Population Growth of Varroa destructor (Acari: Varroidae) in Colonies of Russian and Unselected Honey Bee (Hymenoptera: Apidae) Stocks as Related to Numbers of Foragers With Mites.
Varroa (Varroa destructor Anderson and Trueman) is an external parasite of honey bees (Apis mellifera L.) and a leading cause of colony losses worldwide. Varroa populations can be controlled with miticides, but mite-resistant stocks such as the Russian honey bee (RHB) also are available. Russian honey bee and other mite-resistant stocks limit Varroa population growth by affecting factors that contribute to mite reproduction. However, mite population growth is not entirely due to reproduction. Numbers of foragers with mites (FWM) entering and leaving hives also affect the growth of mite populations. If FWM significantly contribute to Varroa population growth, mite numbers in RHB colonies might not differ from unselected lines (USL). Foragers with mites were monitored at the entrances of RHB and USL hives from August to November, 2015, at two apiary sites. At site 1, RHB colonies had fewer FWM than USL and smaller phoretic mite populations. Russian honey bee also had fewer infested brood cells and lower percentages with Varroa offspring than USL. At site 2, FWM did not differ between RHB and USL, and phoretic mite populations were not significantly different. At both sites, there were sharp increases in phoretic mite populations from September to November that corresponded with increasing numbers of FWM. Under conditions where FWM populations are similar between RHB and USL, attributes that contribute to mite resistance in RHB may not keep Varroa population levels below that of USL.
USDA-ARS, Carl Hayden Bee Research Center, 2000 East Allen Rd., Tucson, AZ 85719 ( gloria.hoffman@ars.usda.gov ; mona.chambers@ars.usda.gov ; ewatkinsdejong@email.arizona.edu ; geoffrey.hidalgo@ars.usda.gov ).|Corresponding author, e-mail: gloria.hoffman@ars.usda.gov.
Gloria
G
DeGrandi-Hoffman
AgScience Consulting LLC, Tucson, AZ 85719 (fabiana@agscience-consulting.com).
Fabiana
F
Ahumada
Genetics and Physiology Laboratory, USDA-ARS Honey Bee Breeding, 1157 Ben Hur Rd., Baton Rouge, LA 70820 (bob.danka@ars.usda.gov).
Robert
R
Danka
USDA-ARS, Carl Hayden Bee Research Center, 2000 East Allen Rd., Tucson, AZ 85719 (gloria.hoffman@ars.usda.gov; mona.chambers@ars.usda.gov; ewatkinsdejong@email.arizona.edu; geoffrey.hidalgo@ars.usda.gov).
Mona
M
Chambers
USDA-ARS, Carl Hayden Bee Research Center, 2000 East Allen Rd., Tucson, AZ 85719 (gloria.hoffman@ars.usda.gov; mona.chambers@ars.usda.gov; ewatkinsdejong@email.arizona.edu; geoffrey.hidalgo@ars.usda.gov).
Emily Watkins
EW
DeJong
USDA-ARS, Carl Hayden Bee Research Center, 2000 East Allen Rd., Tucson, AZ 85719 (gloria.hoffman@ars.usda.gov; mona.chambers@ars.usda.gov; ewatkinsdejong@email.arizona.edu; geoffrey.hidalgo@ars.usda.gov).
Geoff
G
Hidalgo
D000818:Animals; D001516:Bees / Q000469:parasitology*; D006790:Host-Parasite Interactions; D011158:Population Growth; D012426:Russia; D057077:Varroidae / Q000502:physiology*
migration; mite-resistant honey bee; parasite