Self Assessment in Insects: Honeybee Queens Know Their Own Strength

Abstract

Contests mediate access to reproductive opportunities in almost all species of animals. An important aspect of the evolution of contests is the reduction of the costs incurred during intra-specific encounters to a minimum. However, escalated fights are commonly lethal in some species like the honeybee, Apis mellifera. By experimentally reducing honeybee queens' fighting abilities, we demonstrate that they refrain from engaging in lethal contests that typically characterize their reproductive dominance behavior and coexist peacefully within a colony. This suggests that weak queens exploit an alternative reproductive strategy and provides an explanation for rare occurrences of queen cohabitation in nature. Our results further indicate that self-assessment, but not mutual assessment of fighting ability occurs prior to and during the agonistic encounters.

A scientific note on the lack of effect of mandible ablation on the synthesis of royal scent by honeybee queens

“…We have thus found no evidence for a feedback mechanism that affects the synthesis of pheromone when the release site has been manipulated. Our results support the idea that experimentally established polygyny by mandible ablation (Dietemann et al 2008) is not due to changes in mandibular pheromones.…”

“…It is unlikely that manipulation of the mandible affects this gland's secretion, but whether they are involved in the establishment of polygynous honeybee colonies should be investigated. Excluding changes in pheromonal secretion following ablation supports the hypothesis that experimental polygyny in honeybees is a result of self-assessment of the fighting ability of queens (Dietemann et al 2008).…”

“…These colonies functioned normally and were used as supporting units for the faster build-up of productive colonies and for production of royal jelly in China (Zheng et al 2009b). Observations also revealed that queens with a third to a half of one mandible ablated had normal levels of activity compared to intact queens, but they refrained from engaging in lethal contests (Dietemann et al 2008). Mandibles are the release site of the mandibular glands pheromone.…”

Queen introduction into the queenright honey bee colony

“…Both introduced queens were with intact mandibles to eliminate their inability to potential fi ghts contrary to Dietemann et al (2008).…”

“…In order to decrease the fi ghting ability of queens, two thirds of one of their mandibles was cut off with scissors (Dietemann et al, 2008). Such ope rated queens did not contest with each other (even 3 queens).…”