Brood pupation temperature affects the susceptibility of honeybees (Apis mellifera) to infestation by tracheal mites (Acarapis woodi)

Abstract

-An assessment was made of tracheal mite susceptibility in honeybees pupated at a low temperature. Using a laboratory bioassay, an experiment was conducted to compare the performance of newly-emerged (callow) bees raised at 30 ºC with those raised at the more normal brood temperature of 34 ºC. The reduced temperature caused a delay of over 5 days in the emergence of the bees from the brood cells. The callow bees raised at 30 ºC had over twice the mite prevalence level. The fecundity of the mites in the tracheae was similar for both temperature conditions. Increased susceptibility to tracheal mites resulting from reduced brood temperature may help to explain the mortality, in the temperature-stressed late winter/early spring period, of colonies with a moderate mite infestation in autumn. Further work is required to identify the mechanism responsible for this increased susceptibility.Apis mellifera / Acarapis woodi / tracheal mite / brood temperature / susceptibility to infestation

The role of autogrooming in the differential susceptibility to tracheal mite (Acarapis woodi) infestation of honeybees (Apis mellifera) held at both normal and reduced temperatures during pupation

“…• C. This concurs with the results of our previous work (McMullan and Brown, 2005) and reaffirms that a low pupation temperature considerably increases the likelihood of honeybees being infested. Mite fecundity was also shown to be similar for all colonies and treatments.…”

“…• C (McMullan and Brown, 2005). We suggest that this is a link in a chain of events leading to the mortality of temperature stressed colonies in the late winter / early spring period.…”

“…This is a similar approach to that used in the experiment that demonstrated a pupationtemperature effect in susceptibility (McMullan and Brown, 2005). Previous experiments on honeybee susceptibility have shown a good correlation between the results from such short-term bioassays and field colonies (Page and Gary, 1990;Danka and Villa, 1996;Nasr et al, 2001).…”

Differential susceptibility to the tracheal mite Acarapis woodi between Apis cerana and Apis mellifera

“…For instance, mite fecundity in A. mellifera was 1.6 times higher than in A. cerana only in the hive inoculation assay. It is considered that the mite laid more offspring in the tracheae of A. mellifera or that the foundress mite in A. mellifera had migrated further into or out of the trachea as in the cases of Gary et al (1989) and Mcmullan and Brown (2005). The ratio of larvae to eggs is an indicator of developmental rate because the time of entering the tracheae is similar between species as seen in experiment 1 and the distribution of migrating female mites was also not affected by whether tracheae contained mites or not (Gary and Page 1987).…”

“…The number of adult mites of each sex, along with the number of larvae and eggs, was counted and recorded. This method mainly follows Mcmullan and Brown (2005).…”