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Press Release

[Immediate 3/7/13]

Newly described behaviour shows how Asian honey bees Apis cerana defend 
themselves against hornets

In a paper published today in the Journal of Apicultural Research, the Asian honey bee Apis cerana, is shown to swarm and abscond to successfully elude a range of predatory hornet species. This newly described behaviour used together with an armoury of other defensive tactics helps to limit the damage hornets can inflict on colonies.

A. cerana is native and widespread through South and South East Asia where it endures predation by a range of hornets including Vespa velutina (now found in France), V. tropica and V. affinis. Their hunting techniques differ and elicit different reactions from the bees. These bees have previously been observed defending themselves from hornets by “shaking” (where the outer layer or “mantle” of bees shake which makes a whooshing sound), “heat balling” (clustering around the predator and heating them to a lethal temperature) and protean flight which is an evasive zig-zagging flight of worker bees returning to their colonies under attack. Unlike the European honey bee A. mellifera whose speed slows in protean flight, A. cerana bees fly quickly when under hornet attack.

In this new study of A. cerana bee swarms made in Thailand by Dr Willard Robinson of Casper College, USA, the bees were found to make a series of short or “saltatory” swarming flights to effectively rid themselves of attacking hornets. Where the bees settled it is thought they marked the site with an attractant which left some hornets clinging to the site after the swarm flew away. Relieved of these predators, the colony then absconded by taking a much longer flight to a new area. When hornets were absent, despite the presence of colonies of the giant honey bee A. dorsata which would normally attract hornets to the area, only one Apis cerana swarm was observed indicating that they only abscond to evade hornets when hornets are abundant.

Prior to swarming and under constant hornet attack, the swarms also formed downward aerial extensions, called “tails,” together with “arm” extensions formed along their support (such as a tree). The bees in these tails and arms did not fly to defend themselves and were targeted by the attacking hornets. This left the main bulk of the colony free from attack. It is thought, in effect, that these tail and arm bees were expendable decoys sacrificed to preserve the main colony. The main colony was then able to continue functioning and select the next appropriate action to take such as swarming.

IBRA Scientific Director and JAR Senior Editor Norman Carreck says: “Honey bees normally swarm to reproduce by making new colonies and sometimes to find new food sources. This study is important because for the first time it shows bees also use swarming to defend themselves from predators.”

 Press Release


Norman Carreck, Science Director, IBRA +44 (0)791 8670169 Email:



1. 1. The article “Apis cerana swarms abscond to battle and elude hornets (Vespa spp.) in northern Thailand” by Willard S Robinson is available at:-

2. The International Bee Research Association (“IBRA”) is the world’s longest established apicultural research publishers and promotes the value of bees by providing information on bee science and beekeeping worldwide.

3. IBRA publishes the peer reviewed scientific journal the Journal of Apicultural Research founded by IBRA in 1962. It includes original research articles, theoretical papers; scientific notes and comments; together with authoritative reviews on scientific aspects of the biology, ecology, natural history, conservation and culture of all types of bee.

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