The Disappearance of Eggs and Larvae from the Nests of the Mischocyttarus (Monogynoecus) montei Zikán (Hymenoptera: Vespidae), Especially in Autumn and Winter: Can it Mean an Adaptive Cannibalism to Ensure the Survival of Colonies?

Abstract

The aim of this study was to verify the disappearance of eggs and larvae from the nests of the Mischocyttarus (Monogynoecus) montei, especially in autumn and winter, and at the same time, to discuss about the cannibalism as the main reason for survival of the colonies during the unfavorable climatic conditions. Forty one colonies were studied during the seasons of the year, period from March in 1999 to September 2000. A total of 314 disappearances of immature individuals was counted, corresponding to 95 eggs (27,1 %) and 229 larvae (72,9 %). The results showed that the disappearance of eggs and larvae were significantly higher during the autumn and winter . In addition, the disappearance rate of larvae increases with the falling of rainfall and of temperature, in autumn and winter. There were no relation between the disappearance of eggs and any climatic factors. From the total number of disappearances, small larvae disappeared from the cells at a higher frequency (55,9%, n = 128) than medium (18,3%, n = 42) and large (25,8%, n = 49) size larvae. It is probably that these immatures (eggs and larvae) were cannibalized due to scarcity of prey and nectar under unfavorable climatic conditions, especially during the cold and dry periods of the year.

Social life results in social stress protection: a novel concept to explain individual life‐history patterns in social insects

“…Though brood cannibalism may be an emergency response to severe nutritional stress in some instances (Schmickl & Crailsheim, 2001), it appears to be part of the normal colony life cycle in many social insects. For example, in paper wasps of the genera Polistes and Mischocyttarus , brood cannibalism commonly occurs at the end of the growing season (Kudô & Shirai, 2012; Murakami, Sakamoto & Shima, 2016) and may provide an important nutritional resource for gynes preparing to overwinter.…”