Ethan Bright

Hi: It's a collembolan (springtail), probably a species in the family Isotomatidae. Two obvious characters are the furcula (the springtail mechanism) at the end of the abdomen, and an organ called a collaphore that's just anterior to the 3rd set of legs (attached to the metathorax). The prothorax is reduced, but visible, which is another character of this family. Most people don't even notice springtails, and many do not even have the springing mechanism. They are principally terrestrial, although many are found on the surfaces of water (and a few also submerge). Terrestrial springtails are really ubiquitous, and their densities can be truly staggering (sometimes tens of thousands per square meter!). Some interesting links: http://www.missouri.edu/~bioscish/entomobrya.html http://www.geocities.com/~fransjanssens/ Finally, collembolans are not recognized as insects, as they have internal mouthparts and the two features mentioned above (besides a host of internal characters); they're more closely related to Diplura and Protura. Cheers, Ethan

Hi: I think it's a larva of Chauloides (Megaloptera: Corydalidae), but I cannot make out the species based on the photos. I probably can if I have the specimen in hand. Yes, it's a dobsonfly, but it's not a hellgrammite (Corydalus spp.). Corydalus larvae have filamentous gills on the ventral portion of the abdominal segments; larvae of Chauloides and Nigronia do not. To the left there appears to be an elongate respiratory tube (there should be two, but they're markedly uneven in length), which differentiates it from Nigronia. Based on the fish (warmwater bass), it almost certainly Chauloides, as Nigronia tend to be found in cool to cold lotic environments. Indeed, Nigronia has very short respiratory tubes, which isn't a problem in oxygen saturated, cooler running waters, whereas Chauloides are long, which it probably needs in warmer, oxygen-poorer lentic waters. Here's the way to distinguish the species of Chauloides larvae: 1. a. Middorsal stripe of abdomen black; b. Length of the longer respiratory tube as long as combined middorsal lengths of Ab6-8 or Ab5-8 - Chauliodes rastricornis Rambur 1'. a. Middorsal stripe of abdomen yellowish b. Length of the longer respiratory tube as long as combined middorsal lengths of Ab7-8 - Chauliodes pectinicornis (Linneaus). One of these days I'll get some detail photos of these for my web site, Aquatic Insects of Michigan (http://insects.ummz.lsa.umich.edu/~ethanbr/aim/index.html). What ecologists do is take the larva, dissect it, and examine the contents of its gut in order to get an idea of the food web. In southeastern Michigan, I often find Chauloides rasticornis in fens and other wetlands, and they begin to move to woody debris and land to pupate towards the end of April. The adults are very impressive beasts. Cheers, Ethan

Glad to be of some assistance. I'm happy to help any time. And being a novice fisherman, I'll probably have my own set of questions for you experts! Cheers, Ethan

I've just registered to this forum, and saw there was an issue about this caddis larva. (My name and web site (Aquatic Insects of Michigan) were mentioned). Actually, it's a hydropsychid. Here's some thoughts off the top of my head... The distinctive larval characters to recognize are: 1) elongate anal legs (postrate in Rhyacophila); 2) all thoracic segments with thoracic tergites (notum) (e.g., Rhyacophila only has the pronotum completely sclerotized); and 3) abdominal segments with ventral, filamentous gills (some Rhyacophila do have this, but not like hydropsychids). I can make out some detail of the head capsule, and it's probably a species of the Ceratopsyche/Hydropsyche group. If someone could provide me the location from where it was collected, and the type of stream/river (i.e., current, depth, substrate), I can make a more educated guess. If someone has the actual specimen, I'd be glad to identify it. Send me an email ([email protected]) if you're interested. Caddis larvae of the family Hydropsychidae do not make cases, rather they use silk to construct retreats on substrate. The "entrance" to the retreat has a silk mesh, upon which the larva graze captured algae, diatoms, and sometimes dead/live invertebrates. Some retreats are very elaborate; Macrostenum zebratum fashions a retreat under rocks, and its flattened head acts as a hydraulic shunt to control seston capture or water flow across its body for respiratory needs. Others make a loose retreat with a very coarse silk net, e.g. Arctopsyche (sometimes placed in the family Arctopsychidae), which lives in rocky streams with fast current. Other groups construct fine meshes that capture finer material in slower currents. Several papers have documented habitat partitioning by larvae of different species based on current and feeding needs, which correlates with substrate/current parameters. Hydropsychids then pupate in a more secure structure. Rhyacophilids, which as larvae are free-ranging (without building a structure), also build a structure in which to pupate. Cheers, Ethan