The effect of habitat selection on offspring performance in the giant water bug Belostoma bifoveolatum

Abstract

The selection of breeding habitat is crucial for many ectotherms inhabiting aquatic environments. Giant water bugs offer an excellent model for analysis of how temperature affects breeding habitat selection and reproductive success. This work focuses on whether wetland temperature influences habitat selection and offspring success in the giant water bug Belostoma bifoveolatum Spinola, 1852. To determine breeding habitat characteristics of B. bifoveolatum, 21 wetlands lying on the environmental gradients of canopy cover and altitude were sampled in spring; water temperature was monitored and the presence or absence of adult belostomatids, incubating males, and nymphs were recorded. Several environmental variables were measured in sites where males incubated eggs and were compared with those from control sites. Field experiments were also conducted to evaluate the effect of site choice on hatching success. Belostoma bifoveolatum was found up to 1545 m above sea level, but reproduction was observed only in the warmest temporary wetlands, with low forest cover, from 300 to 1000 m above sea level. Incubating males were found in the shallowest and warmest sites within the wetlands where egg incubation time was shortest and hatching success highest. The selection of breeding habitat and incubation site, along with parental care, constitute important adaptations in B. bifoveolatum and could explain its success in this cold region.