Comparative Population Dynamics ofTropilaelaps ClareaeandVarroa JacobsoniMites on Honeybees

Abstract

SummaryA high infestation rate of honeybee (Apis mellifera) colonies by Tropilaelaps clareae mites was found in Afghanistan and southern Vietnam and a low rate in northern Vietnam. The rate of infestation by Varroa jacobsoni was low in both parts of Vietnam. The ratios of brood: worker infestation by T. clareae ranged from 13·5–16·0 in Afghanistan and southern Vietnam and 26·1–36·9 in northern Vietnam. The corresponding ratios for V. jacobsoni were 0·8 in southern Vietnam and 2·9–8·2 in the north. These data suggest that in the colder areas V. jacobsoni mites remain outside sealed brood for a shorter time, resulting in a more rapid population increase there.Some measures of population for T. clareae mites in honeybee colonies with low (26%) and high (72%) rates of infestation were as follows: 1·3 and 2·3 females were found on average per brood cell, 18 and 7·3% of females were infertile, one female produced an average of 1·3 and 1·9 descendants, and the mean overall numbers of mites per brood cell were 2·9 and 5·1. The population of T. clareae increases at a geometrically greater rate than that of V. jacobsoni, owing mainly to the fact that mites of the former species remain outside sealed brood cells for only a small fraction of the time spent outside by the latter.The ratio of males to females for all T. clareae mites, old and young, present in brood ceils was 1:4. On the average one old female produced 0·6 males and 1·4 females. In the offspring the ratio of males to females was 1: 2·3.The mean infestation rate of drone brood by V. jacobsoni was 5·1 times that of worker brood, whereas for T. clareae the rate was 1·5 times as great for worker brood. Thus it would be practically useless to remove drone brood from honeybee colonies as a control measure for T. clareae.