’s hands—and to reassure his mother, who approached me with a rather less enthusiastic demeanor asking anxiously “¿Son peligrosos?” that the vast majority of Oregon’s hundreds of spider species are harmless.

It pays to remember too that the wondrous may well be lurking unexpectedly amidst the common—especially where insects, so perennially understudied and unappreciated, are concerned. For example, a recent community-based bioblitz in Melbourne, Australia uncovered several rare moth species that hadn't been sighted in decades in the city’s most-visited park, and last spring 30 new species of scuttle fly (Phoridae: Megaselia) were discovered living in Los Angeles county, many in people’s backyards.  

​The American naturalist John Burroughs said "The place to study nature is at one's own home - on the farm, in the mountains, by the sea - wherever that may be.” In this spirit, my own quest for the coming year is to try to find and catalog every invertebrate that lives in my yard, from compost pile to mulched path to the underside of my lawn chair.  Who knows what wonders may await?

    Celeste "Zee" Searles Mazzacano, Ph.D

    Entomologist, invertebrate ecologist, educator, environmentalist

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