Anthrax alert in Pennsylvania

Just in case you’re a fan of obscure diptera, I wanted to share some images of an insect I’d never seen before: Anthrax georgicus.

Colin Purrington Photography: Insects &emdash; Anthrax georgicus

I initially identified it as Ogcodocera analis, which looks exactly alike to the untrained eye (like mine) but isn’t found in Pennsylvania. Anthrax georgicus parasitizes tiger beetles, apparently. The females lay eggs near the entrances to tiger beetle burrows and then the larvae attach to the beetle larvae and suck hemolymph. If you live near a place with dense population of tiger beetles, keep your eyes peeled for this fly. Or read about them here, in a fantastic post by Matt Pelikan. I gather they lay eggs by dive bombing.

The next photograph shows what it did in response to my flash.

Colin Purrington Photography: Insects &emdash; Anthrax georgicus with wings spread

I searched around to see if all flies do this, but couldn’t find anything about light-induced wing spreading. I did find an article by Andrei Sourakov on the startle response of a long-legged fly, again caused by a flash — they exhibit a tumbling escape behavior (see paper for pics). In a separate paper, Sourakov discusses the startle response of skippers (Hesperiidae) — again, I highly recommend taking a look at the figures so you can see the insects during their escape tumbles. In hindsight, I should have played around with flash sync speed to see if I could measure how quickly it could spread its wings. The shutter speed I was using was 1/200 second.

Just in case I’m completely wrong about the ID (which I based on this page) and you’re an expert with a moment to spare, I put a better view of a wing at the bottom. The posterior margin of the alula looks convex. I don’t have a better view of the antennae, unfortunately, which I know would be helpful for Bombyllidae. As a side note, insects that are jet black but have shiny white parts are a complete pain to photograph.

Anthrax georgicus wing close-up

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White-footed woods mosquito drinking nectar

Here’s a female white-footed mosquito (Psorophora ferox) that I photographed at the John Heinz National Wildlife Refuge in Tinicum, Pennsylvania. I’m not a mosquito expert, so my ID is a guess based on its green eyes and purple coloration. That’s a terrible way to identify a mosquito, I’m sure. It’s a female because the antennae are not especially fluffy Males have massive, bushy antennae for sensing the wingbeat noise that females make, which is at a higher frequency than that of males. I’m posting this photograph because it’s National Pollinator Week and few people appreciate the pollination that mosquitoes perform. But we could kill them all and we’d be fine, I’m sure.

Colin Purrington Photography: Insects &emdash; White-footed woods mosquito (Psorophora ferox) nectaring on goldenrod

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Nictitating membrane in a sharpie

If you’ve never been up close to a blinking bird, here’s a GIF that slows down the blink in a sharp-shinned hawk (Accipiter striatus). In addition to using the nictitating membrane to moisten their eye, birds of prey invoke them to protect their eyes from branches during a hunting approach and from prey that might fight back. Humans, sadly, don’t have them anymore, save a little bit of tissue called the plica semilunaris.

As an aside, there’s something rather unnerving about a science fiction movie in which a human is portrayed with functioning membranes. I wonder whether part of our reaction (or my reaction, if it’s just me) is that the membranes might signal the onset of aggressive behavior, where the aggressor is about to strike and wants full protection. I wonder whether animals with functioning nictitating membranes have such a perception. Wouldn’t surprise me.

Sharp-shinned hawk nictitating membrane

 

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Kleptoparasitic flies

Here are a few photographs of kleptoparasitic flies stealing hemolymph from a praying mantis dining on a pentatomid. They might be Milichiella arcuata or M. lacteipennis, types of jackal flies, but those are just guesses. Jackal flies (Milichiidae) and frit flies (Chloropidae) are commonly found on dead insects, but the volatiles released by dismembered true bugs are apparently especially attractive (see Zhang and Aldrich 2004). And if you search online for images of jackal flies, they also seem to be common on dead or dying honeybees, so presumably bees exude a volatile that is attractive to flies as well. I’d love to find an article that times the arrival of various kleptoparasitic flies at different types of insects … could use the assemblages to give approximate time of death, I’m sure, just like on CSI. I don’t watch CSI, so I’m guessing here as well.

If you want to know more about jackal flies, I highly recommend Irina Brake‘s “Milichiidae online“, and this post on Ted MacRae’s blog.

Colin Purrington Photography: Insects &emdash; kleptoparasitic-flies-on-hemipteran-2

Colin Purrington Photography: Insects &emdash; kleptoparasitic-flies-on-hemipteran-1-2

Colin Purrington Photography: Insects &emdash; kleptoparasitic-flies-on-hemipteran-3

Colin Purrington Photography: Insects &emdash; kleptoparasitic-fly-with-hemolymph

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