Red mason bee (Osmia bicornis) thermal preferences for nest sites and their effects on offspring survival

Ectotherms usually require a narrow range of thermal conditions for development; thus, parental selection of oviposition sites is crucial. In a field experiment, we investigated female solitary red mason bee (Osmia bicornis) preferences for potential nest site temperatures and their effects on offspring development. The results showed that bees detected and avoided nest sites with high temperatures (28 degrees C) and often chose cooler (24 degrees C) or ambient temperatures (average 18-20 degrees C). This is a protective behaviour because offspring survival decreases with increasing nest temperature, mostly due to mortality at the egg stage. Elevated temperatures also led to weight loss in adult bees. However, hot nest temperatures appeared to deter adults or kill parasite larvae, as the highest numbers of parasites were observed in unheated nests. We concluded that choosing the proper temperature for nests is an important element in bee life strategies, especially in warming environments.

Automated summary

In a field experiment, female solitary red mason bees were found to prefer nest sites with lower temperatures, as higher temperatures led to decreased offspring survival and weight loss in adult bees. Furthermore, hot nest temperatures appeared to deter adults or kill parasite larvae.