Varroa destructor Mites Can Nimbly Climb from Flowers onto Foraging Honey Bees

Abstract

Varroa destructor, the introduced parasite of European honey bees associated with massive colony deaths, spreads readily through populations of honey bee colonies, both managed colonies living crowded together in apiaries and wild colonies living widely dispersed in natural settings. Mites are hypothesized to spread between most managed colonies via phoretically riding forager bees when they engage in robbing colonies or they drift between hives. However, widely spaced wild colonies show Varroa infestation despite limited opportunities for robbing and little or no drifting of bees between colonies. Both wild and managed colonies may also exchange mites via another mechanism that has received remarkably little attention or study: floral transmission. The present study tested the ability of mites to infest foragers at feeders or flowers. We show that Varroa destructor mites are highly capable of phoretically infesting foraging honey bees, detail the mechanisms and maneuvers by which they do so, and describe mite behaviors post-infestation.

Association of Varroa destructor females in multiply infested cells of the honeybee Apis mellifera

“…found in genotypic composition of mites among the five colonies. As the colony level had only very little influence on the population structure of the parasite, our results suggest that Varroa moves readily among hives at the apiary level, in accordance with other studies (Seeley & Smith, 2015;DeGrandi-Hoffman et al, 2016;Peck et al, 2016;Nolan & Delaplane, 2017). The comparison of the genotypes of the foundress pairs suggested that the association of mites in a multiply infested cell is mainly driven by random choice rather than any specific adaptive behavior of the foundresses: mites neither with the same nor different genotypes preferentially coinvaded cells.…”

“…Additionally, our AMOVA showed that the genetic variation between individual mites within colonies was most important while only very few differences were found in genotypic composition of mites among the five colonies. As the colony level had only very little influence on the population structure of the parasite, our results suggest that Varroa moves readily among hives at the apiary level, in accordance with other studies (Seeley & Smith, ; DeGrandi‐Hoffman et al ., ; Peck et al ., ; Nolan & Delaplane, ).…”

Life-history traits of wild honey bee colonies living in forests around Ithaca, NY, USA

“…A recent paper (Mordecai et al 2015) reports, however, that an avirulent variant of DWV exists in some locations in the UK, so perhaps an avirulent variant of DWValso exists in some of the wild colonies near Ithaca, NY. These colonies are widely spaced , so the spread of V. destructor and DWV between colonies may occur more by vertical transmission (from parent colony to offspring colony, by swarming) than by horizontal transmission (among unrelated colonies; by drifting, robbing, and foraging; see Peck et al 2016). If so, then perhaps the mites and viruses in these wild colonies are evolving avirulence (Ewald 1994;Fries and Camazine 2001), but it seems clear that they are not there yet.…”

Using an in vitro system for maintaining Varroa destructor mites on Apis mellifera pupae as hosts: studies of mite longevity and feeding behavior

“…Studies of varroa mites suggest that varroa females feed exclusively on hemolymph (Cabrera et al 2017;Erban et al 2015). Hemolymph surrounds every cell in the hemocoel of most arthropods (Fredrick and Ravichandran 2012;Lawry 2006;Paska et al 2014), and is also a reservoir of nutrients. The abdomen likely contains a high volume of hemolymph.…”