Tarsonemus

 

HARMFUL | NOT HARMFUL | UNCERTAIN

most likely neutral; primarily fungivores; details of association with bees unknown

Name and classification

Tarsonemus Canestrini and Fanzago, 1876

Taxonomy
Superorder Acariformes » Order Trombidiformes » Suborder Prostigmata » Infraorder Eleutherengona » Hyporder Heterostigmata » Family Tarsonemidae » Genus Tarsonemus

Type species
Chironemus minusculus Canestrini and Fanzago, 1876

Diagnosis

Adult: Metapodosomal venter with 2 pairs of setae (3a, 3b; 3c, 4b absent) (Fig. 2). Cheliceral stylets short (Fig 2). Femur I with 3-4 setae, femur II with 2-3 setae (Fig. 2). Dorsal gnathosomal setae filiform (Fig. 1). Dorsal setae of idiosoma simple, unmodified (Fig. 1). Gnathosomal capsule not conspicuously beaklike (Fig 2).

Female: Claw I present, not enlarged (Figs. 1, 3). Ambulacrum I developed (Figs. 1, 3). Prodorsum with a pair of capitate trichobothria Figs. 1, 3). Tegula short, not elongated, rounded (Fig. 2). Pharynx not conspicuously enlarged (Fig 2). Setae sc2 well posterior to stigma Figs. 1, 3). Prodorsal shield not extended hoodlike over gnathosoma and not covering stigmata (Figs. 1, 3). No hornlike protuberances with stigmata Figs. 1, 3). Apodemes 4 not extending posterolaterally to bases of trochanters IV (Fig 2). Setae h not longer than any setae on tergites D and EF (Fig. 1). Leg IV clearly longer than tegula (Fig. 2). Sejugal apodeme (apodeme delimiting propodosoma and hystersoma ventrally) developed (Fig. 2).

Species identification

This is a species-rich genus with nearly 200 described species. Five of these species are associated with bees. A key to all species is not available. Regional keys exist for the Palaearctic region (Kaliszewski, 1993), Central Europe (Krczal, 1957), the former USSR (Sevastyanov, 1978), and China (Lin and Zhang, 2006).

Distribution

The genus is cosmopolitan; species associated with bees have been recorded from all zoogeographic regions but Afrotropical.

Bee hosts

honey bees (Apis), bumble bees (Bombus), large carpenter bees (Xylocopa), and stingless bees of the genus Melipona

Host association level

Permanent

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

Temporary

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

facultative (generalist species)

permanent (Tarsonemus apis, T. platynopodae, and T. xylocopae)

Host associations, feeding, and dispersal

Generalist species

  • All stages are primarily fungivorous in different habitats, including nests of bees.
  • Dispersal probably occurs on adult bees or short-range dispersal can be accomplished by walking.

Tarsonemus apis, T. platynopodae, and T. xylocopae:

  • All stages that live in bee nests presumably feed on various fungi and develop on nest materials or pollen.
  • Female mites disperse on adult bees.

Biology

Out of nearly 200 species of Tarsonemus, five species have been recorded in association with bees: Tarsonemus apis, T. blakemorei, T. fusarii, T. minimax, T. platynopodae, and T. xylocopae.

Among them, Tarsonemus fusarii is a widespread generalist primarily inhabiting stored grain. T. minimax is associated with bark beetles (so the records from bees may be accidental or the species was misidentified). Similarly, T. blakemorei was originally found in nests of birds but then was recorded from various bees in India: Apis mellifera, Apis cerana, and Melipona sp. (Sumangala and Haq, 2001).

Three other species have been found exclusively on bees and/or their nests, indicating close associations: Tarsonemus apis (Apis mellifera), T. platynopodae (Xylocopa latipes, Malaysia), and T. xylocopae (Xylocopa frontalis). Tarsonemus apis has been collected from Apis mellifera (Europe) and other species of Apis in Singapore, both on adult bees and in stored pollen.

Mites of the genus Tarsonemus are common in a great variety of habitats including soil, litter, ground-level and subterranean nests of vertebrate and invertebrate animals, decaying wood, bracket fungi, subcortical habitats where they are associated with insects, stored grain and food products, laboratory cultures, house dust of man-made habitats, and on all sorts of woody and herbaceous plants including conifers, monocotyledonous plants, and especially dicotyledonous plants, both deciduous and evergreen.

Mites of this genus are primarily fungivores. A few species are economically important pests in commercial mushroom cultures and fungal cultures in research laboratories. Species of Tarsonemus sometimes carry fungal spores, mostly in the membranous lateral areas underneath the tergite. For example, Tarsonemus ips may play a role in its beetle host's (southern pine beetle) transmission of the bluestain fungus, Ceratocystis minor, to coniferous trees. Some species may be transitionally phytophagous, attacking plants of agricultural importance, such as crops and ornamentals. One species, T. dispar, associated with passalid beetles, feeds on living animal exudates or products. Other species of Tarsonemus appear to be beneficially important in their association with fungi in the decomposition of soil litter (reviewed in Lindquist, 1985).