Grooming behavior and gene expression of the Indiana “mite-biter” honey bee stock

Abstract

This study was conducted to evaluate the Indiana "mite-biter" honey bee stock, which has been selected for increased mutilation of Varroa destructor mites ("mite biting" behavior). A comparison between colonies of the selected stock and colonies of unselected Italian bees showed that the proportion of mutilated mites, the severity of mutilations, and winter colony survival were higher in Indiana mite-biter colonies. Additionally, the number of fallen mites and the rate of mite population growth were lower in the colonies of the selected genotype than in those of the unselected genotype. The expression of a gene associated with grooming behavior, AmNrx-1 (neurexin), was significantly higher in the selected stock. Moreover, AmNrx-1 expression was positively correlated with the proportion of mutilated mites but not with mite population growth. AmNrx-1 may have the potential to be used for marker-assisted selection. This study provides evidence that selection for mite-biting behavior reduces V. destructor infestations, increases colony survival and increases the expression of a grooming behaviorassociated gene.

Unraveling Honey Bee–Varroa destructor Interaction: Multiple Factors Involved in Differential Resistance between Two Uruguayan Populations

“…In Uruguay, Invernizzi et al [ 41 ] found that Africanized bees expressed more grooming than European bees ( A. m. ligustica ), both at colonial and individual levels. This behavior has already been reported as a valuable trait for the control of V. destructor [ 22 , 23 , 24 , 25 ]. However, we must be cautious when evaluating the importance of grooming behavior as resistance to V. destructor since a significant number of mites collected on the floor come from brood cells [ 74 , 75 ].…”

“…The selection of honey bees possessing these traits appears as a promising alternative to improve the resistance of honey bees to varroosis [ 18 , 19 ]. In this sense, progress has been made in the knowledge of genes associated with both behaviors, which would allow selection based on molecular markers [ 25 , 76 , 77 ].…”

“…In the USA, hygienic honey bees have been selected with a particular capacity to detect pupae parasitized by V. destructor , a trait known as Varroa Sensitive Hygiene (VSH) [ 21 ]. Grooming behavior, by which parasited honey bees can dislodge mites by themselves (autogrooming) or receiving help from other insects (allogrooming) [ 17 ], has been reported as an effective resistance mechanism against V. destructor [ 22 , 23 , 24 , 25 ]. Both hygienic and grooming behaviors are expressed very efficiently in A. cerana and would be key to controlling V. destructor populations [ 5 , 26 ].…”

Grooming Behavior in Naturally Varroa-Resistant Apis mellifera Colonies From North-Central Argentina

“…Recent findings demonstrated a significant correlation between the expression of the gene neurexin and direct observations of grooming behavior (Hamiduzzaman et al, 2017). Furthermore, Morfin et al (2019) found a correlation between this gene and mite mutilation, which reinforces the validity of analyzing mite damage as an indirect measurement of grooming behavior until the development of robust markers for marker-assisted selection. Finally, efforts are being made to characterize the productivity of the selected stock under standard beekeeping management.…”

Three Decades of Selecting Honey Bees that Survive Infestations by the Parasitic Mite <em>Varroa destructor</em>: Outcomes, Limitations and Strategy

“…This widespread monitoring may help to identify numerous loci with a direct impact on the resistance of colonies of western honey bee against the Varroa mite. Many loci linked to diverse resistance traits have already been identified (Arechavaleta-Velasco et al, 2012;Behrens et al, 2011;Broeckx et al, 2019;Guarna et al, 2017;Hamiduzzaman et al, 2017;Harpur et al, 2019;Hu et al, 2016;Jiang et al, 2016;Lapidge et al, 2002;Morfin et al, 2019a;Oxley et al, 2010;Spötter et al, 2016;Spötter et al, 2012;Tsuruda et al, 2012;Zakar et al, 2014). Even though each of these studies mentions the possibility of using marker-assisted or genomic selection in honey bee breeding, to the best of our knowledge, the identified sequences have not been routinely implemented in selection programmes.…”