Colin Purrington

Supranivean insects and spiders

Winter is usually a depressing down time for those who enjoy taking photographs of insects and spiders, but a fresh snowfall can reveal all sorts of critters still crawling around, albeit slowly or not at all. Below are 11 of my recent finds.

1. Some sort of cynipid wasp. It’s nearly wingless (subapterous), so likely a member (female, obviously) of the asexual generation that many of these wasps go through. If I knew the species I could provide a link to the gall they make (usually on an oak), which often looks very different from the gall made by the sexual generation. If you recognize the genus or species, please let me know. Or, if you are a member of iNaturalist, comment on the observation page. Hildacy Farm, Media, PA.

2. This is probably a queen Lasius claviger. This species is a social parasite, so she might be out looking for a nest of some other species in the genus. I couldn’t find any report of queens being active during the winter so perhaps there’s another explanation. This individual was one of two I found, separated by several feet. Thanks to Gordon C. Snelling on iNaturalist for genus ID. If you think my species ID is wrong, you can correct me on iNaturalist (with thanks). Hildacy Farm, Media, PA.

3. Fly in the genus Simulium, per suggestion by John F. Carr on BugGuide. Here’s the iNaturalist page if you know the species and care to leave a comment. I’d even be grateful for a subgenus guess. It’s a black fly, but I’m not sure whether all of them are biting. Hildacy Farm, Media, PA.

4. This seems to be a fly in the genus Pollenia, notable perhaps because they parasitize earthworms, which was news to me. Perhaps I’m easily impressed. Saratoga Springs, NY.

5. Here’s another fly from Saratoga Springs, and I think it’s also a Pollenia. Also not moving but in this case likely dead (its thorax seemed crushed, though ventral view doesn’t show it. If you have ID thoughts, here’s iNaturalist page.

6. This a male Chironomus crassicaudatus. A tad contorted and not moving so not the best photograph. Thanks to John F. Carr for ID. Here’s the iNaturalist page if you’re curious. Hildacy Farm, Media, PA.

7. This female fly was a few feet away from the male above, and is perhaps the same species. But definitely in the same tribe (Chironomini). Thanks, again, to John F. Carr for identification. I’ve also posted the photograph on iNaturalist if you want to weigh in on identification. Hildacy Farm, Media, PA.

8. Another fly in the genus Simulian, per Katja Schulz on iNaturalist. Sure looks like the images on the (Psilozia) vittatum species complex page on BugGuide. Hildacy Farm, Media, PA.

9. Lygus lineolaris, per an identification on iNaturalist. Hildacy Farm, Media, PA.

10. Some type of crab spider (Thomisidae). I haven’t been able to ID further. If you have thoughts, please see the iNaturalist observation page. Hildacy Farm, Media, PA.

11. Long-jawed orbweaver, probably Tetragnatha. The strange thing about this spider is that I found it several feet away from where I found Tetragnatha in the snow one year before. So I was actually looking for a Tetragnatha in the snow when I found it. If you are a member of iNaturalist and want to comment on the species … here’s the page. Hildacy Farm, Media, PA.

Sadly, I didn’t find any snow flies (Chionea) but here’s one I found several years ago. This post has details.

Posted in Biology, Photography | Tagged ant, anti-freeze, Chironomus crassicaudatus, cold, cynipid, cynipidae, diptera, fly, insects, Lasius claviger, Lygus lineolaris, Pollenia, Simulium, snow, social parasite, spider, spiders, subnivean, supranivean, Tetragnatha, wasp, wingless, winter | Leave a comment

Exobasidium ferrugineae

I found this fleshy, flower-like structure growing on Lyonia ferruginea (rusty staggerbush) at Archbold Biological Station (Venus, Florida). Heaths don’t make flowers like this, so I originally thought it might be an insect gall or phytoplasma infection, but I was wrong. After poking around online I think it’s Exobasidium ferrugineae, a Basidiomycetes fungus. Members of the genus grow in between cells of flower and leaf tissue, then in the Spring send hymenial tissue through stomata and other cracks in the epidermis, eventually turning the surface white with spores. I’d never heard of such fungi before. I’ve led a sheltered life.

The above was the largest structure I found (perhaps 3 inches high) but there were dozens of others (see below) at the same location. If you’d like to know more about the species and genus, a good starting point is Kennedy et al. 2012 and references therein. In older literature the fungus was known as Exobasidium vaccinii (Burt 1915), but it seems likely that that species is host specific to Vaccinium vitis-idaea.

: Concavity at leaf tip.

: Concavity at leaf tip.

: Another view of the fungus.

Posted in Biology, Gardening, Photography, Science | Tagged Archbold Research Station, Basidiomycetes, biology, botany, concave, concavity, disease, Ericaceae, Exobasidium, Exobasidium ferrugineae, fleshy, Florida, fungal, fungi, fungus, heath family, hypertrophied, leaf gall, Lyonia ferruginea, mycelia, mycology, peach-colored, pink, plant, revolute, scrub, Venus, waxy | Leave a comment

Theobroma cacao flower

Here are some close-ups of Theobroma cacao flowers at Longwood Gardens in Kennett Square. The plant is economically important (because chocolate) so people fuss over pollination a lot, but its bizarre floral anatomy is noteworthy regardless of the species value. The catchiest structures are the pointy red staminodes, stamens that became neutered over evolutionary time, which probably have roles in visual attraction of pollinators (ceratopogonid midges) and in preventing self pollination. The real stamens are enclosed in translucent petal pouches, though I chose to photograph this flower because one of the anthers has popped out.

According to one scenario I read, the flies first land on the exterior of the pouch, then crawl inside to lap up nectar from minute glands on the adaxial surface near the anthers. During their foraging they get coated with pollen, and some of the pollen gets deposited on the style (small white structure encircled by the staminodes) when they exit the pouch. Here’s a close-up that shows the translucent pouches:

Presumably some of transferred pollen is from previous visits at different trees (because most types are self-incompatible). These flies do such a terrible job pollinating that farmers often just do it themselves with paintbrushes and forceps. There’s even speculation that the domestication of T. cacao some 1500 years ago slowly changed the plant enough that the original pollinator(s) (bees?) were lost, with the midges being the only insects still interested in the meager nectar rewards.

The photograph below shows the cauliflory habit of the flowers, and the “parallel staminodes” variant of the flower.