''Parasitellus'' (formerly ''Parasitus'') is a genus of

mite Mites are small arachnids (eight-legged arthropods). Mites span two large orders of arachnids, the Acariformes and the Parasitiformes, which were historically grouped together in the subclass Acari, but genetic analysis does not show clear evid ...

s in the family

Parasitidae Parasitidae is a family of predatory mites in the order Mesostigmata that has worldwide distribution. They are the only family in the superfamily Parasitoidea. Relatively large for mites, their color is often yellowish to dark brown. The family a ...

which are obligatory parasites of

bumblebee A bumblebee (or bumble bee, bumble-bee, or humble-bee) is any of over 250 species in the genus ''Bombus'', part of Apidae, one of the bee families. This genus is the only extant group in the tribe Bombini, though a few extinct related gener ...

s. These mites can be found clinging to the carapace, sometimes in large numbers. Mites in this genus hibernate in the

deutonymph Mites are small arachnids (eight-legged arthropods). Mites span two large orders of arachnids, the Acariformes and the Parasitiformes, which were historically grouped together in the subclass Acari, but genetic analysis does not show clear evid ...

al stage. In the tritonymph stage they can actively transfer from bumblebee to bumblebee from flowers, where they can survive up to 24 hours. After they arrive in a bumblebee nest, they will moult into adults. Whilst it is not known what factors trigger the mite to molt, in laboratory conditions ''P. fucorum'' were found to moult after eating fresh pollen, although overall moulting success was low. They are kleptoparasitic or neutral to beneficial, depending on life stage; females and deutonymphs feed on provisioned pollen, while other stages are predators of small arthropods.

Taxonomy and identification

Species

* '' Parasitellus crinitus'' (Oudemans, 1903) * ''

Parasitellus ferox ''Parasitellus'' (formerly ''Parasitus'') is a genus of mites in the family Parasitidae which are obligatory parasites of bumblebees. These mites can be found clinging to the carapace, sometimes in large numbers. Mites in this genus hibernate in ...

'' (Trägårdh, 1910) * ''

Parasitellus fucorum ''Parasitellus'' (formerly ''Parasitus'') is a genus of mites in the family Parasitidae which are obligatory parasites of bumblebees. These mites can be found clinging to the carapace, sometimes in large numbers. Mites in this genus hibernate in ...

'' de Geer, 1778 * ''

Parasitellus ignotus ''Parasitellus'' (formerly ''Parasitus'') is a genus of mites in the family Parasitidae which are obligatory parasites of bumblebees. These mites can be found clinging to the carapace, sometimes in large numbers. Mites in this genus hibernate in ...

'' (Vitzthum, 1930) * ''

Parasitellus talparum ''Parasitellus'' (formerly ''Parasitus'') is a genus of mites in the family Parasitidae which are obligatory parasites of bumblebees. These mites can be found clinging to the carapace, sometimes in large numbers. Mites in this genus hibernate in ...

'' (Oudemans, 1913)

Diagnosis

2-Parasitellus talparum DN1 ventr DIC20 BMOC 99-0624-001

Adult and deutonymph: In both adults and deutonymphs, opisthogastric region has more than 40 pairs of

seta In biology, setae (singular seta ; from the Latin word for "bristle") are any of a number of different bristle- or hair-like structures on living organisms. Animal setae Protostomes Annelid setae are stiff bristles present on the body. Th ...

e (see figure). In all other species of Parasitidae, opisthogastric region has fewer than 30 pairs of setae.

Species identification

A key to species from North America is available from th
bee-associated mites website
A key to species from the British Isles is available in Hyatt, 1980.

Similar genera

''Parasitellus ''can be distinguished from all other genera of

by the'' ''opisthogastric region having more than 40 pairs of setae. This region has fewer than 30 pairs of setae in other genera of Parasitidae.

Distribution

Common in the Holarctic region (North America, Europe, Northern Asia, and China). Also reported in the Neotropical region (Argentina and Mexico).

Hosts

Bee hosts

All species of the genus ''Parasitellus'' are obligatory associates of bumble bees (''Bombus''). Several occasional records are from honey bee (''Apis'') hives and burrows of small mammals (which are preferential sites for bumble bee nests).

Host association level

permanent

Host associations, feeding, and dispersal

* All stages live in nests of bumble bees (''Bombus'' spp.), where females and deutonymphs feed on pollen and other stages feed on small arthropods. * Mite deutonymphs disperse and overwinter on adult queen bees. Phoresy on workers and males of bumble bees or cuckoo bumble bees is also documented.

Biology

All species of ''Parasitellus'' inhabit nests of bumble bees (''Bombus''). Mite deutonymphs are commonly

phoretic Phoresis or phoresy is a non-permanent, commensalistic interaction in which one organism (a phoront or phoretic) attaches itself to another (the host) solely for the purpose of travel. Phoresis has been observed directly in ticks and mites s ...

on adult bumble bees or cuckoo bumble bees. Phoretic mites prefer queens to other castes (workers and males), since bumble bee colonies are annual and only young queens overwinter. Mites dispersing on workers and males may try to switch to queens later, either during copulation or on flowers, where bumble bees forage.Huck, K., H. H. Schwarz & P. Schmid-Hempel. 1998. Host choice in the phoretic mite ''Parasitellus fucorum'' (Mesostigmata: Parasitidae): which bumblebee caste is the best? Oecologia.115: 385-390. Species of ''Parasitellus'' are not specific to a particular bumble bee species, with different mite species often co-occurring in a single ''Bombus'' nest or co-dispersing on a single bee individual. The nature of the association between ''Parasitellus'' and its bumble bee hosts is a balance between being harmful and beneficial. In ''Parasitellus fucorum'', males, larvae, protonymphs, and possibly deutonymphs, have been found to be predatory or

oophagous Oophagy ( ) sometimes ovophagy, literally "egg eating", is the practice of embryos feeding on eggs produced by the ovary while still inside the mother's uterus. The word oophagy is formed from the classical Greek (, "egg") and classical Greek (, ...

(egg-feeding) on microarthropods in bumble bee nests and thus, beneficial to the bees, while adult females and deutonymphs preferentially feed on the provisioned pollen and are harmful to the host.Koulianos, S. & H. H. Schwarz. 1999. Reproduction, development and diet of Parasitellus fucorum (Mesostigmata : Parasitidae), a mite associated with bumblebees (Hymenoptera: Apidae). Journal of Zoology.248: 267-269. Mites feed on the upper layer of pollen grains (nectar coating and pollenkitt), without damaging them otherwise. Pollen grains processed in this way lost their normal bright yellow or blue color and became pale and more translucent.

References

{{Taxonbar, from=Q7135942 Parasitidae Parasites of bees