Cold Storage of Adult <I>Gonatocerus ashmeadi</I> (Hymenoptera: Mymaridae) and Effects on Maternal and Progeny Fitness

Abstract

Storage of Conatocerus ashmeadi Girault (Hymenoptera: Mymaridae) adults at 2, 5, and 10 degrees C showed that these parasitoids do not survive at 2 degrees C for 5 d, and exposure to 5 and 10 degrees C shortens their life span. The lethal time (LT) 50 (i.e., length of storage time for 50% wasp survival) at 5 degrees C was 14 d for males and approximately 29 d for females, whereas at 10 degrees C was 32 and 39 d, respectively. Effects of adult storage at 10 degrees C on other factors indicating fitness, such as fecundity, developmental time, parasitism, emergence, and sex ratio, were examined on female wasps and their progeny at 10-d intervals for up to 60 d. Glassy-winged sharpshooter, Homalodisca vitripennis (Germar), eggs were used as hosts for propagation of this wasp and for assessing its oviposition and fecundity. Increasing adult storage time decreased the length of the ovipositional period for the maternal generation, and oviposition was decreased by 90% after 60-d storage. A significant reduction in maternal lifetime fecundity occurred after 20-d storage and in the incidence of parasitism after 40 d. We also found a carryover effect caused by storage of the maternal generation that was expressed in the F1 generation. When cold storage of the adult parents was > or = 20 d, we observed delayed development, decreased fecundity, reduced longevity, and increased male production occurring in the F1 generation. Reduced fitness of the F1 generation was also expressed as a decrease in net reproductive rate (R(o)) and an increase in mean generation time (T(c)). However, none of these deleterious effects were evident in the F2 progeny that descended from grandparents that had experienced cold storage. Damage caused by indirect chilling injury and/or induced maternal aging occurring during storage can account for the decreased fitness of maternal and F1 generations. Providing that the limits of cold tolerance of G. ashmeadi as defined in this study are not exceeded, our results show that short-term cold storage of adults could be used in a mass-rearing program.

Cold Storage of Culex pipiens in the Absence of Diapause

“…Egg production was not restored to normal levels until the F2 generation. Reduced fecundity in the progeny of insects that have undergone stress, including storage, has been previously documented many insects (Leopold 1998, Pitcher et al 2002, Ló pez and Botto 2005, Chen et al 2008.…”

Cell Position During Larval Development Affects Postdiapause Development inMegachile rotundata(Hymenoptera: Megachilidae)

“…For instance, exposing male mice to ionizing radiation induces an increase in mutation rates in their progeny out to the second generation (Dubrova et al 2000, Barber et al 2002. Long-term low-temperature storage of the adult parasitic wasp Gonatocerus ashmeadi Girault (Hymenoptera: Mymaridae) and adults of the northern house mosquito Culex pipiens L. (Diptera: Culicidae) lead to decreased fecundity in their F1 progeny (Chen et al 2008, Rinehart et al 2010. Phenotypic plasticity has been a key research focus for developing management practices for M. rotundata (Stephen and Osgood 1965;Klostermeyer 1970, 1972;Klostermeyer et al 1973;Tepedino and Parker 1988;Maki and Moffett 1986;Mayer 1994;Tepedino et al 1994;Peterson and Roitberg 2006a,b).…”

Biology of Lysiphlebus fabarum following cold storage of larvae and pupae

“…The storage of parasitoids at low temperatures for biological control purposes has been studied for many years (Schread & Garman, ; Hanna, ). The many practical advantages include increased shelf‐life (Leopold, ), convenience for transport to market (Colinet & Boivin, ), longer pre‐release periods for consumers (Leopold, ), and better synchronization of desired developmental stages for release (Hofsvang & Hagvar, ; Chen et al., ). Nevertheless, cold storage can exact physiological costs that result in high rates of mortality (Levie et al., ), and negative effects on life history and behaviour (Colinet & Boivin, ).…”