Sancassania

 

HARMFUL | NOT HARMFUL | UNCERTAIN

scavenger; feeds on debris in hives or feces in failed larval cells

Name and classification

Sancassania Oudemans, 1916

Taxonomy
Superorder Acariformes » Order Sarcoptiformes » Suborder Oribatida » Infraorder Desmonomata » Hyporder Astigmata » Family Acaridae » Genus Sancassania

Type species
Sancassania chelone Oudemans, 1916

Common synonyms
Caloglyphus Berlese, 1923 In the literature, the genus Ctenocolletacarus is treated as valid. However, its adults are indistinguishable from Sancassania and its phoretic deutonymphs have only autapomorphic (unique, derived) diagnostic character states, suggesting that Ctenocolletacarus is part of Sancassania rather than an independent, genus-level lineage.

Common names
wet grain mite (for Sancassania berlesei auct. non Michael)

Diagnosis

Phoretic deutonymph: Vertical setae ve present, short (Figs. 3, 4). Tarsal setae aa I present (Fig. 4). Tarsal setae ba I absent, setae ba II present (Fig. 4). Tarsal seta e I-II with saucer-like tip (Fig. 4). Genua III-IV not distinctly longer than tibiae III-IV (Fig. 5). No dorsal solenidion (σ) on genu III (Fig. 5). Conoidal setae ps2 lateral to median suckers ad1+2 (not anterior) (Fig. 5). No striate membrane posterior to attachment organ (Fig. 5).

Adult: Setae aa present (correlates with character in deutonymph) (Fig. 14). Supracoxal seta filiform (Figs. 12, 13) or short, spiniform; always smooth (never barbed or pectinate) (Figs. 12, 13). Anal opening of female displaced anteriorly, situated in the middle of hysterosoma (Fig. 7). Tarsal setae ra and f II with foliate ends (Figs. 13, 14). Setae ra I-II situated near apex of tarsus (Figs. 13, 14). Seta e I-II spiniform (Figs. 13, 14).

Other diagnostic characters

Heteromorphic males: Legs III enlarged (Figs. 10, 11); serve as weapons when fighting with other males.

Species identification

This genus, which has more than 80 species, needs a revision. Common, widespread stored product pests are treated in two older keys to Sancassania species from Middle Europe (Türk and Türk, 1957) and the Palaearctic (Zachvatkin, 1941). Both keys use the name Caloglyphus (currently a junior synonym of Sancassania). Many taxonomic concepts for Sancassania species names, including those included in these two keys (e.g., S. berlesei, S. rodionovi, and S. mycophaga), require revision and careful examination of type material.

Similar genera

Sancassania is similar to Cosmoglyphus in their anterior displacement of the anal opening and morphology of tarsus I. Phoretic deutonymphs of Sancassania have genua III-IV not distinctly longer than tibiae III-IV (distinctly longer in Cosmoglyphus). Adults of Sancassania have smooth, filiform or spiniform supracoxal setae (lanceolate, with pectinated margins in Cosmoglyphus).

Phoretic deutonymphs of Sancassania can be distinguished from those of Ctenocolletacarus by the non-enlarged rostrum (enlarged in Ctenocolletacarus) and the non-striated idiosoma (transversely striated on Ctenocolletacarus). Adanal suckers are present in the majority of Sancassania species, while Ctenocolletacarus males lack adanal suckers.

Distribution

The genus is cosmopolitan. Records of mites found on bees or bee nests are from the Nearctic, Palaearctic, Oriental, and Australian regions.

Bee hosts

generalists like Sancassania sphaerogaster (= S. mycophaga auct. non Mégnin) and S. rodionovi (=S. berlesei auct. non Michael): Apis mellifera, Apis cerana, Xylocopa flavipes, and Lasioglossum leucozonium

bee specialist Sancassania boharti: alkali bee Nomia melanderi

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 (most species), permanent (Sancassania boharti)

Host associations, feeding, and dispersal

Habitat generalists (e.g., Sancassania rodionovi and S. sphaerogaster)

  • All stages can be found living together in each habitat, including bee nests, where they feed on decomposing organic matter and fungi.
  • Phoretic deutonymphs opportunistically attach to any insect or arthropod carrier they can find nearby and use it for dispersal to a new habitat.

Bee specialists (e.g., Sancassania boharti)

  • All stages live in brood cells of alkali bees (Nomia), probably feeding on pollen, waste, or dead bees (direct observations lacking). Mite deutonymphs probably infest bee hosts mostly in nest exit tunnels rather than in the brood cells.
  • Phoretic deutonymphs disperse on adult bees, most commonly occurring on male bees (Fig. 15), where they usually attach to the ventral mesosoma. In female bees the mites preferentially attach to the dorsal metasoma. Hence venereal transmission of mites from male to female bee is possible.

Biology

Many species of Sancassania are habitat generalists and are not specialized for a particular phoretic host. Phoretic deutonymphs can be found on a variety of insects, diplopods, and millipedes, but they are most common on scarabaeid beetles.

Habitat generalists feed primarily on wet decomposing organic material and fungi. Some species are agricultural and stored product pests. Unspecialized generalists are known from bee nests, commonly from the European honey bee: Sancassania sphaerogaster (= S. mycophaga auct. non Mégnin) and S. rodionovi (=S. berlesei auct. non Michael) from hives of the European honey bee Apis mellifera. Sancassania rodionovi has also been reported from a nest of the carpenter bee (Xylocopa flavipes). Unidentified species of Sancassania have been sampled from nests of Apis cerana and the halictid bee Lasioglossum leucozonium.

A few lineages are specialists. Sancassania boharti is associated with the alkali bee Nomia melanderi. The presumed subgenus Ctenocolletacarus is associated with ground-nesting stenotritid bees of the genus Ctenocolletes and provides sanitary services to host nests. Many Sancassania species are obligate associates of scarabaeid beetles; they are phoretic on the beetle as deutonymphs and feed on the beetle carcass after the host death. Species of the nidicola-species groups specialize in feeding on fruiting bodies of large mushrooms and probably also their mycelium growing underground.

A biological account of Sancassania boharti can be found in Cross and Bohart, 1969. Phoretic deutonymphs of Sancassania boharti are usually found on the metasomal integument, crowded into the intersegmental spaces, where they pattern themselves into partially overlapping layers, their orientation opposite to that of the bee, and where they may be hidden from casual observation. Because these mites are found on the metasoma (dorsally in females and ventrally in males), sometimes on structures modified for copulation, this species is most likely to effect venereal transfer.

Additional observations on Sancassania boharti are available from Eickwort, 1979 and Eickwort, 1994. In nest cells these mites may occur on feces deposited by bee larvae, but they are especially abundant in cells containing dead bees and moldy provisions. The mites burrow through and tear apart the provision masses, consuming pollen, fungi, and dead brood. There is, however, no evidence that the mites kill the brood; they are presumably scavengers that take special advantage of food resources in cells in which brood fail to develop. Deutonymphs are facultatively produced and are phoretic on bees that develop in other cells; it is probable that these deutonymphs move through the soil to locate their hosts in the nest burrows.