Functional response of two soil-dwelling predatory mites, Macrocheles mammifer (Berlese) (Acari: Macrochelidae), and Stratiolaelaps scimitus (Womersley) (Acari: Laelapidae), on thrips Megalurothrips usitatus (Bagnall) (Thysanoptera: Thripidae)

Abstract

Megalurothrips usitatus (Bagnall) (Thysanoptera: Thripidae), commonly known as the Asian bean thrips, is a destructive pest of leguminous crops, causing significant damage and economic losses. In the present study, the functional responses and predation rates of two predatory mites Macrocheles mammifer Berlese (Macrochelidae) and Stratiolaelaps scimitus (Womersley) (Laelapidae) on M. usitatus pupae were evaluated. The former was discovered in a cowpea Vigna unguiculata (Linn.) Walp. field of southern China, while the latter is commonly used as a biological control agent for soil-dwelling pests. Both M. mammifer and S. scimitus females consumed more M. usitatus than protonymphs, and the predation rate of the adult stage of M. mammifer was found to be significantly higher than that of S. scimitus. Likewise, logistic regression analysis revealed that both predators exhibited a type II functional response. Females of M. mammifer and S. scimitus displayed a higher attack rate and shorter handling time (T_h) compared to conspecific protonymphs when preying on pupae of M. usitatus. Female M. mammifer recorded the highest attack rate (a) of 4.028, closely followed by female S. scimitus at 3.994. The protonymph of M. mammifer had an attack rate of 2.651, while the protonymph of S. scimitus displayed the lowest rate of 1.402. Female M. mammifer exhibited the shortest handling time (0.089), indicating superior prey-handling ability. Overall, the predatory mites M. mammifer and S. scimitus demonstrated considerable promise for managing M. usitatus, with M. mammifer displaying higher efficacy than S. scimitus.