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Simple Summary: Thaumetopoea pityocampa caterpillars are a significant pest of conifer trees in Europe and live gregariously in a communal tent with siblings and conspecifics from other colonies. Despite their economic and medical importance, there has been a lack of quantitative information on the tent construction and foraging behaviour in T. pityocampa colonies. In this study, we observed the tent construction and foraging behaviour of T. pityocampa caterpillars in the field at Tregnago, Verona, Italy. At around sunset, large male caterpillars emerged from the tent first to construct the tent, while many female caterpillars emerged later in the night only to forage. As younger instar caterpillars moulted to older larval instars, the environmental temperature decreased, which consequently increased the duration of their foraging activities. The final tent structure constructed by later instar caterpillars was not isodiametric; more silk was applied on the southern side of the tent to receive maximum insolation during the winter months. This study demonstrated the importance of the winter tent and individual variation in tent construction and foraging behaviour of T. pityocampa caterpillars amongst sex, body size, and larval instar and lays the basis for further investigation in polyethism. As a social organism, living in a communal structure is one of the most important physical barriers against environmental elements and natural enemies. Thaumetopoea pityocampa (Notodontidae, Thaumetopoeinae) caterpillars are conifer pests that spend most of their larval stage in winter. Although T. pityocampa holds economic and medical significance, the tent construction and foraging behaviour are poorly understood. We observed the tent construction behaviour in autumn (October and November) when third- and fourth-instar T. pityocampa caterpillars build the 'winter tent' that can withstand winter conditions. Just before sunset, with no rain and temperatures over 12 °C, tent construction was undertaken by early active individuals, primarily larger male caterpillars. Early active caterpillars emerge from the tent first and spin silk on the tent for expansion and strength. Once temperatures dropped below 12 °C and twilight had passed, the early active caterpillars went out to forage and were later joined by the late active caterpillars, which were predominantly smaller females that had remained inside the tent. Foraging behaviour was continuously monitored for the first to fourth larval instars in the field. Foraging was more frequent in younger instars when environmental temperatures were warmer and became continuous and prolonged in later instar caterpillars as temperatures dropped. The final tent structure built by later instar caterpillars had the thickest layer of silk on the southern side of the tent compared to other orientations to receive maximum solar radiation during the winter. Our study provided additional insights into the collective nest building, foraging and social behaviours observed in Lepidoptera, as well as the roles of individuals within non-eusocial insect colonies. [ABSTRACT FROM AUTHOR]

Diamondback moth (DBM), Plutella xylostella L. (Lepidoptera: Plutellidae), eggs are vulnerable to rainfall, but the impact is dependent on host plant properties and the nature of oviposition sites. The effects of host plants, common cabbage (Brassica oleracea L. var. capitata) and Chinese cabbage (Brassica rapa L. var. pekinensis) (Brassicaceae), and oviposition sites on the fate of eggs subjected to simulated raindrops were investigated in laboratory experiments. In oviposition studies, DBM deposited more eggs on leaf veins than on leaf laminas on both host plants. In common cabbage plants, eggs laid on lower leaves (leaf 2) were less susceptible to dislodgment by rainfall than eggs laid on upper leaves (leaf 6). Eggs laid on the veins on the abaxial surfaces of leaves 2 and 6 of common cabbage plants were less susceptible to dislodgment by raindrops than eggs laid at other sites on this host plant. In Chinese cabbage plants, eggs laid on the veins were less susceptible to dislodgment by raindrops than eggs laid on leaf laminas. When DBM laid eggs in clusters, eggs were less susceptible to dislodgment by raindrops. The presence of waxes on leaf surfaces and concave veins affected egg placement and the retention of eggs at oviposition sites when subjected to raindrops. Eggs were more resistant to raindrops on the concave veined and less waxy leaves of Chinese cabbage plants than on waxy surfaces of smooth common cabbage leaves. When epicuticular wax crystals were removed from common cabbage leaves before oviposition, eggs were more resistant to dislodgment by raindrops. Leaf orientation or angle (horizontal plane vs. an angle of 45°) did not affect the susceptibility of eggs to raindrops. However, eggs were affected indirectly, and vibrations caused by the impact of raindrops resulted in egg removal from both adaxial and abaxial surfaces. Overall, eggs were less likely to be dislodged by raindrops when laid on concave veins and less waxy leaf surfaces. In oviposition tests, DBM laid fewer eggs on plant parts from which they were most easily removed by raindrops, and when they did lay eggs at these sites, they often deposited them in clusters which were more resistant than single eggs to removal by raindrops. The study reiterates the species‐specific nature of DBM‐host plant interactions and shows that female DBM can modify their behaviour to improve the probability of egg survival when substrates available for oviposition are sub‐optimal. [ABSTRACT FROM AUTHOR]

Simple Summary: Host specificity in an Australian species of processionary moth was studied over three years in the eastern Australia states of Queensland and New South Wales. The processionary moth Ochrogaster lunifer is known as a species complex, characterised by several nesting forms coexisting in the same geographical area. The canopy nesting forms associated with acacias (Acacia spp.) and eucalypts (Eucalyptus spp. and Corymbia spp.) were recently shown to be genetically distinct, and they were here tested for host specificity by reciprocal transplant experiments. Egg masses and subsequent offspring were moved within and among putative hosts in field settings. Early larval colonies performed significantly better on their natal hosts than on the transplanted ones, with no difference observed for mature larval colonies. The genetic separation identified in previous work is, thus, confirmed by these ecological observations on host specificity, stressing the importance of host specialization in the ongoing speciation process. The 'mother knows best' hypothesis is tested in a species of processionary moth feeding on acacias and eucalypts in Australia. The processionary moth Ochrogaster lunifer (Lepidoptera: Notodontidae; Thaumetopoeinae) is a social caterpillar living in large colonies on a number of tree and shrub species. Five nesting types—canopy, trunk, tree-hugger, hanging, and ground—have been described, and this study deals with canopy nesters on various species of acacias (Acacia spp.) and eucalypts (Eucalyptus spp. and Corymbia spp.). Reciprocal transplant experiments conducted over three years confirm the 'mother knows best' hypothesis, as colonies performed better on the natal host plant than on the recipient ones. Young first instar larvae were less likely to establish on a non-natal host than the mature larvae, and all acacia-sourced canopy egg masses failed to establish on eucalypts. Large larvae were able to establish on transplant hosts. This suggests a strong preference–performance link at what is likely a species level, confirming preliminary results recently published on genetic divergence. Canopy nesting forms also have a lower realised fecundity than the ground nesting form on acacias from the same geographic area, but higher than another canopy nesting form from western Australia. Further observations on ecological and genetic traits are required to draw conclusions about the separation of lineages in the canopy nesting form of O. lunifer, by including populations from other parts of the range for both the herbivore and the host plants. [ABSTRACT FROM AUTHOR]

Details of feeding behaviour of Australian sawfly species on eucalypt hosts are not well known. In this study, we report new findings on two pergid sawflies, Lophyrotoma interrupta and an unidentified species of Lophyrotoma, after observing larvae feed. We confirmed both daily and nightly feeding regimes, with L. interrupta and Lophyrotoma sp. engaged in feeding‐related activities 92.2% and 67.0% of the time, respectively. A colony sometimes splits into subcolonies as a leaf depletes; individuals leave singly and explore surrounding leaves before joining the rest of the colony feeding on the new leaf. As a specific feeding behaviour, the larvae of both species cut midveins on surrounding leaves in one of several ways before and during feeding. Larvae used pre‐processed cut leaves at a ratio ranging from 0.64 to 0.88 of the whole leaves eaten. Of the leaves cut prior to feeding, approximately half were not consumed, whereas the remaining were consumed 2 days after cutting (median time). We observed a decreasing trend of further cuttings when the proportion of damaged leaves in the surrounding area was increased. Feeding of Lophyrotoma sp. followed a clear pattern: Usually, the last individual remaining on the leaf severed the leaf petiole as it left. This petiole snipping occurred in over half the leaves that larvae had used; however, this behaviour was not observed in L. interrupta. [ABSTRACT FROM AUTHOR]

The spatial distribution of an ecological subsidy can change local trophic cascades and create differences among locations; however, its contribution to shaping large-scale ecosystem functions is less well known. Here, using a multi-scale hierarchical design along a nitrogen input gradient, we assessed both local (within field level) and neighborhood (inter-field level) differences in soil nutrients and plant-arthropod communities to explain variation in landscape-scale crop productivity and biocontrol service. We found that the average importance of neighborhood factors increased, approached and even exceeded local factors in explaining the variance in the predator-to-aphid abundance ratio, wheat yield and parasitism rate. Compared to models with only local factors, both local and neighborhood factors when integrated into linear models explained an extra 67% and 18% of the variation in wheat yield and parasitism rate, respectively. Preserving the abundance and variability of biological resources on a specific spatial scale using targeted nitrogen subsidies may be a promising strategy for sustaining multiple ecosystem functions under intensified land use. [ABSTRACT FROM AUTHOR]

Helicoverpa punctigera (Wallengren), the native budworm, is an important highly polyphagous pest that has caused serious damage on a wide variety of crops in Australia. In Australia, its range overlaps that of its congener, Helicoverpa armigera (Hübner), a notorious invasive pest globally. We used CLIMEX, a bioclimatic niche modelling software package, to estimate the potential geographical distribution of H. punctigera under current and future climates (A1B scenario). Under both current and future climate conditions, the model indicates that H. punctigera could establish throughout the tropics and subtropics. Comparing the potential distributions under each climate scenario revealed that in the future its potential distribution is likely to shift poleward and into higher altitudes, into areas that are currently too cold as observed in the South of Brazil, Europe, North America, South East Asia, and South Pacific Islands including New Zealand. The projected potential distribution can inform pre- and post-border biosecurity strategies for the management of this pest in each country. [ABSTRACT FROM AUTHOR]

Excessive mineral fertilizer input results in little extra yield but exacerbates insect herbivory and affects environmental health and ecosystem services. The use of organic fertilizer is considered to have promise for mitigating those impacts. How organic fertilizer amendment modifies crop resistance to insect herbivory and modulates biocontrol services on a landscape scale has not been well studied. We conducted a series of field experiments on a large spatial scale with three fertilization regimes (mineral fertilizer, mineral fertilizer amended with organic matter, and no fertilizer control) in Shandong Province, northern China. Soil nutrient content, wheat plant metabolism, cereal aphid abundance, parasitism rate, and wheat yield were quantified. Maize straw amendment combined with mineral fertilization significantly reduced cereal aphid abundance and promoted parasitism during the peak aphid period, compared with mineral fertilizer alone and the no fertilizer control. Modeling simulations showed increased biological pest control when a larger proportion of fields were additionally treated with maize straw amendment. Foliar chemical analyses revealed that the types and content of plant free amino acids, rather than plant defensive compounds, most likely accounted for the variation in aphid abundance and biological control efficiency. A mineral fertilization regime plus plant straw amendment may promote wheat resistance to herbivory and benefit biocontrol via bottom-up effects. Heterogeneity in fertilizer regimes between fields may be the key ecological force shaping pest control at a landscape scale. [ABSTRACT FROM AUTHOR]

Understanding the seasonal movements of migratory species underpins ecological studies. Several hundred butterfly species show migratory behaviour, yet the spatial pattern of these migrations is poorly understood. We developed climatic niche models for 405 migratory butterfly species globally to estimate patterns of seasonal movement and the distribution of seasonal habitat suitability. We found strong seasonal variation in habitat suitability for most migratory butterflies with >75% of pixels within their distributions showing seasonal switching in predicted occupancy for 85% of species. The greatest rate of seasonal switching occurred in the tropics. Several species showed extreme range fluctuations between seasons, exceeding 10‐fold for 53 species (13%) and more than 100‐fold for nine species (2%), suggesting that such species may be at elevated extinction risk. Our results can be used to search for the ecological processes that underpin migration in insects, as well as to design conservation interventions for declining migratory insects. [ABSTRACT FROM AUTHOR]

The Bag‐shelter moth, Ochrogaster lunifer (Lepidoptera: Notodontidae), is an Australian endemic species of Thaumetopoeinae with a univoltine life cycle and gregarious, herbivorous larvae. It is variable throughout its range across the continent, most noticeably by the species of host tree used and nest‐building behaviour. It has long been considered a species complex by some taxonomists, and the lack of gene flow between populations of ground‐nesters and above‐ground nesters at the same sites provides strong evidence for at least two species. We tested the specificity of host use and nesting behaviour of ground‐nesting and trunk‐nesting forms of O. lunifer by transplanting field‐collected egg masses to the other form's host, either in their natural position or in the position used by the other form. At the study site, ground‐nesting and trunk‐nesting (tree‐hugger) O. lunifer coexist. Ground‐nesting larvae are found on Acacia spp., and egg masses are laid at the base of host tree trunks where nests develop whereas tree‐hugger larvae are found on Blakella tessellaris, egg masses are laid in the outer canopy, and nests develop on the trunk or large branches. Of the 47 egg masses of O. lunifer transplanted to the unnatural host, only one cohort of tree‐hugger larvae developed through to adult moths. Placing an egg mass in its unnatural position on its natural host did not prevent the larvae from developing and successfully establishing nests for either nesting‐form, although all the ground‐nesters moved position (from the canopy to the ground) and the tree‐huggers mostly did not (from the ground to the canopy). Only the tree‐hugger form of O. lunifer developed a viable nest on the unnatural host species, established a nest at the unnatural oviposition site, and shared that nest with larvae of the other nesting‐form, suggesting tree‐hugger larvae are somewhat plastic in their behaviour and ecology. Our findings add to previous studies indicating that Acacia is likely the ancestral host of O. lunifer though large areas of its range remain unstudied. [ABSTRACT FROM AUTHOR]

Establishing in the right location is particularly important for larval insects. Lepidopteran females are generally selective when choosing oviposition sites to ensure the best survival for their offspring. Unlike most social and shelterbuilding Lepidoptera, egg batches of the pine processionary moth, Thaumetopoea pityocampa Denis & Schiffermüller (1775) (Lepidoptera: Notodontidae), are oviposited randomly on the host tree. Thaumetopoea pityocampa is gregarious throughout all larval instars and live in silken tents, spun repeatedly and maintained by the colony during larval development. In this study, a single T. pityocampa egg batch was transplanted on Pinus nigra trees free from natural egg batches in one of four compass orientations: north, east, south or west. The orientation of transplanted egg batches had no significant effect on the final survival of the larvae. Thaumetopoea pityocampa larvae were behavioural thermoregulators from first to final instar and tended to position their tent in a southerly orientation for maximum sun exposure. Thermoregulation was the utmost priority for T. pityocampa larvae as they feed through the winter. Feeding behaviour and number of tents built by early instars changed as larvae became older, and this could be explained by natural enemy avoidance and/or evasion of plant defence. The results can help predict larval movement and assist in pest management strategies for T. pityocampa at a microhabitat level. This study is the first to investigate detailed movement behaviour of all T. pityocampa larval instars on a host tree, describing the transition of larvae starting as patch-restricted foragers to central place foragers. [ABSTRACT FROM AUTHOR]

The bag shelter moth, Ochrogaster lunifer Herrich‐Schäffer, 1855 (Thaumetopoeinae), is abundant and widespread throughout Australia where its larvae have been reported to feed mostly on Acacia and eucalypts. The larvae, known as processionary caterpillars, build silken nests on their host plants either on the ground at the base of the plant (Acacia) or above ground on the trunk or among the canopy (Acacia and eucalypts). The caterpillars are medically important in that they shed tiny setae that can cause dermatitis and other health problems in humans and other mammals, including amnionitis and foetal loss in horses. Despite reports of behavioural, ecological and morphological differences between ground and canopy nesters, caterpillars of all nest types and hosts are currently considered to belong to one species. Here, we use DNA sequence data from the mitochondrial and nuclear genomes of caterpillars taken from different nest types in eastern Australia to determine whether there is evidence for there being more than one species. We find significant genetic divergence between caterpillars from different nest types despite occurrence in sympatry at multiple sites, indicative of a lack of gene flow and the presence of at least two reproductively isolated species. Given the range of hosts and nest locations within hosts throughout Australia, further sampling is needed to determine just how many species there are under the current concept of O. lunifer. [ABSTRACT FROM AUTHOR]

An introduction is presented in which author discusses articles on topics including focuses on the earliest origins of Insecta to "Iron Homeostasis in Insects" and examines insect–plant interactions have been the focus of research labs with concentration on the intricate minutiae of interactions.

Oviposition patterns of the diamondback moth (DBM), Plutella xylostella L. (Lepidoptera: Plutellidae), differ between common cabbage (Brassica oleracea L. var. capitata) and Chinese cabbage (Brassica rapa L. var. pekinensis) (Brassicaceae) host plants. This study shows that the moth prefers to oviposit on adaxial rather than abaxial leaf surfaces and petioles of both host plants. More eggs were laid in leaf veins than on leaf laminas of both host plants, especially in Chinese cabbage, where 94.6% of eggs were laid in veins. On Chinese cabbage, very few eggs were laid in clusters (≥2 eggs), whereas on common cabbage approximately 30% of eggs were laid in groups of 2 or more eggs. Removal of wax from common cabbage leaves dramatically increased the number of eggs laid singly on the leaf lamina of treated plants, suggesting that leaf waxes affect how eggs are distributed by ovipositing DBM. Eggs were most susceptible to removal by rainfall from the plant surface immediately (<1 h) after oviposition and when close to hatching (>72h old) whereas they were least susceptible 24 h after oviposition. Eggs laid on common cabbage plants were more susceptible to simulated rainfall than eggs laid on Chinese cabbage plants. On common cabbage plants, egg susceptibility to rainfall on different plant parts ranked adaxial leaf surfaces>petioles = abaxial leaf surfaces>stem, but there was no difference in egg susceptibility to rainfall on the various plant parts of Chinese cabbage. Furthermore, on common cabbage plants, eggs laid on both adaxial and abaxial leaf surfaces were afforded significant protection from the effects of rainfall by leaves higher in the plant canopy. On common cabbage plants, oviposition patterns reduce the potential impact of rainfall on eggs, possibly reducing the effect of this important abiotic mortality factor in the field. [ABSTRACT FROM AUTHOR]

Sustainable agriculture relies on implementing effective, eco-friendly crop protection strategies. However, the adoption of these green tactics by growers is limited by their high costs resulting from the insufficient integration of various components of Integrated Pest Management (IPM). In response, we propose a framework within IPM termed Multi-Dimensional Management of Multiple Pests (3MP). Within this framework, a spatial dimension considers the interactive effects of soil-crop-pest-natural enemy networks on pest prevalence, while a time dimension addresses pest interactions over the crop season. The 3MP framework aims to bolster the adoption of green IPM tactics, thereby extending environmental benefits beyond crop protection. A theoretical framework, the Multi-Dimensional Management of Multiple Pests, is proposed to enhance the adoption of green Integrated Pest Management (IPM) tactics and encourage a more comprehensive assessment of environmental benefits. [ABSTRACT FROM AUTHOR]

Abstract: Although higher than expected numbers of surviving larvae of Helicoverpa spp. are reported in some Bollgard II cotton fields from time to time, there is no convincing evidence that field resistance has developed. A behavioural component, specifically the avoidance of the toxin, was considered to contribute to larvae surviving on Bacillus thuringiensis (Bt) toxin‐expressing plants. Experiments were conducted with Bt‐susceptible and Bt‐resistant larvae of Helicoverpa armigera to investigate (1) how larval responses to food deprivation might lead to differences in survival and therefore how far neonates could move to find a suitable feeding site and (2) whether larvae that are physiologically susceptible vs. resistant behave differently when feeding on diet with Bt and without Bt toxins. Bt‐susceptible neonates of H. armigera, which were significantly heavier, could survive without food for longer and recover better than Bt‐resistant neonates. Although H. armigera neonates did not shift their behaviour with respect to Bt toxin on artificial diet before their first feeding event, the tendency of Bt‐susceptible larvae to remain on non‐Bt diet and move off Bt diet may allow them to survive in a Bt environment. This behaviour resulted in a higher percentage of survival in situations where a diet choice was offered. [ABSTRACT FROM AUTHOR]

To assess the change in the size of the eastern North American monarch butterfly summer population, studies have used long-term data sets of counts of adult butterflies or eggs per milkweed stem. Despite the observed decline in the monarch population as measured at overwintering sites in Mexico, these studies found no decline in summer counts in the Midwest, the core of the summer breeding range, leading to a suggestion that the cause of the monarch population decline is not the loss of Midwest agricultural milkweeds but increased mortality during the fall migration. Using these counts to estimate population size, however, does not account for the shift of monarch activity from agricultural fields to non-agricultural sites over the past 20 years, as a result of the loss of agricultural milkweeds due to the near-ubiquitous use of glyphosate herbicides. We present the counter-hypotheses that the proportion of the monarch population present in non-agricultural habitats, where counts are made, has increased and that counts reflect both population size and the proportion of the population observed. We use data on the historical change in the proportion of milkweeds, and thus monarch activity, in agricultural fields and non-agricultural habitats to show why using counts can produce misleading conclusions about population size. We then separate out the shifting proportion effect from the counts to estimate the population size and show that these corrected summer monarch counts show a decline over time and are correlated with the size of the overwintering population. In addition, we present evidence against the hypothesis of increased mortality during migration. The milkweed limitation hypothesis for monarch decline remains supported and conservation efforts focusing on adding milkweeds to the landscape in the summer breeding region have a sound scientific basis. [ABSTRACT FROM AUTHOR]

Temporal changes in the pre- and post-alighting responses of mated female diamondback moth, Plutella xylostella L. ( Lepidoptera: Plutellidae), to two species of Brassica ( Brassicaceae) host plants induced by larval feeding were studied using olfactometer and oviposition assays. Females displayed strong olfactory and oviposition preferences for herbivore-induced common cabbage ( Brassica oleracea var. capitata L. cv. sugarloaf) plants over intact plants; these preferences decreased with time and disappeared by the 7th day after induction. In herbivore-induced common cabbage plants, eggs were clustered near feeding damage on the younger leaves (leaves 5-7), whereas in intact plants, eggs were clustered on the stem and lower leaves (leaves 1-4) . However, as the time interval between larval feeding and oviposition increased, more eggs were laid on the lower leaves of induced plants. This demonstrates a change in egg distribution from the pattern associated with induced plants to that associated with intact plants. In contrast, females displayed strong olfactory and oviposition preferences for intact Chinese cabbage [ Brassica rapa ssp. pekinensis (Lour.) Hanelt cv. Wombok] plants over induced plants; these preferences decreased with time and disappeared by the 5th day after induction. More eggs were laid on the upper leaves (leaves 4-6) than on the lower leaves (leaves 1-3) of intact Chinese cabbage plants at first, but the distribution changed over time until there were no significant differences in the egg count between upper and lower leaves by the 4th day post induction. For both host plant species, pre-alighting responses of moths were reliable indicators of post-alighting responses on the first 2 days post induction. The results suggest that temporal changes in a plant's profile (chemical or otherwise) following herbivory may influence attractiveness to an insect herbivore and be accompanied by changes in olfactory and oviposition preferences. [ABSTRACT FROM AUTHOR]

Act 1 - prequel: From the first European settlement to the formation of the Australian Entomological Society, much of Australian entomology was driven by the need to understand and manage a raft of indigenous and invasive pest insect species. This very applied imperative influenced how people approached ecology, which tended to be very much autecological: species focused questions addressing the distribution and abundance of the organism. Not surprisingly that applied focus continued after the formation of the society in 1964, which marks the beginning of Act 2 - The last 50 years. Here I focus in part on what has been published in the flagship journal of the society since its inception and analyse the trends that are evident. The emphasis on basic biology is reflected in the publication trends in the society's journal. I use some of the key native and imported pests - locusts, H elicoverpa, Queensland fruit flies, sugar cane-feeding scarabs, diamondback moth - to illustrate how ecological thinking has developed. There were some Australian giants in the field of population ecology, and their public disagreements continue to reverberate. But there have been many notable contributions by lesser mortals, if only students and their mentors would read and cite appropriately! One can only allude to the encore, or Act 3 - the sequel or the next 25-50 years. The thinking of Australian entomologists continues to be at the forefront of spatial ecology, perhaps reflecting the scale at which fieldwork is undertaken in Australia. Other younger members of the society will no doubt write the epitaph and obituaries of the current crop of researchers and judge their contributions accordingly. [ABSTRACT FROM AUTHOR]

The Bag-shelter moth Ochrogaster lunifer (Lepidoptera: Notodontidae: Thaumetopoeinae) is an endemic species of medical and veterinary importance that occurs throughout Australia. The gregarious species is variable with four phylogenetic clades recently identified. One clade comprises trunk-nesters restricted to one host: the Moreton Bay Ash, Corymbia tessellaris (Myrtaceae). Here, we describe aspects of the biology and ecology of this distinctive nesting form dupped the 'tree-hugger' due to its flattish, thick silk nests that hug the trunk and larger branches. The form is univoltine; egg masses are laid in spring and the gregarious larvae develop through seven instars until the mature larvae stop feeding in autumn and later leave the nest (in a procession). The larvae over-winter in the ground as pre-pupae in a loose cocoon of silk. Pupation occurs in late winter and adults emerge in spring. Forty-six per cent of monitored egg masses succeeded in developing through the lifecycle. Tachinids were common parasites of older larvae. Tree-hugger nests provided some insulation against summer heat during the mornings, but the physical characteristics of the nests and tree trunks and the average southern orientation of the nests likely protect larvae against extreme heat. The tree-hugger form of O. lunifer appears morphologically similar to the more ubiquitous ground-nesting form, but there are differences in the colour of egg masses and adults, and in the behaviour and ecology of the larvae and adults. This information adds to the body of evidence supporting the definition of separate species within what is currently known as O. lunifer. [ABSTRACT FROM AUTHOR]

Transgenic Bt-cotton now dominates the cotton-growing belt in northwestern China where there are few natural plant refuges to act as sources of moths susceptible to Bt toxin. As an initial step towards developing an insect resistance management (IRM) plan for the pest moth, Helicoverpa armigera, on Bt-cotton in this part of China, we assessed the potential of six crops grown in two configurations to act as refuge hosts for susceptible moth production in both broad-acre and small-holder farms. Egg and larval abundance indicated that H. armigera had a preference for chickpea, pigeon pea, and corn, over cotton, sorghum, and benne (sesame). There were no significant differences in egg or larval abundance between plot and strip configurations of these crop hosts. We found that sorghum was not attractive to H. armigera, contrary to the findings in other cotton production areas. Moreover, chickpea, pigeon pea, and corn were determined to be potential refuge hosts based on egg and larval abundance over the growing season. From the adult moth population dynamics in broad-acre and small-holder farms, the efficiency of alternative refuge crops, and local agricultural practices, we recommend that spring corn be grown as a strip crop as part of an IRM strategy to improve the probability of Bt-susceptible moth production and mating with resistant moths in broad-acre farms. In small-holder farms where current agricultural practices are entrenched, wheat and summer corn should be evaluated as refuge crops in the future. [ABSTRACT FROM AUTHOR]

Background: Wolbachia are maternally inherited endosymbiotic bacteria that manipulate the reproductive success of their insect hosts. Uninfected females that mate with Wolbachia infected males do not reproduce due to cytoplasmic incompatibility (CI). CI results in the increased frequency of Wolbachia-infected individuals in populations. Recently, two Wolbachia strains, the benign wMel and virulent wMelPop have been artificially transinfected into the primary vector of dengue virus, the mosquito Ae. aegypti where they have formed stable infections. These Wolbachia infections are being developed for a biological control strategy against dengue virus transmission. While the effects of Wolbachia on female Ae. aegypti have been examined the effects on males are less well characterised. Here we ascertain and compare the effects of the two strains on male fitness in resource-limited environments that may better approximate the natural environment. Methods: A series of population mating trials were conducted to examine the effect of Wolbachia infection status (with strains wMel and wMelPop) and male larval nutrition on insemination frequency, remating rates, the fecundity of females, the hatch rates of eggs and the wing length and fertility of males. Results: wMel and wMelPop infections reduce the fecundity of infected females and wMelPop reduces the viability of eggs. Low nutrition diets for males in the larval phase affects the fecundity of wMel-infected females. Neither strain of Wolbachia affected sperm quality or viability or the ability of males to successfully mate multiple females. Conclusions: The benign strain of Wolbachia, wMel causes similar reductions in fecundity as the more virulent, wMelPop, and neither are too great that they should not still spread given the action of CI. The ability of Wolbachia-infected males to repeat mate as frequently as wildtype mosquitoes indicates that they will be very good agents of delivering CI in field release populations. [ABSTRACT FROM AUTHOR]

Abstract: The aphid parasitoid Lysiphlebus testaceipes is a potentially valuable biological control agent of Aphis gossypii a major worldwide pest of cotton. One means of increasing the abundance of a biological control agent is to provide an alternative host habitat adjacent to cropping, from which they can provide pest control services in the crop. Host selection and parasitism rate of an alternative host aphid, Aphis craccivora by L. testaceipes were studied in a series of experiments that tested its host suitability relative to A. gossypii on cotton, hibiscus and mungbean. Host acceptance, as measured by number of ovipositions was much greater in A. craccivora compared to A. gossypii, while more host aphids were accepted on mungbean than cotton. When given a choice L. testaceipes attacks more 4th instar and adult stages (63% and 70%, respectively) of both hosts than 2nd instar nymphs (47%). In a switching (host choice) experiment, L. testaceipes preferentially attacked A. craccivora on mungbean over A. gossypii on cotton. Observations of parasitoid contact with A. gossypii cornicle secretion suggest it provides a useful deterrent against parasitoid attack. From these experiments it appears L. testaceipes has a preference for A. craccivora and mungbean compared to A. gossypii and cotton, in this respect using A. craccivora and mungbean as alternative habitat may not work as the parasitoid is unlikely to switch away from its preferred host. [Copyright &y& Elsevier]

Body temperature in insects is affected by interactions between environmental variables, behavioural choices and the physiological state of the animal. Insect larvae display a number of tactics for thermoregulation which allow their body temperatures to deviate several degrees from ambient. Thermoregulatory adaptations can reduce generation time and allow higher population growth rates. However, few investigations have examined thermoregulation of moulting larvae. This study measured whether moulting Monarch butterfly ( Danaus plexippus) larvae thermoregulate, and, if so, whether they thermoregulate similarly to feeding larvae. Body temperatures of moulting and feeding larvae were compared to their microhabitat temperatures. In three of four environments, feeding larvae were able to thermoregulate in such a way that their body temperature was higher than ambient at low ambient temperature, and lower than ambient at higher ambient temperature. However, moulting larvae appear not to thermoregulate because their body temperature did not differ from ambient in three of four environments. These results pose the question of whether larvae are behaviourally and/or physiologically constrained from thermoregulating during the moulting process. Additional studies are needed to address such questions and would help to elucidate the impact of thermoregulation of moulting larvae on the ecology and evolution of insects. [ABSTRACT FROM AUTHOR]

Parasitoid survival and fecundity is generally enhanced with access to carbohydrate food sources. In many agricultural ecosystems, there is often a scarcity of suitable carbohydrates for parasitoids. This study compared the suitability of aphid honeydew and buckwheat nectar as diet for the aphid parasitoid Lysiphlebus testaceipes. Wasp lifespan and egg load were both increased with access to carbohydrates, but no differences were detected between the various carbohydrates diets tested. As aphid honeydew is a sufficient source of nutrition and L. testaceipes is a short-lived species, adding additional sources of carbohydrates like floral nectar strips to the agricultural landscape is unlikely to significantly increase the biological control exerted by L. testaceipes. [ABSTRACT FROM AUTHOR]

The potato tuberworm, Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae), is the most destructive pest of potato, Solanum tuberosum L. (Solanaceae), in tropical and subtropical regions in both field and storeroom situations. The modeling of temperature-dependent development can be useful in forecasting occurrence and population dynamics of the pests. Published developmental parameters for this pest vary greatly for many reasons. We determined temperature-dependent development of P. operculella at seven constant temperatures (16, 20, 24, 28, 32, 34 and 36 °C). Developmental period of whole immature stage (egg to the end of the pupal stage) varied from 75.5 days at 16 °C to 17 days at 32 °C. The population failed to survive at 36 °C. The observed data was modeled to determine mathematical functions for simulating P. operculella development in each stage of development and overall. Two linear models, ordinary linear regression and the Ikemoto linear model were used to describe the relationship between temperature and development rate of the different stages of P. operculella and estimating the thermal constant and lower temperature threshold. The lower temperature threshold ( t) and thermal constant ( k) of whole immature stage were estimated to be 11.6 °C and 338.5 DD by Ikemoto linear model, and the estimated parameters were not substantially different with those estimated by ordinary linear models. Different models provided a better fit to the various developmental stages. Of the eleven nonlinear models fitted, the Beriere-1, Logan-6 and Lactin-1 model was found to be the best for modeling development rate of egg, larva and pupa of P. operculella, respectively. Phenological models based on these findings can be part of a decision-support tool to improve the efficiency of pest management programs. [ABSTRACT FROM AUTHOR]

Anthropogenic pressures are driving insect declines across the world. Although protected areas (PAs) play a prominent role in safeguarding many vertebrate species from human-induced threats, insects are not widely considered when designing PA systems or building strategies for PA management. We review the effectiveness of PAs for insect conservation and find substantial taxonomic and geographic gaps in knowledge. Most research focuses on the representation of species, and few studies assess threats to insects or the role that effective PA management can play in insect conservation. We propose a four-step research agenda to help ensure that insects are central in efforts to expand the global PA network under the Post-2020 Global Biodiversity Framework. Insects dominate the biosphere and play a central role in ecosystem processes, but they are rapidly declining across the world. Protected areas (PAs) are designed to insulate biodiversity from human-induced threats, but they have been mainly designated for vertebrates and plants. Most research on insects in PAs focuses on the representation of species, and few studies assess threats to insects or the role that effective PA management can play. We propose a four-step research agenda to help to ensure that insects are central in efforts to expand the global PA network under the Post-2020 Global Biodiversity Framework. [ABSTRACT FROM AUTHOR]

A greater understanding of the relative impact of insecticide use on non-target species is critical for the incorporation of natural enemies into integrated pest management strategies. Here we use a small-plot field trial to examine the relative impact of an insecticide on herbivores and predators found in soybean ( Glycine max L.), and to highlight the issues associated with calculating impact factors from these studies. The pyrethroid insecticide (Deltamethrin) caused a significant reduction in invertebrate abundance in the treated plots, and populations did not recover to pre-treatment levels even 20 days after spraying. To assess the relative impact of the spray on arthropods we first examined the mean difference in abundance in each plot before and after spraying. All herbivores decreased in abundance in the sprayed plots but increased in the control plots after spraying. Most predators (excluding hemipterans) showed a decrease in the control plots but a proportionally greater decrease in the sprayed plots. Next we examined the corrected percentage population reduction calculated using Abbott's formula. All predators (including Araneae) experienced a greater reduction (mean 87% ± 3.54 SE) than herbivores (mean 56% ± 4.37 SE) and Araneae alone (mean 71% ± 8.12 SE). The range in values across the plots varied and made categorising overall impact subjective for some taxa. Despite the constraints associated with small-plot trials, by using a combination of impact factors and examining community-level response across time, we did get some indication of the likely impact of this insecticide if used in a commercial situation. [ABSTRACT FROM AUTHOR]

Most people agree that arthropod natural enemies are good for insect pest management in agriculture. However, the population suppressive effects of predators, which consume their prey and often leave no direct evidence of their activity, are more difficult to study than the effects of parasitoids, which can be sampled from host populations relatively easily. We critically reviewed field studies which investigated the relationship between lepidopteran pests and their associated predatory fauna, published in 11 leading entomology and applied ecology journals between 2003 and 2008. Each study was appraised to determine whether or not it demonstrated that predators had an impact on prey (pest) populations and, if so, whether it was conducted at an ecological scale relevant to pest management. Less than half (43%) of the 54 field studies adopted methodologies that allowed the impact of predators on target pest populations to be measured. Furthermore, 76% of the studies were conducted at the scale of experimental plots rather than at the ecological scale which determines pest and predator population dynamics or at which pest-management decisions are made. In almost one-third of the studies, predator abundance and/or diversity was measured, but this metric was not linked with pest suppression or mortality. We conclude that much current research does not provide evidence that predatory arthropods suppress target lepidopteran pest populations and, consequently, that it has little relevance to pest management. Well-designed ecological experiments combined with recent advances in molecular techniques to identify predator diets and the emergence of organic agriculture provide both the mechanisms and a platform upon which many predator–prey interactions can be investigated at a scale relevant to pest management. However, benefits will only be reaped from this opportunity if current approaches to research are changed and relevant ecological data are collected at appropriate ecological scales. [ABSTRACT FROM AUTHOR]

Introductions of Encarsia dispersa Polaszek (Hymenoptera: Aphelinidae) for the biological control of spiralling whitefly, Aleurodicus dispersus Russell (Hemiptera: Aleyrodidae), were made directly onto Thursday Island, Torres Strait Queensland, in May 1994. Its efficacy was monitored intermittently for 7 years on 10 Acalypha wilkesiana Müll. Arg. (Euphorbiaceae) and two Terminalia catappa L. (Combretaceae) plants. Marked declines in whitefly densities were recorded on all hosts approximately 10 months after parasitoid releases. Declines in whitefly densities over the first 2 years were mostly matched with increases in per cent parasitism; these declines generally coinciding with wet seasons, with small resurgences occurring over the first dry season following the first decline. Whitefly densities and per cent leaves infested on T. catappa, and on A. wilkesiana with flat leaves were low by the latter half of the study. In contrast, A. wilkesiana with convoluted leaves seemed to inhibit the parasitoid by providing physical refuges for whitefly nymphs, resulting in higher whitefly numbers with low parasitism, particularly in dry conditions. Ten to 12 years after these initial declines, whitefly densities have remained low. Adults and larvae of Cryptolaemus affinis Crotch (Coleoptera: Coccinellidae) and larvae of Acletoxenus quadristriatus Duda (Diptera: Drosophilidae) were observed preying on whitefly nymphs during the study. Overall, sampling data suggested that A. dispersus was under biological control. It may be prudent to maintain A. wilkesiana with convoluted leaves (acting as host refuges) on the Torres Strait islands to retain parasitoid persistence, thereby maintaining controlled and stable populations of A. dispersus. In addition, because of the pest's wide host range and the ability for hosts with closed leaf structures, such as A. wilkesiana with convoluted leaves, to harbour higher pest numbers, movements of these plants within or out of tropical areas could pose a significant quarantine risk. [ABSTRACT FROM AUTHOR]

1. We use an individual-based model describing the life of a monarch butterfly, which utilises milkweeds both aggregated in patches and scattered across the wider landscape as a substrate for laying eggs. The model simplifies the metapopulation of milkweed habitat patches by representing them as a proportion of the overall landscape, with the rest of the landscape considered matrix, which may contain some low density of milkweed plants. 2. The model simulates the number of eggs laid daily by a butterfly as it searches for hosts. The likelihood of finding hosts is related to the density of plants and the search ability of the butterfly. For an empty matrix, remaining in a habitat patch results in more eggs laid. However individuals that are good searchers have almost equivalent success without remaining in a habitat patch. These individuals are most affected by the presence of hosts in the matrix. 3. Given realistic values of habitat patch availability, our model shows that the presence of plants at a low density in the matrix has a substantial impact on the number of eggs laid; removing these plants can reduce lifetime potential fecundity by ca. 20%. These results have implications for monarch butterflies inhabiting agricultural landscapes, in which genetically modified soybean that is resistant to herbicides has resulted in the decimation of milkweeds over large areas. [ABSTRACT FROM AUTHOR]

Experiments were conducted to determine feeding site preferences of Crocidolomia pavonana (Fabricius) (Lepidoptera: Crambidae) larvae within cabbage plants, Brassica oleracea L. var. capitata cv. Warrior (Brassicaceae), and to determine whether induced plant responses to herbivory affect the behavior of larvae. In the first experiment, intra-plant damage and larval distribution were recorded to account for the spreading pattern of damage and larval feeding behavior on a plant; larvae initially fed on the base of leaves and moved progressively to the bud, leaf tips were avoided. In the second experiment, larval performance (the duration of the first instar, survival to the second instar, and weight of second instars) was assessed when larvae fed on the bud, the base, and the tip of the youngest fully expanded leaf on a plant. Crocidolomia pavonana larvae performed best when they fed on bud leaf tissue and most poorly when they fed on leaf tissue at the base of leaves. In the third experiment, expression of induced resistance was tested on each of the three plant parts using a first-instar bioassay. Negative impacts on larval growth and development were not detected when larvae fed on the bud or base tissue when plants were damaged prior to the assay. However, negative effects were detected in larvae feeding on tip leaf tissue when the base of the leaf was damaged prior to the assay or if the bud tissue was damaged simultaneously with the assay. The findings indicate that resource heterogeneity for C. pavonana within-cabbage plants is determined by both the initial quality of food at a location and by subsequent induced changes as a result of larval feeding; both contribute to the feeding pattern observed in these gregarious larvae. [ABSTRACT FROM AUTHOR]

The acronym IPM (integrated pest management) has been around for over 50 years and now not only supposedly guides research and extension in pest management but also markets pesticides, is claimed to be undertaken by many growers, and even resonates with public perceptions and politicians. Whether or not IPM programs are sustainable in the longer term under the conflicting stresses and strains of the modern agricultural environment is debatable. We analyse three case studies of IPM development in Australia: citrus IPM in central Queensland, Brassica IPM in southeast Queensland and Helicoverpa management in cotton in eastern Australia. Many management practices for these pests have changed over time. In the more stable citrus system classical biological control along with changed practices (reduced pesticide use) have effectively controlled imported scale insect pests. In Brassicas and cotton, IPM is predominantly of the sample and spray variety where, increasingly, less broad-spectrum insecticides are used and, in cotton, Helicoverpa management includes the deployment of transgenic plants. We question whether or not IPM principles are always consistent with market forces and whether or not the approach is universally applicable for all pest insects when implemented at the small (field or farm) scale. Farmers will adopt cost-effective approaches that minimise their financial risks. For Australia as a whole over the last 30 years insecticide input costs per hectare have increased faster than the price index, reflecting more costly insecticides, changes to the combinations of crops grown and an increase in the overall area of crops cultivated together with possible concomitant changes in pest abundance. Any pest crisis will ensure rapid changes in practice and adoption of technologies, in order to mitigate the short-term financial stresses caused. However, regression to former practices tends to follow (e.g. in Brassica crops). In most cases, we cannot objectively test if changed management practices are responsible for changes in pest abundance, as is often claimed, or if the latter is simply a consequence of the weather and/or related large-scale landscape features (e.g. area of host plants). We argue that for many systems the future of pest management practice will require a change to landscape or area-wide approaches. We suspect, given how entrenched the acronym has become, whatever the nature of the approach it will be called IPM. [ABSTRACT FROM AUTHOR]

Abstract: The use of artificial food sprays to increase the abundance and impact of natural enemies of arthropod pests has been recognized for over 40 years. Nevertheless, artificial food sprays are applied in relatively few conservation biological control programs, possibly because of inconsistent performance. To consider this explanation, using a hierarchical classification approach ranging from altered foraging behavior at the simplest level to profitability of farm production at the highest level, we quantitatively reviewed 234 trials from 77 publications. The levels of assessment of food sprays most commonly found in the publications were the densities of arthropod pests (59 trials) and their natural enemies (124). Although the density of natural enemies increased in 108 of the 124 trials (or 87% of cases) and pest populations declined in 28 of the 59 trials (or 47%), increased profit was not demonstrated in the five trials where it was examined. The most commonly studied natural enemies belonged to the order Neuroptera (104 trials). Nevertheless, the parasitic Hymenoptera had the highest proportion of positive successes (56 of the 69 trials or 81%). Contrary to predictions, the likelihood of a successful result was not affected by the duration of food spray provision, management intensity, application frequency, or replenishment interval. However, success was more likely as spray concentration increased. When analyzed separately, the Coleoptera showed the greatest response to carbohydrates alone, such as honey and sucrose, compared with a mixture of carbohydrates and proteins. To achieve greater success with artificial food sprays, and therefore overcome a major impediment to their adoption, we contend that researchers should: (i) demonstrate greater success across several levels in the hierarchy, especially profit; (ii) consistently demonstrate success in field trials replicated across regions and years; and (iii) combine artificial food sprays with other compatible elements of an integrated pest management strategy. Until these outcomes are demonstrated, it is envisaged that artificial food sprays will form only a small part of future conservation biological control programs. [Copyright &y& Elsevier]

Trichogramma limit pest damage to crops by killing the developing embryo of their insect host at the egg stage. Their impact on the potentially insecticide resistant species, Helicoverpa armigera (Hübner), is considered integral to the resistance management plan for transgenic cotton production in the Ord River Irrigation Area in northern Western Australia. The dominant species of egg parasitoid in Ord River Irrigation Area cotton crops is the introduced Trichogramma pretiosum (Riley). Surveys of similar northern Australian regions earmarked for agricultural expansion revealed that T. pretiosum has been introduced, or has adventitiously dispersed, to all developing agricultural regions of northern Australia. Several previously unsequenced species were collected during surveys in more pristine habitats. Trichogramma pretiosum demonstrates an apparent ability to supersede native Trichogramma species and is perhaps favoured by agricultural expansion. [ABSTRACT FROM AUTHOR]

Surveys for parasitoids attacking larvae and pupae of Plutella xylostella L. (Lepidoptera: Plutellidae) were conducted in the Brassica agro-ecosystem of the Lockyer valley, south-east Queensland between 1999 and 2002. Parasitised hosts were collected from infested plants placed in Brassica crops during the growing season (February–October) and from the natural P. xylostella population on the common weed Rapistrum rugosum L. (Brassicaceae) during the summer production break (November–January). Five species of primary parasitoids were recorded and they ranked in order of abundance: Diadegma semiclausum Hellén (Hymenoptera: Ichneumonidae) > Diadromus collaris Gravenhorst (Hymenoptera: Ichneumonidae) = Apanteles ippeus Nixon (Hymenoptera: Braconidae) > Brachymeria phya Walker (Hymenoptera: Chalcididae) = Oomyzus sokolowskii Kurdjumov (Hymenoptera: Eulophidae). In crops, parasitoids were reared from 23 of the 30 P. xylostella cohorts studied; D. semiclausum was collected at 21 sites, O. sokolowskii at eight sites, D. collaris at six sites, A. ippeus at three sites and B. phya at a single site. The incidence and abundance of hosts parasitised by D. semiclausum increased markedly in winter and early spring months and parasitism rates as high as 95% were recorded. Diadromus collaris and O. sokolowskii were recovered at low levels throughout 2000 and 2001 but parasitism rates never exceeded 11% or 8%, respectively. Parasitism rates are compared with other mortality factors and the contribution that each species of parasitoid makes to the biological control of the pest in the region is considered. Oomyzus sokolowskii has also been reared from P. xylostella collected in Tasmania and Western Australia. This study is the first report of the incidence O. sokolowskii in Australia; however, its wide distribution indicates that its establishment is not a recent event. [ABSTRACT FROM AUTHOR]

Various factors can influence the population dynamics of phytophages post introduction, of which climate is fundamental. Here we present an approach, using a mechanistic modelling package (CLIMEX), that at least enables one to make predictions of likely dynamics based on climate alone. As biological control programs will have minimal funding for basic work (particularly on population dynamics), we show how predictions can be made using a species geographical distribution, relative abundance across its range, seasonal phenology and laboratory rearing data. Many of these data sets are more likely to be available than long-term population data, and some can be incorporated into the exploratory phase of a biocontrol program. Although models are likely to be more robust the more information is available, useful models can be developed using information on species distribution alone. The fitted model estimates a species average response to climate, and can be used to predict likely geographical distribution if introduced, where the agent is likely to be more abundant (i.e. good locations) and more importantly for interpretation of release success, the likely variation in abundance over time due to intra- and inter-year climate variability. The latter will be useful in predicting both the seasonal and long-term impacts of the potential biocontrol agent on the target weed. We believe this tool may not only aid in the agent selection process, but also in the design of release strategies, and for interpretation of post-introduction dynamics and impacts. More importantly we are making testable predictions. If biological control is to become more of a science making and testing such hypothesis will be a key component. [ABSTRACT FROM AUTHOR]

1. The spatial heterogeneity of predator populations is an important component of ecological theories pertaining to predator–prey dynamics. Most studies within agricultural fields show spatial correlation (positive or negative) between mean predator numbers and prey abundance across a whole field over time but generally ignore the within-field spatial dimension. We used explicit spatial mapping to determine if generalist predators aggregated within a soybean field, the size of these aggregations and if predator aggregation was associated with pest aggregation, plant damage and predation rate. 2. The study was conducted at Gatton in the Lockyer Valley, 90 km west of Brisbane, Australia. Intensive sampling grids were used to investigate within-field spatial patterns. The first row of each grid was located in a lucerne field (10 m from interface) and the remaining rows were in an adjacent soybean field. At each point on the grid the abundance of foliage-dwelling and ground-dwelling pests and predators was measured, predation rates [using sentinel Helicoverpa armigera (Hübner) egg cards] and plant damage were estimated. Eight grids were sampled across two summer cropping seasons (2000/01, 2001/02). 3. Predators exhibited strong spatial patterning with regions of high and low abundance and activity within what are considered to be uniform soybean fields. Ground-dwelling and foliage-dwelling predators were often aggregated in patches approximately 40 m across. 4. Lycosidae (wolf spiders) displayed aggregation and were consistently more abundant within the lucerne, with a decreasing trap catch with distance from the lucrene/soybean interface. This trend was consistent between subsequent grids in a single field and between fields. 5. The large amount of spatial variability in within-field arthropod abundance (pests and predators) and activity (egg predation and plant damage) indicates that whole field averages were misleading. This result has serious implications for sampling of arthropod abundance and pest management decision-making based on scouting data. 6. There was a great deal of temporal change in the significant spatial patterns observed within a field at each sampling time point during a single season. Predator and pest aggregations observed in these fields were generally not stable for the entire season. 7. Predator aggregation did not correlate consistently with pest aggregation, plant damage or predation rate. Spatial patterns in predator abundance were not associated consistently with any single parameter measured. The most consistent positive association was between foliage-dwelling predators and pests (significant in four of seven grids). Inferring associations between predators and prey based on an intensive one-off sampling grid is difficult, due to the temporal variability in the abundance of each group. 8. Synthesis and applications. This study demonstrated that generalist predator populations are rarely distributed randomly and field edges and adjacent crops can have an influence on within-field predator abundance. This must be considered when estimating arthropod (pest and predator) abundance from a set of samples taken at random locations within a field. [ABSTRACT FROM AUTHOR]

Lucerne ( Medicago sativa) has been suggested as an ideal refuge habitat as part of an integrated pest management (IPM) program because it harbours high numbers of beneficial arthropods. Whether or not cutting of lucerne encourages the movement of these beneficials into adjacent target crops is unknown. Vacuum samples were used to determine the effects of cutting lucerne on arthropod abundance (pests and predators) within lucerne and adjacent soybean ( Glycine max) crops. Vacuum-sample collections of arthropods were conducted before and after lucerne cutting on seven occasions in four fields over two seasons. In the lucerne, 10 m by 1 m strips parallel to the crop interface were sampled at 5, 10, 15, 20 and 30 m from the interface. In the soybean, 10 m of row were sampled at the same distances from the crop interface. The abundance of predators in lucerne was reduced immediately after cutting at all distances from the interface. Predator abundance in soybean did not show any change. The cutting of lucerne significantly reduced pest numbers within the lucerne but had little effect on pest abundance in the adjacent soybean. The temporal pattern in pest and predator abundance was very different for each field sampled. Generally, arthropods decreased in abundance after cutting and gradually increased as the lucerne grew back. In soybeans, arthropod numbers fluctuated regardless of the cutting of the lucerne. Cutting of lucerne alone does not guarantee movement of predators into the adjacent target crop. The presence of lucerne fields within a cropping area may have some impact on regional predator populations, and so still be useful for IPM programs, but this has yet to be tested critically. [ABSTRACT FROM AUTHOR]

Long-term forecasts of pest pressure are central to the effective management of many agricultural insect pests. In the eastern cropping regions of Australia, serious infestations ofHelicoverpa punctigera(Wallengren) andH. armigera(Hübner)(Lepidoptera: Noctuidae) are experienced annually. Regression analyses of a long series of light-trap catches of adult moths were used to describe the seasonal dynamics of both species. The size of the spring generation in eastern cropping zones could be related to rainfall in putative source areas in inland Australia. Subsequent generations could be related to the abundance of various crops in agricultural areas, rainfall and the magnitude of the spring population peak. As rainfall figured prominently as a predictor variable, and can itself be predicted using the Southern Oscillation Index (SOI), trap catches were also related to this variable. The geographic distribution of each species was modelled in relation to climate and CLIMEX was used to predict temporal variation in abundance at given putative source sites in inland Australia using historical meteorological data. These predictions were then correlated with subsequent pest abundance data in a major cropping region. The regression-based and bioclimatic-based approaches to predicting pest abundance are compared and their utility in predicting and interpreting pest dynamics are discussed. [ABSTRACT FROM AUTHOR]

The lesser wanderer butterfly,Danaus(Anosia)chrysippus petilia(Stoll) (Lepidoptera: Danainae), has been treated as a subspecies for the last 100 years. New mitochondrial DNA sequence data forD. petilia, in conjunction with allozyme, structural, morphometric and pattern characters, constitute a compelling case for its specific rank. The holotype ofD. petiliahas never been located and, as the type location is uncertain, a neotype is designated. Fresh material was collected and examined for this project.Danaus petiliaandD. chrysippushave been separated at Lydekker's Line for an estimated 1.1 million years, and they remain interfertile. However, as an allopatric taxon, diagnosable fromD. chrysippus,D. petiliamerits specific status under the phylogenetic species concept. The following pairs ofD. chrysippussubspecies are considered to be synonyms, the first member of each pair having priority:chrysippus + aegyptius(subspecies),klugii + infumata(hybrid phenotypes) andorientis + liboria(subspecies). [ABSTRACT FROM AUTHOR]

Ballooning is a form of aerial movement practiced by most immature and some adult spiders. Very few studies have investigated the composition and rate of spider ballooning in Australian agroecosystems. Water traps were used to compare ballooning rates in irrigated soybean crops and nearby non-crop areas in southeast Queensland over two summer seasons. The highest ballooning rate (14.8 spiders/m2 per day) was recorded in a soybean field, non-crop areas (7.0 spiders/m2 per day) and a dry land mungbean field (6.8 spiders/m2 per day) having similar rates. Spider ballooning in soybean increased throughout the season and showed three peaks and intervening troughs. A similar pattern in ballooning peaks was observed in non-crop areas however the numbers were lower. Peaks in ballooning activity where synchronised across habitat types and some spider groups. Composition of the ballooning fauna was different from that of the ground-dwelling fauna, some families being present in both. Ballooning is an important behaviour in terms of population dynamics for a number of spider groups in soybean and the implications for pest control are discussed. [Copyright &y& Elsevier]

The `Columbus hypothesis' suggests that the annual north-south return migration of Danaus plexippus in North America is a very recently evolved behaviour, less than 200 years old. This hypothesis rests, in part, on an analysis of the 19th century spread of the monarch across the Pacific that assumes a continuous east to west movement and is based predominantly on one publication. We review all the contemporary literature and present new analysis of the data. The movement of the monarch across the Pacific in the second half of the 19th century is best explained by a model which involves no more than three spot introductions, directly or indirectly aided by human movement, followed by natural spread of the monarch across island groups. Contemporary records refer to `boom' and `bust' population cycles on newly settled islands, which may have led to high rates of monarch movement. We see no evidence in the records to suggest an east to west sweep by monarch populations as suggested by the Columbus hypothesis. [ABSTRACT FROM AUTHOR]

Examines the ecology and behavior of first instar larval Lepidoptera. Survival of neonates and mortality factors; External plant factors faced by neonates; Internal plant factors that impact neonates; Neonate behavior and physiology.

AbstractMortality of first instars is generally very high, but variable, and is caused by many factors, including physical and chemical plant characters, weather and natural enemies. Here, a summary of detailed field-based studies of the early-stage survival of a specialist lepidopteran herbivore is presented. First-instar larvae of the monarch butterfly, Danaus plexippus, a milkweed specialist, generally grew faster and survived better on leaves when latex flow was reduced by partial severance of the leaf petiole. The outcome depended on milkweed species, and was related to the amount of latex produced, as well as other plant characters, such as leaf hairs, microclimate and concentration of secondary metabolites. Even for a so-called ‘milkweed specialist’, larval performance and survival appears to be related to the concentration of cardenolides produced by the plants (a potential chemical defence against herbivory). This case study of monarchs and milkweeds highlights the need for field-based experiments to assess the effect of plant characters on the usually poor survival of early instar phytophagous insects. Few similar studies concerning the performance and survival of first-instar, eucalypt-specific herbivores have been conducted, but this type of study is considered essential based on the findings obtained using D. plexippus. [ABSTRACT FROM AUTHOR]

Abstract A survey of the floors of 3001 empty sea cargo containers in storage was undertaken to estimate the quarantine risk of importing exotic insect pests into Australia, with special reference to pests of timber. More than 7400 live and dead insects were collected from 1174 containers. No live infestations of timber-feeding insects were recorded, but feeding damage detected in one floor indicates a low risk of importing colonies of timber pests in containers. The survey collection of dead insects demonstrates that containers are regularly exposed to economically important quarantinable insects, including timber pests (bostrichids, curculionids, cerambycids, siricids and termites), agricultural pests (including Adoretus sinicus, Adoretus sp., Carpophilus obsoletus and Philaenus spumarius), and nuisance pests (vespids and Solenopsis sp.). Stored product pests were found in more than 10% of containers. The assessment of pest risk associated with shipping containers is discussed in terms of the quantity and quality of opportunities for exotic insects to establish via this pathway. [ABSTRACT FROM AUTHOR]

Summary1. A novel experimental method was developed to study negative physical and chemical effects of latex and cardiac glycosides on first-instar monarch butterfly larvae in their natural environment in north central Florida. Forceps were used to nibble through the petioles of leaves of the sandhill milkweed Asclepias humistrata, mimicking the behaviour of mature monarch larvae. This notching cut off the supply of latex to the leaves without significantly reducing either their cardiac glycoside concentration or water content. 2. The mean cardiac glycoside concentration in larvae that fed on intact leaves was nearly two and a half times greater than in larvae that fed on notched leaves. This was probably because more latex is present in the gut of the larvae that fed on the intact leaves. Supporting this is the fact that the mean concentration of cardiac glycosides in the latex was 34–47 times that in the leaves. 3. Wet weights, dry weights, and growth rates of first-instar larvae that fed on intact leaves over a 72-h period were less than half those of larvae that fed on notched leaves. 4. Mortality due to miring in the latex was 27% on the intact leaves compared with 2% on the notched leaves. 5. Latex, cardiac glycosides, and other as yet undetermined plant factors all have a negative effect on first-instar larval survival. 6. Video-analyses indicated that ingestion of latex caused the larvae to become cataleptic and increased their chances of being mired on the leaf by the setting latex glue. Dysfunction resulting from latex ingestion may lead to the larvae falling off the plant and being killed by invertebrate predators. 7. The difficulty of neonate monarch larvae surviving on A. humistrata – one of the principal milkweed species fed on each spring as monarchs remigrate from Mexico into the southern U.S.A. – is evidence that a co-evolutionary arms race is operating in this plant–herbivore system. [ABSTRACT FROM AUTHOR]

AbstractCaterpillars of Euploea core corinna (W. S. Macleay) sever leaf veins prior to feeding on their latex-bearing host plants, which restricts the flow of latex at feeding sites. The severing of leaf veins by insects feeding on latex-bearing plants is commonly referred to as ‘sabotaging’ and is thought to be an evolved response by the insect to counter the negative effects of feeding on latex-rich leaves. Sabotaging behaviour is described for all instars of E. core corinna, with particular attention given to neonates. Vein cutting by neonate E. core corinna caterpillars can occur within 2 h of hatching, with most caterpillars establishing feeding sites within 10 h. Commonly, first instars cut an arc-shaped row of leaf side-veins parallel to the leaf margin, but they may also cut the leaf mid-rib in a fashion similar to older instar larvae. From a sample of 50 E. core corinna larvae, representing all instars, we found that the diameters of the veins cut by caterpillars are closely correlated to larval head width (r = 0.90). Through manipulative experiments, we demonstrate for the first time that sabotaging behaviour in neonate caterpillars imposes no detectable short-term physiological costs on those caterpillars. [ABSTRACT FROM AUTHOR]

Large numbers of adults of certain species of butterfly flying in an apparently ‘purposeful’ manner are often noted by entomologists and the general public. Occasionally, these are recorded in the literature. Using these records we summarise information regarding the direction of movement in Australian butterflies and test whether there are consistent patterns that could account for known seasonal shifts in geographical range. The data were analysed using contingency tables and directionality statistics. Vanessa itea, Vanessa kershawi, Danaus plexippus, Danaus chrysippus and Badamia exclamationis flew predominately south in the spring–summer and north in the autumn–winter. Tirumala hamata has a strong southern component to its flight in spring but, as in Euploea core, appears non-directional in the autumn. For many supposedly known migratory species, the number of literature records are few, particularly in one season (mainly autumn). Thus, for Appias paulina, four of seven records were south in the spring–summer, as were six of nine records for Catopsilia pomona, and three of five for Zizina labradus. For Belenois java, flight records were only available for the spring and these showed geographical differences; predominantly north-west in northern Australia (Queensland) and south-west in southern Australia (Victoria, New South Wales). There were too few records for Papilio demoleus in the literature (four only) to draw any conclusions. Major exceptions to the seasonal trend of south in the spring and north in the autumn were Junonia villida, which showed a predominant north-westward direction in both seasons, and Eurema smilax, with a predominant southern or western flight in both seasons. We discuss these species specific trends in migration direction in relation to seasonal shifts in suitable habitat conditions, possible cues used in orientation and in timing changes in direction. [ABSTRACT FROM AUTHOR]

A major ongoing debate in population ecology has surrounded the causative factors underlying the abundance of phytophagous insects and whether or not these factors limit or regulate herbivore populations. However, it is often difficult to identify mortality agents in census data, and their distribution and relative importance across large spatial scales are rarely understood. Here, we present life tables for egg batches and larval cohorts of the processionary caterpillar Ochrogaster lunifer Herrich-Schäffer, using intensive local sampling combined with extensive regional monitoring to ascertain the relative importance of different mortality factors at different localities. Extinction of entire cohorts (representing the entire reproductive output of one female) at natural localities was high, with 82% of the initial 492 cohorts going extinct. Mortality was highest in the egg and early instar stages due to predation from dermestid beetles, and while different mortality factors (e.g. hatching failure, egg parasitism and failure to establish on the host) were present at many localities, dermestid predation, either directly observed or inferred from indirect evidence, was the dominant mortality factor at 89% of localities surveyed. Predation was significantly higher in plantations than in natural habitats. The second most important mortality factor was resource depletion, with 14 cohorts defoliating their hosts. Egg and larval parasitism were not major mortality agents. A combination of predation and resource depletion consistently accounted for the majority of mortality across localities, suggesting that both factors are important in limiting population abundance. This evidence shows that O. lunifer is not regulated by natural enemies alone, but that resource patches (Acacia trees) ultimately, and frequently, act together to limit population growth. [ABSTRACT FROM AUTHOR]