Modification of honey bee (Apis mellifera L.) stinging behaviour by within-colony environment and age
Robert J Paxton; Clarice H Sakamoto; Frederick C N Rugiga
Environmental and genotypic influences on components of an individual honey bee's defensive behaviour have proven difficult to quantify, partly because of the methods employed in their measurement. Readiness to sting, a component of defensive behaviour, was quantified in a laboratory assay of individual worker honey bees from two colonies (one gentle, one defensive) by measuring their response thresholds to electrical stimulation which elicited stinging. At all ages, workers from the gentle colony had a higher response threshold, and therefore stung less readily, than workers from the defensive colony. Assaying of bees which had emerged in an incubator and which were then home-fostered into their natal colony or cross-fostered into the other colony allowed the relative importance of self-genotype and within-colony environment on stinging behaviour to be measured. Cross-fostered bees completely modified their readiness to sting to that of the majority of the bees in their host colony; the expression of self-genotype was masked by within-colony environment, which was allimportant in dictating stinging behaviour. The response threshold varied with age and was at a minimum around 20 days of age, probably corresponding with the age of guarding and defence tasks prior to and overlapping with the initiation of foraging. Modification of an individual's defensive behaviour by within-colony environment and its change with age should be incorporated into models of colony defence.