Compromised minds: cognitive decline in a social insect correlates with parasitism status

Area of Science:

• Behavioral Ecology
• Insect Parasitology
• Neuroethology

Background:

• Parasites frequently manipulate host behavior and physiology.
• Cognitive impairment is a common consequence of parasitic infections.

Purpose of the Study:

• To investigate the impact of *Xenos vesparum* infection and parasite load on olfactory learning and memory in *Polistes dominula* workers.
• To determine if parasitization and parasite burden negatively affect host cognition.

Main Methods:

• Utilized a Pavlovian conditioning assay (proboscis extension reflex) to assess olfactory learning and memory.
• Compared unparasitized, singly parasitized, and superparasitized *P. dominula* workers.
• Conditioned wasps to associate a floral odor with sucrose, followed by a memory test.

Main Results:

• Unparasitized wasps performed significantly better than superparasitized wasps in learning and memory.
• Singly parasitized wasps showed intermediate cognitive performance.
• Superparasitized wasps exhibited reduced responsiveness and increased generalization during memory recall.

Conclusions:

• Parasitization by *Xenos vesparum* negatively impacts cognitive function in *Polistes dominula*.
• Parasite load is directly correlated with the degree of cognitive impairment.
• These findings underscore the substantial cognitive costs associated with parasitism in social insects.