The Urban Pantheist

Blue bottle fly Calliphora vicina

It was a warm Saturday--for December--and I was sitting on the porch. There haven't been many insects around, but this one huge (1cm) blue-black fly kept circling. It landed on the rail long enough for a picture. I could tell it was a carrion fly, and other clues and online observers pointed to it being a blue bottle fly. These are said to be native to Europe, but are fully cosmopolitan creatures, thriving wherever there are dead animals. The London Museum of Natural History even calls them the "urban bluebottle blowfly."

As well as cleaning up all the rotten meat that would otherwise pile up, these animals perform another service for us. Their life cycle, as it relates to corpses, is so predictable that they can be used in court to determine various facts about dead bodies, especially the important fact of how long that body has been bereft of life. Besides carrion, adult blue bottle flies may visit flowers for food, providing some important pollination work.

My friend Alex recently bought a new house. She's getting the full experience of being responsible for the animals that let themselves inside. I have to say I'm very proud of her--she was quite aware that there were at least two species in her bedroom, but did not kill them since they will do more good than harm. I identified one right away as a yellow sac spider, but I had more trouble with this one.

My friend Keith identified it for me: it's a broad-faced sac spider, Trachelas tranquilis. It looks fairly similar to the woodlouse hunter but is not closely related. Like the yellow sac spider it makes a silk refuge to hide in during the day and actively hunts at night. The entry on bug guide adds "...will frequently enter houses by accident in the autumn," which also helps identify it. This individual gets its studio-quality portrait from posing on the window blinds (it was trying to hide and I spooked it out to photograph it).

A coworker called me over to identify some insects lurking in a mealworm colony. They were so small (about 2 mm long each) I couldn't even tell what they were at first--I actually thought they were fruit fly pupae.

I took this picture and could see that they were beetles. Not sawtooth grain beetles, because these lack the distinctive teeth on the thorax. I went to my pest control text, since it seemed likely that they were known grain pests.

It soon became clear that these were flour beetles (Tribolium sp.). There are two common types, T. castaneum the red flour beetle--so called because of the reddish brown color--and T. confusum the "confused" flour beetle, which gets its name because it's easily confused with the other. Really. The "confused" is more tolerant of cold temperatures, and is more common in northern climates. However, the red has another field marking that helps remove the confusion: it flies, while the other does not. I was told these beetles had been observed flying, allowing me to identify them to species.

I was also interested to learn that both kinds of flour beetles are in the family Tenebrionidae: the darkling beetles. Darkling beetles are what I call the adult form of mealworms. So the mealworm colony was infested with their own tiny cousins. Hard to consider them contaminants, more like freeloaders.

This weirdly attractive fly is Delphinia picta, a picture-winged fly. The wings are distinctively patterned, and moved in a rowing motion as the fly walks along--perhaps a sexual display or some kind of defense? I found no explanation for the horse-like shape of the fly's head, only the note that one scientist observed "adults feeding on fermenting beetle frass protruding from the bark of a black locust." Larvae feed on decaying vegetable matter, including compost and rotten onions.

I get that most people don't like it when they find an insect or spider in their shower. You're naked, you've taken your glasses off, you're as vulnerable as you get, suddenly you have to deal with a bug. My reaction was, "Oh god, yes! I better go get my camera!" It's been such a long winter--cold and snowy with insects all hidden away for months--that I was honestly delighted to see this tiny beetle on the shower wall. This one looked a little familiar to me--it's shape and colors look very much like the scarlet malachite beetle I found in the yard back in June of 2012.


Only this beetle was a fraction of the size of its larger cousin. It turns out that this is Anthocomus equestris, in the Melyridae family of soft-winged flower beetles, in the same subfamily Malachiinae as the scarlet malachite beetle. This one appears to have no common name, however, aside from "soft-winged flower beetle" among many of its relatives. Also I can't find the origin for the scientific name, which seems to mean "Mounted flower-enjoyer." Flower-enjoyer makes sense, since these beetles are found on flowers, probably eating pollen, but the "equestris" business confuses me--chivalrous? on horseback? Dunno.

Like the scarlet malachite beetle, this beetle is a Eurasian import--insects from that continent had several millennia of practice living among humans and their buildings, and are often brought to our continent without the predators and parasites that keep them in check. Therefore, when a North American finds a small arthropod in their house there's a better than even chance that it's a species from across the pond.

Some zookeepers were passing through one of their exhibit gates only to discover their skin and clothes stained by some purple substance. There were also a lot of flies and yellow jackets flying around. Finally someone noticed the aphids.


A lot of aphids. The purple staining came from the crushed bodies of hundreds of aphids. Since aphids normally spend nearly their whole lives on their host plant, this behavior is a little strange. My best guess is that they overpopulated their host plant and dispersed out of necessity. Above this gate is one of many Austrees in a row. An Austree is a ornamental willow hybrid developed for use as a windbreak--it grows straight and very fast. Researching willow aphids, I found that they feed on second year growth; there would only be so much of this kind of growth on each tree.


Most aphids are wingless, but some are born with wings, allowing them to fly to new host plants to establish new colonies.

Aphids famously produce a waste material called honeydew, which other insects use as a food source. Ants are usually the ones you think of accompanying aphids, but in my experience yellow jackets are drawn to aphids in the fall, when the yellow jackets are desperate for a source of liquid food. (Yellow jacket adults can't feed on solid food, so they feed their larvae solid food and the larvae regurgitate a liquid the adults can eat. In the fall, the queen stops producing new larvae and the workers must find liquid sugar on their own, thus the misery they cause to late summer soda drinkers and ice cream eaters.)

Looking on bugguide, it's clear that these are genus Pterocomma, large aphids that feed on willow or poplar. They most closely resemble, in appearance and behavior, other aphids on bugguide not identified to species, but named "halloween aphids" by one user. Their coloration plus their sudden appearance in October justifies this common name to me. I hope some aphid expert identifies them to species (and keeps the name "halloween aphid.")

European ground beetle Carabus nemoralis

This large (7/8 inch) beetle with a variably iridescent pronotum can be a surprising find underneath a log or in garden debris. Like most ground beetles it is a predator on other invertebrates, and like most animals found in urban soil it is native to Europe. One wonders what the native soil fauna of the various coast of North America might have been, but that fact is lost to history. Soil ballast from European ships contained creatures that had already been living underneath cityfolks' shoes for centuries and was dumped on the shores of The Colonies. Overturn a log in Boston or New York and you will find animals native to London and Amsterdam. I would love to do a global survey, turning over logs and rocks in cities around the world and comparing them all.

I found this individual in Boston, outside the Tropical Forest exhibit in the Franklin Park Zoo.

The ring-necked duck is one of the many duck species that winters in Boston. It dives in fresh water for plants and invertebrates (unlike mallards, who mainly dabble). Its common and scientific names are confusing, since the subtle ring on its neck can best be seen when the bird is in the hand. Many New World animals were named by biologists wielding shotguns, naming birds and others after features easily seen on a carcass, but less so on a creature in the field. The bold ring on its bill is a better field marking.

Ducks migrating to cities like Boston take advantage of the fact that urban waterways often do not freeze, even when temperatures are low for a long time.

Australian cockroach Periplaneta australasiae


The Australian cockroach, like almost all pest roaches, is not originally native to the country it is named for. Most likely it is from tropical Asia, and quickly established itself in Australia once it was introduced into the warm cities there. In North America, this insect is associated with tropical plants, but will happily live alongside its close relative the American cockroach in hot moist basements. It can be distinguished from the American roach by the light yellowish markings on its thorax (behind the head) and along its sides. It doesn't grow quite to the same size, but is still one of the largest roaches regularly found indoors.

Conifer witch's butter, Dacrymyces chryospermus, pushes fruiting bodies out of the thick paint on a pine bench.

This jelly fungus is one of the delights of the mushroom fan in winter. When the ice thaws and a chilly rain falls on everything, the translucent orange lobes of witch's butter appear. On hardwood trees, the witch's butter is Tremella, a parasitic fungus eating the wood-digesting fungus within. On conifers like pine and hemlock, Dacrymyces grows instead. (D. palmatus is the most common binomial listed in online sources, but D. chrysospermus seems to be the more up-to-date scientific name.) Besides habitat, Tremella and Dacrymyces can be distinguished by the microscopic features of their spore-producing cells. Apparently the base of Dacrymyces fruiting bodies can be whitish, but I honestly have not observed this myself. Tremella is known to be edible, but on the question of Dacrymyces, mycologist Gary Lincoff says it "helps if you're a witch."