Analysis of Tropilaelaps clareae populations from the debris of Apis dorsata and Apis mellifera in Thailand.

The analysis of Trapilaelaps populations found in the debris of Apis dorsata and Apis mellifera in northern Thailand, the number of adult mites recovered, the sex ratios, and the number of injured mites are presented. To collect the debris and dead mites from A. dorsata nests hanging on tree limb and under the roof (eaves) of a house, a plastic sheet (2 m x 2 m) was placed 1 m below each nest secured and raised on bamboo poles. The collections ended when the bees left the combs. Debris from A. mellifera colonies were collected from the hive bottom board. The mite counts were highest 5 days before the bees left the combs, indicating that more mites emerged with last emerging brood and the bees had stopped rearing brood in preparation of migration. One deserted comb contained a few capped brood and some young bees on the comb not able to follow the migrating colony. The numbers of injured mites found in the debris of A. dorsata were surprisingly high: 72.5-76.0 % of the mites showed various body injuries. In contrast, T. clareae adults recovered from the debris of A. mellifera hives showed no damages attributed to the bee activity. The data gave strong evidence of A. dorsata bees damaging the mites as a specific defense behaviour against their enemies similar to that of A. cerana. Although this behaviour has not been observed on A. dorsata it can be accounted for the large numbers of injured T. clareae adults. Mites previously collected from capped brood cells showed no body injuries. The male female sex ratio among populations of T. clareae on A. dorsata and A. mellifera varies considerably, and is influenced by the much shorter life span of the males. The ratio is greatly in favor of the females. The males being short-lived and very few function only for mating with the adult females before the latter are dispersed by the bees or invade new brood in the colony.