Impact of host behavioral defenses on parasitization efficacy of a larval and adult parasitoid

Abstract

Koinobiont parasitoid females when attacking host species are faced with barriers at various levels, host behavioral defenses represent one of these barriers. We present data of the effects of host behavioral defenses on host preference of larval and adult parasitoid. We quantified the effects of defensive behaviors of the exotic host, Harmonia axyridis (Pallas), and the indigenous host, Coleomegilla maculata lengi Timberlake (Coleoptera: Coccinellidae), on the handling time and attack preference of the indigenous parasitoid, Dinocampus coccinellae Schrank (Hymenoptera: Braconidae). Successful egg development was also recorded as a consequence of host behavioral defense and unsuitability. Female parasitoids were offered in an interspecific choice test, adult or larvae of both H. axyridis and C. maculata, and in an intraspecific choice test, larval and adult stage of H. axyridis. Adult H. axyridis exhibited a greater number of defensive behaviors compared to adult C. maculata or larval H. axyridis resulting in significantly longer handling time by the parasitoid. Our results suggest that host acceptance cues used by the generalist parasitoid D. coccinellae are inadequate to evaluate adult H. axyridis. These results provide support to the hypothesis that H. axyridis represents an evolutionary trap for D. coccinellae.

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

“…3), with reports both within its native range and in all invaded continents (Table 2), but parasitism and emergence rates are usually low in comparison with other host species (Maeta 1969b;Hoogendoorn and Firlej et al 2005Firlej et al , 2007Firlej et al , 2010Koyama and Majerus 2008;Ceryngier et al 2012;Minnaar et al 2014; Table 4). Koyama and Majerus (2008) demonstrated that D. coccinellae of Japanese origin developed in British H. axyridis more successfully (about 17% successful parasitism rate) compared to wasps of British origin (no successful parasitism).…”

“…Despite its low suitability for development of D. coccinellae, H. axyridis is no less preferred for oviposition by this wasp than more suitable hosts (Hoogendoorn and Heimpel 2002;Koyama and Majerus 2008;Firlej et al 2010). Furthermore, interacting with D. coccinellae females, H. axyridis adults display more behavioural defenses than do the adults of suitable hosts, such as Coleomegilla maculata (DeGeer), which increases the handling time of the parasitoid and hence further reduces its fitness (Firlej et al 2010).…”

“…Furthermore, interacting with D. coccinellae females, H. axyridis adults display more behavioural defenses than do the adults of suitable hosts, such as Coleomegilla maculata (DeGeer), which increases the handling time of the parasitoid and hence further reduces its fitness (Firlej et al 2010). Finally, although H. axyridis larvae are more suitable for development of D. coccinellae than adults (Firlej et al 2007(Firlej et al , 2010Berkvens et al 2010), the latter are more readily parasitized by D. coccinellae (Firlej et al 2010). In conclusion, H. axyridis populations within the invaded range seem unlikely to be reduced to a significant extent by D. coccinellae.…”

“…In conclusion, H. axyridis populations within the invaded range seem unlikely to be reduced to a significant extent by D. coccinellae. Instead, H. axyridis may represent an ecological trap or at least a sink for D. coccinellae eggs (Hoogendoorn and Heimpel 2002;Firlej et al 2010).…”

Characterization of a newly established aggregation of the invasive ladybeetle Harmonia axyridis and current status of the invader in Spain

“…However, a recent study shows that natural enemies are still unable to control populations of H. axyridis in Europe (Raak-van den Berg et al, 2014). In America also, despite the fact that D. coccinellae readily attacks H. axyridis, the success of the parasitism is very low and lower than on other coccinellid species, due to host behavioral defenses and unsuitability (Firlej et al, 2005(Firlej et al, , 2010.…”