Research Reviews
Can you move your hives away from Small Hive Beetles?
Answer: You can run, but you can't hide.
Quarantines are an effective, tried-and-true approach to dealing with parasites. By sequestering an infected host away from other hosts, it gives time for one of three things to happen. First, the host could die (bad for the host) but, along with it, kill off the parasite (good for other potential hosts). Second, the host could rid themselves of the parasite and become cured (bad for the parasite but good for all hosts). Third, the parasite could somehow learn to live with the host so that they are less virulent (good for everyone).
Apiculture officials, like those in the regulatory branch of the NC Department of Agriculture, have therefore long employed quarantines to try and abate invasive species or noxious pests. Sometimes this approach works, sometimes it doesn't. With honey bees, there hasn't been too many success stories. When the varroa mite first came into the state, it spread from west to east like wildfire despite imposed quarantines. Seven years ago, the NCDA lifted a quarantine on the movement of hives to slow the spread of the small hive beetle (SHB), as it didn't seem to mitigate its spread.
A new research project out of Australia, where the SHB has been since 2001, demonstrates why trying to quarantine those pesky beetles is a fairly futile endeavor. The researchers took 12 hives from a commercial apiary that had SHB adults in the colonies but no larvae (the damaging stage of the pest). They removed every single adult SHB from each hive by painstakingly aspirating them into a vial one-by-one (in essence, vacuuming them into a glass jar). They then immediately moved the 12 hives in one of two apiaries over 15 miles away to a remote forested area far removed from any known beekeepers (although they admit there were likely some feral colonies in the area).
The researchers returned to the colonies a mere 5 days later and again captured and counted all of the adult SHB in each hive. Before they were moved they found an average of 38.6 beetles per hive and removed them all. After 5 days in a "remote" area, they found a whopping 326.5 adult beetles per hive! In fact, one colony in each apiary had totally absconded from such bad infestations of SHB larvae.
While clearly this is just one example, and such a pattern cannot be considered universal in all areas, there are some lessons to be learned here. First, even hives devoid of SHB can rapidly obtain them. Second, even if you think your far away from other bees, you aren't immune from SHB. The authors imply that since SHB don't reproduce very well on alternate hosts (such as rotting fruit and the like), the adult SHBs must be able to fly fairly long distances. Third, given these first two points, imposing a quarantine on moving hives probably doesn't have much of a biological impact, making it fairly impractical and ineffective. Thus the NCDA made the correct choice in lifting the ban.
What is unclear from this work, and a matter of speculation, is how on earth the SHBs found these hives so quickly. We know that adults cue in on odors from the hive, most notably the nasanov scent and alarm pheromone. It is possible, then, that beekeepers may take steps when moving hives to avoid undue disruption and agitation to lower the likelihood of attracting SHB. In any event, it is clear that we can't run from the problem, so we'll have to rely on other methods besides quarantining our bees.
Reference
Neumann, P., D. Hoffmann, M. Duncan, and R. Spooner-Hart. (2010). High and rapid infestation of isolated commercial honey bee colonies with small hive beetles in Australia. Journal of Apicultural Research, 49: 343-344.
