Doubling of the current atmospheric CO2 concentration, and an increase in global mean annual temperatures of 1.5–6 °C, have been predicted to occur by the end of this century. Whilst the separate effects of CO2 and temperature on plant–insect interactions have been examined in a number of studies, few have investigated their combined impact. We carried out a factorial experiment to explore the effect of a doubling of CO2 concentration and a 3 °C temperature increase on the development of a complete generation of the leaf‐miner, Dialectica scalariella, in the host plant Paterson's Curse, Echium plantagineum. Elevated CO2 increased biomass, reduced leaf N and increased C:N ratios in the host plants. Leaf thickness also increased under elevated CO2, but only in the high‐temperature treatment. Female D. scalariella did not discriminate between plants grown at the different CO2 levels when ovipositing, despite the reduction in foliage quality under elevated CO2. Overall, the negative response of D. scalariella to elevated CO2 was greater than for many species of free‐living insects, presumably because of the limited mobility imposed by the leaf‐mining habit. Development was accelerated at the high temperature and slowed under elevated CO2. The net result was a reduction in development time of ∼14 days in the elevated CO2/high temperature treatment, compared to the ambient CO2/low temperature treatment. Larval survivorship and adult moth weight were both affected by a significant interaction between CO2 and temperature. At the low temperature, CO2 had little effect on survivorship, but at the high temperature, survivorship was significantly reduced under elevated CO2. Similarly, elevated CO2 had a stronger negative effect on adult moth weight when combined with the high‐temperature treatment. A possible explanation for these results is that the high temperature accelerated insect development to such an extent that the larvae did not have sufficient feeding time to compensate for the poorer quality of the foliage. The frequency with which interactions between CO2 and temperature affected both plant and insect performance in this study highlights the need for caution when predicting the effects of future climate change on plant–insect interactions from single‐factor experiments.

Summary This study compares the effectiveness of using plant species, genera, family or water plant functional group (WPFG) classifications for demonstrating differences in vegetation communities associated with inundation history. Vegetation surveys were undertaken annually for 5 years from 2007–2008 to 2011–2012 at 18 floodplain wetlands. These wetlands are from two geographically separate locations situated along the lower Murray River. Wetlands have different inundation histories and have received varied amounts of environmental water since 2004. All plant species recorded were classified into WPFGs. An inundation classification was determined for each wetland at each survey time based on inundation history and inundation status at the time of survey (wet or dry). This study found that plant species composition at individual wetlands is often unique with few species recorded across multiple wetlands. The use of WPFGs reduced the variability of plant communities between individual wetlands, between the two geographic locations and within inundation classifications. By reducing the variability between samples, broad trends in vegetation responses to different watering histories can be identified. Individual wetlands can develop completely different suites of plant species in response to the same watering regime, particularly when separated over large distances. This variability can reduce the confidence managers have in predicting the plant communities likely to develop in response to prescribed watering regimes. Adaptively applying knowledge gained from monitoring to different wetlands or wetlands in different geographical regions is also difficult if responses are highly variable. This study demonstrates that by classifying wetland vegetation into WPFGs the variability observed between samples can be reduced and the influence of floristic differences between individual wetlands and geographic locations can be negated or lessened. We discuss how the use of WPFGs can assist scientists and managers in demonstrating, predicting and communicating trends in vegetation community responses as a result of different watering regimes. The adoption and application of a consistent approach to the classification of plant species into WPFGs has the potential to enable responses and predictions to watering events to be made across broad spatial scales.

We carried out a factorial experiment to explore the effect of doubled CO2 concentration and a 3 °C temperature increase on the development of a complete generation of the beetles Octotoma championi Baly and O. scabripennis Guérin‐Méneville (Coleoptera: Chrysomelidae). These species are biological control agents of Lantana camara L. (Verbenaceae), with a leaf‐mining larval phase and free‐living, leaf‐chewing adults. Plants grown at elevated CO2 had enhanced above‐ground biomass, thicker leaves, reduced nitrogen concentration, and increased C:N ratios. Under the high temperature treatment, plants grown at ambient CO2 suffered wilting and premature leaf loss, despite daily watering; this effect was ameliorated at elevated CO2. The wilting of plants in the ambient CO2/high temperature treatment reduced the emergence success of the beetles, particularly O. championi. Development time was accelerated by approximately 10–13 days at the higher temperature, but was not affected by CO2. Neither CO2 nor temperature affected adult beetle weight. Consumption rates of free‐living beetles were not affected by either CO2 or temperature. By contrast, in the short‐term trials using excised foliage, beetles given no choice between ambient and elevated CO2‐grown foliage, consumed more from ambient plants. When beetles were offered a choice between foliage grown at the two CO2 levels, O. championi did not display a significant preference but O. scabripennis consumed more ambient CO2‐grown foliage when feeding at the lower temperature. This study indicates that under future conditions of higher temperatures, amelioration of water stress in host plants growing in elevated CO2 may benefit some endophagous insects by reducing premature leaf loss. Under some circumstances, this benefit may outweigh the deleterious effects of lower leaf nitrogen. Our results also indicate that foliage consumption under elevated CO2 by mobile, adult insects on whole plants may not be significantly increased, as was previously indicated by short‐term experiments using excised foliage.

Christmas beetles (Coleoptera: Scarabaeidae) (Anoplognathus spp.) and paropsine leaf beetles (Coleoptera: Chrysomelidae) are common defoliators of eucalypts, including several important plantation species, throughout south-eastern Australia. It has already been demonstrated that populations and individuals of several eucalypt species vary in susceptibility to defoliation by these leaf-chewing beetles. The objective of this study was to determine whether significant variation in resistance to insect herbivory was present in Eucalyptus grandis genotypes selected from the hardwood plantation program of State Forests of NSW.Grafted clones from three young trees with significantly less crown damage than neighbouring trees in a plantation established near Byron Bay, NSW, were tested for attractiveness to Anoplognathus chloropyrus adults in a binary choice experiment in the laboratory. Shoots from the resistant grafted ramets were paired with shoots from susceptible seedlings of similar age, and caged with feeding A. chloropyrus adults for 24 h. The Christmas beetles consumed significantly (P ~ 0.05) less leaf area from the resistant shoots, compared to that consumed from the shoots from susceptible seedlings, when given access to both. The binary choice test method was also used to test feeding preferences of four paropsine chrysomelid species: Paropsis atomaria (adults and larvae), P. variolosa (larvae only), Paropsisterna beata (adults), and a Chrysophtharta sp. (adults), using the same E. grandis genotypes. No significant differences (P > 0.05) in feeding preferences were detected for P. variolosa larvae, P. atomaria adults, P. beata adults or the Chrysophtharta sp. adults. In contrast, P. atomaria larvae displayed a significant preference for foliage from the susceptible seedlings. In a larval development study using P. atomaria larvae, those reared on the susceptible foliage developed approximately five days faster and had significantly higher survival than those reared on resistant foliage.Several leaf traits were also compared between the two types of foliage. Leaves of similar age from the resistant clones did not differ significantly from the susceptible seedlings in terms of carbon to nitrogen content or concentrations of the monoterpene, 1,8-cineole. They did, however, have significantly higher specific leaf weight (SLW). SLW may have the potential for use in rapid screening of E. grandis genotypes for susceptibilty to defoliation by leaf-chewing beetles that prefer young soft foliage.

Parasitoids are becoming an increasingly important part of our biological arsenal in Integrated Pest Management strategies against major insect pests like Helicoverpa armigera (Hübner). Inundative or supplementary releases of parasitoids have been successfully used in the past to help manage insect pests in the field. This paper reports attempts to mass rear two larval parasitoids of Helicoverpa spp., Heteropelma scaposum and Netelia producta . The results suggest that N. producta is the easier species to culture, although the parasitism rates for either wasp species were not high (29% for N. producta and 19% for H. scaposum ). The authors suggest ways in which the parasitism rates could be increased and culturing made easier. It was found that culturing H. scaposum resulted in a male-biased sex ratio that was less suitable for mass release. Possible reasons for the bias are discussed, including singlelocus complementary sex determination (CSD) that can result in a high proportion of homozygotic diploid males occurring in inbred populations. Although single-locus CSD is a plausible explanation for the male biased sex ratio, the authors caution that more work is needed to confirm that it can occur in H. scaposum .