Comparison of feeding efficiency, development time and survival of Tasmanian eucalyptus leaf beetle larvae Chrysophtharta bimaculata (Olivier) (Coleoptera: Chrysomelidae) on two hosts

Abstract

The native Eucalyptus leaf beetle Chrysophtharta bimaculata (Olivier) (Coleoptera: Chrysomelidae) has become a pest of the introduced, plantation species, Eucalyptus nitens Maiden in Tasmania, Australia. However, in the field it prefers to oviposit on the Tasmanian native species, E. regnans F. Muell. This laboratory study found that the performance of C. bimaculata larvae was superior on foliage of E. nitens compared with E. regnans. Larval development was 4 days shorter on E. nitens than on E. regnans foliage. Total food consumption per larva and relative consumption rates were about 30% lower while relative growth rates and weight of emergent adults were more than 25% higher on E. nitens than E. regnans. Efficiency of conversion (ECI) of fresh food into larval wet weight was 0.26 on E. nitens compared with 0.14 on E. regnans. Mortality of larvae feeding on E. nitens (23%) was only one third of that on E. regnans (69%), a result of high first instar mortality on E. regnans. Although the amount of foliage consumed per larva was lower on E. nitens (0.23 g vs 0.32 g), the differential mortality meant that the amount of E. nitens consumed per egg batch was 60% more than that of E. regnans. If these results occurred in the field, then the same monitored population of C. bimaculata eggs may result in heavier defoliation of plantation E. nitens than of E. regnans. These data show that the reported oviposition preference of C. bimaculata for E. regnans in the field cannot be explained by selection of host factors related to superior larval performance.

Intra‐plant host selection, oviposition preference and larval survival of Chrysophtharta agricola (Chapuis) (Coleoptera: Chrysomelidae: Paropsini) between foliage types of a heterophyllous host

“…Here, we examine the oviposition preference and larval performance between the two foliage types within one eucalypt host species, E. nitens. We confirm the findings of Lawrence et al (in press) for C. agricola's feeding preference for adult foliage in the field, and examine oviposition and larval performance in the laboratory to test the hypothesis that paropsine oviposition preference is often not explained by larval performance (Carne, 1966;de Little & Madden, 1975;Baker et al, 2002).…”

“…To date, studies addressing oviposition preference and host choice in the Paropsini have focused on differences between host plant species (de Little & Madden, 1975;Steinbauer et al, 1998b;Howlett et al, 2001;Baker et al, 2002); rarely has the influence of intra-host foliage type on oviposition been considered (Steinbauer, 2002). Here, we examine the oviposition preference and larval performance between the two foliage types within one eucalypt host species, E. nitens.…”

Thermal requirements, field mortality and population phenology modelling of Paropsis atomaria Olivier, an emergent pest in subtropical hardwood plantations

“…Early paropsine instars experience high mortality under laboratory conditions in C. bimaculata (Baker et al, 2002) and C. agricola (Nahrung et al, 2001), and our overall egg-Liv field mortality estimates for P. atomaria were similar to these temperate species (de Little et al, 1990;Nahrung and Allen, 2004a, respectively). Our laboratory trials revealed relatively low survival rates for fourth instar larvae, exacerbated by higher rearing temperatures, especially above 24 8C.…”

Avaliação de danos de adultos de Costalimaita ferruginea (Fabricius) (Col.: Crysomelidae) em Eucalyptus spp. na região de Presidente Prudente, SP

“…Além desses fatores, existem diferenças na constituição de compostos secundários das folhas das espécies de eucalipto, como taninos, outros compostos fenólicos, gorduras e óleos essenciais, que influenciam negativamente o processo de herbivoria (ohmart; Edwards, 1991). BakEr et al (2002) Na comparação entre as espécies de eucalipto, E. camaldulensis apresentou a maior porcentagem de folhas sem danos (76,4%), diferindo dos demais materiais (Tabela 1). Essa espécie não apresentou folhas danificadas por C. ferruginea com notas acima de 5.…”