Polymorphism in the Surface Water Bugs (Hemipt.-Heteropt: Gerroidea)

Differences in Survivorship, Development Rate and Fertility Between the Longwinged and Wingless Morphs of the Waterstrider, Limnoporus canaliculatus

“…Guthrie (1959) and Poisson (1924) reported that the development rate of the short-winged morph was faster than the longwinged morph in Gerris asper and G. lacustris, respectively, similar to the results obtained in this study. However, neither author performed statistical tests on the data, and Poisson (1924) did not report sample sizes in his study (Guthrie [1959] did not report variances of his development rate data and therefore standard errors could not be computed). Neither Anderson (1973) nor Vepsalainen (1973) observed any difference in development rate between morphs of Gerris lacustris, but the tests were weak.…”

“…Although a number of studies have compared development rates of various gerrid morphs (Poisson, 1924;Guthrie, 1959;Anderson, preliminary results, 1973;Vepsalainen, 1973Vepsalainen, , 1974, no conclusions can be drawn from these studies. Guthrie (1959) and Poisson (1924) reported that the development rate of the short-winged morph was faster than the longwinged morph in Gerris asper and G. lacustris, respectively, similar to the results obtained in this study.…”

“…Although a number of studies have compared development rates of various gerrid morphs (Poisson, 1924;Guthrie, 1959;Anderson, preliminary results, 1973;Vepsalainen, 1973Vepsalainen, , 1974, no conclusions can be drawn from these studies. Guthrie (1959) and Poisson (1924) reported that the development rate of the short-winged morph was faster than the longwinged morph in Gerris asper and G. lacustris, respectively, similar to the results obtained in this study. However, neither author performed statistical tests on the data, and Poisson (1924) did not report sample sizes in his study (Guthrie [1959] did not report variances of his development rate data and therefore standard errors could not be computed).…”

“…The only differences which have been documented are in overwintering ability between morphs of Gerris aper (Ekblom, 1941) and G. lacustris (Vepsalainen, 1974) and in the rate of development of reproductive maturity between morphs of G. lacustris (Anderson, 1973). Numerous other traits such as skating ability, various aspects of female fertility, and duration of nymphal development have been investigated in several species, but no signifi cant morph-associated variation in these traits has been documented (Poisson, 1924;Brinkhurst, 1959;Guthrie, 1959;Anderson, 1973;Vepsalainen, 1973Vepsalainen, , 1974. However, in these studies, sample sizes were very small, and only enormous differences in these traits would have been documented (see Discussion); studies employing sample sizes which would contain suffi cient statistical power to discern realistic variation in fi tness among the morphs have yet to be undertaken.…”

GENETIC AND ENVIRONMENTAL DETERMINANTS OF WING POLYMORPHISM IN THE WATERSTRIDER LIMNOPORUS CANALICULATUS

“…Ekblom (1941Ekblom ( , 1949, on the other hand, concluded that wing polymorphism was under polygenic control in G. asper. Results of subsequent genetic studies in G. lacustris and G. lateralis by Vepsäläinen (1974a) and G. lacustris and G. asper by Guthrie (1959) were purported to corroborate Poisson's single locus model in a modifi ed form. Although recognizing that morph determination is infl uenced by environmental factors such as photoperiod and temperature, both Guthrie (1959) and Vepsäläinen (1974a) reported that under certain environmental conditions results of their crossing experiments were consistent with a single locus or supergene (Vepsäläinen, 1974a) model.…”