Coleoptera: Nitidulidae

California Pest Rating for

Aethina tumida Murray: Small Hive Beetle (SHB)

Pest Rating: B

PEST RATING PROFILE

Initiating Event:

On September 12, 2016 Stephen Brown requested a rating proposal for Aethina tumida, small hive beetle.

History & Status:

Background: Adult small hive beetles can fly for several miles in search of beehives. Upon locating a hive, the adult beetles enter and seek out protected cracks and crevices¹ within the hive environment. They are able to feed by rubbing bees with their antennae and inducing the bees to regurgitate food¹. The beetles lay eggs in the hives. Larvae that hatch feed on honey, pollen, and bee brood¹. Once mature they migrate out of the hive and enter the soil to pupate¹. SHB can spread long distances by flying and via transport of infested hives.

Worldwide Distribution: SHB is native to sub-Saharan Africa¹. From there it has spread to Australia, Italy, Brazil, and the United States^1,3,4. The species was first found in the United States in Florida in 1998 but specimens indicate it had been present since 1996¹.

Official Control: Aethina tumida is listed as a harmful organism by Antigua and Barbuda, Grenada, and Taiwan². The EU also restricts SHB infested equipment and hives.

California Distribution: SHB is occasionally found in beehives in southern California and the bay area.

California Interceptions: SHB is frequently intercepted in beehives entering California from other states.

The risk Aethina tumida (small hive beetle (SHB)) would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: Beehives are kept throughout most of California and SHB is likely to establish wherever they are found. SHB receives a High (3) in this category.

Evaluate if the pest would have suitable hosts and climate to establish in California. Score:

– Low (1) Not likely to establish in California; or likely to establish in very limited areas.

– Medium (2) may be able to establish in a larger but limited part of California.

– High (3) likely to establish a widespread distribution in California.

2) Known Pest Host Range: SHB is only known to feed in beehives and receives a Low (1) in this category.

Evaluate the host range of the pest. Score:

– Low (1) has a very limited host range.

– Medium (2) has a moderate host range.

– High (3) has a wide host range.

3) Pest Dispersal Potential: SHB has very high reproductive potential. Each female can lay 1,000-2,000 eggs¹. They can disperse long distances by flying and when infested hives are moved. SHB receives a High (3) in this category.

Evaluate the natural and artificial dispersal potential of the pest. Score:

– Low (1) does not have high reproductive or dispersal potential.

– Medium (2) has either high reproductive or dispersal potential.

– High (3) has both high reproduction and dispersal potential.

4) Economic Impact: SHB has the potential to increase crop production costs by decreasing the number of hives available for pollination services. Beekeepers are advised to alter cultural practices to limit damage from the pest¹. SHB also harms bees by feeding on bee brood, honey, and pollen in hives. SHB receives a High (3) in this category.

Evaluate the economic impact of the pest to California using the criteria below. Score:

A. The pest could lower crop yield.

B. The pest could lower crop value (includes increasing crop production costs).

C. The pest could trigger the loss of markets (includes quarantines).

D. The pest could negatively change normal cultural practices.

E. The pest can vector, or is vectored, by another pestiferous organism.

F. The organism is injurious or poisonous to agriculturally important animals.

G. The organism can interfere with the delivery or supply of water for agricultural uses.

– Low (1) causes 0 or 1 of these impacts.

– Medium (2) causes 2 of these impacts.

– High (3) causes 3 or more of these impacts.

5) Environmental Impact: SHB is not known to lower biodiversity, disrupt natural communities, or change ecosystem processes. It is not likely to directly affect threatened or endangered species or disrupt critical habitats. It may trigger new chemical treatments by beekeepers. It is not known to impact cultural practices, home/urban gardening, or ornamental plantings. SHB receives a Medium (2) in this category.

Evaluate the environmental impact of the pest on California using the criteria below.

A. The pest could have a significant environmental impact such as lowering biodiversity, disrupting natural communities, or changing ecosystem processes.

B. The pest could directly affect threatened or endangered species.

C. The pest could impact threatened or endangered species by disrupting critical habitats.

D. The pest could trigger additional official or private treatment programs.

E. The pest significantly impacts cultural practices, home/urban gardening or ornamental plantings.

Score the pest for Environmental Impact. Score:

– Low (1) causes none of the above to occur.

– Medium (2) causes one of the above to occur.

– High (3) causes two or more of the above to occur.

**Consequences of Introduction to California for Aethina tumida (Small Hive Beetle (SHB)): Medium (12)**

Add up the total score and include it here.

–Low = 5-8 points

–Medium = 9-12 points

–High = 13-15 points

6) Post Entry Distribution and Survey Information: SHB is occasionally found in beehives in many parts of California, but much of northern California remains free from the pest. SHB receives a Medium (-2) in this category.

Evaluate the known distribution in California. Only official records identified by a taxonomic expert and supported by voucher specimens deposited in natural history collections should be considered. Pest incursions that have been eradicated, are under eradication, or have been delimited with no further detections should not be included.

–Not established (0) Pest never detected in California, or known only from incursions.

–Low (-1) Pest has a localized distribution in California, or is established in one suitable climate/host area (region).

–Medium (-2) Pest is widespread in California but not fully established in the endangered area, or pest established in two contiguous suitable climate/host areas.

–High (-3) Pest has fully established in the endangered area, or pest is reported in more than two contiguous or non-contiguous suitable climate/host areas.

Final Score:

The final score is the consequences of introduction score minus the post entry distribution and survey information score: Medium (10)

Uncertainty:

There have not been any recent formal surveys for SHB in California. It is possible that the beetle has a more widespread distribution in the state. There have not been any studies to determine if SHB may affect native bees in CA.

Conclusion and Rating Justification:

SHB is likely to have significant economic and environmental impacts in California. However, it is considered to be established in parts of the state. A “B” rating is justified.

References:

¹ Ellis, James D. and Amanda Ellis. 2013. University of Florida Featured Creatures. http://entnemdept.ufl.edu/creatures/misc/bees/small_hive_beetle.htm

² USDA Phytosanitary Certificate Issuance & Tracking System (PCIT) Phytosanitary Export Database (PExD). https://pcit.aphis.usda.gov/pcit/

³ Mutinelli, F., F. Montarsi, G. Federico, A. Granato, A. Maroni Ponti, G. Grandinetti, N. Ferre, S. Franco, V. Duquesne, M. Pierre Riviere, R. Thiery, P. Henrikx, M. Ribiere-Chabert, and M. Pierre Chauzat. 2014. Detection of Aethina tumida Murray (Coleoptera: Nitidulidae) in Italy: outbreaks and early reaction measures. Journal of Apicultural Research 53: 569-575.

⁴ Official OIE website for Brazil. http://www.oie.int/wahis_2/public/wahid.php/Reviewreport/Review?page_refer=MapFullEventReport&reportid=19529