Tag: insect photography

Categories
diptera Species Profile

Callopistromyia, the Peacock Flies

For this article I’d like to consider one of the most beautiful insects I’ve ever had the pleasure of observing: the Peacock Fly (Callopistromyia annulipes) and its relative, the only other member of its genus the Peahen Fly (Callopistromyia strigula)*. The main difference in appearance between these two species is in their wings: C. strigula contains much narrower wings than C. annulipes (Kameneva and Korneyev 2006).

*There is no common name for C. strigula, so I made one up. You might be surprised that there isn’t a common name, but consider that there are hundreds of thousands of species of Flies, and many of these are only known within specialist groups that study the differences between them. This is also the reason that there isn’t much information available for these Flies despite their beauty and conspicuousness.

Callopistromyia annulipes, the Peacock Fly. Note the wide wings and the position they are held in above the body.
Callopistromyia strigula, the Peahen Fly. Note the relatively narrow wings, and their position held out to the sides of the body.

C. annulipes is distributed across the United States and occurs in three provinces of Canada: British Columbia, Alberta, and Ontario, while C. strigula is found in Manitoba, Ontario and Saskatchewan as well as several States. Over the past several years, this species has spread into Europe as well, no doubt via human means (Pintilioaie and Manci 2020). 

In both species males and females display, contrasting with many fly species in which only the males display for the females to choose from among them. I don’t want to discuss sexual selection and mate choice here in any depth. Suffice to say that because both males and females perform displays there is likely mutual sexual selection going on in these species, meaning that traits are preferred and chosen by both sexes in this species, rather than a female-choice bias or male-choice bias.*

*of course, this only applies if the displays and accompanying appearances are sexually selected for, but there are other ideas for what forces are selecting these displays (see further below).

Video of Peacock Fly (Callopistromyia annulipes) displaying on a bridge railing on the Lynn Valley trail in Simcoe.

Little is known of these species’ biology other than that they display on conspicuous surfaces (more on this below), and there are records of the adults of C. annulipes feeding on the frass from wood-feeding beetle tunnels* (Steyskal 1979). Their puparia** have been found beneath the bark of various deciduous trees, so it’s presumed that their larvae feed on dead wood, or fungi within dead wood or something associated with dead wood. 

*Frass is a fancy way of saying “insect excrement and related material” usually used in connection with wood-boring insects… that ‘related material’ bit is key here since although a lot of what we call frass passes through an insect’s digestive system it can also be broken up bits moved behind a wood-boring beetle, so less insect “poop” and more insect “debris”.

**puparia refers to the hardened larval skin that encloses the pupal stage of derived Diptera… which probably doesn’t explain very much unless you know what those other terms mean. Basically, instead of nothing surrounding the pupa (the transformative stage of insects, between larva and adult), a huge branch of the Fly Family Tree (the Cyclorrapha) hardens their final larval stage skin into a protective case, sort of the fly version of a chrysalis.

As with many Diptera, their larvae are mysterious. After much searching, I managed to find a few pictures of Callopistromyia larvae online. I was amazed and contacted the person who recorded these organisms to obtain permission to share the relevant information and images.

The pictures depict larval and pupal C. strigula which were found feeding on the inner bark of a boxelder tree (Acer negundo) (van der Linden 2018). I can’t find any pictures or information pertaining to C. annulipes larvae, but presumably they have the same or similar feeding habits. 

Finally, the most attractive thing about these species are their displays. The reason I’m writing about these flies is because I noticed them, and the reason I noticed them is because they strutted about on the railings of bridges on the Lynn Valley Trail. The Peacock Fly (Callopistromyia annulipes) in particular raises its large wings so that they meet above its back presenting a very noticeable display. By contrast, C. strigula adults display their wings in a more horizontal fashion. Presumably, these displays are about attracting mates and because the displays are performed by both sexes, they are about mutual mate choice. In other words, males are displaying to attract the attention of females and females are displaying to attract the attention of males. An intriguing possibility is that these wing displays are about more than finding a mate… they could also be an example of predator mimicry.

Can you see the face of a Jumping Spider in the Peacock fly’s wing-pattern?

A fascinating paper with an excellent title* describes how other species of Ulidiidae (the family of Flies that includes Callopistromyia) have wing patterns and displays that mimic the appearance of Jumping Spiders (Salticidae) (Hill et. al. 2019). The reason? Jumping Spiders are visually hunting predators of basically any insect they can catch. The wing patterns are possibly exploiting the visual system of Jumping Spiders by causing the spiders to believe they are staring down another Jumping Spider and so to be cautious. I can’t help but be intrigued by this idea, and somewhat skeptical. Despite its appeal, there are some problems with the hypothesis. One problem that came to my mind is that Jumping Spiders will hunt other Jumping Spiders. So if the pattern is supposed to resemble a Jumping Spider and deter them from predating the fly, why would it? The paper acknowledges that there are still many unknowns, but the authors make a good case that at least some insects are manipulating salticid responses to prey with visually deterrent patterns. And they also note: “In a natural setting even a brief delay in the attack of a salticid could allow these flies to escape” (Hill et. al. 2019). As always in science, more studies are needed…

*The title, for those of you who don’t read through the References section, is “Do jumping spiders (Araneae: Salticidae) draw their own portraits?” The idea is that in avoiding hunting insects that resemble themselves, jumping spiders leave those ones alive to reproduce in like kind and so jumping spider resemblances are crafted by the natural selection of the jumping spiders themselves.

There is always more to learn, and always new organisms to explore in the world. I hope you enjoyed my dive into the beautiful flies of the genus Callopistromyia, the Peacock Flies. 

References:

Hill, David, A. P. C., Abhijith, and Burini, Joao. 2019. “Do jumping spiders (Araneae: Salticidae) draw their own portraits?” Peckhamia 179.1: 1-14. (full pdf available here: https://peckhamia.com/peckhamia/PECKHAMIA_179.1.pdf)

Kameneva, Elena and Korneyev, Valery. 2006. “Myennidini, a New Tribe of the Subfamily Otitinae (Diptera: Ulidiidae), with Discussion of the Suprageneric Classification of the Family”. Israel Journal of Entomology. Vol. 35-36, 2005/6: 497-586.

Pintilioaie A-M, Manci C-O (2020) First record of the peacock fly Callopistromyia annulipes (Diptera: Ulidiidae) in Romania. Travaux du Muséum National d’Histoire Naturelle “Grigore Antipa” 63(1): 87-91. https://doi.org/10.3897/travaux.63.e50920

Steyskal, George C. 1979. “Biological, Anatomical, and Distributional Notes on the Genus Callopistromyia Hendel (Diptera: Otitidae)”. Proceedings of the Entomological Society of Washington. 81(3): 450-455.

van der Linden, John. 2018. https://bugguide.net/node/view/1510354

For other blogposts focused on Flies (the vast insect Order Diptera), see:

–5. Robber Fly Hunting Queen Ant

–Flies: The Natural History and Diversity of Diptera, by Stephen A. Marshall

–Flies Falling to Fungi and Other Dipteran Observations

–Fuzzy Flies and Song Sparrows

–Eastern Band-winged Hover Fly

Categories
Nature Observations

Port Burwell Observations, July 2023

At the beginning of July, my family and I were camping in Port Burwell Provincial Park. While there, as I usually do when camping, I took some photos of the creatures I encountered and I’d like to explore some of them and what I can find out about them here. So here goes…

On my first night there I found myself sitting alone with a book and a small clip-on reading light in a dining tent (which was open to the outside, for at least part of the night). My tiny beacon of light attracted several insect investigators and I quickly became distracted from my reading*.

*If you must know (as I would want to know if I was the blog’s reader), I was reading a collection of sci-fi short stories: Galaxy: Thirty Years of Innovative Science Fiction, edited by Frederik Pohl, Martin H. Greenberg, and Joseph D. Olander.

The most abundant insects alighting on my illuminated pages were members of that vast insect Order: Diptera, the Flies. Two that I photographed were likely the same species, and I suspect were male and female representatives. I have tentatively identified them as members of the genus Neurigona based on iNaturalist. They are certainly long-legged dance flies (Family Dolichopodidae). Dolichopodids are diverse flies (there are around 7000 species in the world (Marshall 2012)) which often hunt other flies and springtails as adults. There are about 150 species in the genus Neurigona (Marshall 2012).

Long-legged Dance Fly (Family Dolichopodidae) attracted to my reading light, possibly of the genus Neurigona.

A beautiful little vinegar fly (a member of the Family Drosophilidae) graced the pages of my book as well: Chymomyza amoena. This species, along with the other members of its genus are “almost invariably present on fallen or wounded trees” (Marshall 2012 p. 477).

Chymomyza amoena, a member of the Family Drosophilidae, of which the most famous member is the Common Fruit Fly Drosophila melanogaster, ubiquitous in kitchens and laboratories the world over.

Two notable non-Flies made their appearance amid the glowing reading light. A tiny pale yellow leafhopper was just barely noticeable among the typed letters on the page, a member of the genus Edwardsiana. 

Tiny tiny leafhopper of the genus Edwardsiana.

A dark beetle also scuttled across the words of my reading material, which I believe to be a Ground Beetle (Family Carabidae), possibly of the genus Bembidion.

Ground Beetle scurrying across the title of the sci-fi story I was reading, “The Holes Around Mars” by Jerome Bixby.

The next day, I did a tour of the campsite with my camera in order to find more subjects to photograph and identify. One creature located on my dining tent was another beautifully patterned fly: Thaumatomyia. This genus of flies contains some species which feed on aphids as larvae and others which bore and feed within grass stems (Marshall 2012).

Chloropid fly in the genus Thaumatomyia.

Nearby was a prowling spider which is possibly the False Pirate Spider (Platnickia tincta):

Sliding slowly across the leaf litter was a pale orange slug of the genus Arion:

I was just able to capture this amazing butterfly that landed for a few moments on the ground, an Appalachian Brown (Lethe appalachia). Appalachian Brown caterpillars feed on sedges (Carex spp) and spend the winter in the caterpillar stage (Hall et. al. 2014).

Appalachian Brown Butterfly (Lethe appalachia).

On the walk to the beach there were plenty of insects worthy of attention but I didn’t want to block the path of water-seeking pedestrians by crouching with my macro lens, so I decided to photograph birds there instead. There were swallows darting above the sands (more evidence of insect abundance) but they proved impossible to photograph. I took several photos of what I believed to be 2 different gull species. While reviewing my photos and posting them on iNaturalist it became clear that despite the contrast between the large brown-feathered birds and the sleek grey-and-white ones the birds were all members of the same species: the Ring-billed Gull (Larus delawarensis). 

Ring-Billed Gull (Larus delawarensis) panting in the heat to keep cool.
Another Ring-billed Gull, lacking the sharp white-and-grey plumage of the individual photographed panting above.
All of the birds in this photo are Ring-billed Gulls (Larus delawarensis) despite the one in the background appearing larger and in a very different plumage, the mottled brown look is that of a 1-2 year old bird before they acquire the more clearly defined gray and white feathers.

My final observation of the trip was a beautiful tiny leafhopper resting on a dining tent: Otiocerus coquebertii. This species is associated with Beech, Maple and Oak, possibly feeding on fungal hyphae (the underground microscopic portions of fungi) as nymphs (Bartlett 2020).

Otiocerus coquebertii, a tiny and beautiful leafhopper.

References:

Bartlett, C. R. 2020 (and updates). Planthoppers of North America (accessed August 12, 2023). https://sites.udel.edu/planthoppers/north-america/north-american-derbidae/genus-otiocerus-kirby-1821/

Hall, Peter, Jones, Colin, Guidotti, Antonia, and Hubley, Brad. 2014. The ROM Field Guide to Butterflies of Ontario. Royal Ontario Museum.

Marshall, Stephen. 2012. Flies: The Natural History and Diversity of Diptera. Firefly Books.

For other related blogposts, see:

–MacGregor Point Observations (May 2018)

–Port Burwell Observations