The Tropilaelaps mites threat: Observations of their reproductive success

Authors: De Guzman, Lilia; PHOKASEM, PATCHARIN - Chiang Mai University; KHONGPHINITBUNJONG, KITIPHONG - Mae Fah Luan University; Frake, Amanda; CHANTAWANNAKUL, PANUWAN - National Center For Agriculture And Forestry Technologies (CENTA)

Submitted to: Bee World
Publication Type: Proceedings
Publication Acceptance Date: 4/1/2018
Publication Date: 4/17/2018
Citation: De Guzman, L.I., Phokasem, P., Khongphinitbunjong, K., Frake, A.M., Chantawannakul, P. 2018. The Tropilaelaps mites threat: Observations of their reproductive success. American Bee Research Conference Proceedings. 95(2):47-72. 10.1080/0005772X.2018.1450208.
DOI: https://doi.org/10.1080/0005772X.2018.1450208

Interpretive Summary:

Technical Abstract: Tropilaelaps spp. are more successful parasitic mites of Apis mellifera than Varroa destructor in Asia (Burgett et al., Bee World 64:25-28). We sought explanations to this success by assessing their fecundity on European bees in three short experiments using the mite transfer technique: 1) fecundity in brood cells with normal wax cappings and recapped brood; 2) fecundity of foundress collected from newly sealed larvae (NSL) and tan-bodied (TB) pupae and inoculated into NSL within 5 hours of mite collection and also in naturally infested brood; and 3) fecundity of foundress and daughter mites collected from TB and inoculated immediately into 4th instar larvae (L4) sealed with gel caps (de Guzman et al., 2013 J. Apic. Res. 52:262-263). The fecundity of foundress tropilaelaps was higher in brood cells with normal wax cappings (3.27 ± 0.27 progeny) than in recapped brood (1.59 ±0.11 progeny). Likewise, foundress or daughters that were deliberately inoculated into brood cells also produced about two offspring each, which corroborated with other findings (reviewed in de Guzman et al., 2017 J. Econ. Entomol. 1-14). It is interesting to note that about ¾ of the inoculum daughter mites with or without males in their natal cells reproduced, with some producing both males and females. This mite transfer technique, which imitated the release of mites when infested brood is opened by bees and the eventual re-invasion of exposed mites into suitable hosts, suggests that hygienic activities may disrupt or delay tropilaelaps mites’ reproduction. This was indicated by the higher proportion of foundress mites that did not reproduce in the recapped brood than in undisturbed brood cells, and the increased presence of nymphal stages in the TB-NSL group (see figure). Nonetheless, hygienic activities and increased production of daughters only (see figure b) may have less negative impact on tropilaelaps mite population since both foundress and daughter tropilaelaps successfully reproduced immediately without spending phoretic period on adult bees. These observations may help explain the competitive advantage of tropilaelaps mites over varroa mites in Asia.