Differential resistance across paternal genotypes of honey bee brood to the pathogenic bacteriumMelissococcus plutonius

Abstract

The bacterium Melissococcus plutonius is the causative agent of European foulbrood (EFB), a disease affecting immature stages (i.e., brood) of honey bees (Forsgren, 2010). This gram-positive bacterium is transmitted by symptomless adult honey bees to young larvae, which become infected after ingesting the pathogen through contaminated food. The bacterium then multiplies in the larvae's gut, which can lead to their death. As a result, within-colony population dynamics are disturbed, to the point that colonies can collapse (Forsgren, 2010). Transmission of EFB between colonies and apiaries is high, leading to local and recurrent outbreaks of increasing frequency in several countries over the last decades (Belloy et al., 2007;Budge et al., 2014;Grossar et al., 2020). Thus, EFB poses a major threat to honey bee health and contributes, together with other biotic and abiotic factors, to recent non-sustainable increases in colony losses in many regions of the Northern hemisphere (Goulson et al., 2015;Neumann & Carreck, 2010).To mitigate the impact of EFB disease, one option for beekeepers is to apply antibiotics, e.g. oxytetracycline hydrochloride. However, antibiotic treatment is not sustainable, as it may (i) remove the symptoms but not the causative agent of the disease (Thompson &

Climatic predictors of prominent honey bee (Apis mellifera) disease agents:Varroa destructor,Melissococcus plutonius, andVairimorphaspp

“…M. plutonius is often described as an opportunistic pathogen that is triggered to cause EFB disease based on a combination of nutritional deficiencies, 16,24,60 pathogen genotype, 61,62 and host genotype, 63 among other factors. Given the possible connection with nutrition, it is conceivable that inopportune foraging conditions could promote disease and increase M. plutonius occurrence, but it has been suggested that strong nectar flows might actually also promote M. plutonius proliferation due to diversion of nursing care.…”