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.

Colin Purrington Photography: Plants &emdash; Theobroma cacao flower

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:

Theobroma cacao anther sacs

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.

Colin Purrington Photography: Plants &emdash; Theobroma cacao flower

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Jumping spider with fly

I think this is Eris flava, but happy to be corrected. Like every jumping spider I’ve photographed it held onto its prey even while I chased it around the leaf to get the shot. I think I’ve seen a jumping spider discard its prey only once, and perhaps that instance was a spider that had pretty much finished the meal. If you know of any papers on the topic of prey retention under threat, I’d be interested.

Paraphidippus aurantius

If you’re curious, the fly probably isn’t dead yet. Just paralyzed and being digested from within with enzymes injected by the spider. I’d wager the process is exquisitely unpleasant for the fly. I’m assuming the spider moves to different parts of the fly to access different pockets of muscle and such but I couldn’t confirm that in the literature.

If you’re interested in identifying something that’s similar, there’s a useful paper on differences of E. flava and E. militaris by Madison 1986 (pdf), but illustrations of the head are only of males. Photographs and other information are at BugGuide.

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Beech blight aphids attacking spider

Here’s a spider being attacked by beech blight aphids (Grylloprociphilus imbricator). The spider eventually dropped off the tree trunk onto the forest floor and crawled away, twitching slightly. This is a known defensive behavior of the aphids, but I’d never seen it before. Apparently the stylets are sharp enough to puncture human skin, too. Wish I’d managed to get better photographs, of course.

Beech blight aphid (Grylloprociphilus imbricator) attacking a spider

Clayton Park, Monmouth County, New Jersey, United States.

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