Small hive beetle
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Small hive beetle ( Aethina tumida ) |
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| Aethina tumida | ||||||||||||
| A. Murray , 1867 |
The small hive beetle ( Aethina tumida ) is a parasite of colonies of the honey bee from the family of the gloss beetles (Nitidulidae). It is indigenous to sub-Saharan Africa and from there to North America, Australia and, more recently, Europe. The species was first described by Andrew Murray in 1867 using animals from Nigeria that had been sent to him for identification in London. The parasitization of honey bee colonies was first described in 1940 in South Africa. The species only received greater attention after it was introduced into the USA.
features
The small hive beetle is about five to six millimeters long and three millimeters wide, with females being slightly larger and heavier than males. It thus reaches about a third of the length of a worker bee. The name was chosen to differentiate it from the large hive beetle ( Hyplostoma fuligineus ), which is only known from Africa so far. The beetle is flattened with an oval body contour, it is red-brown directly after hatching, later dark brown to black. The head and pronotum are wider than they are long, and the pronotum is as wide as the elytra . The pronotum is widest at the base with pointed, slightly protruding rear corners. The elytra are shortened somewhat at the back and leave the last tergites of the abdomen free, the last ( pygidium ) being completely uncovered. The membranous hind wings are normal and the beetle can fly very well. The pronounced, three-segment antenna lobe is typical for the whole family. The shape of the rails ( tibia ) of the hind legs is also important for the determination . These are broadly flattened and parallel in the rear two thirds. To distinguish between similar nitidulid species, especially the genus Cychramus, cf. the identification aid.
The eggs are about 1.4 millimeters long, oval and white in color. In the last stage, the larvae are about 12 millimeters long and whitish in color, often with a washable, brownish coating. More sclerotized only the head capsule and the two-part pronotum . They can be recognized by two characteristic rows of spiked bristles on the back. The spiracles on the sides of the body also sit on slightly raised protrusions. At the rear end there is also a pair of enlarged thorns (urogomphi).
Life cycle and biology
The beetle lays its eggs preferably in cracks and crevices in the bee colony and in capped brood cells. They are deposited in clusters of up to 210 eggs in cracks and crevices of the hive, a total of 1,000 to 2,000 eggs are laid per female in the course of life. The larvae hatching from the eggs after 2-3 days eat passages through the combs. They eat honey, pollen, dead bees and prefer brood and can destroy the combs completely. The larvae eat an average of 13.3 days in the bee colony, but only 5–6 days are required under particularly favorable conditions. Humidity is particularly important for the beetle larvae. They are greatly promoted by humid conditions. Then they leave the hive to pupate in the ground; they can cover longer distances ("wandering larvae"). The larvae leave the hive in the evening hours (peak around 9 p.m.). The pupal phase in a self-dug small hole in the ground takes about 8 days, under unfavorable conditions up to three weeks. Like the larvae, the pupae need moisture and are severely damaged by low soil moisture. The beetles reach sexual maturity about a week after hatching from the pupal chamber. They then look for beehives, whereby the smell, but possibly also as yet unknown pheromones, play a role. The adult beetles feed on pollen and nectar. They survived in the laboratory with feeding for up to 188 days, but only 19 days with only water and wax. Freshly hatched beetles survived for seven days without food. Experimentally, beetles and larvae can be kept alive with substitute foods such as fruit, albeit with less success. They can survive in artificially infected bumblebee nests, but have not yet been found here in the wild.
The small hive beetle overwinters only in the imaginal stage , i.e. H. as a beetle. In cooler areas they smuggle themselves into the clusters of the overwintering bees in order to benefit from their heat development. A temperature of −12 ° C for 24 hours killed all development stages of the species to 100%.
The honey is polluted by the larval droppings and begins to ferment. The leaked, fermented honey from destroyed cells runs down to the bottom of the hives, so that the infestation is noticeable through a putrid smell. Even healthy colonies can be completely destroyed within a few weeks, weakened colonies after two weeks.
Countermeasures by the bee colony include: Keeping adult beetles in empty cells by guard bees and sealing cells, crevices and cavities, including the beetles hidden therein, with propolis . Guardian behavior was comparable between European and African bee colonies, but African colonies use up to four times as much propolis as Europeans. The beetles are at least occasionally able to use the bees' feeding reflex for themselves by cheating with their antennae. The beetles can survive in the guarded cells for up to two months. Bees show different degrees of direct aggression against beetles, but this is not very effective because of their protective body shape and protective posture with their heads drawn up and legs and antennae crossed. They destroy egg clutches that have been discovered and can also carry out entire brood cells or destroy them if they notice an infestation. It is still unclear which of these strategies ultimately results in the greater success of African peoples compared to Europeans in combating them. In Africa, the beetles usually only succeed in reproducing in abandoned or considerably weakened nests.
Spread
The hive beetle appeared in southeastern North America in 1996 (noticed only in 1998) and from there spread at breakneck speed across the United States . Since 2002, the beetle has also spread to the northern regions of the United States and Canada, where it is probably less of a problem for climatic reasons and may not be able to establish itself permanently. To the west he has so far advanced to North Dakota. He was reported from Egypt in 2000 and from Australia in 2001 . Here, the spread has so far been limited to small areas in New South Wales, and no major damage has occurred. He probably came to these countries by ship with fruit or in a bee colony. The first finds in the USA (Charleston, Savannah) and Australia (Sydney, Brisbane) come from port cities. After it had long been expected that it would eventually reach Europe, this was true in 2004, when larvae and beetles of hive beetles were first detected in Portugal , albeit only in cages of imported queen bees, which meant that the beetle could be quickly and successfully destroyed. In North America the beetle has spread to California and Mexico, and in Australia from New South Wales to Townsville (Neumann and Ellis 2008).
In September 2014, beetles and larvae of the small hive beetle were found in three offshoots near the Italian port of Gioia Tauro in the northwest of the province of Reggio Calabria . By mid-December 2014, more than 50 infested colonies had been identified in this area, the infested peoples were burned and the soil was chemically treated. Another infestation was diagnosed on a migrant bee farm in Sicily. The authorities created two restricted zones (20 km and 100 km radius) around the infested apiaries. No bees may be moved from these restricted areas. In 2015, beetles and larvae were found to a lesser extent in the 20 km exclusion zone in Calabria. The hive beetle infestation has not yet occurred in Germany.
Combat
The small hive beetle is one of the most feared bee parasites, as a whole colony can be destroyed within a very short time in the event of a mass infestation. In contrast to the African honey bee subspecies, which can efficiently defend themselves against the small hive beetle, the European subspecies are less able to do so. The chemical control measures currently available carry the risk of the formation of resistance, contamination of the bee products and effects on the bees themselves. Alternative measures are being developed. The beetle infestation is subject to notification in Germany . It is also classified as a notifiable animal disease in the other EU countries and Switzerland .
Web links
- Small hive beetle (Aethina tumida). Friedrich Loeffler Institute
- BMVEL : "The small hive beetle - Recognizing and fighting" (PDF; 852 kB)
- Literature list Aethina tumida (partly with abstracts) . Beetle campaign (completed), Mellifera eV, Association for appropriate beekeeping.
- Federal Food Safety and Veterinary Office: Small hive beetle detected in southern Italy , September 2014 (accessed on October 15, 2014)
Individual evidence
- ^ AE Lundie (1940): The Small Hive Beetle, Aethina tumida. In: Miscellaneous Science Bulletin. Department of Agriculture and Forestry, Union of South Africa No. 220. 30 pp.
- ↑ Malcolm T. Sanford: Small Hive Beetle, Aethina tumida (Murray) (Insecta: Coleoptera: Nitidulidae) , University of Florida, Institute of Food and Agricultural Sciences (IFAS) Extension, Gainesville, USA, Doc. EENY-094, last revision: September 2005, last revision: March 2008, doi: 10.1.1.508.681
- ↑ determining aid (PDF, 318 kB)
- ^ A b c Michael Hood (2004): The small hive beetle, Aethina tumida: a review. Bee World 85 (3): 51-59.
- ↑ a b c d Peter Neumann & Patti J. Elzen (2004): The biology of the small hive beetle (Aethina tumida, Coleoptera: Nitidulidae): Gaps in our knowledge of an invasive species. Apidology 35: 229-247.
- ↑ Istituto Zooprofilattico Sperimentale delle Venezie: Status of the development of the small hive beetle in Italy current .
- ↑ Animal Disease Report 2011 by the BMELV . In: Deutsches Tierärzteblatt. (DTBL) Volume 60, May 2012, pp. 714–715.