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Spodoptera frugiperda (J.E. Smith) is a highly invasive noctuid pest first reported in northern Australia during early 2020. To document current status of resistance in S. frugiperda in Australia, insecticide toxicity was tested in field populations collected during the first year of establishment, between March 2020 and March 2021. Dose-response was measured by larval bioassay in 11 populations of S. frugiperda and a susceptible laboratory strain of Helicoverpa armigera. Emamectin benzoate was the most efficacious insecticide (LC50 0.023μg/ml) followed by chlorantraniliprole (LC50 0.055μg/ml), spinetoram (LC50 0.098μg/ml), spinosad (LC50 0.526μg/ml), and methoxyfenozide (1.413μg/ml). Indoxacarb was the least toxic selective insecticide on S. frugiperda (LC50 3.789μg/ml). Emamectin benzoate, chlorantraniliprole and methoxyfenozide were 2- to 7-fold less toxic on S. frugiperda compared with H. armigera while spinosyns were equally toxic on both species. Indoxacarb was 28-fold less toxic on S. frugiperda compared with H. armigera. There was decreased sensitivity to Group 1 insecticides and synthetic pyrethroids in S. frugiperda compared with H. armigera: toxicity was reduced up to 11-fold for methomyl, 56 to 199-fold for cyhalothrin, and 44 to 132-fold for alpha cypermethrin. Synergism bioassays with metabolic inhibitors suggest involvement of mixed function oxidase in pyrethroid resistance. Recommended diagnostic doses for emamectin benzoate, chlorantraniliprole, spinetoram, spinosad, methoxyfenozide and indoxacarb are 0.19, 1.0, 0.75, 6, 12 and 48μg/μl, respectively.

Much of the scientific research in the United States is conducted in the public interest and funded through tax dollars, with exact funding allocations controlled through a variety of high-level processes, including through legislation. Scientists can provide expert opinions to government officials and their staff in this and other processes of establishing and enforcing governmental legislation, policies, and regulations, although such expertise is often underutilized. This is partly due to the paucity of scientists who have training to engage policymakers. To address this deficit, many scientific societies now provide organized training in science policy, including how to seek out opportunities to engage with policymakers. One such example is the Entomological Society of America’s Science Policy Fellowship (ESA SPF) program. This article is written by ESA SPF members and discusses the importance of interfacing with policymakers, some challenges this group encountered, and lessons learned through our experiences in the program. Through efforts like this, we hope to inspire other scientists to engage their societies in advocacy work and make their voice heard.

There is a need for and interest in research scientists participating more in the politicoscientific community, and there are several places on the policy continuum where specialist scientific knowledge and perspective can be useful for governance and policy. Science policy is diverse and complicated; involving different branches, departments, agencies, and committees in the Federal government and within state and local government. Advocating, as scientists, on matters of science policy, is challenging, and scientists who do so must engage thoughtfully and deliberately. One consideration is whether the scientist communicates only facts, advocates for a position based on their values, or positions themselves somewhere along a facts-to-values continuum. Another consideration is whether engaging in science advocacy undermines credibility of the scientist and science, more generally. Science itself is a complex enterprise and it is difficult to communicate such complexity in a short period of time, even for any one issue, therefore, engagement in science policy will entail trade-offs in communicating detail and complexity particularly on issues that challenge individual or societal values. There is a growing body of resources and perspectives, including those in this special collection of papers, to encourage and assist scientists in the politicoscientific community and help them develop the skills to be effective members of this community.

Following the detection of fall armyworm Spodoptera frugiperda (J.E. Smith, Lepidoptera: Noctuidae) in Western Australia in early 2020 and the lack of government response action, we estimate the impact it is likely to have on the state’s agriculture. A bioeconomic model is used to estimate cost and revenue implications for broadacre cropping and horticulture industries. We assume permanent S. frugiperda populations are likely to establish in areas of the state’s north and mid-west over the next decade, and other regions may experience sporadic outbreaks over single seasons. Over 0.8 million hectares of host crops could be permanently affected, while sporadic outbreaks may affect a further 150,000 hectares. Expressed in Australian dollars (A$), S. frugiperda is likely to add a A$14.2–39.3 million burden to agricultural producers per annum by year 10 of the outbreak. Approximately 55% of these damage costs are attributable to yield loss and 45% to increased variable production costs.

Melon fly, Zeugodacus cucurbitae (Coquillett) (Diptera: Tephritidae), is an important quarantine tephritid fruit fly with resident populations established in Hawai'i, USA. In the male‐annihilation approach, male flies are targeted using dispensers with cue‐lure (C‐L) and insecticides, typically organophosphates. The efficacy of the male annihilation approach is thought to be limited to individual male flies, contacting the lure and the pesticide, after which they die. Alternative classes of insecticides, such as fipronil, have been investigated for use in male‐annihilation. We hypothesized that ingestion of fipronil by male flies could lead to horizontal transfer and mortality in female flies. Horizontal insecticide transfer extends pesticide control beyond the individual contacting the toxicant through indirect contact via food sharing or other mechanisms. We tested the possibility for horizontal transfer of fipronil from male to female Z. cucurbitae through field and laboratory studies. Two repeated field trials were conducted to compare the numbers of female flies collected in fields treated with Amulet C‐L (0.34% fipronil active ingredient) bait stations, sanitation, and spot treatments of GF‐120 Fruit Fly Bait to numbers collected in fields where sanitation and spot‐treatments were used without Amulet C‐L. In fields with Amulet C‐L bait stations in conjunction with sanitation and weekly protein bait spot treatments of GF‐120 Fruit Fly Bait, female captures were significantly lower than those in field plots treated with weekly protein bait spot treatments and sanitation. In subsequent laboratory studies, all females died within 6 h after direct exposure to male flies that had access to Amulet C‐L for 1–4 min. The possibility that male regurgitant could be a mechanism for horizontal transfer and subsequent female mortality was determined by collecting regurgitated droplets from fipronil‐fed male flies and feeding them to males and females. Both male and female flies exposed to regurgitant from fipronil‐fed male flies or droplets containing fipronil had higher mortality than the male and female flies that were exposed to regurgitant or droplets with only the C‐L compound or sugar solution. Thus, female flies do experience mortality from exposure to regurgitant from males that have fed on fipronil laced solutions. This provides evidence of at least one mechanism of horizontal transfer of insecticide in tephritid fruit flies. These findings are discussed in the context of Z. cucurbitae integrated pest management programs in Hawai'i.

Although granivorous ants are known to collect weed seeds from cropping areas in Australia, the fate of these seeds has not been adequately investigated. Seeds of annual ryegrass (Lolium rigidum Gaud.) and wild radish (Raphanus raphanistrum L.) were placed around the nests of five native ant species (Iridomyrmex greensladei Shattuck, Rhytidoponera metallica Smith, Melophorus turneri Forel, Monomorium rothsteini Forel, and Pheidole hartmeyeri Forel) and tracked continuously over a 24-h period. Removal rates and seed preference of the ant species were evaluated. Ant nests were then excavated to determine the placement of seeds that were taken into each nest. Seed preference, seed removal efficiencies, activity, and seed storage all varied between the ant species. Annual ryegrass seed was collected by three species of ants and was removed from the soil surface more efficiently than wild radish seed. Most ant species stored seed below ground at a depth that is inhibitory to emergence, thereby potentially removing that portion of seed from the seed bank, but some seed was placed at germinable depths. Pheidole hartmeyeri was identified as a likely biological control agent for annual ryegrass seeds and wild radish, while Me. turneri and Mo. rothsteini have potential as biocontrol agents for annual ryegrass, but further research is needed.

Pickleworm, Diaphania nitidalis Cramer (Lepidoptera: Crambidae), is a major pest of cucurbits. The current management approach for this pest is weekly insecticide applications. A push–pull cropping approach may be an alternative management practice and could reduce reliance on pesticides. One potential push–pull scenario is the use of squash ( Cucurbita pepo L.) as a trap crop and watermelon ( Citrullus lanatus [Thunb.] Matsum. & Nakai) as a deterrent intercrop to manage pickleworm on cantaloupe ( Cucumis melo L.). This study investigated if the underlying mechanism required for the success of this management approach (a female oviposition preference or nonpreference among squash, cantaloupe, and watermelon) is present. A series of oviposition preference experiments was conducted to see how individual females responded when presented with different host plants for oviposition. Under laboratory conditions, when females had the choice of a leaf from squash, cantaloupe, and watermelon, they laid a higher proportion of their eggs on the cantaloupe leaf. However, under greenhouse conditions, when females were presented with whole plants of the three different species, they laid a higher percent of their eggs on the squash plant. Females laid a similar number of eggs on watermelon as compared with cantaloupe under greenhouse conditions, and appeared to not be averse to laying their eggs on watermelon. However, when presented with a noncucurbit, such as bean, females laid a low number of total eggs. Overall, it appears that squash may be more preferred as an oviposition substrate than cantaloupe or watermelon and may be a useful trap crop or pull. Further study to determine a suitable deterrent intercrop or push and evaluation of the proposed system under field conditions are needed.

The mosquito microbiome alters the physiological traits of medically important mosquitoes, which can scale to impact how mosquito populations sustain disease transmission. The mosquito microbiome varies significantly within individual mosquitoes and among populations, however the ecological and environmental factors that contribute to this variation are poorly understood. To further understand the factors that influence variation and diversity of the mosquito microbiome, we conducted a survey of the bacterial microbiome in the medically important mosquito, Aedes albopictus, on the high Pacific island of Maui, Hawai‘i. We detected three bacterial Phyla and twelve bacterial families: Proteobacteria, Acitinobacteria, and Firmicutes; and Anaplasmataceae, Acetobacteraceae, Enterobacteriaceae, Burkholderiaceae, Xanthobacteraceae, Pseudomonadaceae, Streptomycetaceae, Staphylococcaceae, Xanthomonadaceae, Beijerinckiaceae, Rhizobiaceae, and Sphingomonadaceae. The Ae. albopictus bacterial microbiota varied among geographic locations, but temperature and rainfall were uncorrelated with this spatial variation. Infection status with an ampicomplexan pathosymbiont Ascogregarina taiwanensis was significantly associated with the composition of the Ae. albopictus bacteriome. The bacteriomes of mosquitoes with an A. taiwanensis infection were more likely to include several bacterial symbionts, including the most abundant lineage of Wolbachia sp. Other symbionts like Asaia sp. and several Enterobacteriaceae lineages were less prevalent in A. taiwanensis-infected mosquitoes. This highlights the possibility that inter- and intra-domain interactions may structure the Ae. albopictus microbiome., Author summary The microbiome is defined as a community of microorganisms (bacteria, archaea, fungi, protozoa, and viruses) living on or within a host organism. The microbiome influences physiological traits of medically important mosquitoes and can alter disease transmission dynamics in vector populations. The composition of the mosquito microbiome varies across mosquito populations; however, the factors that contribute to this variation are poorly understood. Understanding the factors that shape the mosquito microbiome will inform how mosquito-borne disease transmission varies among environments and help to develop effective disease-mitigating strategies. In this study, we assessed the diversity and variation of the microbiome of a medically important mosquito, Aedes albopictus. We found that the mosquito microbiome composition varies across geographic locations but is not affected by rainfall or temperature. We discovered that mosquitoes infected with the parasite Ascogregarina taiwanensis had a different microbiome composition than that of mosquitoes with little to no infection. This study contributes to our understanding of the factors that influence the diversity and variation in the mosquito microbiome. This and other studies like it will contribute to the development of new and innovative strategies to prevent and mitigate diseases vectored by mosquitoes.

The coconut rhinoceros beetle (CRB), Oryctes rhinoceros (L.) (Coleoptera: Scarabaeidae), has become one of the most important coconut and oil palm pests. This species was detected attacking coconut palms on Oʻahu, Hawaiʻi in December 2013, and an eradication program was initiated. One of the major challenges for eradication has been the identification of new breeding sites. Information on the factors influencing oviposition is needed to aid in finding sites likely to host the immature stages of this insect. In this study, a series of choice tests were conducted to assess the oviposition preferences of both laboratory-reared and wild-caught CRB. Mated females, of both lab-reared and wild-caught beetles, were offered for oviposition a choice between sand and two mulch substrates, one with small and one with large particle sizes. Both types of CRB laid eggs preferentially in substrate of small particle size rather than large and none laid eggs in sand. Lab-reared and wild-caught CRB differed in their oviposition behavior and size. These results can be used to aid in the identification of breeding sites for management programs and eradication efforts.

The coconut rhinoceros beetle (CRB), Oryctes rhinoceros (L.) (Coleoptera: Scarabaeidae), has become one of the most important coconut and oil palm pests. This species was detected attacking coconut palms on Oʻahu, Hawaiʻi in December 2013, and an eradication program was initiated. One of the major challenges for eradication has been the identification of new breeding sites. Information on the factors influencing oviposition is needed to aid in finding sites likely to host the immature stages of this insect. In this study, a series of choice tests were conducted to assess the oviposition preferences of both laboratory-reared and wild-caught CRB. Mated females, of both lab-reared and wild-caught beetles, were offered for oviposition a choice between sand and two mulch substrates, one with small and one with large particle sizes. Both types of CRB laid eggs preferentially in substrate of small particle size rather than large and none laid eggs in sand. Lab-reared and wild-caught CRB differed in their oviposition behavior and size. These results can be used to aid in the identification of breeding sites for management programs and eradication efforts.

Hawaii is home to over 60 ant species, including five of the six most damaging invasive ants. Although there have been many surveys of ants in Hawaii, the last island-wide hand-collection survey of ants on Oahu was conducted in 1988–1994. In 2012, a timed hand-collection of ants was made at 44 sites in a systematic, roadside survey throughout Oahu. Ants were identified and species distribution in relation to elevation, precipitation and soil type was analyzed. To assess possible convenience sampling bias, 15 additional sites were sampled further from roads to compare with the samples near roads. Twenty-four species of ants were found and mapped; Pheidole megacephala (F.), Ochetellus glaber (Mayr), and Technomyrmex difficilis Forel were the most frequently encountered ants. For six ant species, a logistic regression was performed with elevation, average annual precipitation, and soil order as explanatory variables. O. glaber was found in areas with lower precipitation around Oahu. Paratrechina longicornis (Latrielle) and Tetramorium simillimum (Smith, F.) were found more often in lower elevations and in areas with the Mollisol soil order. Elevation, precipitation, and soil type were not significant sources of variation for P. megacephala, Plagiolepis alluaudi Emery, and T. difficilis. P. megacephala was associated with fewer mean numbers of ants where it occurred. Ant assemblages near and far from roads did not significantly differ. Many species of ants remain established on Oahu, and recent invaders are spreading throughout the island. Mapping ant distributions contributes to continued documentation and understanding of these pests.

Termites are economically-important structural pests, costing residents of Hawaii over $100 million annually. On Oahu, the last published termite swarming survey occurred from 1969 to 1971, and the last termite hand-collection survey occurred from 1998 to 2000. To contribute data on termite occurrences on Oahu, a light-trap survey took place from February 2011 to September 2012, and a hand-collection survey occurred from September to November 2012. Formosan subterranean termite, Coptotermes formosanus Shiraki, swarming was compared over the duration of the study, finding peak swarming in May 2011. C. formosanus alate activity density was regressed with environmental factors, finding a negative correlation with average wind speed and a positive correlation with average rainfall. Coptotermes gestroi (Wasmann) alates were observed in April, June, and July 2011 and in June 2012. Four species of termites were found in the hand-collection survey of 44 sites: Incisitermes immigrans (Snyder) (n = 8/44), C. formosanus (n = 2/44), Cryptotermes cynocephalus Light (n = 1/44), and Neotermes sp. (n = 1/44). This study contributes to distribution data for termite species on Oahu and records alate activity for two important termite pests.

Consuming natural male lure compounds enables the males of some fruit flies (Diptera: Tephritidae) to mate more successfully within their femalechoice mating systems. However, it remains unclear what benefits females derive from mating with lure-fed males. With Bactrocera tryoni (Froggatt) (Diptera: Tephritidae), feeding on the lures cue-lure and zingerone is associated with increased fecundity of mated females, but this direct fitness benefit was not apparent with B. dorsalis (Hendel) (with the lure methyl eugenol) or Zeugodacus cucurbitae (Coquillett) (with the lure cue-lure). Expanding on previous observations, we fed Z. cucurbitae males zingerone, but we observed no evidence of direct fitness benefits to males feeding on zingerone (i.e., mating success and virgin longevity), or to females mated to zingerone-fed males (i.e., longevity, fecundity, and egg viability). We therefore find no reason to reject the runaway selection hypothesis that previously has been proposed to explain lure attraction in B. dorsalis and Z. cucurbitae. ResumenEl consumo de compuestos naturales para senuelos de machos permite que los machos de algunas moscas de la fruta (Diptera: Tephritidae) puedan aparearse y escoger con mas exito dentro de su sistema de apareamiento con las hembras. Sin embargo, todavia no esta claro que beneficios obtienen las hembras de aparearse con machos alimentados con senuelos. Con Bactrocera tryoni (Froggatt) (Diptera: Tephritidae), la alimentacion con los senuelos, el “cue-lure” y la zingerona se asocia con un aumento de la fecundidad de las hembras apareadas, pero este beneficio directo a su desempeno no fue evidente con B. dorsalis (Hendel) (con el senuelo de eugenol metilo) ni en Zeugodacus cucurbitae (Coquillett) (con el senuelo “cue-lure”). Ampliando sobre observaciones hechas anteriormente, alimentamos a los machos de Z. cucurbitae con zingerona, pero no observamos evidencia de beneficios directos sobre el desempeno de los machos que se alimentaron de zingerona (en cuanto de su exito de apareamiento y longevidad de las hembras virgenes), ni tampoco en las hembras apareadas con machos alimentados con zingerona (en cuanto de su longevidad, fecundidad y viabilidad de los huevos). Por lo tanto, no encontramos ninguna razon para rechazar la hipotesis que la seleccion de su pareja esta fuera de control que se propuso anteriormente para explicar la atraccion de senuelos en B. dorsalis y Z. cucurbitae.View this article in BioOne

The Chinese rose beetle (Adoretus sinicus Burmeister (Coleoptera: Scarabaeidae)) is an introduced, widely-established pest in Hawai’i. The adult beetles feed on the leaves of cacao (Theobroma cacao L.), which can lead to defoliation and even death of young trees. We evaluated the impact of five commercially available products with different active ingredients (imidacloprid, azadirachtin, Beauveria bassiana (Bals.-Criv.) Vuill., kaolin clay, and pyrethrin) and the presence or absence of weed mat cover in reducing adult beetle feeding on sapling cacao in the field. The use of weed mat cover reduced feeding damage compared to the untreated control, as did foliar application of imidacloprid, azadirachtin, and B. bassiana. In the laboratory, field-collected adult beetles were presented cacao leaf samples dipped in one of the five products and compared to a control. Beetles exposed to pyrethrin died rapidly. Among the other treatments, only exposure to imidacloprid significantly reduced survival relative to the control. Beetles fed very little on leaf samples with azadirachtin but their longevity was not significantly reduced. Imidacloprid, azadirachtin, and weed mat application had the most promise for reducing adult Chinese rose beetle feeding damage in young cacao and deserve further investigation for successful management of this significant pest.

Frankliniella occidentalis (Pergande) is a serious pest of a wide range of horticultural and ornamental crops. Populations resistant to most conventional insecticides, including–spinosad, have been detected. To control spinosad-resistant thrips, growers could use a ‘high-rate’/biological control strategy. The proposed strategy is based on a single application of spinosad at double the recommended application rate followed by releasing predatory mites (Acari), which are used as biological control agents of F. occidentalis . This study compared two resistance management strategies on a spinosad-resistant F. occidentalis strain: applying spinosad at twice the recommended rate, and spraying at twice the rate then releasing predatory mites, Typhlodromips montdorensis (Schicha), Neoseiulus cucumeris (Oudemans) and Hypoaspis miles (Berlese). Direct exposure to twice the recommended rate of spinosad killed 100% of all adults of all species of predatory mites. Spinosad residues aged 2–48 h were also highly toxic to adults of all three mite species, causing 96–100% mortality. Spinosad residues aged 48–168 h were less toxic to N. cucumeris than to T. montdorensis and H. miles . LT 25 of double the recommended rate of spinosad for T. montdorensis , N. cucumeris and H. miles were calculated as 6.02, 5.3, and 7.08 days, respectively. When released after applying spinosad, T. montdorensis was the most successful species in reducing thrips numbers, followed by N. cucumeris and H. miles . By releasing mites 6–7 days after a spinosad application, our results suggest that F. occidentalis can be effectively controlled. The practical implications of implementing a ’high-dose/biological control’ strategy are discussed.

Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) is a major pest of strawberry. The efficacy of three species of predatory mites, Typhlodromips montdorensis (Schicha), Neoseiulus cucumeris (Oudemans) (both: Acari: Phytoseiidae), and Hypoaspis miles (Berlese) (Acari: Laelapidae), and their compatibility with spinosad for the control of this thrips was evaluated in commercial strawberry in spring. Low tunnel-grown strawberry was treated with ‘water then mites’, ‘spinosad then mites’, or ‘mites then spinosad’. Predatory mites were released as single-, two- and three-species combinations. Overall, spinosad-treated plants had fewer thrips than water-treated plants (control). In all treatment regimes, each species of predatory mite reduced the number of thrips relative to those plants that received no mites. Predatory mites were most effective in reducing thrips when released after spinosad was applied. Any multiple-species combination of predatory mites reduced thrips numbers more than single-species releases. The two-species combination of T. montdorensis (foliage inhabiting) and H. miles (soil dwelling) was the most effective in suppressing thrips. The next most effective combination was a three-species release. Of multiple-species combinations, the two-species combination of T. montdorensis and N. cucumeris was the least effective in suppressing thrips numbers. The spinosad and mites only temporarily reduced the numbers of F. occidentalis. This suggests that further application of predatory mites, spinosad, or both is required to maintain F. occidentalis populations below an economically damaging level.

Bridal creeper has become a serious environmental weed in southern Australia. Historically the invaded areas had low soil nutrient levels. However, our field surveys indicate that soils in bridal creeper–invaded areas have higher phosphorus and iron levels than soils in nearby native reference areas regardless of the proximity to agriculture or other disturbances. A glasshouse experiment was undertaken to determine the influence of increased nutrients on plants that co-occur with bridal creeper in order to (1) assess the impact of changed soil conditions and (2) predict the response of dominant species following the biological control of bridal creeper. The relative growth rate (RGR) of bridal creeper, two native shrubs (narrow-leaved thomasia [Thomasia angustifolia] and bluebell creeper [Billardiera heterophylla]), and an invasive exotic grass (annual veldt grass [Ehrharta longiflora]) were determined in three soil types: soil collected within a bridal creeper stand, soil collected from a nearby reference area, and a potting mix with nutrient levels higher than that recorded in the field. The plant species were chosen due to their association with bridal creeper. For example, the native species narrow-leaved thomasia was identified in a previous survey as the most abundant shrub at the invaded site where the soil was collected. The two other species, bluebell creeper and annual veldt grass, were identified from a previous seedbank trial as being abundant (in the seedbank) and able to readily germinate in invaded areas. When grown in either the bridal creeper–invaded soil or reference soil, bluebell creeper had significantly lower RGRs than narrow-leaved thomasia and annual veldt grass. However, as all these species showed increases in RGRs between reference soil and bridal creeper soil, this study indicates that for at least these three species the impact of increased nutrients may not be a barrier to the recovery of invaded areas following the control of bridal creeper.

Western flower thrips, Frankliniella occidentalis (Pergande), is a major pest of strawberry and other horticultural and ornamental crops. Biological control of F. occidentalis with predatory mites is recommended as an additional management strategy to chemical control in glasshouse and protected crops. However, it is not known whether multiple (two or three) species releases of predatory mites are more effective than single species releases. The effect of an application of spinosad followed by mite releases could further increase suppression of F. occidentalis. In a series of trials in the glasshouse, we evaluated three commercially available predatory mite species, Typhlodromips montdorensis (Schicha), Neoseiulus cucumeris (Oudemans) and Hypoaspis miles (Berlese). Strawberry plants were sprayed once with either spinosad at the recommended rate or with water. F. occidentalis adults were released onto plants 24 h after spraying, and mites were released six days later. Spinosad significantly reduced F. occidentalis compared to the control (water). T. montdorensis, N. cucumeris and H. miles significantly reduced F. occidentalis compared to the ‘no mite’ treatment. Spinosad had no effect on T. montdorensis and N. cucumeris, as their numbers did not differ between the spinosad and control treatments; H. miles was not recovered. When mites were released after an application of spinosad, greater suppression of F. occidentalis was achieved than with releases of predatory mites alone. When released as a double species combination, ‘T. montdorensis and H. miles’ was the most effective combination. There was no difference in efficacy between releases of ‘T. montdorensis and H. miles’ or ‘T. montdorensis, N. cucumeris and H. miles’. We conclude that multiple species releases are more effective than single species releases, and that biological control of F. occidentalis with predatory mites can be used together with spinosad.

Western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), is a major pest of strawberry, Fragaria x ananassa Duchesne (Rosaceae). Spinosad is highly efficacious against F. occidentalis, and spinosad is believed to be compatible in an integrated pest management program. This study determined whether F. occidentalis could be controlled with predatory mites [Typhlodromips montdorensis (Schicha), Neoseiulus cucumeris (Oudemans) (both Acari: Phytoseiidae), and Hypoaspis miles (Berlese) (Acari: Laelapidae)] and spinosad in strawberry. In the glasshouse, three strawberry cultivars (Camarosa, Camino Real, and Albion) were sprayed once with spinosad at the recommended rate (80 ml 100 l -1 rate, 0.096 g a.i. l -1 ) or with water (control). Thrips adults were released onto plants 24 h after spraying and predatory mites released 6 days later. Spinosad significantly reduced thrips numbers compared with water. All three mite species reduced F. occidentalis numbers, and spinosad had no effect on predatory mites. Though H. miles could not be counted, the numbers of thrips in treatments with H. miles were lower than those in treatments without the mite. Thrips numbers were lowest on Camino Real and highest on Camarosa. These results suggest that the use of Camino Real with spinosad applications followed by releases of predatory mites can significantly reduce thrips numbers.

Studies that consider both biotic and abiotic determinants of organisms are rare, but critical to delineate underlying determinants of community richness (number of taxa) and abundance (number of larvae per water body). In this study, we consider the importance of disturbance (salinity) and predator and competitor variables on mosquitoes (Diptera: Culicidae) in small ephemeral water bodies across the Wheatbelt of Western Australia. Similar to mosquitoes, and contrary to general perceptions, nonculicid aquatic fauna (aquatic fauna) had a common occurrence (number or percentage of water bodies occupied) and were abundant (average density) in ephemeral water bodies, albeit with a simplified trophic structure. The occurrence and density (number per unit area) of aquatic fauna between water bodies were highly variable, but general relationships of aquatic fauna with rainfall, water body surface area, salinity, and mosquitoes were apparent. In contrast to mosquitoes, the density of aquatic fauna declined with recent rainfall, implying mosquitoes may colonize newly created water bodies more quickly than aquatic fauna. Assemblages (richness and density of taxa) of aquatic fauna changed along a salinity gradient, as did mosquitoes, and this was pronounced for predator groups. Densities of mosquitoes were not limited by any single taxonomic group, by a negative relationship. However, the density and richness of mosquitoes generally declined in association with increased richness of predators and density of all other taxa (taxa not specifically classified as predators or competitors of mosquitoes). These relationships may account for higher densities of mosquitoes in smaller water bodies, where richness of predators is reduced and the density of other taxa does not differ from larger water bodies. Our results also suggest salinity in the Western Australia Wheatbelt may facilitate greater abundance of halotolerant mosquitoes, Aedes alboannulatus Macquart and Aedes camptorhynchus Thomson (a vector of Ross River virus [Togoviridae: Alphavirus ]), by releasing them from biotic regulation. Refereed/Peer-reviewed

The effects of temperature and host species on the development of Nasonia vitripennis Walker (Hymenoptera: Pteromalidae), a forensically important parasitoid of carrion flies, were studied under laboratory conditions. Development time of N. vitripennis on five species of Calliphoridae (Diptera), Calliphora albifrontalis Malloch, Calliphora dubia Macquart, Lucilia sericata Meigen, Chrysomya rufifacies Macquart, and Chrysomya megacephala Fabricius, were determined under eight constant temperatures (15, 18, 21, 24, 27, 30, 33, and 36 °C). Thermal requirements for development (developmental thresholds, thermal constant, and optimum temperature) of N. vitripennis in each host species were estimated using linear and nonlinear models. Upper and lower developmental thresholds ranged between 36.6–38.4 and 9.6–11.1 °C, respectively. The optimum temperature for development was estimated at between 30.6 and 31.8 °C. Statistical differences in the development time of N. vitripennis on the various calliphorid host species were evident within all temperature treatments, particularly at the upper and lower temperature range investigated. As such, it is recommended that insect-based estimates of time since death in forensic investigations relying on parasitoid evidence should use host-specific development data where available.

This study considered annual, seasonal and shorter term variation in patterns of insect succession onto decomposing remains at two contrasting locations in Western Australia, bushland and agricultural. The degree of consistency in insect succession patterns over spatial and temporal scales was evaluated through multivariate analysis of occurrence-based distance matrices. Insect assemblages were strongly correlated between locations, within corresponding time periods, indicating that patterns of insect succession were similar between localised sites within the same broad geographic area. This suggests that there is reasonable scope for the application of baseline succession data generated at a single study site to a range of decomposition sites within a given region. Differences were largely due to species absences at the agricultural site. Three species of Coleoptera were identified as possible representatives of bushland habitat, Ptomaphila lacrymosa (Silphidae), Omorgus tatei (Trogidae) and Helea castor (Tenebrionidae), and may be indicative of post mortem movement between habitat types. Within locations, variation in insect assemblages was not significant between years. Within years, insect assemblages varied significantly over time on a seasonal time scale and as decomposition progressed through defined decomposition stages. Forensically relevant data detailing the seasonal pattern of insect succession onto decomposing remains for Western Australia are reported. Additional focus has been directed towards hymenopteran parasitoids that frequent decomposing remains and parasitise Diptera colonisers. Parasitoids can be used to provide an extended PMI timeframe in cases where traditional forensic indicators have completed their development.

Aedes camptorhynchus (Thomson) (Diptera: Culicidae) is widely distributed throughout southwestern Australia in both coastal and inland sites, and is a vector of Ross River virus (Togoviridae: Alphavirus). Larvae of this species are most commonly found in brackish to saline and hypersaline waters. In inland southwestern Australia secondary (anthropogenic) salinisation of agricultural land has led to widespread increases in the amount and saline standing water and available breeding habitat for Ae. camptorhynchus. Given the epidemiological significance of this mosquito species it is particularly important to understand the fundamental biology in order to inform vector management and environmental remediation strategies. We therefore sought to determine the salinity tolerance of Ae. camptorhynchus larvae collected from the coastal saltmarshes (coastal) and the southern wheatbelt (inland) of Western Australia. Ae. camptorhynchus neonate larvae were collected from the two sites and then reared in seawater or water from the source locations which were manipulated to saline concentrations ranging from 2.96 to 88.8 parts per thousand (p.p.t.) by dilution or addition of NaCl. Overall, Ae. camptorhynchus tolerated a wide range of salinities. The majority of Ae. camptorhynchus from the inland site that survived to adulthood did so at salinities between 8 and 30 p.p.t., whereas the majority of coastal mosquitoes that survived to adulthood did so in salinities between 22 and 52 p.p.t. Larvae were able to complete development in salinities up to 62 p.p.t., but none survived to adulthood at higher salinities. An increase in the number and distribution of Ae. camptorhynchus, associated with rising salinity, in previously freshwater habitats of inland southwestern Australia could have health consequences by increasing the potential for Ross River virus activity. Refereed/Peer-reviewed

1. To overcome the challenge of host location in patchy and complex environments, many parasitoids exploit host-habitat derived odour cues. This study investigated the role of odour cues used during host location by the generalist parasitoid, Tachinaephagus zealandicus, a common parasitoid of Dipteran larvae found in association with decomposing carrion. 2. A Y-tube olfactometer was used to test aspects of host searching behaviour of T. zealandicus females under different choice scenarios: combinations of host–liver complex, eaten liver, unwashed host larvae, washed host larvae, liver in six stages of decay, and control (no odour). 3. T. zealandicus females demonstrated an innate response to, and preference for, odours arising from liver substrates following interaction with the host. However, this was dependent on the stage of meat decay. Females were not attracted to liver that had never been in contact with a host, regardless of the stage of decay. There were discernible differences in parasitoid movement and behaviour under different choice scenarios. The absence of odour stimulus elicited limited movement about the olfactometer. In the presence of any odour stimuli, females were more active within the olfactometer, and when presented with two odour options T. zealandicus females demonstrate a heightened investigation response, moving across all regions of the olfactometer. 4. Knowledge of the cues that mediate host location for T. zealandicus can contribute to fields such as forensic entomology, where the presence of parasitoids on decomposing remains can be used to estimate time since death.

To protect native biodiversity from environmental weeds, the impacts that these weeds cause need to be known before weed control commences. Asparagus asparagoides (L.) Druce (bridal creeper) (Asparagaceae) is a serious environmental weed and has been selected for biological control in Australia. To predict the responses of plant communities to the control of bridal creeper, a prerelease baseline of the impacts of bridal creeper on native plant communities was undertaken. Plant assemblages in areas invaded by bridal creeper were compared with reference areas that contained little or no bridal creeper. Areas invaded by bridal creeper contained 52% fewer native plant species when compared with nearby reference areas. However, there was no difference in the number of other exotic plant species between areas. Similar trends were found for the germinable seed bank. Although a greater number of exotic species were present in the seed bank compared with the vegetation surveys, there was still no difference between areas with and without bridal creeper. In a glasshouse trial, exotic species germinated more frequently compared with native species. This could indicate that as bridal creeper density decreases following control, exotic species have an advantage over native species when colonizing areas left vacant by bridal creeper. Second, as bridal creeper areas contained reduced native species richness and cover, they may be susceptible to further weed invasion after bridal creeper is removed. Therefore, simply reducing the presence of bridal creeper may not guarantee successful restoration of invaded areas and additional restoration efforts will be needed to ensure the ultimate goal of protecting native biodiversity is reached.

To understand how environmental change will modify community assembly and the distribution of organisms it is valuable to understand mechanisms that drive the occurrence of organisms across the landscape. Salinisation of agricultural land in southwest Western Australia, as a result of land clearing, is a widespread environmental change, which threatens numerous taxa, but provides an opportunity to elucidate such mechanisms. Although salinisation affects terrestrial fauna and flora, the greatest impacts are seen in wetlands and waterways. Many aquatic insect taxa colonise ephemeral water bodies directly as adults or by oviposition. Few empirical studies, however, evaluate the influence of abiotic factors, such as water body salinity, on the colonisation behaviour of aquatic fauna. We conducted a manipulative experiment using mesocosms to test whether colonising insect fauna select aquatic habitats based upon salinity. We found that halosensitive fauna selected less saline mesocosms for oviposition and colonisation, demonstrating that behaviour can influence the distribution of aquatic organisms. Additionally, we utilised field surveys of insects from ephemeral water bodies across a broad region of southwest Western Australia to determine if mesocosm results reflected field observation. The abundance of the same insect taxa and taxonomic groups in the field were highly variable and, with the exceptions of Culex australicus Dobrotworksy and Drummond and Anopheles annulipes Giles (Diptera: Culicidae), did not show similar patterns of distribution to those observed in the mesocosm experiment. Both mesocosm and field assemblages exhibited similar and significant trajectories associated with the salinity gradient, even though there were differences in assemblage structure between the two. Our findings give empirical support to the importance of behaviour in the spatial distribution and assembly of some aquatic insects.

Some weed biological control agents are released despite predictions that they might damage nontarget host plants in the field. Based on prerelease laboratory tests it was predicted that Neurostrota gunniella, an agent released in Australia against Mimosa pigra, may occasionally use Neptunia spp. as hosts. However, due to high larval mortality on these species, N. gunniella was not expected to persist on Neptunia spp., nor have a significant effect on them. N. gunniella has established widely and is now abundant on the target weed, which grows sympatrically with at least one species of Neptunia. We investigated the nontarget attack of Neptunia major in the field, and the effect of that attack on plant growth and reproduction. Although an average of 61% of N. major plants growing adjacent to M. pigra thickets had evidence of N. gunniella attack, the intensity of attack was relatively low. At sites where M. pigra was not present, use of N. major plants by N. gunniella was noticeably reduced or absent. From glasshouse experiments, we determined that N. gunniella attack causes increased stem tip death and hinders plant growth in both plantlets and mature plants. At the highest level of attack recorded on N. major in the field, tip death increases by 54% and plant height would decrease by 6%. The effect of N. gunniella on the reproductive output of N. major could not be clearly resolved, but is likely to be small. Our findings support the predictions made during prerelease studies of N. gunniella .

A leaf beetle, Crioceris sp. (Coleoptera: Chrysomelidae), was introduced into Australia as a biological control agent of bridal creeper (Asparagus asparagoides L. Druce) during October 2002. Rearing of Crioceris sp. is labour intensive therefore all releases of Crioceris sp. have been under 1000 individuals, which may be too low to ensure establishment if high mortality and high competition with other agents occurs. The aim of this study is to understand how the presence of two well-established biocontrol agents, a rust fungus (Puccinia myrsiphylli (Thuem) Wint [Basidiomycota: Uredinales]) and a leafhopper (Zygina sp. [Hemiptera: Cicadellidae]), might influence Crioceris sp. establishment. Crioceris sp. neonate larvae were placed on bridal creeper plants with or without the leafhopper and/or rust. The number of larvae that pupated was reduced by 38 and 65% in the presence of the rust fungus and leafhopper, respectively and by 45% in the presence of both agents. As the area infected by the rust increased the area damaged by the leafhopper decreased. The rust appeared to be negatively impacted by the presence of the leafhopper. In a second experiment, female Crioceris sp. adults were given a choice between uninfested bridal creeper plants and those infested with the rust or the leafhopper. The females preferred to lay their eggs on plants without leafhoppers but did not seem to be deterred by the presence of the rust. Consequently, the performance and impact of Crioceris sp. on bridal creeper may be reduced if populations overlap with the other biocontrol agents in the field.

A new species of wasp, Stethynium sp. (Hymenoptera: Mymaridae), was found parasitizing eggs of an introduced weed biological control agent, Zygina sp. (Hemiptera: Cicadellidae), a leafhopper released against bridal creeper (Asparagus asparagoides L. Druce). A series of laboratory experiments was conducted to determine the development time and longevity of the wasp under different temperatures and the oviposition preference of the wasp for leafhopper eggs of different ages. Parasitized leafhopper eggs were placed in controlled temperature rooms set at either 15, 20, or 25°C and monitored for adult emergence. It was determined that development time of Stethynium sp. from egg to adult eclosion decreased as temperature increased and female wasps took longer to develop than males. Adult male and female wasps were placed in controlled temperature rooms set at these same temperatures and provided either water, a 10% sugar solution, or no food at all. Female wasps lived longer than males and sugar solution increased longevity significantly over no food or water alone, but this effect decreased with increasing temperature. Adult female wasps, given a choice between 1-, 2-, 3-, 5-, and 7-d-old eggs, showed no preference, and all progeny were able to develop and emerge at the same rate from any aged egg. Adult females also laid eggs in 8- and 9-d-old host eggs. There was a slight decrease in emergence rate from 9-d-old host eggs compared with 8-d-old eggs.

Postdispersal weed seed predation by animals during the summer fallow period may lead to a reduction in the number of weeds that grow in the following winter cropping season. In this study, we investigated the patterns of weed seed removal, the influence of crop residue cover on seed removal, the types of granivores present and their seed preferences in a 16-ha postharvest cropping field in Western Australia during the summer months over 2 yr. Seed removal from caches was extremely variable (from 0 to 100%). Removal rates were generally highest along the edges of the field near bordering vegetation and lowest in the center of the field and within the bordering vegetation. However, there were many deviations from this general pattern. There was no change in rates of predation with different levels of residue cover. Ants or other small invertebrates were found to remove the most seeds. However, seed removal by other animals, such as rodents, was also evident. Annual ryegrass seeds were preferred over wild oat seeds, followed by wild radish pod segments. Seed harvesting was lowest in late January, peaked in February, and decreased in March. Results from this study suggest seed harvesters could reduce the number of surface seeds in the field, reducing the weed seed bank. Management options that increase the activity of the seed harvesters may lead to less variability in seed predation and could, therefore, be incorporated into an integrated weed management program.

Prophylactic use of broad-spectrum insecticides is a common feature of broad-acre grains production systems around the world. Efforts to reduce pesticide use in these systems have the potential to deliver environmental benefits to large areas of agricultural land. However, research and extension initiatives aimed at decoupling pest management decisions from the simple act of applying a cheap insecticide have languished. This places farmers in a vulnerable position of high reliance on a few products that may lose their efficacy due to pests developing resistance, or be lost from use due to regulatory changes. The first step towards developing Integrated Pest Management (IPM) strategies involves an increased efficiency of pesticide inputs. Especially challenging is an understanding of when and where an insecticide application can be withheld without risking yield loss. Here, we quantify the effect of different pest management strategies on the abundance of pest and beneficial arthropods, crop damage and yield, across five sites that span the diversity of contexts in which grains crops are grown in southern Australia. Our results show that while greater insecticide use did reduce the abundance of many pests, this was not coupled with higher yields. Feeding damage by arthropod pests was seen in plots with lower insecticide use but this did not translate into yield losses. For canola, we found that plots that used insecticide seed treatments were most likely to deliver a yield benefit; however other insecticides appear to be unnecessary and economically costly. When considering wheat, none of the insecticide inputs provided an economically justifiable yield gain. These results indicate that there are opportunities for Australian grain growers to reduce insecticide inputs without risking yield loss in some seasons. We see this as the critical first step towards developing IPM practices that will be widely adopted across intensive production systems.

Push-pull cropping approaches for pest management target the oviposition behavior of adult females. However, insect larvae may move from the natal host and undermine the effectiveness of this approach. We investigated the longevity and feeding preference of pickleworm neonates (Diaphania nitidalis Cramer (Lepidoptera: Crambidae)) in relation to a potential push-pull cropping approach incorporating squash as a trap crop (pull) and watermelon as a deterrent intercrop (push) to protect a main crop of cantaloupe. Neonates could survive between 24 to 64 h without food, indicating they have some initial energy reserves to keep alive while in search of a suitable feeding site. To assess neonate feeding preferences, naive neonates were given the choice of five foods; leaves of squash, cantaloupe, watermelon, bean, and a pinto bean-based artificial diet. To assess if previous feeding experience influences neonate food source preference, neonates were allowed to feed on one of the five foods for 24 h and then given the same choice of the five food sources. The neonates, with or without previous feeding experience, did not appear to have a significant preference for any of the cucurbits: squash, cantaloupe, or watermelon, but they did prefer a cucurbit to the bean leaf or artificial diet. Feeding experience on one of these non-host foods made neonates more accepting of these food sources in the choice arena even when host plant food sources became available. It appears that neonate feeding preferences of pickleworm would neither hinder nor enhance the potential success of the proposed cucurbits to be used in a potential push-pull cropping approach for pickleworm management.

Insect pests are estimated to cause losses of 16% to world attainable crop production with post-harvest losses another 10%, in spite of widespread use of pesticides. Losses due to pests have been estimated for key rainfed crops in different regions of the world. Pest species attack every phenological stage of crop growth; sometimes they are the same species and sometimes different. No one tool can be used to successfully control a pest; integrated pest management principles have been widely adopted and include determining the economic threshold at which control is cost effective. Chemical control is widely used but excessive use can cause resistance in the insect and adverse environmental effects. The enhancement of use of natural enemies of pest insects, and use of crop cultivars resistant to the insects are both very important. Crop management practices used to reduce the impact of pests include crop rotations, intercropping, sowing rates, sowing time and soil tillage. Management of pests requires growers to understand the interactions between the pests and crops in their regions and to use the most appropriate tools to reduce the potential damage. While no one system would be applicable to a crop or to a pest in all rainfed farming systems, some general principles are relevant across regions.

Western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), is a major pest of strawberry, causing substantial yield loss through direct feeding on the flowers and fruit. Insecticides are the main method used for its control; however, F. occidentalis has developed resistance to insecticides from all major chemical classes. Chemical control is not a long-term strategy and integrated pest management is required. This study determined whether F. occidentalis damage could be reduced by host plant resistance or tolerance in three commercial strawberry cultivars (Fragaria × ananassa [Rosaceae]: ‘Albion’, ‘Camarosa’, and ‘Camino Real’). Determination of resistance or tolerance to F. occidentalis was based on olfactory response, feeding damage, ovipositional preference, and host suitability for reproduction on leaves. F. occidentalis adults preferred to feed on Camarosa; however, if leaves had been fed on previously by conspecifics, there was no difference in feeding preference. Camarosa was the most preferred cultivar for oviposition, and more eggs were laid by F. occidentalis on Camarosa than either Albion or Camino Real. More larvae hatched and adults were reared from Camarosa than either Albion or Camino Real. The percentage of unhatched eggs, larvae, and pupae that died was highest on Camino Real. Survival rate was highest on Camarosa. Egg incubation, prepupation, pupation, and total developmental periods were shortest on Camarosa, but the larval period was longest on Camarosa. Camarosa was the most favorable cultivar for F. occidentalis population growth on leaves.

BACKGROUND: Spinosad is a biopesticide widely used for control of Frankliniella occidentalis (Pergande). It is reported to be non-toxic to several predatory mite species used for the biological control of thrips. Predatory mites Typhlodromips montdorensis (Schicha), Neoseiulus cucumeris (Oudemans) and Hypoaspis miles (Berlese) have been used for control of F. occidentalis. This study investigated the impact of direct and residual toxicity of spinosad on F. occidentalis and predatory mites. The repellency of spinosad residues to these predatory mites was also investigated. RESULTS: Direct contact to spinosad effectively reduced the number of F. occidentalis adults and larvae, causing > 96% mortality. Spinosad residues aged 2–96 h were also toxic to F. occidentalis. Direct exposure to spinosad resulted in > 90% mortality of all three mite species. Thresholds for the residual toxicity (contact) of spinosad (LT25) were estimated as 4.2, 3.2 and 5.8 days for T. montdorensis, N. cucumeris and H. miles respectively. When mites were simultaneously exposed to spinosad residues and fed spinosad-intoxicated thrips larvae, toxicity increased. Residual thresholds were re-estimated as 5.4, 3.9 and 6.1 days for T. montdorensis, N. cucumeris and H. miles respectively. Residues aged 2–48 h repelled T. montdorensis and H. miles, and residues aged 2–24 h repelled N. cucumeris. CONCLUSION: Predatory mites can be safely released 6 days after spinosad is applied for the management of F. occidentalis. Copyright © 2011 Society of Chemical Industry

The influences of temperature and host species on the development of the forensically important parasitoid Tachinaephagus zealandicus Ashmead (Hymenoptera: Encyrtidae) were studied at six constant temperatures in the range of 15-30 degrees C. T. zealandicus completed development successfully between 15 degrees C and 27 degrees C on five species of Calliphoridae, Calliphora albifrontalis Malloch, Calliphora dubia Macquart, Lucilia sericata Meigen, Chrysomya rufifacies Macquart and Chrysomya megacephala Fabricius. No adult parasitoids emerged from any of the host species reared at 30 degrees C. Temperature and host species significantly influenced development time, emergence success and progeny size. Development was significantly longer on Ch. megacephala and Ch. rufifacies at 18-24 degrees C and significantly longer on Ch. rufifacies and C. albifrontalis at 15 degrees C and 27 degrees C. Parasitoid emergence success was greatest at 21 degrees C, declined at the temperature extremes (15 degrees C and 27 degrees C) and was significantly lower on Ch. megacephala and Ch. rufifacies than on the three other host species. Progeny numbers per host pupa were highest at 21-24 degrees C, declined on either side of this temperature range and were significantly lower on L. sericata, Ch. rufifacies and Ch. megacephala than on either C. dubia or C. albifrontalis. An effect of host species on sex ratio was only observed at 27 degrees C, at which a higher proportion of T. zealandicus females emerged from Ch. megacephala and Ch. rufifacies than from the other host species. The thermal requirements for development (developmental thresholds, thermal constant, optimum temperature) of T. zealandicus in each host species were estimated using linear and non-linear models. Upper and lower developmental thresholds ranged between 29.90 degrees C and 31.73 degrees C, and 9.73 degrees C and 10.08 degrees C, respectively. The optimum temperature for development was estimated at between 25.81 degrees C and 27.05 degrees C. Given the significant effect of host species on development time, the use of parasitoid-host-specific developmental data in forensic application is recommended.

Environmental disturbance may have direct and indirect impacts on organisms. We studied the colonization of ephemeral water bodies by mosquitoes (Diptera: Culicidae) in the Wheatbelt region of southwest Western Australia, an area substantially affected by an expanding anthropogenic salinization. Mosquitoes frequently colonized ephemeral water bodies, responded positively to rainfall, and populated smaller water bodies more densely than larger water bodies. We found that the habitat characteristics of ephemeral water bodies changed in association with salinity. Consequently relationships between salinity and abundance of colonizing mosquitoes were direct (salinity-mosquito) and indirect (salinity-water body characteristics-mosquito). Overall, the structure of mosquito assemblages changed with increasing salinity, favoring an increased regional distribution and abundance of Aedes camptorhynchus Thomson (Diptera: Culicidae), a vector of Ross river virus (RRV; Togoviridae: Alphavirus). We conclude secondary salinization in the Western Australia Wheatbelt results in enhanced vectorial potential for RRV transmission.

A 2-yr survey of hymenopteran parasitoids associated with carrion-breeding flies was conducted to establish the parasitoid species of potential forensic significance in Western Australia. Host associations, seasonality, and rates of parasitism in the field were examined to assess the value of the identified parasitoids as forensic indicators of time since death. Four species of parasitoid emerged from dipteran specimens collected from carcasses: Tachinaephagus zealandicus Ashmead (Encryptidae), Nasonia vitripennis Walker (Pteromalidae), Spilomicrus sp. (Diapriidae), and Aphaereta sp. (Braconidae). Overall parasitism of carrion-breeding flies was 11.8%. T. zealandicus and N. vitripennis were the predominant species, accounting for 86.3 and 11.5% of parasitism observed, respectively. In contrast, Aphaereta sp. and Spilomicrus sp. were intermittently collected from carcasses throughout the study and the parasitism rates of both species were low (< or = 3.0%). Our findings provide forensically important biological and behavioral data of parasitoid-host interactions within carcass environments. The cosmopolitan parasitoids T. zealandicus and N. vitripennis have the greatest potential as indicators of time since death in forensic investigations based on their broad host ranges, rates of parasitism, and seasonal prevalence. In combination, these two species are present throughout the year and they parasitized nearly all of the dipteran species that colonize carcasses. Because both are cosmopolitan species, the data presented here are applicable to regions experiencing a similar Mediterranean climate. This work reports the first incidence of T. zealandicus and N. vitripennis parasitizing the dipteran species Calliphora albifrontalis Malloch (Calliphoridae), Calliphora dubia Macquart (Calliphoridae), and Hydrotaea rostrata Robineau-Desvoidy (Muscidae).

Alterations in transmission of vector-borne zoonoses are often linked to environmental change. However, ecological processes that determine variability in potential for transmission are generally not well understood. Ross River virus (RRV, Togoviridae: Alphavirus) is a mosquito-borne zoonosis in Australia with a significant human disease burden. The inland southwest (Wheatbelt) of Western Australia (WA) is substantially affected by an anthropogenic salinization of agricultural land (dryland salinity). Aedes camptorhynchus Thomson (Diptera: Culicidae) is the dominant vector of RRV in southwest WA and is halophilic. As such, dryland salinity may influence potential for RRV transmission by influencing interactions between Ae. camptorhynchus and mammalian hosts. We surveyed areas of the Wheatbelt with varying salinity impacts and found Ae. camptorhynchus was more abundant in saline areas, whereas sheep Ovis aries (Linnaeus 1758, Bovidae) declined with increasing salinity. We used a deterministic model to examine interactions between Ae. camptorhynchus and mammals, and we assessed potential for RRV transmission. We found variation in potential for RRV transmission was positively related to increasing salinity and abundance of Ae. camptorhynchus and negatively associated with increasing abundance of Macropus fuliginosus (Desmarest 1817, Macropodidae). Abundance of Ae. camptorhynchus determined more variation in potential for RRV transmission than other variables. Accordingly, dryland salinity increases the zoonotic potential for RRV transmission primarily by facilitating abundance of Ae. camptorhynchus. Human RRV notifications do not currently reflect the salinity-RRV transmission potential in the Wheatbelt but appear to be associated with RRV activity in the enzootic coastal zone. We speculate dryland salinity is a determinant of potential for RRV transmission but not activity. Dryland salinity is predicted to expand two- to four-fold by 2050. Preservation and restoration of freshwater ecosystems may ameliorate the potential for transmission of RRV and possibly incidence of human disease. Refereed/Peer-reviewed