TLC: Tropilaelaps spp. (Trop), Lotmaria passim (Lpa), Crithidia mellificae (Cme)
Tropilaelaps spp. is a mite native to Asia and has yet to make an appearance in the US. However, surveillance of this pest is of high importance as a confirmed case in the US would be devastating to the beekeeping industry. Similar to the Varroa mite, they parasitize the brood and cause chronic issues to pupae and adults, including stunting or body deformities that result in rapid colony loss (de Guzman et al., 2017). The rapid lifecycle of these mites, an estimated 3x faster than Varroa mites, and the increased fecundity are major concerns if they invade the U.S. (de Guzman et al., 2017). Currently, a few visual field tests are used for screening purposes (e.g., bump test), but these have limited sensitivity (range: 36-56%) and require field inspectors to test multiple colonies to increase the probability of detecting infested colonies (Pettis et al., 2013). NAGC’s pathogen panel, using qPCR technology, can provide a sensitive method for larger-scale screening of apiaries.
Lotmaria passim and Crithidia mellificae are both intestinal protozoans of the family Trypanosomatida and seem to be associated with honeybee health (Lannutti et al., 2020). Controlled laboratory inoculations of these intestinal protozoans resulted in shorter lifespans compared to control bees, with L. passim infections having the highest bee mortality rates (Gómez-Moracho et al., 2020). Winter mortality of colonies has also been attributed to C. mellificae infections (Ravoet et al., 2013). Less is known about L. passim, as it was first described five years ago, and now is considered the more widespread of the two trypanosomids (Schwarz et al., 2015). Both trypanosomes have been found in honey bee colonies within the U.S. (Xu et al., 2018) and can be transmitted by the invasive small hive beetle, a frequent colony pest (Nanetti et al., 2021).
de Guzman, L. I., et al. (2017). Ecology, Life History, and Management of Tropilaelaps Mites. Journal of Economic Entomology, 110(2), 319-332. doi:10.1093/jee/tow304
Gómez-Moracho, T., et al. (2020). Experimental evidence of harmful effects of Crithidia mellificae and Lotmaria passim on honey bees. Int J Parasitol, 50(13), 1117-1124. doi:10.1016/j.ijpara.2020.06.009
Lannutti, L., et al. (2022). Molecular Detection and Differentiation of Arthropod, Fungal, Protozoan, Bacterial and Viral Pathogens of Honeybees. Vet Sci, 9(5). doi:10.3390/vetsci9050221
Nanetti, A., et al. (2021). Detection of Lotmaria passim, Crithidia mellificae and Replicative Forms of Deformed Wing Virus and Kashmir Bee Virus in the Small Hive Beetle (Aethina tumida). Pathogens, 10(3). doi:10.3390/pathogens10030372
Pettis, J. S., et al. (2013). A rapid survey technique for Tropilaelaps mite (Mesostigmata: Laelapidae) detection. J Econ Entomol, 106(4), 1535-1544. doi:10.1603/ec12339
Ravoet, J., et al. (2013). Comprehensive bee pathogen screening in Belgium reveals Crithidia mellificae as a new contributory factor to winter mortality. PLOS ONE, 8(8), e72443. doi:10.1371/journal.pone.0072443
Schwarz, R. S., et al. (2015). Characterization of Two Species of Trypanosomatidae from the Honey Bee Apis mellifera: Crithidia mellificae Langridge and McGhee, and Lotmaria passim n. gen., n. sp. J Eukaryot Microbiol, 62(5), 567-583. doi:10.1111/jeu.12209