The beaver beetle (''Platypsyllus castoris'') is an

ectoparasitic Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson ha ...

beetle Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 describ ...

that is only found on its host species,

beaver Beavers are large, semiaquatic rodents in the genus ''Castor'' native to the temperate Northern Hemisphere. There are two extant species: the North American beaver (''Castor canadensis'') and the Eurasian beaver (''C. fiber''). Beavers a ...

s, and the sole member of the genus ''Platypsyllus''. It is flattened and eyeless, resembling a flea or tick. It used to be placed in a separate family called Leptinidae, but is now placed in the family

Leiodidae Leiodidae is a family of beetles with around 3800 described species found worldwide. Members of this family are commonly called round fungus beetles due to the globular shape of many species, although some are more elongated in shape. They are g ...

, in the subfamily

Platypsyllinae Platypsyllinae is a subfamily of the family Leiodidae, known as mammal-nest beetles. The group was formerly known as the family Leptinidae but the name Platypsyllidae had seniority, and is now ranked as a subfamily. Genera *'' Leptinillus'' Hor ...

Description

The beaver beetle has various modifications to suit its ectoparasitic mode of life. It resembles a flea or a louse in appearance and was originally placed in the flea family Platypsyllidae. It has no wings and no eyes, and its antennal clubs have the antennomeres numbered 3 to 11 shortened, compacted globularly, and partly enclosed in a scoop-shaped antennomere. The larvae are also ectoparasitic on beavers and have hooks on the three thoracic segments which enable it to cling to its host.

Distribution

The beetle exists only in the northern hemisphere (

holarctic The Holarctic realm is a biogeographic realm that comprises the majority of habitats found throughout the continents in the Northern Hemisphere. It corresponds to the floristic Boreal Kingdom. It includes both the Nearctic zoogeographical reg ...

) and is restricted to areas in which beavers are found, North America and northern Europe and Asia.

Behaviour

Besides the

North American beaver The North American beaver (''Castor canadensis'') is one of two extant beaver species, along with the Eurasian beaver (''Castor fiber''). It is native to North America and introduced in South America ( Patagonia) and Europe (primarily Finland ...

(''Castor canadensis'') and the

Eurasian beaver The Eurasian beaver (''Castor fiber'') or European beaver is a beaver species that was once widespread in Eurasia, but was hunted to near-extinction for both its fur and castoreum. At the turn of the 20th century, only about 1,200 beavers survi ...

(''Castor fiber''), the only other host on which this beetle has been found is the

North American river otter The North American river otter (''Lontra canadensis''), also known as the northern river otter and river otter, is a semiaquatic mammal that only lives on the North American continent, along its waterways and coasts. An adult North American rive ...

(''Lontra canadensis''), and this was only on one occasion. It is hypothesized that the otter may have picked up the parasite when it entered a beaver lodge or perhaps killed a young beaver, a thing that otters are believed to do on occasion. Both adult beetles and larvae feed on epidermal tissue, and also perhaps on skin secretions and liquids oozing from wounds. It is possible that the larvae may also act as

scavenger Scavengers are animals that consume dead organisms that have died from causes other than predation or have been killed by other predators. While scavenging generally refers to carnivores feeding on carrion, it is also a herbivorous feedin ...

s in the beaver lodge.

References

External links

Beaver Beetles
by David Moskowitz {{Taxonbar, from=Q2064126 Parasitic insects Wingless beetles Leiodidae Beetles described in 1869