Implications For Pest Management Research Articles

Impact of trellis system on blackberry crop canopy architecture and microclimate with implications for pest management

Impact of trellis system on blackberry crop canopy architecture and microclimate with implications for pest management

Cladosporium-Insect Relationships.

The range of interactions between Cladosporium, a ubiquitous fungal genus, and insects, a class including about 60% of the animal species, is extremely diverse. The broad case history of antagonism and mutualism connecting Cladosporium and insects is reviewed in this paper based on the examination of the available literature. Certain strains establish direct interactions with pests or beneficial insects or indirectly influence them through their endophytic development in plants. Entomopathogenicity is often connected to the production of toxic secondary metabolites, although there is a case where these compounds have been reported to favor pollinator attraction, suggesting an important role in angiosperm reproduction. Other relationships include mycophagy, which, on the other hand, may reflect an ecological advantage for these extremely adaptable fungi using insects as carriers for spreading in the environment. Several Cladosporium species colonize insect structures, such as galleries of ambrosia beetles, leaf rolls of attelabid weevils and galls formed by cecidomyid midges, playing a still uncertain symbiotic role. Finally, the occurrence of Cladosporium in the gut of several insect species has intriguing implications for pest management, also considering that some strains have proven to be able to degrade insecticides. These interactions especially deserve further investigation to understand the impact of these fungi on pest control measures and strategies to preserve beneficial insects.

Evaluation of the inheritance and dominance of behavioral resistance to imidacloprid in the house fly (Musca domestica L.) (Diptera: Muscidae).

The house fly, Musca domestica, is a cosmopolitan species known for its pestiferous nature and potential to mechanically vector numerous human and animal pathogens. Control of adult house flies often relies on insecticides formulated into food baits. However, due to the overuse of these baits, insecticide resistance has developed to all insecticide classes currently registered for use in the United States. Field populations of house flies have developed resistance to imidacloprid, the most widely used neonicotinoid insecticide for fly control, through both physiological and behavioral resistance mechanisms. In the current study, we conducted a comprehensive analysis of the inheritance and dominance of behavioral resistance to imidacloprid in a lab-selected behaviorally resistant house fly strain. Additionally, we conducted feeding preference assays to assess the feeding responses of genetic cross progeny to imidacloprid. Our results confirmed that behavioral resistance to imidacloprid is inherited as a polygenic trait, though it is inherited differently between male and female flies. We also demonstrated that feeding preference assays can be instrumental in future genetic inheritance studies as they provide direct insight into the behavior of different strains under controlled conditions that reveal, interactions between the organism and the insecticide. The findings of this study carry significant implications for pest management and underscore the need for integrated pest control approaches that consider genetic and ecological factors contributing to resistance.

Assessing genome-wide adaptations associated with range expansion in the pink rice borer, Sesamia inferens.

Understanding the genetic basis of adaptive evolution following habitat expansion can have important implications for pest management. The pink rice borer (PRB), Sesamia inferens (Walker), is a destructive pest of rice that was historically restricted to regions south of 34°N latitude in China. However, with changes in global climate and farming practices, the distribution of this moth has progressively expanded, encompassing most regions in North China. Here, 3 highly differentiated subpopulations were discovered using high-quality single-nucleotide polymorphism and structural variant datasets across China, corresponding to northern, southern China regions, and the Yunnan-Guizhou Plateau, with significant patterns of isolation by geographic and environmental distances. Our estimates of evolutionary history indicate asymmetric migration with varying population sizes across the 3 subpopulations. Selective sweep analyses estimated strong selection at insect cuticle glycine-rich cuticular protein genes which are associated with enhanced desiccation adaptability in the northern group, and at the histone-lysine-N-methyltransferase gene associated with range expansion and local adaptation in the Shandong population. Our findings have significant implications for the development of effective strategies to control this pest.

Temperature effects on the hormetic response of Myzus persicae after sublethal exposure to insecticides

Studies on insecticide-induced stimulatory effects in pest insects have become of utmost importance due to their potential implications in pest management. Temperature influences the physiology and biology of ectothermic organisms like pest insects. It can also affect the toxicity and relative efficacy of insecticides that are used in agricultural fields. However, the impact of temperature on the insect stimulatory responses after exposure to mild insecticide-induced stresses has frequently been overlooked. Here, we investigated how different temperature levels (15; 20; 25; 28 °C) can modulate the toxicity of two synthetic insecticides chlorpyrifos (organophosphate) and deltamethrin pyrethroid); and subsequently how temperature impacts the survival and reproduction of the green peach aphid Myzus persicae exposed to sublethal concentrations of the two insecticides. Our findings indicated temperature-dependent effects of the two chemicals on mortality, longevity, and the number of nymphs produced by the aphids after lethal and sublethal exposures. In fact, besides the high toxicity induced by temperature at lower concentrations, the change’s magnitude and occurrence of stimulatory responses varied between temperatures and depended on the sublethal concentrations faced by the aphid females. Temperature increase from 15 to 28 °C increased chlorpyrifos and deltamethrin toxicity 4 and fivefold. Sublethal exposure of aphids extended the longevities for individuals treated with chlorpyrifos at 15 (all sublethal concentrations) and 25 °C (LC15 and LC20) and with deltamethrin at 20 (LC1) and 28 °C (LC20). Additionally, the total number of nymphs produced during the females' lifespan was increased after sublethal exposure to chlorpyrifos at 15 °C (LC1, LC5, and LC20) and at 20 °C (LC10) and to deltamethrin at 20 °C (LC1), 25 °C (LC5 and LC10) and 28 °C (LC1, LC5, and LC20). Our results reinforce the importance of a shift from studies focusing on the stimulatory effects of single stresses to studies investigating the effects of stressors’ combinations on insect hormetic response.

Female melon fruit flies, Zeugodacus cucurbitae, are attracted to a synthetic chemical blend based on male epicuticular components

AbstractThe melon fly, Zeugodacus cucurbitae (Coquillett) (Diptera: Tephritidae), is considered to be the most destructive pest of melons and other related cucurbit crops worldwide. Despite the potential of behaviour-based control strategies, little is known about the mechanisms involved in female mate choice. Herein, we investigated the production and chemoreception of cuticular hydrocarbons in both sexes of Z. cucurbitae, and the behavioural responses they induce. We studied the epicuticular composition of virgin males and females, using two-dimensional gas chromatography coupled with mass spectrometric detection. Data were interpreted using multivariate factorial analysis. The differentiation of chemical profiles was consistently observed over time. In young individuals, the chemical profiles did not differ between sexes, while sex-specific differences were noted in mature flies. The fly olfactory sensitivity to these compounds was explored using gas chromatography combined with chopped triple electroantennography and electropalpography detectors. This extensive exploration of the pest olfactory sensitivity highlighted three compounds produced by the male. When blended, they induced a robust positive response in unmated naive females in a six-choice olfactometer. The responsiveness of other Tephritidae species (a polyphagous species Bactrocera dorsalis (Hendel) and the cucurbit specialist Dacus demmerezi (Bezzi)) to whole body extracts of Z. cucurbitae was also investigated. Our findings showed that Z. cucurbitae uses species-specific olfactory receptors to detect male produced compounds. In addition, the palps were sensitive to a female-specific component, 1,7-dioxaspiro[5.5]undecane, which the males produce in minute quantities. Overall, this study provides a starting point for a pheromone-based tephritid lure that targets unmated females. The potential implications for pest management are discussed.

Prediction of seasonal population dynamics of Grapholita molesta (Busck) and Adoxophyes orana (Fischer von Röslerstamm) in peach orchards using sex pheromone trap and degree-days and its implications in pest management

The successful management of lepidopteran moths in orchards usually depends on the precise forecast of adult activity. However, the seasonal phenology of moths varies between crop cultivars and years, making it difficult to schedule the control measures. Here, we monitored male flight activity of oriental fruit moth Grapholita molesta and summer fruit tortrix moth Adoxophyes orana by using sex pheromone traps in peach orchards of three different cultivars for three successive years. We developed a logistic multiple-peaks model to fit data and then calculated degree-days (DD) required for male activity and neonate emergency. Results show that G. molesta and A. orana males had 4–5 and 3 flight peaks per year, respectively. The seasonal phenology of G. molesta or A. orana was quite stable with an identical timing of each flight peak between cultivars in a year. The flight activity was usually higher in the second and third peaks for both moths, with a higher cumulative number of G. molesta males captured than that of A. orana. Compared to A. orana, G. molesta emerged early in spring and required lower degree-days to reach the subsequent flight peaks and for neonate emergency. Our results suggest that to decline the possibility of outbreaks of moths during the growing seasons, pheromone traps should be scheduled in April with a cumulative DD between 49.6 and 207.1 for G. molesta and in mid-May–early June with a cumulative DD between 450.4 and 866.7 for A. orana, aiming to trap the newly emerged male adults or disrupting female mating success of overwintered moths in orchards. Based on the thermal requirement for egg hatching (i.e., 79.4 DD for G. molesta and 90.0 DD for A. orana), insecticide treatments would be applied in late-April–early May and late May–early June to reduce the field population density of neonates of G. molesta and A. orana, respectively, to reduce fruit damage in orchards. Furthermore, pheromone traps set up in late July–early August (573.8–1025.2 DD) for G. molesta and in mid-September (1539.7–1788.9 DD) for A. orana may suppress overwintering populations and thus decrease pest infestation in next year.

Farmers’ knowledge and perception of cocoa insect pests and damage and the implications for pest management on cocoa in Ghana

Farmers’ knowledge and perception of cocoa insect pests and damage and the implications for pest management on cocoa in Ghana

Population genomics of fall armyworm by genotyping-by-sequencing: Implications for pest management.

The fall armyworm (FAW), Spodoptera frugiperda, is a significant pest of many crops in the world and it is native to the Americas, where the species has shown the ability to rapidly evolve resistance to insecticides and transgenic plants. Despite the importance of this species, there is a gap in the knowledge regarding the genetic structure of FAW in South America. Here, we examined the genetic diversity of FAW populations across a wide agricultural area of Brazil and Argentina using a Genotyping-by-Sequencing (GBS) approach. We also characterized samples by their host strain based on mitochondrial and Z-linked genetic markers. The GBS methodology enabled us to discover 3309 SNPs, including neutral and outlier markers. Data showed significant genetic structure between Brazil and Argentina populations, and also among the Argentinian ecoregions. Populations inside Brazil showed little genetic differentiation indicating high gene flow among locations and confirming that structure is related to the presence of corn and rice strains. Outlier analysis indicated 456 loci putatively under selection, including genes possibly related to resistance evolution. This study provides clarification of the population genetic structure of FAW in South America and highlights the importance of genomic research to understand the risks of spread of resistance genes.

Global perspectives on field-evolved resistance to transgenic Bt crops: a special collection.

Crops genetically engineered to produce insect-killing proteins from Bacillus thuringiensis (Bt) have revolutionized management of some major pests, but their efficacy is reduced when pests evolve resistance. Practical resistance, which is field-evolved resistance that reduces the efficacy of Bt crops and has practical implications for pest management, has been reported in 26 cases in seven countries involving 11 pest species. This special collection includes six original papers that present a global perspective on field-evolved resistance to Bt crops. One is a synthetic review providing a comprehensive global summary of the status of the resistance or susceptibility to Bt crops of 24 pest species in 12 countries. Another evaluates the inheritance and fitness costs of resistance of Diabrotica virgifera virgifera to Gpp34/Tpp35Ab (formerly called Cry34/35Ab). Two papers describe and demonstrate advances in techniques for monitoring field-evolved resistance. One uses a modified F2 screen for resistance to Cry1Ac and Cry2Ab in Helicoverpa zea in the United States. The other uses genomics to analyze nonrecessive resistance to Cry1Ac in Helicoverpa armigera in China. Two papers provide multi-year monitoring data for resistance to Bt corn in Spain and Canada, respectively. The monitoring data from Spain evaluate responses to Cry1Ab of the corn borers Sesamia nonagrioides and Ostrinia nubilalis, whereas the data from Canada track responses of O. nubilalis to Cry1Ab, Cry1Fa, Cry1A.105, and Cry2Ab. We hope the new methods, results, and conclusions reported here will spur additional research and help to enhance the sustainability of current and future transgenic insecticidal crops.

Colonization of oak stumps by the oak pinhole borer in temperate forests and the efficacy of pheromone traps: Implications for pest management

IntroductionThe present changes in climate and land use have led to an increase in pest population densities. The oak pinhole borer, Platypus cylindrus, is one of the ambrosia beetles, which are known to infect wood tissue with fungi from their mycangia. These fungi are responsible for cellulose degradation. This species is now responsible for more frequent timber damage throughout Europe. Therefore, it is assumed that there is a high risk of P. cylindrus outbreaks in the future with possible subsequent oak diebacks. We focused on (1) the influence of stump diameter on P. cylindrus attraction and abundance; (2) the trapping efficacy by a specific pheromone and the impact on nontarget arthropods; and (3) interannual changes in trap catches.MethodsThe research was performed from 2015–2017 with a postharvest survey of stumps. We further analyzed the catches of P. cylindrus and of nontarget arthropods on pheromone traps compared to ethanol-baited traps.Results and discussionIn total, 12,504 adults were trapped during the 3 years of the study. P. cylindrus abundance was positively correlated with stump diameter and interannual changes. The type of compound used for trapping positively affected the trapping efficacy. However, the pheromone type did not have an impact on nontarget beetles. We consider oak stumps to be a reservoir the oak pinhole borer. Therefore, we recommend their debarking or removal, especially in the case of stumps with a larger diameter (over 61 cm).

Semi-natural habitats support populations of stink bug pests in agricultural landscapes

Semi-natural habitats are considered fundamental for biodiversity conservation and the provision of biological control services in agroecosystems. However, crop pests that exploit different types of habitats during their life cycle might thrive in complex landscapes. Understanding how crop pests use a range of resources across the agroecosystem is fundamental to plan sustainable crop protection strategies. Here we explored the effects of local habitat type (i.e., annual crop, perennial crop, dry grassland and forest) and landscape composition (increasing cover of forest and dry grassland) on stink bug pests in Mediterranean agroecosystems. Stink bugs (Hemiptera: Pentatomoidea) are polyphagous and highly mobile organisms considered a serious threat for numerous crops worldwide. To better understand how stink bugs used different habitats, we sampled active adults and juveniles in spring and summer, and overwintering individuals in autumn and winter. Our results showed that semi-natural habitats supported more abundant stink bug populations, potentially providing alternative feeding, reproduction, and overwintering sites. Specifically, we found more active adults and juveniles in dry grasslands, while forests hosted greater numbers of overwintering individuals. Moreover, forest cover in the landscape was positively related to active stink bug abundance in all sampled habitats. Finally, we found complex landscapes rich in overall semi-natural habitats to support higher abundance of overwintering individuals in both forests and dry grasslands, while perennial crop might provide suitable overwintering sites in highly simplified landscape. These results have important implications for pest management as crop fields situated in complex landscapes might be more susceptible to pest infestation. Effective control strategies may require a landscape-based approach.

Cross-protection interactions in insect pests: Implications for pest management in a changing climate.

Agricultural insect pests display an exceptional ability to adapt quickly to natural and anthropogenic stressors. Emerging evidence suggests that frequent and varied sources of stress play an important role in driving protective physiological responses; therefore, intensively managed agroecosystems combined with climatic shifts might be an ideal crucible for stress adaptation. Cross-protection, where responses to one stressor offers protection against another type of stressor, has been well documented in many insect species, yet the molecular and epigenetic underpinnings that drive overlapping protective responses in insect pests remain unclear. In this perspective, we discuss cross-protection mechanisms and provide an argument for its potential role in increasing tolerance to a wide range of natural and anthropogenic stressors in agricultural insect pests. By drawing from existing literature on single and multiple stressor studies, we outline the processes that facilitate cross-protective interactions, including epigenetic modifications, which are understudied in insect stress responses. Finally, we discuss the implications of cross-protection for insect pest management, focusing on the consequences of cross-protection between insecticides and elevated temperatures associated with climate change. Given the multiple ways that insect pests are intensively managed in agroecosystems, we suggest that examining the role of multiple stressors can be important in understanding the wide adaptability of agricultural insect pests. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Coping with global warming: Adult thermal thresholds in four pestiferous Anastrepha species determined under experimental laboratory conditions and development/survival times of immatures and adults under natural field conditions.

Climate change, particularly global warming, is disturbing biological processes in unexpected ways and forcing us to re-study/reanalyze the effects of varying temperatures, among them extreme ones, on insect functional traits such as lifespan and fecundity/fertility. Here we experimentally tested, under both laboratory and field conditions, the effects of an extreme range of temperatures (5, 10, 15, 20, 30, 40, and 45 °C, and the naturally varying conditions experienced in the field), on survivorship/lifespan, fecundity, and fertility of four pestiferous fruit fly species exhibiting contrasting life histories and belonging to two phylogenetic groups within the genus Anastrepha: A. ludens, A. obliqua, A. striata, and A. serpentina. In the field, we also measured the length of the entire life cycle (egg to adult), and in one species (A. ludens), the effect on the latter of the host plant (mango and grapefruit). Under laboratory conditions, none of the adults, independent of species, could survive a single day when exposed to a constant temperature of 45 °C, but A. striata and A. serpentina females/males survived at the highly contrasting temperatures of 5 and 40 °C at least 7 days. Maximum longevity was achieved in all species at 15 °C (375, 225, 175 and 160 days in A. ludens, A. serpentina, A. striata and A. obliqua females, respectively). Anastrepha ludens layed many eggs until late in life (368 days) at 15 °C, but none eclosed. Eclosion was only observed in all species at 20 and 30 °C. Under natural conditions, flies lived ca. 100 days less than in the laboratory at 15 °C, likely due to the physiological cost of dealing with the highly varying environmental patterns over 24 h (minimum and maximum temperatures and relative humidity of ca. 10–40 °C, and 22–100%, respectively). In the case of A. ludens, the immature’s developmental time was shorter in mango, but adult survival was longer than in grapefruit. We discuss our results considering the physiological processes regulating the traits measured and tie them to the increasing problem of global warming and its hidden effects on the physiology of insects, as well as the ecological and pest management implications.

Predator- and killed prey-induced fears bear significant cost to an invasive spider mite: Implications in pest management.

The success of biological control using predators is normally assumed to be achieved through direct predation. Yet it is largely unknown how the predator- and killed prey-induced stress to prey may contribute to biological control effectiveness. Here, we investigate variations in life-history traits and offspring fitness of the spider mite Tetranychus ludeni in response to cues from the predatory mite Phytoseiulus persimilis and killed T. ludeni, providing knowledge for evaluation of the nonconsumptive contribution to the biological control of T. ludeni and for future development of novel spider mite control measures using these cues. Cues from predators and killed prey shortened longevity by 23-25% and oviposition period by 35-40%, and reduced fecundity by 31-37% in T. ludeni females. These cues significantly reduced the intrinsic rate of increase (rm ) and net population growth rate (R0 ), and extended time to double the population size (Dt ). Predator cues significantly delayed lifetime production of daughters. Mothers exposed to predator cues laid significantly smaller eggs and their offspring developed significantly more slowly but these eggs had significantly higher hatch rate. Predator- and killed prey-induced fears significantly lower the fitness of T. ludeni, suggesting that these nonconsumptive effects can contribute to the effectiveness of biological control to a great extent. Our study provides critical information for evaluation of biological control effectiveness using predators and paves the way for identification of chemical odors from the predator and killed prey, and development of new materials and methods for the control of spider mite pests. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Habitat heterogeneity and topographic variation as the drivers of insect pest distributions in alpine landscapes

Insect pests pose a large threat to alpine landscapes, especially under global environmental change conditions. It is necessary to explore the effects of environmental factors on the distribution of pests and provide implications for pest management in alpine landscapes. The main objective of this study was to explore whether habitat heterogeneity and topographic variation could drive insect pest distributions in alpine landscapes. We used species distribution modelling to project the distributions of 58 insect pest species in alpine landscapes based on occurrence records from 5513 field sites and different sets of environmental variables (i.e., climate, climate + habitat heterogeneity, climate + topographic variation, and climate + habitat heterogeneity + topographic variation). Then, we applied the jackknife method to determine the contribution of environmental variables to insect pest distributions. We found that habitat heterogeneity and topographic variation could significantly affect the distribution probability for all insect pest species in Qinghai, China. The response curves of the probability of pest distribution to habitat heterogeneity and topographic variation vary depending on the species present in alpine landscapes. There were four types of response curves of habitat heterogeneity and topographic variation to insect pest distribution probability, namely, 1) increasing, 2) decreasing, 3) increasing and then decreasing, and 4) decreasing and then increasing. Habitat heterogeneity and topographic variation should be integrated into modelling the distributions of insect pest species in alpine landscapes for pest risk assessment.

Quantitative prey species detection in predator guts across multiple trophic levels by mapping unassembled shotgun reads.

Quantifying species trophic interaction strengths is crucial for understanding community dynamics and has significant implications for pest management and species conservation. DNA-based methods to identify species interactions have revolutionized these efforts, but a significant limitation is the poor ability to quantify the strength of trophic interactions, that is the biomass or number of prey consumed. We present an improved pipeline, called Lazaro, to map unassembled shotgun reads to a comprehensive arthropod mitogenome database and show that the number of prey reads detected is quantitatively predicted from the prey biomass consumed, even for indirect predation. Two feeding bioassays were performed: starved coccinellid larvae consuming different numbers of aphids (Prey Quantity bioassay), and starved coccinellid larvae consuming a chrysopid larvae that had consumed aphids (Direct and Indirect Predation bioassay). Prey taxonomic assignment against a mitochondrial genome database had high accuracy (99.8% positive predictive value) and the number of prey reads was directly related to the number of prey consumed and inversely related to the elapsed time since consumption with high significance (r2 = .932, p= 4.92E-6). Aphids were detected up to 6h after direct predation plus 3h after indirect predation (9h in total) and detection was related to the predator-specific decay rates. Lazaro enabled quantitative predictions of prey consumption across multiple trophic levels with high taxonomic resolution while eliminating all false positives, except for a few confirmed contaminants, and may be valuable for characterizing prey consumed by field-sampled predators. Moreover, Lazaro is readily applicable for species diversity determination from any degraded environmental DNA.

Spatio‐temporal co‐occurrence of Anastrepha species in papaya orchards in the state of Espírito Santo, Brazil

AbstractThe variation in co‐occurrence between pests may influence spatio‐temporal persistence strategies of species, with implications for pest management. The co‐occurrence of Anastrepha species (Diptera: Tephritidae) in papaya orchards was investigated in areas at different distances from a native forest reserve in Espírito Santo, Brazil, to investigate positive, negative, or random interactions, understood as potential coexistence, interspecific competition, or neutral interactions, respectively. Data were obtained from a papaya‐growing area divided into three sub‐areas – a buffer zone bordering the forest, neighbourhood 1, and neighbourhood 2 – and the co‐occurrence results were compared with the entire area. The buffer zone along the protected native Atlantic Forest (semideciduous seasonal forest vegetation) was created to filter negative environmental impacts. Neighbourhood 1 was closer to the forest than neighbourhood 2. Based on a long‐term dataset from 1998 to 2010, co‐occurrence of fruit flies was investigated by comparing two periods: from 1998 to 2003, when a special pest management system was implemented, termed the systems approach, and from 2004 to 2010, showing the impact of this system on fruit fly diversity. The strength of interaction between species was also evaluated for significant co‐occurrences. The patterns of co‐occurrence and interaction of Anastrepha species were influenced by area and time. In all scenarios, only positive and random associations were observed, with Anastrepha fraterculus (Wiedemann) and Anastrepha obliqua (Macquart) showing the most positive associations. Co‐occurrence was greater in areas farther from the reserve. However, the strength of the interaction between the areas showed little variation. We concluded that the distance from the reserve and the pest management (systems approach) influenced co‐occurrence, as species co‐occurred much more frequently when collected far from the native forest. The impact during the period of the systems approach (1998–2003) provided fewer positive associations, but with stronger interactions over time. These results confirm that identifying pest co‐occurrence distribution patterns in crops and the respective neighbourhoods can be helpful in improving strategies for pest management associated with a systems approach.

Do Invasive and Naturalized Aphid Pest Populations Respond Differently to Climatic and Landscape Factors?

Ongoing environmental change affects pest populations, migration, and propensity to damage crops, but the responses to climatic drivers could vary among newly invasive and already naturalized closely related species. To compare these responses of a newly invasive aphid, Metopolophium festucae cerealium (Stroyan), with its naturalized congeneric [M. dirhodum (Walker)] and confamilial [Sitobian avenae (Fab.)], we conducted annual surveys over four years across a total of 141 winter wheat fields in the inland Pacific Northwest, USA. Key climatic factors (cumulative precipitation for each calendar year to sampling date, cumulative degree days), landscape factors (proportion of wheat and landscape diversity within the sample year), and Julian day were calculated for each sampling event, and aphid abundance by species, total aphid abundance, overall species richness, diversity, and aphid community composition were assessed. Metopolophium f. cerealium, the second most abundant species, was positively associated with precipitation, suggesting a projected increase in precipitation in winter and spring in the region could favor its establishment and expansion. Although M. dirhodum and S. avenae linearly (positively) associated with temperature, M. f. cerealium did not, indicating that continued warming may be detrimental to the species. Despite the weak impacts of landscape factors, our study indicated that more wheat generally facilitates cereal aphid abundance. Metopolophium f. cerealium abundance tended to be higher in earlier (May/early June vs. late June/July) samples when wheat crop could be vulnerable to aphid feeding. This study suggests that the new presence of M. f. cerealium has important pest management implications in the region.

Multi-locus genotyping of stored sperm reveals female remating rates in wild populations of the Queensland fruit fly.

Female insects commonly have more than one mate during a breeding period ('polyandry'), storing and using sperm from multiple males. In addition to its evolutionary significance, insect polyandry has practical implications for pest management that relies on the sterile insect technique (SIT). The Queensland fruit fly, Bactrocera tryoni (Froggatt), is a major horticultural pest in Australia, and outbreaks are managed by SIT in some regions. The present study provides the first evidence for polyandry in female B. tryoni from field populations from New South Wales (NSW) and Queensland (QLD) through multi-locus genotyping (ten microsatellite markers in four fluorescent multiplexes) of the stored sperm in ovipositing females. Polyandry level was significantly higher in the NSW collection (80.0 %) than the QLD collection (26.1 %), suggesting substantial regional and/or temporal variation. These findings have important implications for the use of SIT to suppress B. tryoni populations and to eradicate outbreaks.