Usurpation of African Apis mellifera scutellata colonies by parasitic Apis mellifera capensis workers

Abstract

-Thelytokous Apis mellifera capensis workers recently brought into regions occupied by the arrkenotokous African bee A. m. scutellata, parasitise these colonies, causing colony death. These capensis workers are genetically almost identical and are referred to as a 'pseudo-clone'. We surveyed 120 scutellata colonies, 27 in detail, at various stages of usurpation by the pseudo-clone. The scutellata queen could co-exist with egg-laying pseudo-clones for 50+ days in one case but disappeared 1-15 days in three other cases. Despite the presence of emerged queen cells no new adult queens of either race were observed in usurped colonies. Only 11 ± 13% of the pseudo-clone population had fully active ovaries, suggesting ovarian development is inhibited in the majority of the pseudo-clones. Only 2.7 ± 1.7% of the foraging force were pseudo-clones. The data were modelled and showed the rapid (56-105 days) growth of the pseudo-clone population and colony death over a wide range of initial conditions. Apis mellifera capensis / pseudo-clone / usurpation / reproduction / Apis mellifera scutellata / honeybee reproduction / South Africa

Reproduction of Varroa destructor in South African honey bees: does cell space influence Varroa male survivorship?

“…These changes in the colony are caused by usurpation of the host A. m. scutellata colony by invading pseudo-clones whose offspring rapidly replace the host worker population. This eventually leads to the death of the colony since the pseudo-clones do not forage so new brood cannot be reared (Martin et al, 2002).…”

“…This would result in very slow, if any, growth of the mite population. However, the host A. m. scutellata colony would collapse due the presence of the pseudo-clone long before any effect of mites was seen (Martin et al, 2002). This low reproductive success is due to the high levels of mother and male protonymph mite mortality and not the 56 S.J.…”

Honeybee health in Africa—a review

“…Upon entering A. m. scutellata colonies, A. m. capensis workers, which have the predisposition to become social parasites (Zheng et al 2010), compete for reproduction. A. m. capensis workers are able to lay diploid eggs and produce queen-like signals (Onions 1912;Martin et al 2002;Neumann and Moritz 2002;Pirk et al 2012). These A. mellifera capensis social parasites do not contribute to the work force and their offspring do not replace the host workers, but these social parasites and their clonal offspring just reproduce which then results in the collapse of the host colony (Hillesheim et al 1989;Neumann et al 2001;Moritz 2002;Neumann and Hepburn 2002).…”

Parasitic Cape honeybee workers, Apis mellifera capensis, evade policing

“…Two measures were used to quantify the colour and cue-location selectivity. First, transmitted information 12,13 , which indicates the reliability of differences in ®ring rate between two sets of trials, was separately calculated for cue location and colour (Fig. 2c, d).…”

“…This leads to the death of the host colony on which they depend. An important factor causing the death of a colony seems to be the dwindling numbers of A. m. scutellata workers that perform foraging duties (A. m. capensis workers are greatly under-represented in the foraging force of an an infected colony) owing to death of the queen, and, before queen death, competition for egg laying between A. m. capensis workers and the queen 13 . Unfortunately, bee-keeping practices such as collecting wild swarms, seasonal movement of colonies by truck, and the close siting of hives in apiaries facilitate the horizontal spread of the A. m. capensis workers between colonies and provide a continuing source of hosts.…”