A quantitative threshold for nest-mate recognition in a paper social wasp

Area of Science:

• Chemical ecology
• Animal behavior
• Social insect biology

Background:

• Nest-mate recognition is crucial for social insect colony defense against intruders.
• Cuticular semiochemicals mediate aggression between resident and intruder social insects.
• The relationship between cue quantity and response intensity is often assumed but rarely tested.

Purpose of the Study:

• To test the hypothesis that increased cuticular hydrocarbon (CHC) quantity elicits a stronger aggressive response in social wasps.
• To investigate the role of CHC quantity in the chemical insignificance strategy of social parasites.
• To examine the chemical recognition system in the social wasp Polistes dominulus.

Main Methods:

• Experimental manipulation of cuticular hydrocarbon (CHC) amounts on foreign females.
• Observation of resident foundress behavioral reactions (aggression) to varying CHC loads.
• Utilizing Polistes dominulus as a model system, known for its social parasites.

Main Results:

• Different amounts of cuticular hydrocarbons (CHCs) from foreign females evoked quantitatively distinct behavioral reactions in resident foundresses.
• A threshold in the chemical recognition system was identified, correlating CHC quantity with elicited response.
• The findings support the chemical insignificance hypothesis in a Polistes wasp host-parasite system.

Conclusions:

• The quantity of cuticular hydrocarbons (CHCs) plays a significant role in nest-mate recognition and aggression in Polistes wasps.
• The chemical insignificance hypothesis is supported in this host-parasite system, explaining reduced semiochemicals in some parasites.
• While supporting the hypothesis, other explanations for semiochemical reduction should not be disregarded.