Vol. 1 1 3, No. 1 . January & February, 2002 U NEW RECORDS AND OBSERVATIONS FOR PARASITIC CHIRONOMID MIDGES (DIPTERA: CHIRONOMIDAE) AND THEIR MAYFLY (EPHEMEROPTERA) HOSTS 1 B. A. Caldwell 2 , N. A. Wiersema 3 ABSTRACT: An additional population of the parasitic chironomid midge genus Symbiocladius has been found on a species of mayfly (Heptageniidae) not known previously as a host in Geor-gia. In on-going studies of the mayfly fauna of Texas, another chironomid midge, Nanocladius (Plecopteracoluthus) bubrachiatus, was found on two species of Leptophlebiidae, a previously unreported association with these taxa, and provides the first report of N. bubrachiatus outside of the neotropics. The chironomid midge genus Symbiocladius, previously known in Geor-gia to the first author from only two localities, has been recently found on Leucrocuta maculipennis (Walsh) (Ephemeroptera:Heptageniidae). Specimen data is as follows: Georgia, Heard County, Town Creek, approx. 0.75 miles from confluence with Hillabahatchee Creek, 20 August 1998, leg. J. Maudsley and L. Dorn, 3 L. maculipennis larvae, 2 with Symbiocladius larva, 1 with larval exuviae in pupal case. All specimens are in the collection of the first author. A species determination was not possible since the Nearctic S. equitans Claassen and 5. chattahoocheensis Caldwell are currently inseparable except as males, with females undescribed. Also recorded from the collection site was a single mayfly larva identifi-able as L. aphrodite (McDunnough). It showed no signs of parasitism, but could possibly also serve as a host. Although L. maculipennis presence in Geor-gia is widely accepted, the record reported here is the first published for the state. S. equitans has previously been reported from L. maculipennis (as Heptagenia maculipennis) by Wiens et al. (1975) for Canada, and listed in Jacobsen(1995). The characters that separate males of S. chattahoocheensis from S. equitans are a single gonostylar megaseta and more rounded volsella (Caldwell 1984). However, southern hemisphere Symbiocladius have been shown to vary in megaseta number both among and within species (Gonser and Spies 1997): thus S. renatae Spies carries megasetae, S. wygodzinskyi Roback 1 or more, and S. aurifodinae Hynes 3 to 5. Moreover, occasional doubling of the megasetae frequently occurs in some other chironomid species, e.g. the tanypod Coelotanypus concinnus (Coquillett), see Sublette et al. (1998). Thus, a comparative examination of Symbiocladius females and additional reared 1 Received June 5, 200 1 . Accepted August 25, 200 1 . 2 1035 Lewis Ridge Circle, Lawrenceville, GA 30045. 3 4857 Briarbend Drive, Houston, TX 77035. ENT. NEWS 1 13(1): 1 1-14, January & February, 2002
BioStor
