Host plant effects on parasitoid attack on the leaf beetle Chrysomela lapponica

Abstract

Larvae of the leaf beetle Chrysomela lapponica obtain salicyl glucosides (SGs) from the host plant to produce a defensive secretion with salicylaldehyde. In northern Russia, larvae and pupae experience high parasitism by the phorid fly Megaselia opacicornis and tachinid fly Cleonice nitidiuscula. We compared the suitability of the SG-rich Salix borealis and SG-poor S. caprea and S. phylicifolia to Ch. lapponica and tested whether enemy pressure on Ch. lapponica varies among host species that differ in SG content. In the laboratory, survival of Ch. lapponica larvae was higher on S. borealis than on S. caprea and S. phylicifolia, while adult body mass was higher on S. borealis and S. caprea than on S. phylicifolia. In the field, parasitism by both M. opacicornis and Cl. nitidiuscula was greater on beetles from S. borealis than from the SG-poor S. caprea or S. phylicifolia. In a laboratory choice test, the pupal parasitoid M. opacicornis laid similar numbers of eggs on beetles reared on SG-rich and SG-poor willows, suggesting that the host plant-derived defence is not effective against this parasitoid. In a field enemy-exclusion experiment, beetle survival was greatly enhanced by the exclusion of enemies, but survival rates did not differ between S. borealis and S. caprea, although larvae developed faster on S. borealis. On the other hand, parasitism and predation were observed more often on S. borealis than on S. caprea. Thus, beetle larvae perform better but also suffer higher predation and parasitism on S. borealis than on SG-poor willows. Ch. lapponica does not appear to obtain enemy-free space by feeding on SG-rich willow species.

Fly parasitoid Megaselia opacicornis uses defensive secretions of the leaf beetle Chrysomela lapponica to locate its host

“…Parasitism by M. opacicornis is spatially density dependent, which suggests that this parasitoid may use chemical cues to locate prey from a distance (Zvereva and Kozlov 2000). In addition, Zvereva and Rank (2003) recently demonstrated that M. opacicornis parasitism and oviposition was greater on beetles on SG-rich host species than on beetles on SG-poor species (Zvereva and Rank 2003). These results indicate that the beetle's defensive secretion attracts M. opacicornis for prey location and oviposition.…”

“…The pupal parasitoid Megaselia opacicornis Schmitz (Diptera, Phoridae) causes up to 40% mortality in natural populations of Ch. lapponica in NW Russia and Finnish Lapland (Zvereva and Kozlov 2000;Zvereva and Rank 2003). Parasitism by M. opacicornis is spatially density dependent, which suggests that this parasitoid may use chemical cues to locate prey from a distance (Zvereva and Kozlov 2000).…”

Enemy-free space maintains swallowtail butterfly host shift

“…Why have there been so few studies documenting EFS (12,(18)(19)(20)(21)? Only three studies have satisfactorily established the occurrence of EFS, but they have been agricultural systems (22,23) or artificial host shifts (24).…”

Population genetic structure of two primary parasitoids of Spodoptera frugiperda (Lepidoptera), Chelonus insularis and Campoletis sonorensis (Hymenoptera): to what extent is the host plant important?

“…These effects can strongly vary among plant species (Smith 1957;Altahtawy et al 1976;Bhatt & Singh 1989;Senrayan & Annadurai 1991;Werren et al 1992;Fox et al 1996;Kruse & Raffa 1997;Eben et al 2000;Harvey et al 2003;Zvereva & Rank 2003;Lu et al 2004) and even among cultivars of a same plant species (Kauffman & Flanders 1985;Orr & Boethel 1985;Hare & Luck 1991;Reed et al 1991;Rogers & Sullivan 1991;Riggin et al 1992;Stark et al 1992;Dosdall & Ulmer 2004;KahuthiaGathu et al 2008).…”