Oviposition behavior of Zabrotes subfasciatus females (Coleoptera, Bruchidae) under conditions of host deprivation

Abstract

Oviposition of Zabrotes subfasciatus (Boheman, 1833) on Phaseolus vulgaris (Linnaeus, 1753) was studied immediately after emergence of the adults throughout the females life and in situations of host deprivation lasting for 1 to 10 days. The number of eggs laid daily, longevity, duration of oviposition and distribution of eggs per grain were studied. The number of eggs laid per day varied significantly, with the oviposition peak in the presence of the host (control group) occurring between day 2 and day 5 of oviposition. In the absence of the host, a shift in the oviposition peak to the first day after deprivation was observed, except for the group deprived for one day which showed a peak between days 1 and 4 after introduction of the host. The distribution of the eggs per grain in the control group and in the groups deprived of the host for 2, 5, 8 and 10 days, a larger egg aggregation was observed for all deprived groups compared to the control group

Oviposition behavior of wild Zabrotes subfasciatus (Coleoptera, Chrysomelidae) females deprived of the host Phaseolus vulgaris (Fabaceae)

“…Consequently, we observed more aggregates in the deprived females. They concentrated oviposition in the 1 st seed that they found at 29° C and 70 % R. H. (SPERANDIO & ZUCOLOTO, 2004). ROSENHEIM & ROSEN (1991) also observed that in the A. lingnanensis parasitoid, the females with larger loads of eggs laid larger aggregates.…”

“…This can be due to the fact that the deprived females probably contained a large load of eggs in their ovaries (SPERANDIO & ZUCOLOTO, 2004); this may have led the females to oviposit therefore avoiding a more intense resorption of their eggs, since in pro-ovigenic species, egg resorption can markedly reduce fecundity since eggs are not replenished (FLEURY & BOULETREAU, 1993). Notwithstanding, ROSENHEIM & ROSEN (1991) shows that the manipulation period with the host was inversely related to the load of eggs in the parasitoid A. lingnanensis, as well as of each component of the activities that comprise host manipulation, including preparation for oviposition, post-oviposition period, grooming and rest.…”

“…obs.). With less time to lay the eggs, aggregation would be more advantageous, since the females would spare time, avoiding the recognition of each seed individually (SPERANDIO & ZUCOLOTO, 2004).…”

“…Experiments with host deprivation for wild Z. subfasciatus, using P. vulgaris variety Rosinha as host, have shown that the temporary deprivation period (2 to 10 days) of the host alters the oviposition peak for the 1 st day after its inclusion, as also aggregates more eggs in relation to the P. vulgaris seeds (SPERANDIO & ZUCOLOTO, 2004). However, the frequence the females manifested different kinds of behavior was not observed.…”

“…In the Bruchinae subfamily, the adult weevils usually deposit and adhere their eggs in the bean seed surface apparently at random, but the Z. subfasciatus females lay some of their eggs in the seed surface in groups of 2, 3, 4 or more eggs (UTIDA, 1967;SARI et al, 2003;SPERANDIO & ZUCOLOTO, 2004). Therefore, as the adults in general do not feed themselves (CARVALHO & ROSSETTO, 1968) the adult females "determine" the amount of available resources for each of the descendants in potential (DENDY & CREDLAND, 1991); probably, they develop the behavior of maximizing their fitness, for instance, distributing a higher amount of eggs in the largest hosts (YANG & HORNG, 2002;COPE & FOX, 2003;SZENTESI, 2003).…”