Inter- and intraspecific interactions in two mealybug predators Spalgis epius and Cryptolaemus montrouzieri in the presence and absence of prey

Abstract

Spalgis epius and Cryptolaemus montrouzieri are the two potential predators of different species of mealybugs. However, the mode of their interactions is not known to use these predators together in the field. Hence, we investigated on the possible interactions i.e., cannibalism, intraguild predation (IGP) and competition between the predators in the presence and absence of prey Planococcus citri. In the presence of prey, no cannibalism and predation were observed in both S. epius and C. montrouzieri larvae. A pair of S. epius larvae consumed significantly more number of mealybugs than one S. epius/C. montrouzieri larva or a pair of C. montrouzieri larvae. The predation of S. epius larva by C. montrouzieri larva was significantly more than the predation of C. montrouzieri by S. epius. Conspecific and interspecific egg predation was absent both in S. epius and C. montrouzieri. Cannibalism in C. montrouzieri was more than that in S. epius. The study indicated that C. montrouzieri larvae can be used as an additive along with voracious S. epius larvae under abundant prey population. IGP was asymmetric between the two predators in the absence of prey. Both S. epius and C. montrouzieri larvae can maintain a stable coexistence when prey is abundantly available, however, in the complete absence of prey C. montrouzieri may dominate the guild. This study provides an insight into the possible complex inter-and intraspecific predatory phenomena in the field to use these two predators in the biological control of mealybugs.

Compatibility between the predators Cryptolaemus montrouzieri (Coleoptera: Coccinellidae) and Chrysoperla externa (Neuroptera: Chrysopidae) in the control of Planococcus citri (Hemiptera: Pseudococcidae) associated with rose crop

“…Although C. montrouzieri and C. externa are reported as intraguild predators in coccydophagous guilds (Dinesh and Venkatesha, 2014;Cardoso, 2015), no intraguild predation was observed. This result may be due to the use of predators at different stages of development (adult of C. montrouzieri and larvae of C. externa), which reduces the chances of intraguild predation (Polis et al, 1989).…”

Cannibalism and intraguild predation between endemic and introduced coccidophagous lady beetles (Coleoptera: Coccinellidae)

“…Chong and Oetting (2007) found a reduction from 13% to 6% parasitism of Planococcus citri by Leptomastix dactylopii Howard (Hymenoptera: Encyrtidae) when C. montrouzieri was present in the same habitat. Similarly, Dinesh and Venkatesha (2014) found that C. montrouzieri preyed upon larvae of Spalgis epius (Westwood, 1851) (Lepidoptera: Lycaenidae) and suggested that they should be used in biological control only when prey density is high. Thus, the action of exotic lady beetles on indigenous species can be negative, reducing the population of the latter or even causing the displacement of them as a result of intraguild predation and competition when the preferred prey are at low abundance or absent.…”

Intraguild Interactions between the Mealybug Predators Cryptolaemus montrouzieri and Chrysoperla carnea

“…Intraguild predation (IGP) may eventually affect the success of pest suppression [ 8 , 9 ]. C. montrouzieri has been reported to act as an intraguild predator of a number of natural enemies, mealybug parasitoids in particular [ 10 , 11 , 12 ], but also other predators [ 13 , 14 ]. The incidence of IGP between green lacewings and other predators in the aphidophagous guild has also been frequently documented, e.g., [ 15 , 16 , 17 , 18 , 19 ].…”