Egg Maturation and Events Leading to Embryonic Development in the Sawfly, Athalia rosae (Hymenoptera)

All members of the insect order Hymenoptera reproduce parthenogenetically: most species reproduce by arrhenotoky (haploid males develop from unfertilized eggs and diploid females from fertilized eggs) and some do so by thelytoky (diploid females develop from unfertilized eggs) or cyclical parthenogenesis (White, 1973; Crozier, 1975; Suomalainen et al., 1987; Luck et al., 1993). Because of these unique modes of reproduction and also because large numbers of species in the order have unique and/or economically important characteristics such as sociality and parasitoidism, the Hymenoptera, especially those of the higher suborder Apocrita (bees, wasps, ants, etc.), have been extensively studied in terms of genetics, ecology, developmental biology, and evolution (see DuPraw, 1967; Rothenbuhler, 1975; Cassidy, 1975; Winston, 1987; Gauld and Bolton, 1988; Ross and Matthews, 1991; Moritz and Southwick, 1992; Wrensch and Ebbert, 1993). Less is known about species of the lower suborder, Symphyta (sawflies, horntails, etc.).