Saturday, January 9, 2021

The Mayfly Analogy

Metamorphosis is a wonderful thing. It is physiologically compulsory for insects, many other invertebrates, amphibians, and some fish. It is a conscious choice in humans from the perspective of emotional, social, and intellectual maturity. Some people choose to remain forever neotenous, never advancing their ability to empathize with others, or accept that diversity and equality enhance our species rather than impede our collective evolution.

Small minnow mayfly, Callibaetis sp., Mueller State Park, Colorado, USA

Mayflies, aquatic insects in the order Ephemeroptera, are best known for their ephemeral adult lifespans, often only a day or two, several days maximum, and as short as one hour. As underwater naiads, their youth may last three months to three years, depending on the species.

Mayflies are the only insects that molt after reaching adulthood. The naiad emerges from the water, splits its exoskeleton down the middle of the thorax, and a winged insect slowly draws itself out. This is the subimago, or “dun” in the parlance of anglers who model their imitation flies after certain mayflies.

The dun flies to another perch, such as foliage overhanging the water, or a bridge abutment, or similar platform. There, it repeats the molting process, becoming a fully-fledged, sexually mature imago that fly fishermen call a “spinner.” These adults lack functional mouthparts, as there is no time for feeding. There is only mating and, in the case of females, laying eggs. At least one species, Cloeon dipterum of the British Isles, births live naiads, having incubated the eggs within her body.

Common burrower mayfly, Hexagenia sp., along the Missouri River in Leavenworth, Kansas, USA

The evolutionary origin of mayflies dates back to the middle of the Carboniferous Period in the Paleozoic Era, about 325 million years ago. This places them near the most basal root of the phylogenetic tree of all winged insects.

The Ephemeroptera are the “E” in EPT, a biological index that informs water quality in environmental health assessments. Together with stoneflies (Plecoptera) and caddisflies (Trichoptera), mayfly naiads vary in their sensitivity to pollutants, overly turbid, and warmer-than-normal streams, rivers, and lakes. Generally, the more species diversity in these insect orders in a given watershed, the healthier the aquatic ecosystem is.

Our own children thrive best in environments devoid of toxic ideologies, and well-oxygenated with empathy, equality, justice, and peace instead of turbidity. The more diverse our neighborhoods, schools, and institutions are, the better.

True, the naiads of prongill mayflies, in the family Leptophlebiidae, ensconce themselves in crevices and shun the light, and burrowing mayflies in the family Ephemeridae tunnel into the silt or sand of streambeds and lake bottoms. That does not mean we should bury our own heads in the sand, stubbornly clinging to outdated social strategies that further divide us.

Small square-gilled mayfly, Caenis sp., Colorado Springs, Colorado, USA

Adult mayflies often emerge synchronously, in overwhelmingly abundant “hatches” that anglers attempt to time appropriately with their feather-and-thread imposters. Major rivers are often the site of these eruptions, and the Great Lakes are beginning to see a resurgence in numbers that have been at a historic ebb for decades thanks to pollution. Bulldozers are often necessary to sweep the dead insects from roadways lest they become a slick, greasy hazard.

Homo sapiens has been on this planet for barely the geological equivalent of one day, so perhaps we are all subimagos, having not yet graduated to full adulthood in appreciation of our own diversity. I like to think that I have entered that stage, aware, yet still awkward in my attempts to help others out of their own prejudicial entanglements, their ecdysis mired and twisted by privilege and entitlement.

Maybe I’m wrong. Maybe I am a cicada, and thirteen or seventeen years hence I will realize I knew nothing. Still, the idea that just when you thought you were done, you are only a dun, resonates more. We may never arrive, never become spinners, but we are certainly farther away than we think we are.

A "slate drake" mayfly, Isonychia sp., from Leavenworth, Kansas, USA

Sources: Fauceglia, Ted. 2005. Mayflies: Major Eastern and Midwestern Hatches. Mechanicsburg: Stackpole Books. 196 pp.
Grimaldi, David, and Michael S. Engel. 2005. Evolution of the Insects. Cambridge: Cambridge University Press. 755 pp.
McGavin, George C. 1998. The Pocket Guide to Insects of the Northern Hemisphere. London: Parkgate Books, Ltd. 208 pp.

Sunday, December 27, 2020

Year-end Wrap-up

Year-end Wrap-up

This calendar year has been challenging, to put it politely, for everyone. Many people have lost family members, friends, pets, or multiples of each. Not every tragedy was directly related to the global novel coronavirus pandemic, but everything was complicated by that pall. Businesses failed or took heavy losses. In-person socializing has been nearly non-existent, at least for those who behave in the responsible ways that epidemiologists advise. You have my empathy, and sincere condolences where that applies. What good news is there?

Much of our "bugwatching" was done close to home in 2020, like this angle-winged katydid, Microcentrum sp. in our backyard.

My wife has remained miraculously healthy because her coworkers have been disciplined in their social interactions outside of the workplace. We celebrated another friend’s victory over COVID-19 after she had been on a ventilator. In record time she was out birding again, between physical therapy appointments and at-home exercise regimens.

We managed to get outdoors, though not as frequently as we had hoped. Colorado has a new state park, Fisher's Peak State Park! We got to make one last invertebrate survey there before it opened. We also participated in a responsibly executed, socially-distanced bioblitz in one of the local open spaces not open to the public. We were even finally able to blacklight at Jimmy Camp Creek Park without rain.

A nice mydas fly, Neomydas sp., from the bioblitz at Jimmy Camp Creek Park, Colorado Springs, Colorado, July 18, 2020.

Our one long-distance trip was to visit my wife’s parents in northeast Kansas in mid-summer. We found lots of insects and birds at various points along the Missouri River. Missouri in particular has many parks and conservation areas to explore.

Common Sanddragon dragonfly, Progomphus obscurus, in downtown Leavenworth, Kansas, July 25, 2020.

Now for a truly joyous announcement: The major reason this blog has been dormant is not one but two book contracts I needed to fulfill. Both manuscripts are now completed, but I am at liberty to speak only of Wasps: The Astonishing Diversity of a Misunderstood Insect, published by Princeton University Press. It is available for pre-order in the U.S. and Canada only (see link in sidebar), and will be widely available in late February. The book currently has no publisher abroad, so if you are a “foreign” publisher, or can suggest one, please let me know.

I encourage readers to please order and purchase my books through their local, independent bookseller if at all possible. Thank you. The other book will likely come out next fall, but naturally I will post updates here as I am permitted to by the publishing house. Meanwhile, I have at least two other ideas in mind that I need to peddle to prospective buyers.

Steel Blue Cricket Killer wasp, Chlorion aerarium, from Leavenworth, Kansas, July 21, 2020.

In other news, with my major online client in limbo, I will need to seek new revenue streams in 2021. Please feel free to refer any potential contractors to me. All my speaking engagements for 2020 were cancelled for obvious reasons, and I do not see anything changing for in-person events until at least 2022.

Western Green Hairstreak, Callophrys affinis, from what is now Fisher's Peak State Park, Colorado, June 28, 2020.

Thank you for your patience while this blog was in diapause. Because of the wasp book, you will likely see numerous future posts about Hymenoptera, or perhaps an entire new website devoted just to the book. We shall see. I also want to add a new tab to this website, featuring links to where you can find more of my writing online.

Remember that your own personal setbacks and successes are not trivial. You deserve empathy for your grief, and congratulations for your achievements. Surround yourself with people who understand that. Please continue to persevere, practice self-care, and help others when you are able.

Red-shanked Grasshopper, Xanthippus corallipes, ready to jump into 2021 (from Colorado Springs, Colorado, on May 30, 2020).

Thursday, July 9, 2020


Having just completed one book manuscript, with another one due at the end of this year, I don’t have time for the angst and depression that grips me currently. The global pandemic has impacted all of us in a myriad of ways, only to be compounded by personal challenges that each of us face. What does this have to do with entomology? Nothing. Everything.

Yeah, I'm in there somewhere....

While I am not cavalier in my approach to covid-19, the virus has not, by itself, caused me panic nor worry. It is not the reason I stay indoors. More on that later. I am in a very privileged place compared to many people and can weather at least a degree of economic upheaval. I am relatively healthy physically, though that does not necessarily mean I would have a mild case if I contracted the virus. Many patients that “recover” still have chronic, debilitating illnesses that may last the rest of their lives. The press has not emphasized this.

What is most stressful is the selfish reaction of so many to a catastrophe that impacts everyone regardless of race, sex, economic status, religion, or politics. The best analogy I can make for my own experience is the movie Invasion of the Body Snatchers. I feel like I walk today among pod people who have no understanding of science, no empathy for anyone else, and who devote all their energy to shaming those who do possess those qualities. I have decreasing patience daily.

Also in the current social pot is simmering racism, and the complementary intolerance of that continued bigotry. The cauldron reached the boiling point in May with the murder of George Floyd by police officers. Much like our collective reactions to coronavirus, the Black Lives Matter protests have revealed a schizophrenic socio-political divide where monuments to confederate figures are held more sacred than the lives of contemporary humans suffering from systemic, institutionalized oppression, if not outright violence.

Let me make this clear, at the least: white privilege deserves to be challenged, to be eroded, to be leveled. As events unfold, I ask myself consistently whether this is a sacrifice I am willing to make. So far, the answer has been an unequivocal “yes.” I can live without the statues, even if they are works of art. I would rather have a celebration of indigenous peoples than recognize Columbus Day. I love football, but the Redskins must change their name. I am willing to be educated about the racist flaws of all historical “heroes.”

Until last month, I would make a daily walk through my neighborhood. Some days I would go to the top of the hill, a vast former landfill that had metamorphosed into a degraded semblance of shortgrass prairie, and look for insects, birds, and other wildlife. I lost the fight to preserve it, and now bulldozers have rendered it a denuded plot for a housing development. I have not been on a walk since I first encountered the machines. It is too painful.

I am left without a refuge now, and given that my spouse can no longer carpool to work, I also have no way to escape to another nature spot. Even if I did, I would encounter far more people than I did up the hill. It matters less and less to me as I feel resigned to the continued burning of the world. I just don’t want to watch it any more. My daily walk is now limited to getting the mail.

Were it not for my wife, and my current obligations to publishers, I’m not sure I’d be making the feeble efforts at survival and routine that I somehow manage. My short-term memory is fading, to the point that today I could not recall, in the space of even twenty seconds, whether I had taken my allergy medication. Why can’t that phenomenon apply to memories and situations I want to forget? Why must any of us be tortured that way?

Friends recommend taking a break from social media as one way to limit negative input, but then you also limit positive stimuli. Ignoring reality is not a healthy way to navigate your life, either, but the human race in general has never been even adequate at coping skills. My message to myself is to accept that you are going to have slumps in productivity, fall into bad habits, and otherwise be a wreck periodically. It won’t last forever.

Sunday, May 24, 2020

A Case of Predator Mimicry in the Bee Fly Genus Epacmus? (Diptera: Bombyliidae)

In the course of photographing insects in Colorado Springs, Colorado, USA, at a nearby vacant expanse of prairie, soon to be a new housing development, I stumbled upon something interesting. Not until I got home and reviewed my images did I recognize something startling on an otherwise ordinary little bee fly in the genus Epacmus (assuming my identification is correct). Whether this has been documented before I do not know, but the phenomenon is well known in other insects.

Epacmus sp. bee fly. Nothing to see here....yet

Predator mimicry, or elusive mimicry, or aggressive mimicry, is when a prey species mimics one of its predators. This is probably a more widespread strategy than we currently recognize because we are not at the same scale as the predator and prey, and cannot easily interpret what constitutes such mimicry. We do not even enjoy the same perspective, so rarely experience the full effect.

It was not formally recognized, or at least not published, until 2006, that metalmark moths in the genus Brenthia have underside wing patterns that greatly resemble the face and legs of an oncoming jumping spider. They eye arrangement, chelicerae (jaws), and front two pairs of legs are all illustrated on the wings of the moth, when properly displayed by the insect. The moth would make an easy meal for the spider, but not if it presents the illusion that it is a spider. Evolutionary genius.

Spider mimicry is also exploited by other insects, including some fruit flies (family Tephritidae) and planthoppers (Fulguroidea). The bold patterns on the wings of some fruit flies greatly resemble the leg posture of some spiders. Some of the flies enhance the graphic imagery by moving their wings deliberately in a manner utterly convincing of a spider’s movements.

Whoah! Spider eyes and "mustache"

This brings me to the little bee fly I noticed on flowers in that prairie habitat. Viewed from above, Epacmus is an attractive, tapered, fuzzy insect about 7-10 millimeters in length, with delicate wings and something of a smiley-face pattern where the abdomen meets the thorax. Cute. Look at one directly from behind and you get an entirely different picture. Suddenly, you see the big black eyes of a jumping spider. Four black, polished, hemispherical bumps on the rear of the thorax are a perfect match for the eyes of a small salticid (jumping spider). This is reminiscent of raised features on the thorax of the Brazilian fruit fly Ceratitis alba (See Hill, David E., et al. 2019).

Habronattus sp. jumping spider stalking a Andrena sp. mining bee

Ok, so how often might the fly encounter a jumping spider? More frequently than you might imagine, even on flowers. Another photo I took of a mining bee revealed a jumping spider right on her tail. I hadn’t noticed the spider until I looked at the image later, at home. Habronattus jumping spiders are abundant in this prairie habitat, and hunt exactly where you expect to see bee flies: on the ground, vegetation close to the ground, and on flowers. The spiders are small and cryptic, easily overlooked.

Male Epacmus bee fly

What else are we missing in our observations of insects and their spider predators? Keep observing and you, too, may make a startling addition to our collective scientific knowledge.

Note: At least one world authority on bee flies (Bombyliidae) asserts that Epacmus may not be a valid genus, but a subset of the genus Aphoebantus instead.

Female Epacmus bee fly

Sources:Rota, Jadranka, and David L. Wagner. 2006. “Predator Mimicry: Metalmark Moths Mimic Their Jumping Spider Predators,” PlosOne.
Mather, Monica H. and Bernard D. Roitberg. 1987. “A Sheep in Wolf’s Clothing: Tephritid Flies Mimic Spider Predators,” Science 236: 308-310.
Hill, David E., A.P.C. Abhijith, and Joao P. Burini. 2019. “Do jumping spiders (Araneae: Salticidae) draw their own portraits?,”Peckhamia 179.1
Melander, Axel Leonard. 1950. “Aphoebantus and its Relatives Epacmus and Eucessia,” Annals Ent. Soc. Amer. 43(1): 1-45.
Hull, Frank M. 1973. Bee Flies of the World. Washington, DC: Smithsonian Institution Press. 687 pp.
Cole, Frank R. 1969. The Flies of Western North America. Berkeley: University of California Press. 693 pp.

Spider or fly?