Seasonal variation in defense behavior in European and scutellata-hybrid honey bees (Apis mellifera) in southern California

Nest defense in the honey bee (Apis mellifera) is a complex collective
behavior modulated by various interacting social, environmental, and
genetic factors. Scutellata-hybrid (“Africanized”) honey bees are usually
considered to be far more defensive than European honey bees which are
therefore preferred for commercial and hobbyist beekeeping. In the most
recent zone of scutellata hybridization, the southern USA, the degree to
which this defensiveness differs among current strains, and the extent to
which defensiveness varies across a season has not been measured. We
quantified the levels of A. m. scutellata ancestry in colonies and
conducted a seasonal assessment (May through November) of colony nest
defensiveness in feral scutellata-hybrid and managed European honey bee
(A. mellifera ligustica) hives at two apiaries in Southern California.
Standard measures of defensiveness were low in both scutellata-hybrid and
European colonies during May. Defensiveness increased during the later
months of the study in scutellata-hybrid colonies. Most measures of
defensiveness did not increase in managed colonies. Defensiveness in the
scutellata-hybrids appears lower than what has been previously documented
in Brazil and Mexico, possibly due to their lower proportion of A. m.
scutellata ancestry.