BACKGROUND: Helicoverpa armigera is a major pest of pigeonpea (Cajanus cajan). Efforts to develop pigeonpea varieties resistant to H. armigera attack have been met with limited success, despite reports of high levels of resistance to H. armigera in wild relatives of pigeonpea and reports of low to moderate levels of resistance in cultivated varieties. Here we examined H. armigera oviposition preference and larval performance on whole plants of three cultivars of short-duration pigeonpea: a susceptible control (ICPL 87) and two cultivars with purported host-plant resistance (ICPL 86012 and ICPL 88039).RESULTS: In our no-choice oviposition experiment, H. armigera laid similar numbers of eggs on all three cultivars tested, but under choice conditions moths laid slightly more eggs on ICPL 88039. Larval growth and development were affected by cultivar, and larvae grew to the largest size (weight) and developed fastest on ICPL 86012. Moths laid most of their eggs on floral structures, sites where subsequent early instar larvae overwhelmingly fed. Experimentally placing neonate larvae at different locations on plants demonstrated that larvae placed on flowers experienced greater survival, faster development, and greater weight gain than those placed on leaves. The type and density of trichomes (a potential resistance trait) differed among cultivars and plant structures, but larvae selected to feed at sites where trichomes were absent. CONCLUSION: Future work examining host-plant resistance against H. armigera should incorporate the behavioural preference of moths and larvae in experiments using whole plants as opposed to bioassays of excised plant parts in Petri dishes.

When an invasive species first breaches quarantine and establishes in yet another country, it invariably causes consternation for growers, in part because of incomplete understanding of the plants that are at risk. The Fall Armyworm, Spodoptera frugiperda (J.E. Smith) is the most recent example in Australia. The number of plants that this polyphagous noctuid is reported to attack is vast, including many crop species. Consequently, initial reactions from grower industry groups that perceived themselves at risk were to demand emergency use of insecticides. Yet the field evidence suggests that many crops might not be at risk and since S. frugiperda arrived in Australia, maize crops have suffered most damage, followed by sorghum. We question the accuracy of some of the claims of reported host plants of S. frugiperda and report experiments that compared oviposition behavior, neonate silking behavior, and larval performance on five crops: the known hosts maize and sorghum, and the putative hosts cotton, peanut, and pigeon pea. Maize ranked highest in all preference and performance measures, followed by sorghum and peanut, with pigeon pea and cotton ranking lowest. Although S. frugiperda can survive, develop, and pupate on the crop species we examined, cotton and pigeon pea are not preferred by the pest in either the larval or adult stages. We suggest that before a plant is listed as a host for a given insect that the evidence should be fully reported and carefully evaluated. Collecting an immature insect from a plant does not make that plant a host!

Melomys cervinipes (Gould, 1852) is a murid rodent commonly called the fawn-footed mosaic-tailed rat. A small, russet brown rodent with light fawn-colored feet, it is 1 of 21 currently recognized species in the genus Melomys. The species is endemic to Australia, occurring in the rainforests and forests along the eastern coast. M. cervinipes is listed as "Least Concern" by the International Union for the Conservation of Nature and Natural Resources.

Yellow crazy ants (Anoplolepis gracilipes) threaten invertebrates on many tropical islands, but little work has been done in continental ecosystems. We found 4.4-16.0 times more cruiser butterfly caterpillars were attacked in Australian rain forest sites with A. gracilipes than in native ant sites, and extrafloral nectar had little influence. , which may be more susceptible to effects of invasive species than continental ecosystems (Simberloff 1995). Only one published study has investigated effects of A. gracilipes on invertebrate communities on mainlands, and it found no significant effect of A. gracilipes on the abundance or richness of ground invertebrates (Hoffmann & Saul 2010).Butterflies are a group of invertebrates that may be particularly susceptible to invasions by A. gracilipes because their larval stages forage on plants. Larvae that forage on plants with EFN may be particularly at risk because A. gracilipes increases recruitment and aggressive behavior with increasing EFN availability (Savage & Whitney 2011). The aim of our study was to compare attack rates of a native caterpillar by the invasive A. gracilipes and native O. smaragdina. We conducted our experiments on two species of host plants and manipulated access to EFN on one of them. We addressed two questions: (1) are attack rates of caterpillars by A. gracilipes higher than by O. smaragdina? And (2) how does availability of EFN influence attack rates by the invasive and native ant species?We conducted our study with the native cruiser butterfly, Vindula arsinoe (Nymphalidae), an excellent proxy for many threatened butterfly species in the Wet Tropics. It oviposits in clusters, its instars have spines, and it does not sequester phytotoxins. Its preference for lowland rain forest and vine thickets (Braby 2009) overlaps with habitat invaded by A. gracilipes. Vindula arsinoe oviposits and develops on the introduced weedy vine, Passiflora foetida and the native vine, Adenia heterophylla (both Passifloraceae). Passiflora foetida has multiple minuscule extrafloral nectaries on its leaf margins, and A. heterophylla has two prominent extrafloral nectaries at the base of the petiole and underside of

BACKGROUND Recent research on multiple invasive ant species has revealed the importance of carbohydrates for achieving high activity levels and outcompeting native ants. However, comparatively little is known about the role of diet and macronutrient preferences for uptake of insecticidal baits used to control invasive ants. We tested whether diet affected yellow crazy ant (Anoplolepis gracilipes Fr Smith) survival and behavior, and whether bait preference would be complementary to past diet. RESULTS We found that colonies fed only crickets for 28 days had fewer live workers and queens, and less brood per live queen than colonies fed crickets + honeydew but did not differ significantly from colonies fed only honeydew. Colonies that had been fed only crickets were more active (as assessed by interaction with a novel object), retrieved 16–17 times more bait per worker overall, and consumed more of the six bait types than cricket + honeydew and honeydew‐only fed colonies. However, prior diet did not affect bait choice. The two highest sugar bait formulations combined accounted for most of the bait consumed across all treatments (cricket‐only 74.8% ± 28.1; cricket + honeydew 69.2% ± 12.4; honeydew‐only 62.5% ± 30.4). CONCLUSION Yellow crazy ant colonies fare better without protein than without carbohydrates. Yellow crazy ants ate the most bait when fed only crickets but did not choose baits complementary to their previous diet. Baits in a sugar‐rich carrier may be most effective for the control of yellow crazy ants, regardless of the relative availability of macronutrients. © 2019 Society of Chemical Industry