Coragyps

A couple of minutes with Encyclopedia Brittanica (remember those?) gave me the impression that the Ephemoptera are the order with no functional mouthparts as adults, but that several other sorts of insects - caddisflies, moths - have non-functional mandibles as adults, but feed with another apparatus. Moths and butterflies, for instance, chew things as larvae but have a "straw" for feeding as adults. Britannica did mention caddisflies chewing out of their coccoon.

Non-praying Mantis

Entomologist in the hizzzouse!

OK, the orders which have species which have adults that do not feed are probably:

Ephemeroptera (mayflies - these often live about a week, not a day)
Plecoptera (stoneflies - some of these live about two weeks)
Homoptera (cicadas and probably some scale insects)
Neuroptera (probably antlionflies or owlflies)
Strepsiptera (twisted-wing parasites - females are parasitic on several other orders of insect and males probably don't feed)
Diptera (fruit flies live about 1 day to a week as adults)
Trichoptera (insects similar to moths)
Hymenoptera (some parasitoid wasps - they lay eggs on other insects and the larvae kill their host as they develop)

I'm not sure about the Neuroptera and Hymenoptera, but the others certainly do have non-feeding adults.

Insects, with their metamorphosis can separate their larval/nymph stages ecologically from the adult stage because they have different forms. Larvae and nymphs main purpose is to feed, and adults main purpose is to breed. Feeding is only necessary in adults that live a relatively long time and/or require additional food resources before laying eggs.

NPM

scombrid

I know of several aquatic insects that fit the bill. These have feeding aquatic larval stages and short lived breeding adult terrestrial stages. Some larvae lived for years in the stream before the final molt.

Ephemoptera (mayflies)

Trichoptera (caddis flies)

Plecoptera (stone flies) 1,500species, some feed others don't

Neuroptera (sub> Megaloptera). I'm thinking specifically of the Dobson Flies. The larvae (hellgramites) are a popular bait for stream fishing, get quite large, and are voracious predators in the stream (bight pretty hard too when captured for bait). Adults retain the huge mandibles. Sexual selection seems to be at play here as the males have ENORMOUS mandibles (you sure got a purty mouth)

Well, that's four but I'm a fishologist so somebody else is going to have to step in with terrestrial buggers. Are there any non-feeding Lepidopterans (butterflies, moths)?

Non-praying Mantis

Actually, larvae do have mouthparts, but they are usually of the chewing type. Larvae live to feed, it's the main purpose for the stage. They can also use their mouthparts for injecting poison (certain water bugs), or for getting out of coccoons, or even for shaping coccoons (larvae have silk glands in their mouths).

NPM

Non-praying Mantis

I'm not certain, but it is certainly possible. I do know that some adult lepidoptera have chewing mouthparts (clothes moths) and not the normal drinking-straw-like sucking mouthparts.

NPM

Non-praying Mantis

IIRC, Nope. If the mandibles are non-functional, then they do not feed. For mouthparts such as piercing-sucking, the mandibles are heavily modified to be part of the modified mouthpart.

NPM

Non-praying Mantis

I'll second that. I have actually seen mayflies molt in front of my eyes. Mayflies are the only insects that molt when they have wings. The stage that has wings, but does not mate, is called a sub-adult.

All other insect orders with wings have them functional only as adults.

NPM

Non-praying Mantis

It is a good strategy, many insects use it.

Actually, there is an insect that does not crap as a larva! It is a member of the order Neuroptera, and it feeds on fresh water sponges in streams and lakes. It has no functional anus as a larva, and it only gets to crap when it emerges from its cocoon as an adult!

Talk about character building...

NPM

beastmaster

So, NPM, is it your opinion that these adult mouthparts (in the orders you have identified) have no purpose whatsoever? No use for fighting, for manipulating objects, for assisting in communication through the tasting/smelling of chemicals like pheremones, etc.?

Duvenoy

(chuckle) check out my bio.

I currently have ten 'hot' snakes in residence. The coppers are the mildest of them. These are used for educational presentations. Most came to me from doing snake removal or were given to me under duress: Man buys pretty snake; wife finds out what snake is, "You ain't keepin' that @%#&*! thing here!"; man calls snake man to come get it. I've a gorgeous, Arican puff adder aquired just that way. And I caught a couple of them in the field. Whilst pretty much pampered, they are certainly not pets.

This thread has got me to thinking about a subject I'd not considered in years. Aquatic insects are fascinating and I don't know nearly enough about them. I guess I'll do a little research -- thank Quetzacoatl for Google!

doov