Mite infestation during development alters the in-hive behaviour of adult honeybees

Abstract

Honeybee colonies (Apis mellifera ) host a number of parasites, among which the mite Varroa destructor has been implicated in colony losses recorded around the world in recent years. Although many studies have been carried out on the direct and indirect damage caused by the mite to its host, the possible influence of mite infestation on the in-hive behaviour of honeybees has received little attention so far; moreover, to our knowledge, no behavioural study has been performed on adult bees infested during the pupal stage, which is when the mite causes most of its detrimental effects. In order to assess any possible consequence of infestation on the in-hive behaviour of honeybees, we carried out detailed observations on adult bees artificially infested during the pupal stage. We recorded a higher proportion of inactive bees among the infested ones; moreover, we observed that infested bees are less involved in tending larvae and dealing with hive duties compared to their uninfested mates. These results allow to draw some hypotheses which could be tested using the infestation method presented here.Apis mellifera / Varroa destructor / deformed wing virus / behaviour / in-hive activity

Transcriptional signatures of parasitization and markers of colony decline in Varroa-infested honey bees (Apis mellifera)

“…These included the aforementioned GB45779, which encodes for UNC93 protein involved in regulation or coordination of muscle contraction in Caenorhabditis elegans (Levin and Horvitz, 1992), up-regulated in presence of high infestation levels and GB45180, which encodes for myosin-1-like, an ATP dependent motor protein involved in muscle contraction, down-regulated in bees from high-infested colonies. The differential expression of these genes may be correlated with the previously observed effects of mite infestation on the behaviour of infested bees which show a reduced activity within the colony (Annoscia et al, 2015). Altered expression of these genes may also result from the impairment of nutritional uptake associated to the parasitization or disease (Aronstein et al, 2012).…”

“…uninfested nestmates and, in particular, display a limited brood caring activity (Annoscia et al, 2015). One of the DEGs identified in our study was Krueppel homolog-1 (Kr-h1 GB45427), a transcription factor involved in the juvenile hormone pathway in bees and other insects whose expression is significantly higher in foragers than in nurse bees (Amsalem et al, 2015;Grozinger and Robinson, 2006).…”

“…These changes may be related to an accelerated behavioural maturation in response to Varroa infestation (Annoscia et al, 2015;Even et al, 2012). Finally, expression of a nicotinic acetylcholine receptor was downregulated, which may be related, as discussed before, to an interplay between immunity and nervous system (Olofsson et al, 2012).…”

Distance between honey bee Apis mellifera colonies regulates populations of Varroa destructor at a landscape scale

“…They postulate the increase in drifter acceptance is attributed to an impaired ability for guard bees to assess incoming heterocolonial foragers. It has been shown in numerous studies that developing honey bees parasitized by mites are less involved in brood care, hive ventilation, food collecting (Annoscia et al 2015), and reduced homing abilities (Kralj and Fuchs 2006). A model calculated by Pfeiffer and Crailsheim (1998) predicted that hives placed linearly 26 cm apart and facing the same direction contain up to 42 ± 6% alien workers.…”

Colony impact of pesticide‐induced sublethal effects on honeybee workers: A simulation study using BEEHAVE

“…The reason is that in-hive bees have received full energetic costs from the colony but not yet started to forage (and thereby returning some of the costs), so from an energetic point of view, in-hive bees are the most expensive life stage to lose [31]. There is some evidence that varroa mites make in-hive bees less active in brood care [40], and our brood care scenarios show how that could add to the damage varroa mites cause honeybee colonies. There is some evidence that varroa mites make in-hive bees less active in brood care [40], and our brood care scenarios show how that could add to the damage varroa mites cause honeybee colonies.…”