Small hive beetle infestation levels of honey bee colonies correlate with precipitation and forest cover

Abstract

Small hive beetles (SHBs) are parasites of social bee colonies endemic to Africa and have become a widely distributed invasive species. Damage to colonies in the new ranges seems to be governed by higher infestation levels, but the factors underlying SHB numbers are poorly understood. Since SHBs pupate in the soil outside of colonies, local temperature and humidity are likely to underlie infestation levels. Here, we conducted a survey in Nigeria of 82 honey bee colonies, Apis mellifera adansonii (26 apiaries, 14 states), in both forest and savannah with a range of temperatures and precipitation. We recorded significantly higher SHB infestation levels in forests compared to savannah. While there was no significant correlation between local temperature and SHB infestation levels, a significant positive correlation was found between local rainfall and SHB numbers in colonies. Under the temperature conditions of the study region, precipitation and a forest cover appear to impact SHB infestation levels of honey bee colonies. Our data suggest that new SHB distribution ranges with both forests and high precipitation will be especially at risk.