Cupedids: Triassic relics in our backyards

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Cupedid Tenomerga cinerea from Ithaca, NY.

Some exciting nature discoveries come with equally thrilling stories of pursuit through field and forest. Others involve no adventuring at all, no action-packed hunt or anything. Such has been the case with my encounters with the odd beetle family Cupedidae. These insects’ strange biology and evolutionary history, however, more than make up for any excitement lost in capture, for cupedids are one of the oldest relic beetle families in the world. Their fossils date back to the Triassic Period 199 million years ago, and their basic structure hasn’t changed a whole lot since then. At first glance they resemble squared-off longhorn beetles (Cerambycidae), but the “reticulated” pattern of their elytra (hardenedforewings) and the little protuberances on their heads mark them as something very different. Cupedids tend to have long antennae and a parallel-sided body, and are covered in scaly setae. There are only 33 living species worldwide, 4 of which occur in the U.S. Two of those species, Priacma serrata and Prolixocupes lobiceps, live in the western U.S, while the other two, Tenomerga cinerea and Cupes capitatus, make their homes in deciduous woodlands of the east. Very little is known about how any cupedids make their living, but the few that have been studied feed on fungus-infested wood as larvae. Oddly, Priacma is supposedly attracted to household bleach, suggesting that some chemical component of bleach mimics one of the beetle’s pheromones. Undoubtedly there is much to be learned about these mysterious animals.

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Cupes capitatus (Kennebunk, ME)

I have been fortunate enough to see both eastern U.S. species of Cupedidae, but unfortunately there is not much to say about my finding of either. My first and only Cupes capitatus was found sitting on the wall of my old middle school in southern Maine back in July 2013. It lived for several weeks in captivity, but rarely did anything other than stand around on the piece of wood in its container. When I handled the beetle, it retracted its legs and played dead, often not moving again for hours. I found it a rather cute little animal, with its big eyes and knobby head. Cupes is actually the rarer of the two eastern cupedids (nothing is known about its larvae or food source!), so I half expected to find Tenomerga that year too. Instead, fast forward to July 2017, where I was walking behind a building on the Cornell University campus checking the lights for insects. Many spiders like to build their webs here to take advantage of the bounty, and I make it a point to see what they have caught, but I was shocked to spot a Tenomerga cinerea hanging from a strand! The spider was nowhere in sight, and the beetle was still alive as I carefully plucked it from the web. This cupedid acted much the same as the Cupes, just standing around and playing dead whenever handled. Unfortunately it only lived for about a week indoors. For those of you who might want to see these interesting beetles for yourselves, I have no special advice other than to spend a lot of time outdoors. It’s really just a matter of being in the right place at the right time.

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Tenomerga cinerea on its back, showing how neatly packaged the beetle appears when playing dead.

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Sphagnum bogs, home of weird and wonderful creatures

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The Big Heath in Bass Harbor, MDI, Maine, is a good example of a northern sphagnum bog. Note the ericaceous shrubs in the foreground and the black spruce trees behind them.

Most of us have heard the term bog used colloquially to describe any wet, muddy area, but the true definition of a bog is a wetland that accumulates large deposits of dead plant material known as peat. Often this comes in the form of sphagnum, a genus of about 380 species of mosses that retain water especially well. True bogs are typically acidic and low in nutrients, and in many cases all water in the bog comes from precipitation. Most ordinary plants would die under these conditions, but of course there are quite a few that have adapted to these unfavorable circumstances, creating a distinct community of species that is nonexistent elsewhere. Unique plants, in turn, play host to unique insects.

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McLean Bogs in Tompkins county, NY, is an odd area containing a very small round sphagnum bog surrounded by glacial eskers.

I have had the fortune to be able to visit several sphagnum bogs in Maine and New York, and although each one has its own character, the same familiar plants and animals tend to greet me at every spot. The most obvious player is sphagnum moss, which forms a soft, spongy mat across every bog. When the mat is pressed, it gives up its water like a giant sponge, often evicting many small insects from their hideouts as they swim to safety. This is the primary way I find the dominant orthopteran inhabitant of eastern U.S. bogs, Neonemobius palustris. This tiny ground cricket lives exclusively in these habitats, and were it not for its song one would be hard pressed to detect its presence. Their tie to the sphagnum is quite obvious at the bog’s edge; there one can discern that where the sphagnum ends, the singing ends as well.

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A female nymph of the sphagnum ground cricket, Neonemobius palustris (McLean, NY).

Before I visited bogs to look for insects, I visited them to see a very special group of plants: the carnivorous plants. These unbelievable organisms that have to be seen to be believed only grow in places extremely deficient in nutrients, such as bogs or rock outcrops. They make up for the lack of soil nutrients by capturing and digesting insects and occasionally other small animals. Carnivory has apparently evolved independently in 9 different groups of plants, and thus there are a wide range of different prey capture strategies. The most well-known is the snap-trap of the venus’s fly trap (Dionaea muscipula), but that species is restricted to bogs in North and South Carolina (it is also widely cultivated in captivity). The types found in most eastern sphagnum bogs are several species of sundews and pitcher plants. Sundews (Drosera), which I surprisingly have no good photos of, consist of flattened leaves with hairs that bear drops of sticky sugary liquid on their tips. These attract insects, which get stuck and are eventually digested by the plant. Pitcher plants (Sarracenia), in contrast, are literally pitchers of liquid containing nectar bribes that lure insects to the edge, where they fall in and cannot escape. I am always guaranteed to see these fascinating little plants every time I enter a sphagnum bog.

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Northern pitcher plant, Sarracenia purpurea (McLean, NY).

Although carnivorous plants may seem to have turned the tables on insects, some insects have turned the tables again and evolved to take advantage of their captors. Wyeomyia smithii mosquitoes only breed in the pitchers of pitcher plants; moths of the genus Exyra feed exclusively on pitcher plants; Buckleria parvulus plume moth caterpillars feed on the sticky glue of sundews; Camponotus schmitzi ants are known as diving ants because of their habit of diving into the pitchers of pitcher plants and retrieving the plant’s food items. Unfortunately I have never had the good luck to encounter any of these tricky little animals at work.

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Lichnanthe vulpina, the bumblebee scarab. A member of the family Glaphyridae (once part of Scarabaeidae), this animal looks uncannily like a bumblebee in flight. Another name for this species is cranberry root grub because the larvae feed on the roots of cranberry plants (Kennebunk, ME).

Sphagnum moss and carnivorous plants are not the only plants present in bogs. Many specialized sedges and orchids live in bogs, as well as plants of the family Ericaceae (which includes such things as heaths, heathers, blueberries, and cranberries). Heaths are often host to some very strange insects, such as Lichnanthe vulpina, a bee-mimicking scarab beetle. Most trees cannot survive in bogs, but black spruce (Picea mariana) and tamarack (Larix laricina) often invade the open bogs, albeit in stunted form.

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Tamarack (Larix laricina), a common bog tree. This is a highly unusual tree that is a deciduous conifer – that is, it has all the characteristics of typical evergreens such as pines and spruces, except it loses its needles every fall! This photo was taken in October (Saco, ME).

If you have never experienced a bog before, do yourself a favor and visit one. Many bogs have boardwalks through them to facilitate public encounters, since walking directly on the sphagnum tramples and destroys the rare plants there. There are tons of awesome organisms in bogs, and I have only attempted to depict a few of the most interesting ones that I have seen here.

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The Saco Heath, a large bog open to the public with a long boardwalk. The white tufts are the seed heads of cotton grass (Eriophorum), a characteristic sedge in bogs.

Dinocampus

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The lady beetle Coleomegilla maculata atop the cocoon of its parasite, Dinocampus coccinellae (Ithaca, NY).

On one of my first days at Cornell, I stumbled upon an interesting scene. A pink-spotted ladybeetle (Coleomegilla maculata) stood motionless on a lamppost. Underneath the beetle was a brown fuzzy object, with strands wrapped around the beetle’s feet. What was going on here?

This scene was the result of the handiwork of a fascinating parasitoid wasp, Dinocampus coccinellae. Like many parasitic wasps, it is tiny, only a few millimeters long. The species is mostly parthenogenic, with occasional males found. The female lays an egg in a lady beetle, commonly either C. maculata or the 7-spotted lady beetle, Coccinella septempunctata). When the wasp larva hatches out, it first feeds with the help of “trophic cells” that absorb nutrients directly from the host. Later, the larva feeds directly on the lady beetle. Once the larva has finished development, it severs the nerves in the lady beetle’s legs and then pupates underneath the beetle. This leaves the beetle alive, but immobilized, essentially turning it into a zombie. The helpless beetle can only twitch and reflex bleed from its joints. The fascinating thing is that since lady beetles are poisonous to most predators, the presence of the stricken beetle above the wasp larva’s cocoon affords protection for the wasp. After a few days, the adult wasp emerges and flies off to start the cycle again. Interestingly, about 25% of parasitized lady beetles recover from this situation, highly unusual for most hosts of parasitoid wasps. Dinocampus is a concern in the UK because the rate of parasitism of lady beetles is very high. Because lady beetles are important in controlling aphids in gardens, this represents a real threat to gardeners. However in most places where the wasp occurs, it is simply an interesting creature going about its business.

I collected the lady beetle and wasp cocoon, and in 4 days the wasp emerged. It is a pretty red and black animal with greenish blue eyes. A very cool insect to see. Watch for an unmoving lady beetle and perhaps you will find one of these interesting wasps yourself.

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Adult female Dinocampus coccinellae, freshly emerged from its cocoon.

References:

Species Dinocampus coccinellae – BugGuide.net. (2009, November 20). Retrieved from http://bugguide.net/node/view/157232

Bruce, A. Parasitoid Wasp threatens Scottish Seven Spot Ladybird. Retrieved from http://www.microscopy-uk.org.uk/mag/indexmag.html?http://www.microscopy-uk.org.uk/mag/art98/ladybird.html

Dinocampus coccinellae. (2015, February 18). Retrieved from https://en.wikipedia.org/wiki/Dinocampus_coccinellae

Various shots from Gorongosa

A few photos from the past few days of several of the more spectacular animals found in Gorongosa National Park, in no particular order.

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A beautiful grasshopper Acrida acuminata, about the length of my hand.

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Enormous carabid beetle Thermophilum sp, with my index finger for scale.

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Nymph of the Precious Sibyll Mantis, Sibylla pretiosa. One of the oddest looking mantids out there, and one of my favorites. 

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A gorgeous day-flying noctuid moth, Egybolis vaillantina.

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Something a little larger – an adult male Impala (Aepyceros melampus) at the edge of the miombo forest. Not what I usually shoot, but definitely fun to see. 

A Model and its Mimic

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Velvet ant-mimicking carabid beetle from Gorongosa National Park, Mozambique.

Yesterday I was flipping rocks in Chitengo Camp, and under one of them I saw a large black and white spotted insect that I recognized as a velvet ant (Mutillidae), a family of wingless wasps known for their extremely painful stings. I watched it race under the rock, and then decided to catch it. This proved to be an easy thing to do, as when I lifted the rock again, it ran right into my container. When I got a closer look at it, I was shocked – this was no velvet ant! It was a harmless carabid beetle that seemed exactly like a velvet ant. A super cool animal.
A few hours later, a very similar-looking insect came into my possession from the same area. When I looked at it, I realized that here was the model, the real velvet ant that could seriously sting me. Now I had a wonderful opportunity to shoot the model and mimic together. I placed both animals in my photo studio and placed a petri dish over them. The velvet ant raced around like crazy, while the carabid beetle sat quietly. Once the velvet ant calmed down a few minutes later, I gently herded the carabid over to the velvet ant, and took the shot. Below is the result. I was blown away by the unbelievable similarity between the velvet ant and the carabid beetle, how two insects so unrelated can seem so alike. The mimicry is almost perfect, right down to the positioning of the white spots and the dull red coloration of the thorax.

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The model velvet ant (left), and its mimic, a carabid beetle (right).