PROC. ENTOMOL. SOC. WASH. 83(4). 1981, pp. 607-619 BIOLOGY AND IMMATURE STAGES OF PELINA TRUNCATULA, A CONSUMER OF BLUE-GREEN ALGAE (DIPTERA: EPHYDRIDAE)' B. A. FooTE Department of Biological Sciences, Kent State University, Kent, Ohio 44242. Abstract. — Information is presented on the life cycle and feeding habits of Pelina truncatula Loew, a common and widely distributed shore fly whose larvae feed on colonies of the blue-green algal genus Cylindrosper-miim. The egg, mature larva, and puparium are described and illustrated. A key is given that distinguishes the immature stages of P. truncatula from those of Lytogaster excavata (Sturtevant and Wheeler), another common inhabitant of Cylindrospermuiu colonies. Containing at least 1200 species, the family Ephydridae is one of the largest entities within the acalyptrate Diptera. It is generally placed close to the family Drosophilidae in the superfamily Drosophiloidea (Griffiths, 1972). Although larvae of both families are basically microphagous in feed-ing habits, the drosophilids mostly utilize yeasts and other heterotrophic microorganisms, whereas the ephydrids primarily ingest autotrophic algal cells. Foote (1979) discussed the utilization of algae by different groups of Ephydridae and emphasized that certain species are trophically generalized (e.g. Scatella stagnalis (Fallen); Zack and Foote, 1978), while others are quite specialized (e.g. Parydra quadrituherculata Loew; Deonier and Re-gensburg, 1978). This is the third contribution in a series dealing with the utilization of blue-green algae by ephydrid larvae. The first paper (Foote, 1977) presented j general observations on the feeding habits of 12 species, and the second 1 elucidated the life cycle and natural history of Lytogaster excavata (Stur-' tevant and Wheeler), a consumer of soil-inhabiting blue-green algae belong-I ing to the genus Cylindrospermum (Foote, 1981). The present paper is con-' cerned with another grazer of Cylindrospermum, Pelina truncatula Loew, I a common and widely distributed species in shoreline and wetland habitats. j Information is given on the life cycle and larval feeding habits, along with I descriptions and illustrations of the egg, mature larva, and puparium. ' Research supported by NSF grant DEB 79-1224]
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