Lateral vibrations by social wasps signal larvae to withhold salivary secretions (Polistes fuscatus, Hymenoptera : Vespidae)

The communicative meaning of an oscillation (lateral vibration) performed b y foundresses of social wasps (Polistes fuscatus) was investigated by sampl ing larval saliva from 12 postworker, single-foundress colonies and by view ing videotapes of 17 multiple-foundress (139.3 h) and 16 single-foundress ( 32 H) preworker colonies. Foundresses spent significantly more time inspect ing cells before performing a lateral vibration (LV) than after and commonl y became inactive after performing an LV. The proportion of departures temp orally proximate to LVs was significantly greater in single- than in multip le-foundress colonies. Departures and LVs were significantly more likely to perform an LV prior to departing on longer than shorter trips. In multiple -foundress colonies there was a significant temporal relationship between L Vs and departures that left the nest unattended. Larvae secreted significan tly less saliva, a nutritious substance provided to adults, immediately aft er an LV than in the absence of an LV. Contextual evidence and results of s ampling larval saliva indicate that LVs by foundresses signal larvae to wit hhold or reduce their secretion of saliva.