Repellency of conspecific and heterospecific larval residues to Hippodamia convergens (Coleoptera: Coccinellidae) ovipositing on sorghum plants

Abstract

Abstract. We examined oviposition decisions by Hippodamia convergens Guérin in semi-natural arenas in the laboratory. Gravid females were presented individually with an array of four young sorghum plants, Sorghum bicolor, bearing (1) no additional stimulus, (2) an established colony of greenbug, Schizaphis graminum Rondani, (3) residues of conspecific larvae, and (4) greenbugs plus residues of conspecific larvae. Females laid no egg masses on type 3 plants, significantly fewer than expected by chance on type 4 plants, and significantly more on type 1 plants, with type 2 plants receiving expected numbers. Females laid 50% of egg masses on elements of the arena other than the plants, especially the cage screen, suggesting that females sought to distance their eggs farther from larval residues than the spacing of plants in the arena permitted (15 cm). When the experiment was repeated with plants exposed to larvae of Coleomegilla maculata DeGeer, the repellency was weaker. Once again, clean plants were the most preferred and aphids did not increase the acceptability of plants with larval residues. Nevertheless, only 18% of egg masses occurred off the plants and larval residues did not reduce the acceptability of aphid-bearing plants as did conspecific larval residues. Simultaneous choice tests conducted with individual third instars of both species revealed that C. maculata larvae consumed H. convergens eggs as readily as conspecific eggs, but H. convergens larvae preferred conspecific eggs to those of C. maculata. We conclude that H. convergens oviposition decisions are shaped by the risks of both egg cannibalism and predation.

Behavioral and Immunological Features Promoting the Invasive Performance of the Harlequin Ladybird Harmonia axyridis

“…Chemical markings deposited by syrphid and coccinellid larvae did not deter H. axyridis females from laying eggs. Similar results were observed in other ladybeetle species, including C. septempunctata, Hippodamia convergens, and A. bipunctata, where oviposition was deterred in the presence of conspecific larvae, but not in presence of heterospecific competitors (Ruzicka, 1997;Doumbia et al, 1998;Michaud and Jyoti, 2007). These results suggest the presence of a species-dependent oviposition-deterring pheromone in ladybeetles, which remains to be characterized and compared among coccinellid species.…”

Intraguild interactions between the predatory hoverfly Episyrphus balteatus (Diptera: Syrphidae) and the Asian ladybird, Harmonia axyridis (Coleoptera: Coccinellidae): Effect of larval tracks

“…ovipositiondeterrents) indicating that a prey patch is already being exploited by conspecific larvae (RĤžiþka, 1994(RĤžiþka, , 1996(RĤžiþka, , 1997Doumbia et al, 1998;RĤžiþka & Havelka, 1998;Yasuda et al, 2000;Oliver et al, 2006;Michaud & Jyoti, 2007). Most of these studies have focused on coccinellids and chrysopids, while studies on syrphids are very recent and scarce (e.g.…”

Effect of presence and semiochemicals of conspecific stages on oviposition by ladybirds (Coleoptera: Coccinellidae)

“…The effect of oviposition deterring pheromone (ODP) has been most intensively studied in coccinellids but in such arenas that allowed contact with conspecific females, a situation that has been shown to affect oviposition behavior in aphid parasitoids (Michaud & Mackauer, 1995) and coccinellids (Hemptinne et al, 1993;Mishra & Omkar, 2006), with an increased incident of superparasitism being observed in the former. To account for the possibly important influences of prey, host plant and conspecific interference, Yasuda et al (2000) and Michaud & Jyoti (2007) studied oviposition responses by solitary females to larval tracks in Harmonia axyridis (Pallas) and Coccinella septempunctata Linnaeus, and Hippodamia convergens Guerin respectively, in the presence of host plants and aphids. It is also now known that the secretion of ODP takes place from the anal disk on the 10 th abdominal segment of larvae (Laubertie et al, 2006).…”

“…The ODP primarily signals the presence and density of larvae in a patch, thereby allowing assessment of predation and cannibalism risk to eggs that may be laid (Martini et al, 2009;Moser et al, 2010;Meisner et al, 2011). Studies indicate that the deterrence induced by ODP is more prominent amongst conspecifics than heterospecifics owing to qualitative similarity; the closer the phylogenetic relations, the more the deterrence (Michaud & Jyoti 2007;Magro et al, 2007Magro et al, , 2010.…”