Evidence of associative blocking during foraging in the social wasp Vespula germanica

Abstract

While foraging, Vespula germanica usually return to abundant food sites. During this relocation behavior, these wasps learn to identify contextual cues associated with food position. We analyzed associative blocking in this species, that is, how an association with a conditioned stimulus (CS1) blocks subsequent learning when a novel stimulus (CS2) is added on a second foraging visit. Three groups of wasps (A, B, and C; total 74 individual wasps) were observed while collecting meat during one or two consecutive visits. In group A, an environmental cue (CS1) was paired with food placed at a specific site, and on the second visit, a second cue (CS2) was added while food remained in the same position. In a subsequent testing phase, CS1 was removed and the food source displaced nearby. We then recorded the number of hovers performed over the empty dish (previously baited). Group A wasps appeared to ignore the addition of CS2 on their second visit because they performed fewer hovers over the learned site. For group A, the duration of the decision-making process to finally fly toward the baited dish was shorter than when CS1 and CS2 were presented together on their first visit (group B). This is the first study to demonstrate the occurrence of associative blocking in vespids, confirming that a prior foraging experience influences subsequent food relocation in V. germanica. Our findings reveal that first learning episodes block further associations with novel contextual cues, contributing to understanding of complex cognitive processes involved in V. germanica´s foraging behavior.

Spatio–Environmental Analysis of Vespula germanica Nest Records Explains Slow Invasion in South Africa

“…Their impact on natural Mediterranean ecosystems will thus be limited (i.e., Fynbos [Mediterranean] vegetation) unless bordered by human land uses. The close association with human settlements (which aid invasion by providing additional food resources and water [28,53]) means that V. germanica will persist and likely increase in density where it occurs in suitable habitats in close proximity to human habitation. This increases the likelihood of accidental transport of mated queens, which in turn increases the chances of jump dispersal.…”

Spatial configuration learning in Vespula germanica forager wasps

“…A researcher recorded wasp behaviour by sitting .5 m away from the device. In all the experiments, we recorded the number of hovers (H) and landings (L) on the second visit during 3 min, as in Lozada and D'Adamo (2014) and Moreyra et al (2021), performed at each dish located at the entrance (E), at the previously chosen exit (CEx) and at the previously non‐chosen exit (NCEx). We considered a hovering episode each time the target forager crossed over the dish beating its wings but not landing on it.…”

“…The social wasp Vespula germanica , which has invaded several regions worldwide, shows diverse foraging patterns (D'Adamo & Lozada, 2003, 2008, 2011; Lozada & D'Adamo, 2014; Moreyra et al, 2006, 2012, 2014, 2016, 2021; Moreyra & Lozada, 2020, 2021; Taylor et al, 2012). As a social insect, when they collect abundant stationary resources, foragers make several trips from the nest to the food source.…”