Neighborhood Nature (Pt. 11) — The Invertebrate Edition

Photo - Widow skimmer dragonfly

I hope you’re not tiring of these Neighborhood Nature posts, because I like doing them too much to stop. Or, really, I’ll stop when Nature does.

Alert Gazette readers will recall that we’re wrangling a herd of black swallowtail caterpillars that have sprung to life in the parsley planted in a pot on our back porch. This is an update on what’s happening with them.

But first…here’s a dragonfly that posed for me on a nearby plastic plant stake. Unless the internet has let me down (yet again), this is a female widow skimmer dragonfly (Libellula luctuosa). According to this website, unlike some other species where males guard egg-laying females, Widow Skimmer males leave the female by herself, ‘widowing’ her as she lays her eggs just under the surface of the water. (Ladies, please save your remarks for another time.)

Widow skimmer dragonfly

Now, back to the main event.

Most of the caterpillars have grown quickly, and have been equally quick to strip the parsley of its leaves. Some of the larger larvae are getting ready to pupate…i.e. form a chrysalis (or cocoon, to be non-technical), while the smaller ones are now simply trying to survive both the disappearing food source as well as the appearance of a specific predator: an assassin bug belonging to the genus Pselliopus.

I’ve previously reported on assassin bugs (scroll about halfway down that post). They are deadly predators of some less-than-welcome pests, but I never realized that they might also prey on non-threatening animals such as our caterpillars. But seeing is believing.

Above & below: Assassin bug capturing a tiny black swallowtail caterpillar

Forgive the poor quality of the photos, but I think you get the idea. Anyway, this is the first time I’ve seen this particular species of assassin bug; most of them are, frankly, a bit terrifying looking. And they will administer a nasty bite if you pick them up (which, of course, I would never do. Really.). But this one is kind of pretty, even if we don’t appreciate it culling our caterpillar population. Fortunately, they’re small enough that they don’t pick on the bigger larvae.

So, back to the caterpillars. At least one of them has already formed a chrysalis. The following photos show the chrysalis on the end of a bare parsley stem. Debbie read that the caterpillars attempt to form chrysalises somewhere other than where they feed in order to evade predators; we’ve now moved the pot close a basil plant and at least one caterpillar has claimed a spot on it.

I intentionally included — as opposed to my frequent accidental intrusions — the tip of my finger in the first photo to give you a sense of scale.

Above & below: Larvae and chrysalis

The chrysalis is affixed to the stem by the slender silk thread that’s visible in both of the preceding photos.

Assuming nothing untoward occurs, the pupa will remain in the chrysalis for up to two weeks before emerging as an adult butterfly. We were not so fortunate as to observe this amazing phenomenon last year. Maybe this year will be different.

Animation: caterpillar eating parsleyI mentioned above that the parsley has been almost completely consumed by the very hungry caterpillars (say, that gives me a completely original idea for a book!). Debbie took pity on them and bought some parsley at the local grocery store and put it in the pot. It’s now wilted and they don’t seem to be too interested — can’t say as I blame them — but for a while, they seemed to enjoy the fresh salad.

The above gif shows one small larva eating the new parsley; the following video captured a Sunday morning breakfast when the original plants were still intact.

nom nom nom

I hope I’ve piqued your interest a bit and you’ll stay tuned for future developments!

Update (15 June 2022): If one needed any convincing that Nature can be at best mysterious and at worst cruel, here’s proof. As of 4:00 p.m. today there remains nary a trace of a caterpillar or chrysalis on our back porch. It’s as if all of the above was a dream. I have no idea about the fate of the subjects of this post. I assume that a bird might have picked off the caterpillars, but that wouldn’t explain the missing chrysalis. Welp. Maybe next year…

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