Dragonfly Nymph Shed Skin – More elongated than usual

2014 April 26

Here’s a shed skin from a dragonfly nymph that Sandy and Rosie found while they were out fishing. This one has a longer, thinner abdomen than dragonfly nymph molts that we’ve found previously.

Some poking around on BugGuide suggests that the more-elongated nymphs are likely to be Darners in the family Aeshnidae, which are some of the dragonflies with extremely long, narrow abdomens as adults. It also looked like identifying it more closely than this would have required seeing the adult.

I was particularly interested in trying to get better pictures of the extensible lip that these nymphs use to catch prey. You can see it folded up underneath the head.
This shoots out forward so that the nymph can grab prey as it swims by, without the nymph actually having to move its body through the water. This allows it to catch things that swim much faster than the nymph can.

The “grabbers” at the end of the lip are pretty distinct here. They are multi-pronged, and look like they would hold onto small prey items pretty securely. Even though these look a lot like standard insect mandibles, they are not. The actual mandibles that the nymph uses to chew up food are hidden underneath. The grabbers are actually derived from one of the pairs of “palps” that insects have around their mouths to aid in food handling.

I had hoped to be able to extend the lip, but the molt was too dry and fragile, and the head popped off instead. Although, this did make it easier to get a clear view of the folded lip, at least.

Someday, I’ll manage to get a picture of a nymph with the lip extended, I’ll just have to keep trying.

A note about comments: I’ve been getting a lot of spam comments for years, and until recently I gave at least a cursory look at the stuff the spam filter caught to make sure that legitimate comments weren’t getting weeded out. And I’ve confirmed that the spam filter has been doing an excellent job of discriminating between them – I never actually found a proper comment that had been erroneously marked as spam. But as of the last few months, we have to take the quality of the spam filter completely on faith. I’ve gotten over 10,000 spam comments just in the last two weeks (and 1200 today!), and there’s just no way I can give all of those even a cursory glance. So if you post a comment, and it doesn’t show up, let me know by email.

Incidentally, the spam filter says it has caught 315,717 spam comments since it was installed. This is over 100 spams for every actual comment (of which there are only 3,087). I really don’t know what the spammers think they are gaining with all this crap, but I wish they’d give it up.

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