Laboratory rearing and biological parameters of the eulophid Pnigalio agraules, a parasitoid of Cameraria ohridella

Abstract

Predators as well as parasitoids native to Europe accept the exotic horse chestnut leafminer, Cameraria ohridellaDeschka and Dimić 1986 (Lepidoptera: Gracillariidae), either as prey or as host. However, the influence of these antagonists on the populations of the pest insect is so far very low. Therefore, efforts to develop an integrated pest management system against C. ohridella should include methods which foster the natural enemy complex. In the present study we developed a laboratory rearing method and investigated several biological parameters of Pnigalio agraules (Walker 1839) (Hymenoptera: Eulophidae), a dominant species in the horse chestnut leafminer’s parasitoid complex in many European regions. This native parasitoid satisfies three basic requirements for successful use as a biocontrol agent with regard to C. ohridella. The parasitoid’s fecundity, longevity and the speed of juvenile development by far exceeds that of the leafminer, enabling the parasitoid population to increase faster than that of the host. Furthermore, our results show that the impact of this species on C. ohridella populations has been previously underestimated, because non‐reproductive killing (i.e. host‐feeding and host‐stinging) of the hosts, resulting in considerable larval mortality of the leafminer, has not been quantitatively assessed. However, naturally occurring parasitoid populations have negligible impact on C. ohridella populations. Further studies, including experimental releases of P. agraules, are necessary to understand the constraints limiting the parasitoid’s performance in the field and to assess the potential benefits of releases for the control of C. ohridella.

Can we predict indirect interactions from quantitative food webs? - an experimental approach

“…Another, more common mechanism for interference among parasitoids may be host feeding (e.g. Askew & Shaw 1979a,b; Grabenweger et al. 2009), where high parasitoid densities may lead to resource depletion (in terms of live hosts) and host‐feeding on parasitized host larvae – or even on parasitoid larvae.…”

“…Another, more common mechanism for interference among parasitoids may be host feeding (e.g. Askew & Shaw 1979a,b;Grabenweger et al 2009), where high parasitoid densities may lead to resource depletion (in terms of live hosts) and host-feeding on parasitized host larvae -or even on parasitoid larvae. That host-feeding might be relatively common in our system is suggested by the discrepancy between the relatively low parasitism rates detected here (see Fig.…”

Nonreproductive Effects of Insect Parasitoids on Their Hosts

“…Despite their potential detrimental effects on host populations, mutilation and pseudoparasitism have often been underestimated. Indeed, these effects are not always discernible from other causes (Legner 1979;Barrett and Brunner 1990;Mandeville and Mulleins 1992;Urbaneja et al 2000;Lysyk et al 2004;Grabenweger et al 2009;Keinan et al 2012), or are sometimes erroneously attributed to host feeding (e.g.,…”

Fungi Associated with Horse-Chestnut Leaf Miner Moth Cameraria ohridella Mortality

“…The moth's region of origin was obscure for a long time; however based on DNA analysis, the Balkan origin of the C. ohridella was revealed [9], and the species has been attributed to invasive ones in many countries. The horse-chestnut leaf miner has been widely studied, including moth biology and distribution [10][11][12][13][14], potential predators [15][16][17][18] and competition either with native leaf miners [19] or phytopathogenic fungi [20].…”