APICULTURE AND SOCIAL INSECTS Comparative Resistance of Russian and Italian Honey Bees (Hymenoptera: Apidae) to Small Hive Beetles (Coleoptera: Nitidulidae)

Tocompare resistance to small hive beetles (Coleoptera:Nitidulidae)betweenRussian and commercial Italian honey bees (Hymenoptera: Apidae), the numbers of invading beetles, their population levels through timeand small hivebeetle reproduction inside the coloniesweremonitored. We found that the genotype of queens introduced into nucleus colonies had no immediate effect on small hive beetle invasion. However, the inßuence of honey bee stock on small hive beetle invasion was pronounced once test bees populated the hives. In colonies deliberately freed from small hive beetleduringeachobservationperiod, theaveragenumberof invadingbeetleswashigher in the Italian colonies (29 5 beetles) than in the Russian honey bee colonies (16 3 beetles). A similar trend was observed in colonies that were allowed to be freely colonized by beetles throughout the experimental period (Italian, 11.46 1.35; Russian, 5.21 0.66 beetles). A linear regression analysis showedno relationships between thenumber of beetles in the colonies and adult beepopulation (r 0.1034, P 0.297), brood produced (r 0.1488, P 0.132), or amount of pollen (r 0.1036, P 0.295). There were more Italian colonies that supported small hive beetle reproduction than Russian colonies. Regardless of stock, the use of entrance reducers had a signiÞcant effect on the average number of small hive beetle (with reducer, 16 3; without reducer, 27 5 beetles). However, there was no effect on bee population (with reducer, 13.20 0.71; without reducer, 14.60 0.70 frames) or brood production (with reducer, 6.12 0.30; without reducer, 6.44 0.34 frames).Overall, Russian honey bees were more resistant to small hive beetle than Italian honey bees as indicated by fewer invading beetles, lower small hive beetle population through time, and lesser reproduction.