Prey preference and predation efficacy of Sycanus collaris (F.) (Hemiptera: Reduviidae) on Tenebrio molitor (L.) (Coleoptera: Tenebrionidae)

บทคัดย่อ

An assassin bug, Sycanus collaris (F.), has records to control pests in teak, marigold, and tea and has shown potential as a biological agent. Although the predator can be mass reared on alternative prey, Tenebrio molitor (L.), effects of different sizes of yellow mealworm to S. collaris preference, development and survival remains unknown. Hence, small, medium and large sized-larvae and pupae of yellow mealworm were offered to second- to fifth instar and adult S. collaris using choice test. Overall, the predator seemed to prefer larger prey as they grew. The choice-test experiment revealed that the most preference prey of 2^nd, 3^rd, 4^th and 5^th instar were small larvae (55%), medium larvae (33%) and pupae (33%), large larvae (40%), and medium larvae (80%), respectively. Both female and male attacked most frequently on large larvae (56% and 44%, respectively). In no-choice test, four prey choices did not affect developmental time in 2^nd to 4^th instar, but 5^th instar grew faster when fed on pupae than medium larvae. Pupae enhanced female lifespan but did not affect male lifespan. Moreover, the findings indicated that S. collaris was expected to have a higher effect on the suppression of small sized-pest populations. Feeding each predator stage with their preferred prey size can improve feeding capacity, survival and later likely to increase reproduction output which is advantageous to the mass rearing program. Understanding the effect of different alternative prey sizes on the predator development and survival will provide evidence whether their preferred prey choice is suitable for the predator and may also provide implications on the predator feeding preference in the field after being released.