Say my name and I will show myself

A quick Dipteran interlude from the Orthoptera.

While returning to Ithaca from a trip to Mississippi with Jason Dombroskie, we stopped at a Subway restaurant in Tennessee. Over dinner, we mused over the fact that neither of us had ever seen Hermetia illucens, the black soldier fly, despite it being a common, widespread insect that shows up in Cornell’s Insect Diagnostic Lab with regularity. This species is a compost feeder and is considered a beneficial insect as it breaks down compost and also outcompetes the house fly, Musca domestica, which can spread many diseases (Hermetia is completely innocuous). Jason went to the bathroom, and came back saying “You’ll never guess what I found”. It was, of course, a black soldier fly.

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Hermetia illucens, the black soldier fly (White Pine, TN).

Moral of the story: keep saying the name of the insect/plant/mushroom/bird/whatever organism that you want to see, and sooner or later (sometimes very much sooner!) that organism will show up in your life.

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Hermetia illucens.

A katydid’s nightmare

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Something is clearly wrong with this katydid – note the discoloration and the head hanging by a thread.

One day in late July of this year, I was out on an early morning walk on the trails around Cornell’s campus. Heading down some stairs down to the Fall Creek gorge, I noticed a dead katydid on the ground and picked it up. I recognized it as a male Scudderia fasciata, the treetop bush katydid. This species lives high in conifers, and has dark striped wings to match its habitat. I usually find them either at lights or by accident, so I figured I’d keep this one as a specimen. I noticed that its head was hanging by a thread and that the entire head and thorax seemed to be empty. In stark contrast to this, the katydid’s abdomen was brown and bulging. Perhaps it was rotting? As I peered at it closer, a scene straight out of the movie Alien – four huge wriggling fly maggots burst forth from the katydid’s carcass! I am not one to be creeped out by insects, but this was such a shock that I dropped the whole mess! This was an especially creepy scene given that katydids are some of my favorite insects. After a moment I realized that this was a golden opportunity to see what fly species would be parasitizing bush katydids in upstate New York. I gathered up the fly larvae and dead katydid and placed them in a container with some soil.

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This is what keeps katydids up at night – a sarcophagid fly parasitoid of Scudderia fasciata, as yet unidentified.

In a few hours, the maggots had dug into the soil and pupated. I had no idea how long they would remain there, but less than two weeks later I looked at the container and four small flies were flitting around. They were sarcophagids, a group known as “flesh flies” that are known for feeding on dead bodies but which also contains species that parasitize other invertebrates. They are quite difficult to identify from photos alone, but I kept the specimens and hopefully I will be able to pin an ID on them some day.

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A healthy male Scudderia fasciata, found nearby several days later (Ithaca, NY).

Common Insects of the Kennebunk Beaches

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Parson’s beach in Kennebunk, ME. At first glance, not much to be seen besides some algae.

In contrast to a meadow or forest, ocean beaches can often seem devoid of insect life. At first glance, there is not much to be seen besides seagulls and the occasional washed up dead jellyfish. However, there is often more than meets the eye on a beach. In particular, the wrack line, the highest reach of the high tide where dead seaweed and other debris piles up, is often teeming with life. The most obvious animals there will invariably be the small leaping beach hoppers (Talitridae), but these are crustaceans, not insects. The next most obvious animal will be this fly:

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Coelopa frigida – kelp fly (two different individuals) – Kennebunk, ME.

This is Coelopa frigida, the kelp fly. The 35 species in its small family, Coelopidae, all live in the coastal wrack zone and feed exclusively on decaying kelp. C. frigida is the only species in its genus in the eastern U.S. and can be found up and down the coast. These animals can be extremely, extremely abundant in their preferred habitat, but go less than a mile inland and you’ll be hard pressed to find even a single one. Having lived near a beach for about seven years, I never paid much thought to Coelopa. It was always a very common species in my area, even into very late fall, and was one of the first insects to emerge in the early spring. However, while taking Insect Biology during my first semester at Cornell, a class which required one to make an insect collection, I realized that here was a distinctive family that nobody could collect in Ithaca, there being no rotting seaweed anywhere near! While back home over Thanksgiving break, I collected a large series of them (which entailed about a minute of knocking the contents of a lump of old seaweed into a vial) and brought them back to Cornell with me to share. They were eagerly snapped up by other students looking for additional families to fulfill the class requirements.

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A weird sepsid – Orygma luctuosum (Kennebunk, ME). Note the differences in head shape, wing venation, and color from Coelopa

Occasionally while observing Coelopa swarming over the wrack on the beach, I would catch sight of another species of fly, quite similar to Coelopa, but larger and darker. These turned out to be Orygma luctuosum, another specialist on rotting seaweed. Orygma has its own monotypic subfamily in the family Sepsidae. This species much prefers to run than fly, and will often just try to hide under seaweed, rocks, or other debris rather than simply fly away. They seem to be less common than Coelopa but they are certainly around; you just need to search a bit more actively to get a good look at one.

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Female Anisolabis maritima, the maritime earwig. Note the symmetrical forceps.

The third insect I almost always see at the beach is a very large, black, entirely wingless earwig called Anisolabis maritima. Commonly known as the maritime earwig, this is a European species that has spread to most shorelines worldwide. They are generalist scavengers/predators and usually feed on the kelp flies or beach hoppers that are so abundant in wrack. Anisolabis is likewise extremely abundant in this habitat, although I have found isolated individuals somewhat further inland, suggesting that they do get around a bit. Females tend clutches of eggs and supply food to young nymphs.

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In males of Anisolabis, the right forcep is much more bent inward than the left one, an easy way to tell the gender of your specimen. 

These three species I can almost always expect to see whenever I venture down to the Kennebunk beaches. However, on very windy days, there is often an abundance of other insect species, blown out of their field or forest habitats onto the beach. Beach collecting on windy days can be extremely productive, yielding tons of uncommonly seen stuff. But, I’ll leave that topic for another post.

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The tracks of a maritime earwig in the sand.

Gorongosa Mountain

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A part of the Murombodzi waterfall on Mt. Gorongosa

On August 6th, two days before leaving Mozambique, I took a much-anticipated day trip to Mt. Gorongosa. This mountain, the highest peak in the country, is home to a montane rainforest environment uncommon in southern Africa, and thus bursting with unusual and often endemic species. The drive there was a wonderful 2-hour or so ride along extremely bumpy mountain roads, but it was totally worth it. I first explored the Murombodzi waterfall, a stunningly beautiful area unfortunately surrounded by a lot of slash-and-burn destruction. It was thrilling to be in a place that I had seen so many photos of in the past. Piotr had told me to collect everything, as virtually every species on the mountain is unique. I collected quite a few insects, including two species of katydids that are very uncommon and possibly new to science. I also found a positively spectacular spiny orb weaver spider.

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Almost every surface around the waterfalls is covered in swarms of Stalk-eyed Flies (Diopsidae). These are likely genus Sphyracephala.

The hike down to the falls from the mountain campsite (basically skiing down a sheer dirt slope) was tough, but hiking back up was even tougher. I was so tired and out of breath that I wasn’t sure I was going to make it, but make it I did.

Later in the day, I had the chance to visit some of the fields on the mountain where crops are being grown with coffee trees. There is an ambitious coffee project going on which has a lot of momentum. The mountain was made part of the park in 2010 when officials realized that without the rain-catching power of the mountain forest, the rest of the park would die. Unfortunately, there are a lot of people living on the mountain, and most are subsistence farmers. The only way of life they know is to slash and burn large chunks of rainforest, leaving huge areas dead. The new coffee project aims to give these people control of coffee plantations, which will yield much-needed revenue. The coffee trees require shade to grow, so creating coffee plantations also requires planting rainforest trees. The idea is that this will create a source of income for the people and also rejuvenate the damaged rainforests. However, the coffee trees take 4 years to fully mature, so it is a slow and difficult process. I was called upon to collect samples of pests that were infesting some of the crops. I collected several pest species, including thrips and planthoppers. Hopefully they will be controlled with minimal use of pesticides. While there I also found a wonderful large pyrgomorphid grasshopper Dictyophorus griseus. This animal is deadly toxic to vertebrates and advertises this fact with bright red underwings when threatened. Since it knows it is protected, it rarely jumps and is very docile when handled.

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The pyrgomorphid grasshopper Dictyophorus griseus on my hand.

Hopefully I will be able to return to the mountain at some point in the future and do some night collecting. I would especially love to see the Mount Gorongosa pygmy chameleon, endemic to this mountain. Someday…

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A stunning jewel of a spider, Gasteracantha sp.

Getting their Feet stuck in the Milkweed

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Odontomyia cincta from Kennebunk, ME.

A few days ago I discovered a contender for the most colorful fly in my yard (Idana marginata is a serious competitor for this title): Odontomyia cincta. With lovely orange legs and a body pattern of black and brilliant green stripes, this is one beautiful animal. Most people would probably be surprised to learn that this is a fly at all, given the popular image of flies as dull-colored disease-spreading organisms. I see Odontomyia off and on in my yard, usually either sitting on leaves or nectaring on the dogwood that is flowering in my front garden right now. The genus contains about 31 species in the U.S, and adults are found in woodlands and fields near freshwater habitats, where the young develop. The larvae are “butt breathers” that stick the tip of their abdomen through the water’s surface to obtain air while they graze on algae underwater.

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Odontomyia trapped by its tarsi in a milkweed flower. Note the bright orange pollinia (Kennebunk, ME). And yes, I freed it after taking its photo.

Although these are interesting animals in themselves, I was reminded of an even more interesting phenomenon I observed a few years ago that involved Odontomyia. While out “bugging” in a large open field, I stumbled upon quite a few individuals of Odontomyia in a patch of common milkweed. All were trapped by their feet (tarsi) by the milkweed flowers. Nor were they alone – I observed at least three other insect species that had encountered the same problem. Some had managed to escape the flowers’ grasp, while others hung helpless, trying in vain to extricate themselves. What was going on here?

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Common Milkweed (Asclepias syriacia)

Common milkweed (Asclepias syriaca) is an amazingly interesting plant native to southern Canada and most of the eastern U.S. It is perhaps most well known as the houseplant for the Monarch butterfly, but it is also host to many other specialist feeders, including two seed bugs, several beetles, and a tiger moth (idea for a future blog post!). When a leaf is broken, a milky substance oozes forth (giving the plant its name), which contains toxic cardiac glycosides that can kill or incapacitate most vertebrates, including humans. These chemicals do not harm the specialist insects that feed on the plant, of course. But it is not only the leaves that pose a threat to other organisms. The large masses of pink flowers contain structures that contain pollen in little packages called pollinia. When an insect brushes against one of these structures, the pollinia clamp onto its leg or proboscis. The idea here is that the insect will break off the pollinia and then visit another milkweed flower, thus completing the process of pollination. However, many insects simply don’t have the muscle to break off the pollinia, and thus end up, like the Odontomyia, stuck helplessly. Only the strongest of insects, such as bumblebees and monarchs, can break loose. Despite the dangers involved, the nectar of milkweed flowers must be very attractive to insects, as individuals that have managed to escape the flowers often return. The fact that the milkweed flowers end up killing quite a few insects does not seem to have any benefit to the plant; it is not carnivorous. Perhaps the decaying insect carcasses, when they finally fall to the ground, provide nutrients to the soil surrounding the milkweed. Something interesting to look into. In any case, yet another reason I’m glad I’m not an insect. Otherwise I’d have to worry about being snared in a bear trap every time I eat something.

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One that didn’t make it: an unidentified fly hanging dead from a milkweed flower, with numerous pollinia attached to its tarsi.

Reference:

Frost, S. W. (1965). Insects and pollinia. Ecology, 46(4), 556-558. Retrieved from http://www.jstor.org/stable/1934896?seq=1

Picture-winged Flies

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My first (and not so good) photo of Idana marginata. (Kennebunk, ME)

Walking around my yard one morning a few years ago, I looked up into a maple tree to see an unbelievably beautiful insect. Golden yellow and tan, with a striking pattern of black stripes and splotches, the critter looked down at me, rowing its wings back and forth with a feeling of knowing exactly what it was doing. It was unmistakably a fly, but it was huge by Maine fly standards – about 10 mm long. It was also perched high up on the tree trunk, too high to be reached by hand or net. Luckily I had my camera with me. Unluckily, it was only my little point and shoot. I took aim and fired off three shots before the fly, well, flew. Only one photo was in focus, and since the critter was so far away, it was not a very good photo at all. Something as distinctive as this had to be identifiable, though. “Well”, I thought, “I’ll post it on BugGuide and see if anyone can point me in the right direction”. Two hours later I had my answer, courtesy of veteran BG editor v belov. It was Idana marginata, eastern North America’s largest picture-winged fly. This family, Ulidiidae, contains about 130 species in North America, many of which are very brightly colored and patterned, hence the common name. Most develop in decaying organic matter, or in roots. One of North America’s most commonly photographed flies (judging from BugGuide records), Delphinia picta, belongs to this family. It is widespread across eastern North America, and can seemingly be found in just about any habitat. Strangely, I have only run across this species twice, and both times were before I really learned to take good insect photos. This is a recurring theme for me – I seem to be good at finding scarce species, but supposedly common and abundant ones seem to slip by me. I guess it shows that our definitions of “common” and “rare” really depend on the luck of being at the right place at the right time.

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My best shot of Delphinia picta. (Eastchester, NY) Need to find another one of these!

Another interesting genus of Ulidiids is Chaetopsis. This group includes about 7 species in North America, several of which are confined to various types of marshes. One species that I found last year, C. aenea, is a specialist feeder on Spartina grass. This grass is the major component of East Coast salt marshes. Guess where I found my specimens?

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Chaetopsis aenea, found on Spartina grass. (Scarborough Marsh Audubon Center, ME)

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Another species of Chaetopsis, probably C. massyla, which is found in freshwater marshes in the eastern U.S. (Sanbornville, NH)

I found my second individual of Idana marginata about a week ago, again in my yard. I was looking out onto my back deck from inside, and spotted it sitting on a deck chair. In a minute I was outside with a vial, and quickly snapped up the animal, still warming itself in the morning sun. This time I was finally able to get some good photos of it. Amazing to think that such a beautiful animal can arise from a backyard compost pile. Actually there are a ton of interesting life forms to be found in compost, but I’ll leave that for another post.

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Idana marginata (Kennebunk, ME)

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Face-to-face with the subject of this post!