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style='font-siz I see a few of these wasps cruising very slowly over my "lawn" (actually mostly moss) in Halifax in late August most years. Of some related interest is the extremely overdeveloped tibia of the hindlegs of these female pelecinids, nicely visible as the seemingly swollen part both on Cindy's nice photo and on the one in the Wikipedia article that Randy listed, link copied below. Most insects have a vibration-sensitive organ in each tibia (the SGO or subgenual organ = the under-the-knee organ). The SGO in the back legs of cockroaches is extremely sensitive -- it can detect vibrations on the order of 1 nanometer (= a billionth of a meter) at frequencies around 1 kilohertz. As the pelecinid's hind tibia is much more developed than the roach's, it could be specialized to detect and localize vibrations made by the June beetle larvae moving underground, in whatever frequency band these larvae emit (not measured as far as I know, and I'm not sure technically how you'd do it in soil). Perhaps they use their tibial SGOs to locate the appropriate place to insert the abdomen into the soil. Some years back I sent a couple of pickled legs to a German academic who had a mutual interest in pursuing this possibility, but as far as I know, he never got round to doing anything with them. Incidentally, language purists may wish to scrutinize the one-paragraph Wikipedia article on this for a creative re-definition of the word "attenuated", used in reference to the extreme length of the pelecinid's abdomen. Steve, Halifax. **************************************** Quoting Christopher Majka <c.majka@ns.sympatico.ca>: > Hi Cindy and Randy, > Pelecinus polyturator (Drury) is an endoparasite of the larvae of > June Beetles (Phyllophaga). The very long abdomen is used to extend > into the soil to locate the larvae on which the female deposits eggs. > > In tropical populations both males and females are present and the > species is normally bisexual. In temperate regions males are almost > non-existent and females reproduce by parthenogenesis (the species > occurs from Canada to Argentina). They are very striking and > beautiful wasps. > > Cheers, > > Chris > > On 11-Aug-08, at 3:06 PM, Randy Lauff wrote: > >> This is a pelecinid wasp, a female. I don't know much about them, >> but males are tough to find. Here's the Wikipedia entry: >> >> http://en.wikipedia.org/wiki/Pelecinus >> >> >> >> 2008/8/11 Cindy Creighton <creighton@eastlink.ca> >> Hi All: >> >> >> We were over at a friend's place in Greenwood on Saturday and saw >> this weird bug in the garden and Jeff took a photo of it. The tail >> (which looks like it has a stinger) reminded me a bit of a >> scorpion. Does anyone know what this is? >> >> >> http://www.pbase.com/image/101524127 >> >> >> Cheers, >> >> Cindy >> >> >> >> >> Randy >> _________________________________ >> RF Lauff >> Way in the boonies of >> Antigonish County, NS. > > Christopher Majka > Nova Scotia Museum, 1747 Summer St., Halifax, Nova Scotia, Canada B3H 3A6 > c.majka@ns.sympatico.ca > >
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