neutral to potentially beneficial; feed primarily on fungi

Name and classification

Scutacarus Gros, 1845

Superorder Acariformes » Order Trombidiformes » Suborder Prostigmata » Infraorder Eleutherengona » Hyporder Heterostigmata » Family Scutacaridae » Genus Scutacarus

Type species
Acarus acarorum Goeze, 1780


Female: Setae c1 in central part of tergite C (not on its free, striated margin) (Fig. 1). Legs IV 4-segmented (trochanter, femur, genu, and tibiotarsus) (Fig. 6). Tibiotarsus IV with more than 4 setae (Fig. 6).

Species identification

This is a species-rich genus, containing both bee-associated and non bee-associated mites. Except for a key to Palaearctic species (Khaustov, 2008), no other keys are available. There are five species associated with bees. Four species associated with bumble bees (Scutacarus acarorum, S. deserticolus, S. mendax, and S. occultatus) can be identified using Jagersbacher-Baumann, 2014 and Khaustov, 2008. The remaining species, Scutacarus eickworti, from halictid bees in the USA, can be identified using Delfinado and Baker, 1978.


Cosmopolitan. Species associated with bees have been found in the Holarctic region.

Bee hosts

commonly found on bumble bees (Bombus) (Fig. 7) and accidentally on the European honey bee, Apis mellifera (as a result of transfer from bumble bees); one species found on Lasioglossum (Dialictus).

Host association level


associated exclusively with bees or their close relative, wasps; cannot live without these hosts


some life stages are associated with bees, while others are not

Facultative or opportunistic

can complete entire life cycle without bees or their close relative, wasps

Species found on bees display a tendency toward permanent associations: they normally live in bee nests but can also live in other habitats.

Host associations, feeding, and dispersal

  • All stages live in nests of bees, feeding primarily on fungi.
  • Mite females disperse on adult bees; bumble bee associates prefer queens.


Most species of this genus are free-living in litter and moss. Many species are associated with ants, living in their nests and using adult insects for dispersal. A few species have been found to be phoretic on beetles and flies. The occurence of Scutacarus acarorum, normally associated with bumble bees, on the honey bee or in its nest is attributable to the fact that overwintered Bombus queens often enter honey bee hives (Schousboe, 1986). It is unknown whether S. acarorum can live sustainably in association with honey bees. Scutacarus acarorum has been found hyperphoretic on mite deutonymphs of the genus Parasitellus (Parasitidae) that are in turn phoretic on their bumble bee hosts.