Larval Ecology of Some Lower Michigan Black Flies (Diptera: Simuliidae) With Keys to the Immature Stages

The species composition, succession, and seasonal abundance of -immature simuliids ocmrrhg in the Rose Lake Wildlife Research Area in lower Michigan are presented. Selected physical and chemical characteristics of streams in the above area were examined and compared in relation to faunal distributions. Comparisons of species differences between permanent and temporary streams were made utilizing the functional group concept based on feeding mechanisms. Keys and illustrations are presented for the identiiication of larvae and pupae of four genera (Prosimulium, Simulium, Stegopterna, Cnephia) and 19 species of Simuliidae known to occur in lower Michigan. Two species, Cnephia ornithophilia and Simulium vemum, were recorded for the first time in Michigan. Few studies have been conducted on the black flies (Diptera: Simuliidae) of Michigan. Wu (1931) studied various aspects of the biology and life history of several Simulium species in northern lower Michigan. Laboratory experiments were also conducted on factors influencing larval black fly distribution in streams. She concluded that larvae had a def i i te requirement for current and that high dissolved oxygen content of the water was w t the determining factor for their presence or absence. Gill and West (1955) recorded biological observations on several species of black flies in Michigan's Upper Peninsula. Tarshis (unpubl data, 1963-1973) and Desser et al. (1978) investigated the role of black flies in waterfowl disease transmission in the Upper Peninsula (mainly Seney National Wildlife Refuge), where the former author recorded 55 species (I. B. Tarshis, pers. wmm.). Ross and Merritt (1978) studied the population dynamics of five species of black flies in the Lower Peninsula and their responses to selected environmental factors. They found that stream temperature was the most important physical factor -regulating larval black fly population dynamics, determining hatching time and developmental rates. This study was initiated to: (1) determine the species composition, succession, and seasonal abundance of immature simuliids in the Rose Lake Wildlife Research Area in lower Michigan; (2) examine selected physical and chemical characteristics of streams in the above area in relation to faunal distributions; and (3) provide a standard key to the major genera and species of immature black flies found in Michigan's Lower Peninsula. Prior to this paper, there have been no published keys to Michigan Simuliidae. MATERIALS AND METHODS Extensive collections of Simuliidae were made at the Rose Lake Wildlife Research Area (RLWRA) from March, 1975, through May, 1977, (Fig. 1, Table 1). This 1350 ha research area in Clinton and Shiawassee counties, Michigan, is located 13 km northeast of the Michigan State University campus. In addition, over 4000 specimens of black flies (mainly Simuiium spp.) were sorted and identified from stream invertebrate survey collections made throughout the Lower Peninsula during June through September l~esea rch partially supported by Regional Black Fly Research Project NE-118 and the Michigan State University Agricultural Experiment Station, Journal Article No. 8675. 2 ~ e ~ t . of Entomology, Michigan State University, East Lansing, MI 48824. 3Resent address: Dept. of Entomology, University of Georgia, Athens, GA 30602. 4~iosystematics Research Institute, Agriculture Canada, Ottawa, Ontario, Canada. 1 Merritt et al.: Larval Ecology of Some Lower Michigan Black Flies (Diptera: Simul Published by ValpoScholar, 1978