Intraguild predation among ladybeetles and a green lacewing: do the larval spines of Curinus coeruleus(Coleoptera: Coccinellidae) serve a defensive function?

Abstract

Laboratory experiments examined interspecific interactions between larvae of three coccinellid species, Curinus coeruleus Mulsant (Chilocorinae), Harmonia axyridis Pallas and Olla v-nigrum (Mulsant) (Coccinellinae), and between these and larvae of the green lacewing, Chrysoperla rufilabris (Burmeister). Larvae of C. coeruleus, although defended on their dorsal surface with long spines, had the smallest mandibles, were the slowest-moving, and the least successful in interspecific larval combat. The long spines of third instar C. coeruleusappeared to reduce their palatability as food to H. axyridis and O. v-nigrum larvae in choice tests with dead larvae, but were not an effective defence against these species in Petri dish arenas. Larvae of O. v-nigrum had a smooth dorsal surface, were intermediate in terms of mandible size, but were the fastest moving, a trait that benefited their survival in intraguild combat. Larvae of H. axyridis were intermediate with respect to dorsal spines and speed of movement, but had the largest mandibles. This species was the most effective intraguild combatant among the coccinellids and the only one to successfully compete against C. rufilabris larvae of similar age. The speed, manoeuverability and long mandibles of C. rufilabris enabled them to impale coccinellid larvae at a relatively safe distance. The spines of C. coeruleus larvae impeded laterally oriented attacks by C. rufilabris, but did not provide sustained protection from repeated attacks. Success in these interactions appeared largely a function of offensive weaponry (mandible size and morphology) and speed of movement, although the role of dorsal spines as defensive structures was not ruled out. Rates of larval cannibalism were highest for C. rufilabris and largely mirrored the level of aggression observed in interspecific combat for each species.

Predators and parasitoids of the harlequin ladybird, Harmonia axyridis, in its native range and invaded areas

“…Instead, these lacewing larvae are equipped with very long and sharp jaws that deter predators from attacking them and, on the other hand, enable them to effectively attack predators (Michaud and Grant 2003;Nedvȇd et al 2010Nedvȇd et al , 2013Wells et al 2017). Larvae of C. carnea have also been observed preying on the larvae of H. axyridis in the field (Fremlin 2007, Table 1).…”

“…Indeed, in experiments testing the outcomes of intraguild interactions involving H. axyridis, it usually appears superior to other aphidophagous predators (Yasuda and Ohnuma 1999;Yasuda et al 2004;Ware and Majerus 2008;Raak-van den Berg et al 2012; Katsanis et al 2013). A few exceptions include larvae of the ladybird Anatis ocellata (L.) Katsanis et al 2013) and of the lacewings Chrysoperla carnea (Stephens) (Nedvȇd et al 2010(Nedvȇd et al , 2013 and C. rufilabris (Burmeister) (Michaud and Grant 2003). Larvae of A. ocellata are covered with sclerotized spines and, additionally, are larger than larvae of H. axyridis of the same instar.…”

Why is Coccinella septempunctata so successful? (A point-of-view)

“…The larvae of C7 lack morphological features such as spines or waxy coverings that may defend some ladybird species from predation (Volkl & Vohland, 1996;Agarwala & Yasuda, 2001;Michaud & Grant, 2003). It has been suggested that the most efficient way for defenceless young larvae to escape the attacks of older larvae or those of more aggressive species (e.g.…”

Oviposition-deterring effects of conspecific and heterospecific larval tracks on Cheilomenes sexmaculata (Coleoptera: Coccinellidae)

“…High arrival and oviposition may occasionally cause a considerable mortality rate among the progeny (Osawa, 1993). If finite aggregates of prey are prematurely depleted, overcrowded larvae suffer from cannibalism (Michaud & Grant, 2003;Snyder et al, 2004) and attack prepupae and pupae (Takahashi, 1989). Along with cannibalism, interspecific predation occurred in the field and in the laboratory (Dimetry, 1976a, b;Agarwala & Dixon, 1992).…”