Functional response in coccinellid beetles (Coleoptera: Coccinellidae) is modified by prey-density experience

Abstract

In the present study, we assessed functional response curves of two generalist coccinellid beetles (Coleoptera: Coccinellidae), specifically Menochilus sexmaculatus and Propylea dissecta, using fluctuating densities of aphid prey as a stimulus. In what may be the first such study, we investigated how the prey density experienced during the early larval development of these two predatory beetle species shaped the functional response curves of the late instar–larval and adult stages. The predators were switched from their rearing prey-density environments of scarce, optimal, or abundant prey to five testing density environments of extremely scarce, scarce, suboptimal, optimal, or abundant prey. The individuals of M. sexmaculatus that were reared on either scarce- and optimal- or abundant-prey densities exhibited type II functional response curves as both larvae and adults. However, individuals of P. dissecta that were reared on scarce- and abundant-prey densities displayed modified type II functional response curves as larvae and type II functional response curves as adults. In contrast, individuals of P. dissecta reared on the optimal-prey density displayed type II functional response curves as larvae and modified type II functional response curves as adults. The fourth-instar larvae and adult females of M. sexmaculatus and P. dissecta also exhibited highest prey consumption (T/Th) and shortest prey-handling time (Th) on the scarce-prey rearing density. Thus, under fluctuating-prey conditions, M. sexmaculatus is a better biological control agent of aphids than P. dissecta is.

Larval and/or Adult Exposure to Intraguild Predator Harmonia axyridis Alters Reproductive Allocation Decisions and Offspring Growth in Menochilus sexmaculatus

“…The present study investigated the ladybird species Menochilus sexmaculatus (Fabricius) (Coleoptera: Coccinellidae), which is an efficient enemy of many insect pests, such as Aphis craccivora Koch (Hemiptera: Aphididae) [ 26 , 27 , 28 ]. In the field, M. sexmaculatus is abundant throughout the year and interacts with other ladybird species within the guild, including Harmonia axyridis (Pallas) [ 29 , 30 ].…”

Effect of temperature on the life cycle of Harmonia axyridis (Pallas), and its predation rate on the Spodoptera litura (Fabricius) eggs

“…Many coccinellids are important predators of hemipterans, including aphids 10,18 , whitefly 19 , mealybugs 20 , scale insects 21 and immature lepidopterans 22,23 . Resource quality, thermal surroundings, mobility 24 , nutritional status 25 , as well as density and size of the prey 26 are critical determinants of predator development, biology 16 and predation parameters 12,[27][28][29] . The biological control effectiveness of the predator can thus be evaluated by combining development, survival rates, and reproductive potential with age-specific predation rates 30 .…”