neutral to beneficial; feeds on potentially harmful fungi

Name and classification

Ameroseius Berlese, 1904 (some authors cite the year as 1903; here we verified the original publication date)

Superorder Parasitiformes » Order Mesostigmata » Suborder Monogynaspida » Hyporder Dermanyssiae » Family Ameroseiidae » Genus Ameroseius

Type species
Seius echinatus C. L. Koch, 1839 (= Acarus corbicula Sowerby, 1806 = Seius muricatus Koch, 1839)

Common synonyms
Kleemannia Oudemans is considered either as a junior synonym (Halliday, 1997) or as a valid genus (Evans and Till, 1979). Here we follow the most recent works by considering Kleemannia a junior synonym of Ameroseius. However, below we give diagnostic character states of Kleemannia to differentiate it from the typical Ameroseius.


Female: Dorsal shield rugose, strongly sculptured or ornamented with a series of interconnecting ridges (Fig. 1). Dorsal shield with usually 29, or rarely 30 pairs of setae; dorsal shield setae usually large, plumose or serrated (Fig. 1). Marginal dorsal shield setae not conspicuously longer than setae in center of shield (Fig. 1). Sternal shield with 2 pairs of setae (rarely 3) (Figs. 2, 3). Corniculi distally bifid or otherwise subdivided (Figs. 2, 7, 8). Legs I with ambulacrum I (claws and pulvillus) present (Figs. 1, 2). Genu II with 1 or 2 (Kleemannia) ventral setae. Palp apotele 3-tined or 2-tined (Kleemannia). With anal shield (similar to that of Ameroseiella) (Fig. 10) or ventrianal shield (Kleemannia) (Figs. 2, 4, 5, 6).

Species identification

This is a species-rich genus. The two species found in hives of honey bees and nests of bumble bees in the Old World, Ameroseius plumigerus and A. plumosus, can be identified using keys from Karg, 1971 and Bregetova, 1977b. Two other species collected from large carpenter bees in Africa, Ameroseius bembix ealensis and Ameroseius benoiti, should be identified using the original description (Elsen, 1973). In addition, Sertitympanum aegyptiacus has been reported from bee hives (as Ameroseius aegyptiacus). This species has a single cog-wheel-like structure on the sternal shield, dorsal shield not rugose, short dorsal setae, and longitudinally elongated ventrianal shield. Based on these characteristics it probably does not belong to either Sertitympanum or Ameroseius.

Similar genera

Ameroseiella. Can be distinguished by the absence of the ambulacrum on tarsi I (Figs. 9, 10) (present in Ameroseius, Figs. 1, 2).

Sertitympanum. Can be distinguished by the presence of three cog-wheel-like structures on the sternal shield (none or one in Ameroseius) and the presence of excrescences on the legs (absent in Ameroseius).


Distributed worldwide; bee records are from Europe and Africa.

Bee hosts

These mites are generalists that have been found in nests of honey bees (Apis) and bumble bees (Bombus) in Europe and phoretic on large carpenter bees (Xylocopa) in Africa.

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


Host associations, feeding, and dispersal

  • All stages are fungivorous in different habitats, including nests of honey bees, bumble bees, and probably large carpenter bees.
  • Mites may disperse to bee nests by walking if a nest is nearby and/or by phoresy on bee hosts. Female is the phoretic stage.


Mites of the genus Ameroseius are generalist species feeding on fungi in all post-embryonic stages. Mites occur in soil, plant litter, and nests of small rodents and insectivores; under bark; and in stored food products, debris in granaries and haystacks. Occasionally found in honey bee hives and bumble bee nests (Ameroseius plumigerus and A. plumosus). Some species are phoretically associated with rodents and insects, particularly sphecid wasps and large carpenter bees in Africa (Ameroseius bembix ealensis and Ameroseius benoiti).