Life-history stage determines the diet of ectoparasitic mites on their honey bee hosts

Abstract

Ectoparasitic mites of the genera Varroa and Tropilaelaps have evolved to exclusively exploit honey bees as food sources during alternating dispersal and reproductive life history stages. Here we show that the primary food source utilized by Varroa destructor depends on the host life history stage. While feeding on adult bees, dispersing V. destructor feed on the abdominal membranes to access to the fat body as reported previously. However, when V. destructor feed on honey bee pupae during their reproductive stage, they primarily consume hemolymph, indicated by wound analysis, preferential transfer of biostains, and a proteomic comparison between parasite and host tissues. Biostaining and proteomic results were paralleled by corresponding findings in Tropilaelaps mercedesae, a mite that only feeds on brood and has a strongly reduced dispersal stage. Metabolomic profiling of V. destructor corroborates differences between the diet of the dispersing adults and reproductive foundresses. The proteome and metabolome differences between reproductive and dispersing V. destructor suggest that the hemolymph diet coincides with amino acid metabolism and protein synthesis in the foundresses while the metabolism of non-reproductive adults is tuned to lipid metabolism. Thus, we demonstrate within-host dietary specialization of ectoparasitic mites that coincides with life history of hosts and parasites.

Sequence-based genome-wide association studies reveal the polygenic architecture ofVarroa destructorresistance in Western honey beesApis mellifera

“…Finally markers 4:10789077:T>C and 8:1551638:C>T fell into genes found by Ament et al 2011 as linked to protein abundance in fat body and haemolymph of the adult honey bee. We know that varroa, while infesting the colony, survives by feeding on these bee biological fluids, the fat bodies when on adult bees and the haemolymph when on pupae (Han et al 2024). These markers might signal either an impact of varroa infestation, or the resilience to such infestation, on biological pathways linked to composition of the honey bee haemolymph and fat body.…”

Proteomics profiling of the honeybee parasite Tropilaelaps mercedesae across post-embryonic development

“…Upon hatching, the eggs develop to maturity after passing through the protonymph stage and the deutonymph stage. During this period, the foundress mite and her offspring feed on the hemolymph of honeybee pupae 14 . By the time their host bees emerge from the cell, almost all female T. mercedesae offspring have become mature adults, emerge together with their hosts, and enter the next reproductive cycle 15 .…”

Honey bee (Apis mellifera) nurse bee visitation of worker and drone larvae increases Varroa destructor mite cell invasion

“…Typically, high mite infestations can result in colonies collapsing and dying within 2 yr if they are left untreated ( Thompson et al 2014 ). Varroa also acts as a highly efficient vector of several honey bee-associated viruses by feeding on the hemolymph and fat body tissue of their bee hosts ( Ramsey et al 2019 , Han et al 2024 ).…”