Chemical acaricides in Apis mellifera (Hymenoptera : Apidae) colonies; do they cause nonlethal effects?

Colonies of the honey bee, Apis mellifera Linnaeus, infested with the paras itic mites Acarcrpis woodi (Rennie) (Acari: Tarsonemidae) or Varroa jacobso ni Oudemans (Acari: Varroidae) require acaricidal treatment to control infe stations that could affect colony growth and honey production. We investiga ted the effects of three acaricides, fluvalinate (formulated as Apistan(R)) , formic acid, and menthol, on honey bee colony population growth, foraging activity, adult worker longevity, and honey production. Effects of in-hive treatments of Apistan(R) and formic acid were measured by examining colony weight gain, brood survival, sealed-brood area, emerged-bee weight, number of returning foragers, pollen-load weight, and worker longevity. These cha racteristics were not different between fluvalinate-treated colonies, formi c-acid-treated colonies, and control colonies. Adult bee population, brood survival, number of returning foragers, and honey production did not vary a mong menthol-treated colonies, formic-acid-treated colonies, and control co lonies. Sealed-brood area was lower in formic-acid-treated colonies than co ntrol colonies, but not different from menthol-treated colonies. Although n ot statistically significant, formic-acid-treated colonies experienced lowe r honey production than both menthol-treated and control colonies. Numbers of workers attending the queen in the retinue and queen behaviour patterns were not different after colonies were treated with formic acid.