Small hive beetle

Species of beetle

Aethina tumida, commonly known as small hive beetle (SHB), is a beekeeping pest. It is native to sub Saharan Africa, but has spread to many other regions, including North America, Australia, and the Philippines. The small hive beetle primarily lives within the beehive and they are fed on pollen, honey and dead bees. The colonization can cause severe damage to honeycomb, stored honey, and pollen. In Mexico, the small hive beetle has become established in at least eight states. Infestation levels are especially high in tropical areas such as the Yucatán. The small hive beetle was first detected in Belize in 2016 in the Corozal District and was reported in Honduras in 2024

The small hive beetle has also spread to Australia in areas of Richmond, New South Wales, Queensland and New South Wales. It was not found in Northern Territory and has no longer been a notifiable pest in Victoria and South Australia. In Western Australia, it is restricted to the Kimberly region. It is possible that the import of package bees, honeybee or bumblebee colonies, queens, hive equipment or even soil constituted the potential invasion pathway of the small hive beetle; however, at the current state of evidence it is still unclear how small hive beetles actually reached Australia. The small hive beetle has now reached southern Mindanao in the Philippines. It might lead to a spread through the country if hives and bees are moved to other areas. Small hive beetle was first detected in Calabria, southern Italy in September 2014. It is currently confined to the provinces of Reggio Calabria and part of Vibo Valentia, where it has now become naturalized. In 2014 and 2019, outbreaks of infestation occurred in eastern Sicily.

Females lay eggs within the bee brood and larvae would hatch inside. Pupation happens under the soil. The adults primarily live within the host hive and seek for food from the hosts. Adults can overwinter with the bee population in colder climates.

Small hive beetles are insectivores, and they can be fed on both animal and plant diets. Animal diets include the bee eggs, host body fluids and dead bees. Plant diets include fruit, nectar and pollen. Adults and larvae are fed by the same food.

The peak of reproduction period varies in different places. Most small hive beetle populations reach the highest density during the summer and early autumn season with high temperature. Some populations show preference for the rainy season while others prefer the dry season. It has been proved that the antennae of SHBs has a lower threshold to sense the component of the volatiles released from the hive entrance compared to the honeybee. They can also sense more types of chemicals than the host workers and foragers. This ability highly improves the beetle’s fitness to recognize and invade the colony quickly since the bees are not able to sense and initiate attack at the invader under low pheromone concentration.

Larvae are about 1cm long upon complete development with a white color. Their body is segmented with 3 pairs of legs in front of the head. This stage continues about 13.3 days within the host hive and about 3 more days in the soil to prepare for the pupation. This stage creates the most severe damage toward the host hive as fermentation occurs when the larvae tunnel through the hive.

Adult beetles are about 5 7mm long and 3 4.5mm wide. Their lifespan highly depends on the food sources. They may live for 6 months when fed by honey, but can only live for 19 days when fed by water and beeswax. They can live for about 10 days without any food or water intake, which gives them a period to look for a new host when they first emerge from the soil. If the beetles enter the hive, the guards would catch them and keep them in the propolis confinement sites. Patrolling behavior around the nest and combs is well observed in the brood area within the hive. The third strategy is to remove beetle eggs and larvae. SHB can hide from the patrolling behavior by ovipositing in the combs. To deal with this counter strategy, honeybee workers developed the adaptation to remove the beetle’s eggs and larvae. However, SHBs can still lay clutch of eggs in the crevices to escape from the host’s defense response.

The captured beetles have been observed to live up to 2 months without the ability to find food within the hive and their reserved food can only support them to live for 2 weeks. The observed behavior of bees feeding the beetle might be the result of behavioral mimicry. The beetle constantly taps the bees with their antennae. This behavior mimics the action of other bees and traps the host to feed the beetle. Small hive beetle is also a vector for honeybee viruses, including deformed wing virus and sacbrood virus. They can bring the viruses to the honeybee host and cause widespread infection.

Adult SHBs have strong flying ability up to 16 kilometers. The ant Pheidole megacephala is the predator specifically to small hive beetle larvae in Kenya.

There is no direct competitor with small hive beetles within honeybee colonies. Competition may appear when other organisms occasionally share the food left within the honeybee colonies and other resources with small hive beetles. Two haplotypes found in US are proved to show different frequency in different areas, which might be the result of more than two separate introduction of the species into US, possible selection in different regions or the genetic bottleneck when beetle colonizers new sites. There is no selection pressure found between two haplotypes.

Small hive beetles demonstrate an age dependent gender preference during copulation. Within the window of 18 days after adults emerge, the male beetles show mating behavior with other males. After 18 days, both genders spend more time to interact and copulate with the opposite sex. The heavy infestation also negatively affects the queen and package bee production around the world. Prevention strategy has been implemented in UK to eliminate potential spread of SHB as multiple areas have the preferred condition for SHB survival.

Fungal pathogens have shown to kill SHB in laboratory trials. Metarhizium fungi was found to kill the larvae when it is added to soil containing the beetle. It was also found that the fungi could negatively impact the fertility of the beetles.

The beekeeper should keep the honeybee hive well populated and avoid over stress, which can maintain a productive colony and eliminate the beetle from the colony. can be used as fumigants to control SHB within the stored comb. The chemical product composed of 40% permethrin from Gard Star has been used in the USA. It is mixed with water and applied to the soil which can kill SHB larvae and pupae underneath the ground. It is also used in areas where the infested colony is removed and the beetles are left. The 10% coumaphos plastic strip by Bayer Corp. is also widely used in USA. It traps the beetles within the box which contains the chemical and then the beetle would die upon lethal dose inhalation. There are also several traps currently on the market. The more effective ones are the Beetlejail Baitable, Hood Trap, the Freeman Beetle Trap, the West trap, the Australian, AJ's Beetle Eater, and the Beetle Blaster. All these traps use non toxic oil to suffocate the beetles. This allows beekeepers to avoid having toxic chemicals in their beehives.