Studies on Biology of Ascid mite, Blattisocius keegani (Acari: Gamasida: Ascidae) When Fed on Two Astigmatid Mites at Different Laboratory Conditions

Abstract

Blattisocius keegani (Mesostigmata: Ascidae) is a predatory mite that has traditionally been studied as a biological control agent in stored products. The developmental time (incubation period, life cycle and longevity), fecundity and food consumption of the predatory mite B. keegani (Fox) (Ascidae) were investigated at 25 and 35°C and 75% R.H when fed on the two astigmatid mites, Rhizoglyphus echinopus and Lepidoglyphus destructor. The incubation period of B. keegani was not affected when fed on the preys at tested temperature. The duration of life cycle for both sexes of B. keegani was obviously affected by the type of food employed at different temperature. The longest period lasted 12.6 days when predatory females fed on R. echinopus larvae at 25ºC, but the shortest period recorded on L. destructor larvae at 35ºC for predator males was 10.22 days. The female longevity of B. keegani was also affected when the predator fed on the two tested preys at two temperature, as the maximum longevity was 26.7 days for female at 25ºC on R. echinopus larvae, and the minimum corresponding period was 16.54 days for male on L. destructor at 25ºC. The adult female of B. keegani laid the highest number of eggs (41.6) when fed on R. echinopus at 35ºC, while the lowest number of eggs was observed when fed on L. destructor larvae (35.4 eggs) at 25ºC. The food consumption of the different predator stages increased with its growth. The larval stage of both female and male had the least prey consumption than the other stages (protonymph and deutonymph) and the predator male individuals consumed lower number of introduced prey than the female individuals. The total amount of consumed prey individuals during the whole life span was 88.9 larvae of R. echinopus at 25ºC, changed to record 98.0 preys at 35ºC, while, the number of devoured L. destructor was 81.6 and 87.2 prey at 25 and 35ºC, respectively. The B. keegani male devoured 80.0 & 85.0 larvae of R. echinopus and 74.8 & 80.7 larvae of L. destructor at 25 and 35ºC., respectively.