Feeding strategies and intraspecific competition in German yellowjacket (Vespula germanica)

Abstract

The German yellowjacket (Vespula germanica) is an opportunist predator and a scavenger, whose eclectic diet also includes honey, brood, dead and live honey-bees. There is no evidence in this species of coordinated attacks against bees involving other conspecifics, although intraspecific competition has been already reported between two or more individuals during feeding. Our aim was to gain further knowledge on the feeding behavior of V. germanica in order to evaluate its role in an apiary. Sight observations of predation and necrophagy behaviors were carried out at the ground level near hives. We also investigated how intraspecific competition can influence the feeding display in this species. Our results confirm the major role of the German yellowjacket as a scavenger, because its diet is based mostly on bee carrions. Intraspecific competition during feeding was sometimes observed. When these events occurred, the interference of another wasp led to the bee escaping only in three cases. Our study also revealed that intraspecific competition events increase when the resource is fresh (predation vs necrophagy), and that the number of competing wasps was significantly higher when the food consisted of pupae and drones, compared to adult bees. When competition involved two individuals (the most frequent case), the winner was frequently the first wasp to reach the resource in both predation and necrophagy events. This suggests that the energy invested in foraging or predating activity and in defence of prey is usually rewarded.

Testing muzzle and ploy devices to reduce predation of bees by Asian hornets

“…In fact, whereas several other insects species are highly social and tend to cooperate (Fontich & Sardanyés, 2009;Schwagmeyer, 2014), V. velutina individuals appear to be unable to coordinate their hunting. Similar aggressive behaviour has often been observed in Vespidae (Itô, 1985;Parrish & Fowler, 1983;Pusceddu et al, 2018) but never in Asian yellow-legged hornet foragers. Surprisingly, while we observed up to 14.…”

Deciphering the diet of a wandering spider (Phoneutria boliviensis; Araneae: Ctenidae) by DNA metabarcoding of gut contents

“…Predator-prey interactions are a main driver of natural selection, population dynamics, food web structure, community assembly, and ecosystem functioning (Portalier et al, 2019;Severtsov & Shubkina, 2015;Start et al, 2020). Spiders are among the most abundant predators in terrestrial ecosystems, playing an important role in controlling prey species populations (Betz & Tscharntke, 2017;Michalko et al, 2019;Pekár et al, 2011;Pusceddu et al, 2018). Almost all spiders are carnivores, feeding predominantly on arthropods including, to a lesser extent, other spiders (Klaus Birkhofer & Wolters, 2012;Nyffeler, 1999;Pekár & Toft, 2015).…”

Using verified citizen science as a tool for monitoring the European hornet (Vespa crabro) in the island of Sardinia (Italy)

“…In fact, the introduction of alien generalist predators may impact the food web, by modifying the interspecific relationships through predation and/ or competition (Snyder and Evans 2006;Bourdeau et al 2011). This is the case for V. germanica, which is a harmless species to honeybees in its native region (Pusceddu et al 2018), but becomes a threat in areas where it is introduced (Lester and Beggs 2019). Despite having a preference for bees as food source (Cini et al 2018), V. crabro is known as a mild predator of Apis mellifera in Europe (Morse and Nowogrodzki 1990), being subjected to protection measures in Germany since 1987 (Monceau et al 2015b).…”