Longevity of worker honey bees (Apis mellifera Linnaeus) on the Darling Downs, Queensland

Abstract

A study of the expected life span of worker honey bees (Apis mellifera Linnaeus) emerging at different times of the year was undertaken, The effects of sixteen internal and external hive factors operating on three honey bee development stages were measured in order to determine thier influence on one lifespan of worker honey bee. Multiple regression equations were fitted to express the average life span as a function of 14 of the factors. An equation was formulated representing average life span as a function of four factors with a Coefficient of Determination of 62%, no significant improvement in fit was obtained by including a fifth factor.Average life spans were determined for each of the 34 groups of bees examined. Longest lived bees were autumn bees (emerging during April) with an average life span of 66.3 days, the shortest lived bees (excluding one group with a high incidence of Nosema disease) were spring bees (emerging during November) with an average life span of 21. 8 days. Wide variability of life span of individual bees within each group was found e.g. bees emerging in March lived an average of 44.6 days while the longest lived individual bees emerging during that month lived about 136.5 days. In contrast bees emerging in September had an average life span of 24.8 days with the longest lived individual bees emerging in that month surviving for about 59.5 days.Nosema apis Zander (Nosema disease) incidence was significant (P>0.01) and negatively correlated against average life span. One group of bees with a N. apis incidence of 63.7 x 106 spores per bee had an average life span of 17.7 days. Nosema disease is now considered to be of greater economic importance than previously believed.The effects of the availability of increasing quantities of pollen on the average life span of bees when in their larval stage and during their foraging stage were significant (P<0.01) and negatively correlated. The effects of pollen were found to be the major single factor affecting average life span.An attempt has been made to explain these unexpected results.The on average life span of foraging for nectar was found to be minimal.Increasing areas of unsealed brood were found to reduce (P<0.01) average life span of bees of house bee (nursing) age at the time of brood increase.Factors causing a condition known as Winter Dwindling in hives were expected to be isolated and identified. This did not occur. No factor was found to operate directly on a cause and effect basis. Complex inter-relationships were found to operate on all factors considered.