Blattisocius tarsalis (Berlese)
(Formerly assigned to Melichares, family Ascidae).
Common name: None.
Geographical distribution: Cosmopolitan.
Morphology: The smooth, slightly reticulate body is about 0.55 mm in length, pale yellow. The dorsal shield with 33 pairs of setae, and there are another 12 pairs on the shield’s margin. The sternal plate is slightly reticulate and bears three pairs of setae. The anal plate is oblong, with 3 pairs of setae. The peritremes are short, reaching only to the bases of legs II.
Life history: Blattisocius tarsalis is a predator of several stored-products insects, especially Lepidoptera, and is dispersed by these moths. When offered eggs of Ephestia cautella , its development took 6 days and mortality came to 7%. On the eggs of Tribolium castaneum, development required 7·4 days and mortality to 48%, the latter eggs being rarely taken. When given eggs of different ages of Ephestia kuehniella, the predator preferred the eldest. Fecundity, on the eggs of Plodia interpunctella, came to 60/female. The predator developed faster on the eggs of Oryzaephilus surinamensis than on the eggs of T. castaneum. The threshold of development was calculated to be at 10.2ºC, and the adults live for almost 2 months.
Economic importance: In stores the rate of increase of B. tarsalis exceeds that of E. cautella, which suggests that it is an efficient enemy of this moth. When co-occurring with another acarine predator, Cheyletus, the latter may eliminate B. dentriticus. A related species, Blattisocius dentriticus (Berlese), preys on Acarus Siro and other stored-product pests.
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Darst, P.H. and King, E.W. 1969. Biology of Melichares tarsalis in association with Plodia interpunctella. Annals of the American Society of Entomology 62: 747-749.
Haines, C.P. 1981. Laboratory studies on the role of an egg predator, Blattisocius tarsalis (Berlese) (Acari: Ascidae), in relation to the natural control of Ephestia cautella) (Walker) (Lepidoptera: Pyralidae) in Warehouses. Bulletin of Entomological Research 71: 557-574.
Hafeez, S.M., Taher, S.H. and Mallawani, M.A. 1988. Biological studies on Blattisocius tarsalis Keggan, a predatory mite inhabiting stored food in Egypt. Annals of Agricultural Science 33: 1387-1393.
Nielsen, P.S. 1998. The use of Blattisocius tarsalis (Acari: Ascidae) for biological control in flour mills. Proceedings of the 7th Interternational Working Conference on Stored-product Protection, 1265-1268.
Nielsen, P.S. 2001. Developmental time of Blattisocius tarsalis (Acari: Ascidae) at different temperatures. Experimental and Applied Acarology 25: 605-608.
Oliveira, D.C., Chandrapatya, A. and De Moraes, G.J. 2015. A new species of Blattisocius (Acari: Mesostigmata: Blattisociidae), with a new characterisation of the genus. Zootaxa 4040: 93-100.