RufusAtticus

At my old apartment I actually watched as a copperhead caught a fish from the bream beds by my deck.

Doubting Didymus

Why focus on mouthparts? I imagine these adults would have entire (or possibly vestigial) digestive systems that never get put to use. I might be wrong, and the metamorphosis completely removes the whole digestive system, but I'd put good money on there being some useless remnants.

Non-praying Mantis

More than likely the mouthparts would be vestigial. Although, the male dobsonfly (of the order Neuroptera) does use its mandibles for fighting over females. Some other species probably use the mandibles for grooming or getting out of coccoons, but mostly the mouthparts are small and vestigial. I would guess (in your words: put good money on), Doubting Didymus, that the digestive tract is also reduced and vestigial in these adults, although I have no idea.

NPM

MrDarwin

I was an entomologist in another lifetime, so if I stretch my memory to its very limits I can offer my guesses as to the orders in which (at least some) species have non-feeding adults:

Ephemeroptera
Plectoptera
Homoptera*
Diptera
Coleoptera
Neuroptera (pretty sure a few)
Lepidoptera
Trichoptera
Strepsiptera

That makes 8--now I'm curious to see if I got them all right! (Although I wouldn't be surprised to find a few odd species in even more orders.)

Note also that most are in the Holometabola--it seems to be a function of metamorphosis and the extreme differences between larvae and adults (I would call Ephemeroptera and Plectoptera honorary Holometabola because the transition from fully aquatic to fully terrestrial life stages is pretty abrupt and dramatic, even if it doesn't technically fulfill the definition).

*edited to add Homoptera because Duvenoy is right about cicadas.

MrDarwin

Here's another tidbit about mayflies that Oolon may find useful: they are the only (living) insects that molt after having functional wings. They emerge from the water in their penultimate instar (dun) with wings and can fly (but poorly), but then molt again within a matter of hours to become a fully mature adult that is a good flier and capable of breeding. Why not do like all other aquatic insects do, and go straight from the aquatic nymph to the fully functional winged adult????

*edited to note that NPM beat me on both counts. I really gotta start reading these things before I post! Although I do list Coleoptera, and NPM didn't. Bottom line, I think we can probably come up with more than 8 orders--there's a lotta bugs out there!

MrDarwin

There are several moths that have non-functional mouthparts as adults (although oddly enough, their mouthparts go through the metamorphosis from chewing to sucking anyway--a doubly bad design!). I'm pretty sure all the Saturniidae (giant silk moths) fall into this category, as well as various members of other families (Noctuidae, Geometridae, etc.).

Non-praying Mantis

Thanks, MrDarwin! I didn't know there were so many species of non-feeding adults in Lepidoptera, especially a "popular" family like Saturniidae.

NPM

Blinn

Doov,

Check out this site on periodical cicadas. I became interested in periodicals when I found several 3 years ago. They're quite different in appearance from the dog-day cicadas I'm used to. When I found these critters, I was aware that there had been a brood emergence in SE Ohio/W Va. the year before. Was central Ohio having an emergence in 2000? Looked it up - nope, not due until 2004. What was going on? Turns out that a portion of a brood often emerges 4 years early. Some are hypothesizing that those individuals are skipping the last instar and emerging early, possibly leading to the birth of new broods. Cool stuff.

Duvenoy

Thanks Zetek! An interesting site.

It appears that I'm wrong about cicacas not feeding as adults. From the site:

I'm going to look for more info on this, and the next one I find, I'll check it out.

Again, thanks!

doov

Peez

But only one includes true bugs!

Peez