Tydeus

Name and classification

Tydeus Koch, 1836

Note: There is no agreement on the year of the original description of Tydeus Koch. Most workers agree that the first description of Tydeus appeared in "Koch, C.L. Deutschlands Crustaceen, Myriapoden und Arachniden. Ein Beitrag zur deutschen Fauna, Heft 4 (=Heft 137)" (not seen by us). The most recent treatment cites the year as 1836 (André, 2005), with a discussion on publication date of Heft 4 - either 1836 or 1837 and the warrant that the year cannot be found on the author's personal reprint. Oudemans gives the same year for Heft 4 (Oudemans, 1937b). However, the Nomenclator Zoologicus online database indicates that Heft 4 had been published in 1837. Kaźmierski gives 1835 for Tydeus Koch, without explicitly citing the original Koch's work or any further discussion on the matter (Kaźmierski, 1989). Here we follow André, 2005 and André and Kaźmierski, 2006, citing the year of the original description of Tydeus as 1836.

Taxonomy
Superorder Acariformes » Order Trombidiformes » Suborder Prostigmata » Infraorder Eupodina » Family Tydeidae » Genus Tydeus

Type species
Tydeus spathulatus Oudemans, 1928. Designated by Opinion 2190 ICZN (2008), see Case 3354 (André and Kaźmierski, 2006).

Common synonyms
The complicated synonymy of this genus was discussed in André, 2005.

Diagnosis

Female: Palptarsus unmodified, not thumblike (Fig. 1). No markedly elongated setae on palptarsus (Fig. 2). Palptibia without claw-like setae. Chelicerae contiguous (Fig. 1). Movable digit of chelicerae stylet-like (Fig. 1). Naso absent (Fig. 1). Prodorsal bothridial setae present (Fig. 1). Ovipore longitudinal (Fig. 2). No net-like ornamentation on legs and prodorsum (Fig. 1). Tarsus I with claws (Fig. 2). No trichobothria on tibia IV (Fig. 2).

Species identification

Only two species of Tydeus have been recorded in association with bees: Tydeus interruptus Thor, 1932 and Tydeus xylocopae Oudemans, 1926. The former species was redescribed in Hughes, 1976. However, these two species were recently treated as species inquirendae, since the original and subsequent descriptions are not sufficient for reliable identifications (Kaźmierski, 1998). No key to species is available.

Distribution

Cosmopolitan; bee-associated species have been found in Palaearctic, Oriental, and Australian regions.

Bee hosts

A few species have been recorded from nests of bumble bees (Bombus), the European honey bee (Apis mellifera), and a carpenter bee (Xylocopa sp.).

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

Host associations, feeding, and dispersal

All stages live in a variety of habitats (plant leaves, moss, stored products, barn debris, and vertebrate nests), where they feed as omnivorous scavengers. They can also prey on small arthropods and their eggs.
Mites probably enter bee nests by walking if a nest is nearby, without need for a host.

Biology

The majority of species of Tydeus are moss inhabitants (Momen and Lundqvist, 2005). Some species occur on tree foliage, stored products, vertebrate nests, and beehives. They are omnivorous scavengers and can also prey on the smallest arthropods and their eggs (Kaźmierski, 2009). Unidentified species of Tydeus have repeatedly been collected in beehives throughout the world (Haragsim et al., 1987, Homann, 1933, Kamali et al., 2001; Malabanan and Corpuz-Raros, 1998) or in bumble bee nests (Chmielewski, 1971). Tydeus interruptus has been found in nests of introduced bumble bees in New Zealand (Macfarlane, 2005), and Tydeus xylocopae in the nest of a large carpenter bee (Xylocopa sp.) in Indonesia (Oudemans, 1926b).

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