Each spring, billions of Bogong moths escape hot conditions across southeast Australia by migrating up to 1,000 km to a place that they have never previously visited—a limited number of cool caves in the Australian Alps, historically used for aestivating over summer 1,2 . At the beginning of autumn, the same individuals make a return migration to their breeding grounds to reproduce and die. Here we show that Bogong moths use the starry night sky as a compass to distinguish between specific geographical directions, thereby navigating in their inherited migratory direction towards their distant goal. By tethering spring and autumn migratory moths in a flight simulator 3–5 , we found that, under naturalistic moonless night skies and in a nulled geomagnetic field (disabling the moth’s known magnetic sense 4 ), moths flew in their seasonally appropriate migratory directions. Visual interneurons in different regions of the moth’s brain responded specifically to rotations of the night sky and were tuned to a common sky orientation, firing maximally when the moth was headed southwards. Our results suggest that Bogong moths use stellar cues and the Earth’s magnetic field to create a robust compass system for long-distance nocturnal navigation towards a specific destination.

Transgenic Bt cotton was developed to control lepidopteran pests like the cotton bollworm, Helicoverpa armigera . However, there was concern that H. armigera would develop resistance to Bt cotton as this species had developed resistance to many insecticides and Bt toxins. To counter resistance, the cotton industry developed a resistance management plan (RMP) that included techniques to block resistant genes surviving from one season to the next (seasonal quarantining). One such technique is pupae busting, where cotton fields are cultivated after harvest, destroying potentially resistant pupating Helicoverpa spp. While pupae busting was important when there was only one insecticidal gene in Bt cotton, is it still relevant now Bt cotton has three insecticidal Bt genes? To address this question, we reviewed the development of pupae busting as a tool and its role in the current RMP. This included examining the ecology and behavioural characteristics of Helicoverpa spp. that impact on pupae busting efficacy (e.g., diapause, pupal mortality and pupae depth); the effect of soil type and different tillage techniques on pupae busting efficacy; and pupae busting within the context of Australia's current cotton farming system. We also looked at alternative forms of seasonal quarantining, such as using bisexual attract‐and‐kill techniques against adults. We confirmed that soil for pupae busting needs to be checked for moisture, which ideally should be less than the soil plastic limit. Comparisons between reports indicated that under good conditions, ‘go‐devils’ and chisel ploughs were excellent pupae busters. While a bisexual attract‐and‐kill strategy of late season moths has a place within the industry, pupae busting is still the best method in seasonal quarantining and has a good fit within the modern cotton industry, particularly given differences in the biology and ecology of H. armigera and H. punctigera , and the presence of dominant resistance to Bt toxins by H. armigera in China.

Foliage- and ground-dwelling arthropods provide ecosystem services, including decomposition and biological control of agricultural pests. Despite this, there is little information on the ground-dwelling arthropod community associated with cotton crops and about their role under pest control practices. Identifying these communities and their preservation would assist smallholder cotton growers in considering an Integrated Pest Management (IPM) approach to pest control. In this context, the strategy of using selective- or broad-spectrum insecticides (both applied only once the pests reached an economic threshold) was assessed using field plots set up within non-Bt cotton structured refuge of a grower field measuring the response of both foliage- and ground-dwelling arthropods and yield. The abundance, species richness, dominance indices, and foliage-dwelling predators and pest species and ground-dwelling predators and decomposers were compared between untreated and insecticide treatments, as was the crop yield. In response to pest monitoring, insecticides were applied 5 and 3 times during the 2018 and 2020 growing seasons, respectively. In 2018 and 2020, 16 and 12 foliage-dwelling predator arthropods and 43 and 47 ground-dwelling predator and decomposer arthropods were collected, respectively. During the 2018 season, broad-spectrum insecticide applications reduced the abundance of foliage-dwelling predators, but had no significant impact on the ground-dwelling community. Principal response curves (PRC) indicated a negative impact of broad-spectrum insecticides only on the foliage-dwelling community, particularly among the Formicidae and Araneae species. Insecticide applications in the 2020 season were only required at the end of the crop season and did not significantly influence the foliage- or ground-dwelling communities. The selective insecticide regime yielded as well as the broad-spectrum insecticide regimes higher yielded than untreated plots. These results demonstrated to the small landholders engaging conservation biological control for the first time, the advantages of an IPM approach to pest management.

The management of arthropods in urban environments is complex. Although there are species that threaten human health and property, there are also extensive communities of beneficial species that need to be conserved. Current management of arthropod pests in cities relies heavily on the use of synthetic chemicals, which have a range of potential environmental and health impacts. In order to mitigate the impacts of insecticides, urban stakeholders need to be encouraged to reduce reliance on chemical control and adopt more ecologically sustainable approaches. Integrated pest management (IPM) has been globally successful in managing pests in agriculture, but has yet to be broadly practiced in urban systems. Here, we address the global problem of lack of IPM uptake in urban areas. We summarise current arthropod management practices, with comparisons made between the management of pests in urban and agricultural systems, and highlight the benefits of IPM. We then give examples of successful IPM to demonstrate the useful implementation strategies and identify key barriers to the adoption of this approach in urban systems. In particular, the high diversity of stakeholder interests and management practices is a key barrier to overcome in cities, along with lack of awareness of the benefits and implementation strategies of IPM, little emphasis on monitoring pests, restrictions in time/resources, and social factors such as negative public perceptions of insects and policy regulations. We offer suggestions for overcoming these barriers in the hope of encouraging greater application of sustainable arthropod pest management practices for all urban stakeholders.

Multiple predator species that coexist with each other and their mutual prey can have combined effects on prey mortality that are similar to the sum of each predator's individual impact (linear effects), greater than the sum of each predator's individual impact (risk enhancement), or less than the sum of each predator's individual impact (risk reduction). Understanding multiple predator effects is important to determine the impact of predators on pest prey in agroecosystems. If two predators share the same broad spatial domain and hunting mode and engage in intraguild predation, then their combination is expected to result in risk reduction for a mutual prey. We tested this hypothesis using both additive and replacement experimental designs on two species of generalist wolf spider predators (Tasmanicosa leuckartii and Hogna crispipes) that hunt in the same domain, and a mutual insect prey (cotton bollworm Helicoverpa armigera). We used two types of enclosures: a small simple laboratory enclosure, and a larger more complex cotton plant enclosure. We found that in the small simple laboratory enclosures, the presence of two spiders led to risk reduction of Helicoverpa larva mortality as expected, but in larger more complex cotton plant enclosures the presence of both species resulted in linear effects rather than risk reduction on Helicoverpa mortality. Furthermore, intraguild predation did not change multiple predator effects in laboratory or plant enclosures. This study has implications for managing arthropod predators in agroecosystems; contrary to predictions of ecological frameworks, coexistence of predators that share the same hunting mode and hunting domain may not lead to risk reduction on a mutual prey in more complex environments, where encounters among predators can be lower. Conservation of multiple predators of a single guild can play an essential role on biological control of insect pests.

Wolf spiders are abundant and voracious predators at the soil-plant interface in cotton crops. Among other prey, they attack late-instar larvae of the cotton bollworm Helicoverpa spp., an economically important pest. Consequently, wolf spiders in transgenic Bt cotton could provide significant biological control of Bt-resistant Helicoverpa larvae that descend to the soil to pupate. The predator-prey interactions between wolf spiders and Helicoverpa could, however, be constrained by the presence of alternative prey and intraguild predators. This study used laboratory enclosures to analyse the effect of alternative prey on predatory selection of the wolf spider Tasmanicosa leuckartii Thorell. The prey included another wolf spider Hogna crispipes Koch (potential intraguild predator), the ground cricket Teleogryllus commodus Walker (minor pest), and Helicoverpa armigera larvae (major pest). We tested if encounter rates, prey vulnerability, and prey nutritional content influenced the likelihood that a prey was attacked. In three-way food webs, Tasmanicosa encountered and attacked Teleogryllus and Helicoverpa in similar frequencies. However, in the presence of a competing intraguild predator and potential prey (Hogna) in a four-way food web, Tasmanicosa did not always attack Teleogryllus at first encounter, but still attacked Helicoverpa at each encounter. Helicoverpa (protein-poor) and Hogna (protein-rich) were consumed by Tasmanicosa in similar proportions, suggesting that Tasmanicosa might benefit from nutrient balance as an outcome of diverse prey in this food web. As Teleogryllus (protein rich) escapes quicker than Helicoverpa and Hogna, Hogna may be an easier protein-rich option than Teleogryllus. Field surveys showed that while Teleogryllus was the most common prey, wolf spiders feed on diverse insect taxa, as well as other spiders. That Tasmanicosa readily attacked Helicoverpa larvae in the presence of alternative prey is an encouraging result that supports the potential of Tasmanicosa predation to assist in the control of Bt-resistant Helicoverpa larvae and thereby inhibit the proliferation and spread of resistance.

New Zealand’s pastoral sector faces significant challenges to pest management as long-standing insecticides are deregistered. To protect their pastures, farmers need to shift from reactive responses that lead to poor economic outcomes to pre-emptive responses that are viable in the long term. Current management practices (insecticides, endophytes, biological control) for New Zealand’s pasture insect pests were assessed from the perspective of Integrated Pest Management (IPM). Potential impacts from novel control strategies and emerging digital technologies were evaluated to determine how these could improve pest management. Cryptic IPM is present within the New Zealand pastoral sector: that is, farmers practise various elements of IPM but these elements are not integrated into a cohesive system, so farmers often fail to recognise pest impacts until significant economic losses have occurred. We identified important networks by which farmers, industry and researchers communicate and share information, and can develop strategies to raise awareness of IPM. To encourage adoption, farmers need to feel ownership of pasture IPM. Investment in IPM training for farmers through industry extension networks is essential to prepare farmers for the shift away from chemical insecticides to new biologically based control methods. Adoption of IPM will help pastoralists respond to current and new pest challenges.

The Australian cotton industry progressively embraced integrated pest management (IPM) to alleviate escalating insecticide resistance issues. A systems IPM approach was used with core principles that were built around pest ecology/biology and insecticide resistance management; together, these were integrated into a flexible, year-round approach that facilitated easy incorporation of new science, strategies, and pests. The approach emphasized both strategic and tactical elements to reduce pest abundance and rationalize decisions about pest control, with insecticides as a last resort. Industry involvement in developing the approach was vital to embedding IPM within the farming system. Adoption of IPM was facilitated by the introduction of Bt cotton, availability of selective insecticides, economic validation, and an industry-wide extension campaign. Surveys indicate IPM is now embedded in industry, confirming the effectiveness of an industry-led, backed-by-science approach. The amount of insecticide active ingredient applied per hectare against pests has also declined dramatically. Though challenges remain, pest management has transitioned from reactively attempting to eradicate pests from fields to proactively managing them year-round, considering the farm within the wider landscape.

Wolf spiders (Araneae: Lycosidae) are abundant ground predators in cotton fields that can provide important pest management services. These spiders can kill and consume larvae of the cotton bollworm Helicoverpa spp. (Lepidoptera: Noctuidae) that survive foraging on Bt cotton and descend from the plant to pupate in the soil. To determine predation frequency by wolf spiders in a Bt cotton field, we indirectly assessed predation using Helicoverpa spp. larvae marked with rabbit immunoglobulin G (IgG; "immunomarking"), and carried out capture-mark-recapture surveys to assess the likelihood of recapturing spiders. A laboratory feeding study with IgG-marked larva demonstrated that IgG is readily detected in spiders for up to 72 h after feeding. Following the release of IgG-marked larvae in a cotton field edge, 2.1% of spiders collected tested positive for the presence of IgG, providing indirect evidence of predation. A capture-mark-recapture survey revealed that spiders had opportunity to encounter IgG-marked larvae released along field edges, but only 6.7% of the spiders were recaptured, likely reflecting high spider mobility. In field feeding arenas, all three commonly encountered wolf spider species (Tasmanicosa leuckartii, Hogna crispipes, Hogna kuyani) ate Helicoverpa spp. larvae. These studies suggest that the low likelihood of spider recapture, and not prey rejection, is the most likely explanation for the low proportion of field-collected spiders testing positive for IgG marked prey remains, and that the frequency of IgG detection in spiders likely underestimated the frequency of predation events. We conclude that use of prey immunomarking together with capture-mark-recapture surveys can provide a powerful tool for assessing the effect of a predator on a prey species under field conditions.

Like many birds [1], numerous species of nocturnal moths undertake spectacular long-distance migrations at night [2]. Each spring, billions of Bogong moths (Agrotis infusa) escape hot conditions in different regions of southeast Australia by making a highly directed migration of over 1,000 km to a limited number of cool caves in the Australian Alps, historically used for aestivating over the summer [3, 4]. How moths determine the direction of inherited migratory trajectories at night and locate their destination (i.e., navigate) is currently unknown [5-7]. Here we show that Bogong moths can sense the Earth's magnetic field and use it in conjunction with visual landmarks to steer migratory flight behavior. By tethering migrating moths in an outdoor flight simulator [8], we found that their flight direction turned predictably when dominant visual landmarks and a natural Earth-strength magnetic field were turned together, but that the moths became disoriented within a few minutes when these cues were set in conflict. We thus conclude that Bogong moths, like nocturnally migrating birds [9], can use a magnetic sense. Our results represent the first reliable demonstration of the use of the Earth's magnetic field to steer flight behavior in a nocturnal migratory insect.

The cotton bollworm, Helicoverpa armigera (Hübner) is one of the most serious insect pest species to evolve resistance against many insecticides from different chemical classes. This species has evolved resistance to the pyrethroid insecticides across its native range and is becoming a truly global pest after establishing in South America and having been recently recorded in North America. A chimeric cytochrome P450 gene, CYP337B3, has been identified as a resistance mechanism for resistance to fenvalerate and cypermethrin. Here we show that this resistance mechanism is common around the world with at least eight different alleles. It is present in South America and has probably introgressed into its closely related native sibling species, Helicoverpa zea. The different alleles of CYP337B3 are likely to have arisen independently in different geographic locations from selection on existing diversity. The alleles found in Brazil are those most commonly found in Asia, suggesting a potential origin for the incursion of H. armigera into the Americas.

Helicoverpa armigera (Hübner) and H. punctigera (Wallengren) are destructive pests that could develop resistance to Bt-cotton (Gossypium hirsutum L.). In Australia resistance is countered within a season by diluting resistance genes with susceptible genes (“Genetic Dilution”); or limiting the gene flow of resistance genes between seasons (“Season Quarantining”). Planting non-Bt host plants (“refuges”) like pigeon pea (Cajanus cajan (L.)) to produce sufficient susceptible genes to dilute resistance genes from Bt-cotton, is part of the Genetic Dilution strategy. The current resistance management plan for Bt-cotton mandates that pigeon pea refuges are half the size of non-Bt-cotton refuges because pigeon pea can produce twice as many moths as cotton. We tested this assumption on commercial farms using eggs and pupae of both Helicoverpa species as measures of attractiveness and productivity respectively.

In small invertebrates with limited cognitive facilities, learning is restricted. Given these constraints, factors encouraging the development of learning in vertebrates may be relevant to invertebrates. Increased social complexity, where living in groups can result in more complex intrasexual interactions, could lead to increased cognitive abilities elsewhere, such as foraging behaviour. This study looks at the effect of training on the ability of Argyrodes antipodianus to perform common (kleptoparasitic) and uncommon (capturing spiderlings) foraging behaviours. Females did not improve the common foraging behaviour with training, but did improve the uncommon behaviour; while males improved both (but compared to females may use a different learning strategy to improve the uncommon behaviour). Males and possibly females solved kleptoparasitic problems to better exploit their hosts. Males appeared better than females at modifying their foraging techniques, which could be linked to more complex intrasexual interactions by males caused by living in mixed-sex groups.

Larvae of the cotton bollworm, H elicoverpa armigera (H übner) ( L epidoptera: N octuidae) that survive on genetically modified Bt cotton ( G ossypium hirsutum L ., M alvaceae) contribute to the risk of widespread resistance to Bt toxins. Current resistance management techniques include pupae busting, which involves deep tilling of the soil to kill overwintering pupae. Unfortunately, pupae busting runs counter to soil and water conserving techniques, such as minimum tillage. This problem could be relieved with biological control methods, whereby predators attack either larvae going to ground to pupate or moths emerging from the ground. We found that the wolf spider T asmanicosa leuckartii ( T horell) ( A raneae: L ycosidae), a common inhabitant of A ustralian cotton agroecosystems, is an effective predator of H . armigera , attacking and killing most larvae (66%) and emerging moths (77%) in simple laboratory arenas. T asmanicosa leuckartii also reduced the number of emerging moths by 66% on average in more structurally complex glasshouse arenas. Males, females, and late‐instar juveniles of T . leuckartii were similarly effective. T asmanicosa leuckartii also imposed non‐consumptive effects on H . armigera , as when a spider was present larvae in the laboratory areas spent less time on the cotton boll and more time on the soil and more mass was lost from the cotton boll. Increased loss of boll mass likely reflects changes in H . armigera foraging behavior induced by the presence of spiders (indirect non‐consumptive effects). H elicoverpa armigera spent more time as pupae when the spider was present in simple laboratory arenas, but not in more complex glasshouse enclosures. Overall, results indicate that T . leuckartii spiders can be effective predators of H . armigera late instars and moths but also suggest that, under some conditions, the presence of spiders could increase the damage to individual cotton bolls.

Wolf spiders (Lycosidae) are the most abundant ground-hunting spiders in the Australian cotton (Gossypium hirsutum L.) agroecosystems. These spiders have potential in controlling pest bollworms, Helicoverpa spp. (Lepidoptera: Noctuidae) in minimum-tilled fields. A study was carried out during a wet growing season (2011-2012) in Narrabri, New South Wales, Australia, to determine how different crop rotations and tillage affect wolf spider assemblages in cotton fields. Spider abundance and species richness did not differ significantly between simple plots (no winter crop) and complex plots (cotton-wheat Triticum aestivum L.-vetch Vicia benghalensis L. rotation). However, the wolf spider biodiversity, as expressed by the Shannon-Weaver and Simpson's indices, was significantly higher in complex plots. Higher biodiversity reflected a more even distribution of the most dominant species (Venatrix konei Berland, Hogna crispipes Koch, and Tasmanicosa leuckartii Thorell) and the presence of more rare species in complex plots. T. leuckartii was more abundant in complex plots and appears to be sensitive to farming disturbances, whereas V. konei and H. crispipes were similarly abundant in the two plot types, suggesting higher resilience or recolonizing abilities. The demographic structure of these three species varied through the season, but not between plot types. Environmental variables had a significant effect on spider assemblage, but effects of environment and plot treatment were overshadowed by the seasonal progression of cotton stages. Maintaining a high density and even distribution of wolf spiders that prey on Helicoverpa spp. should be considered as a conservation biological control element when implementing agronomic and pest management strategies.

Transgenic cotton varieties (Bollgard II) expressing two proteins (Cry1Ac and Cry2Ab) from Bacillus thuringiensis (Bt) have been widely adopted in Australia to control larvae of Helicoverpa. A triple-stacked Bt-transgenic cotton producing Cry1Ac, Cry2Ab, and Vip3A proteins (Genuity Bollgard III) is being developed to reduce the chance that Helicoverpa will develop resistance to the Bt proteins. Before its introduction, nontarget effects on the agro-ecosystem need to be evaluated under field conditions. By using beatsheet and suction sampling methods, we compared the invertebrate communities of unsprayed non-Bt-cotton, Bollgard II, and Bollgard III in five experiments across three sites in Australia. We found significant differences between invertebrate communities of non-Bt and Bt (Bollgard II and Bollgard III) cotton only in experiments where lepidopteran larval abundance was high. In beatsheet samples where lepidopterans were absent (Bt crops), organisms associated with flowers and bolls in Bt-cotton were more abundant. In suction samples, where Lepidoptera were present (i.e., in non-Bt-cotton), organisms associated with damaged plant tissue and frass were more common. Hence in our study, Bt- and non-Bt-cotton communities only differed when sufficient lepidopteran larvae were present to exert both direct and indirect effects on species assemblages. There was no overall significant difference between Bollgard II and III communities, despite the addition of the Vip gene in Bollgard III. Consequently, the use of Bollgard III in Australian cotton provides additional protection against the development of resistance by Helicoverpa to Bt toxins, while having no additional effect on cotton invertebrate communities.

The Cotton Catchment Communities Cooperative Research Centre began during a period of rapid uptake of Bollgard II® cotton, which contains genes to express two Bt proteins that control the primary pests of cotton in Australia, Helicoverpa armigera and H. punctigera. The dramatic uptake of this technology presumably resulted in strong selection pressure for resistance in Helicoverpa spp. against the Bt proteins. The discovery of higher than expected levels of resistance in both species against one of the proteins in Bollgard II® cotton (Cry2Ab) led to significant re-evaluation of the resistance management plan developed for this technology, which was a core area of research for the Cotton CRC. The uptake of Bollgard II® cotton also led to a substantial decline in pesticide applications against Helicoverpa spp. (from 10–14 to 0–3 applications per season). The low spray environment allowed some pests not controlled by the Bt proteins to emerge as more significant pests, especially sucking species such as Creontiades dilutus and Nezara viridula. A range of other minor pests have also sporadically arisen as problems. Lack of knowledge and experience with these pests created uncertainty and encouraged insecticide use, which threatened to undermine the gains made with Bollgard II® cotton. Here we chronicle the achievements of the Cotton CRC in providing the industry with new knowledge and management strategies for these pests.

Little information is available on spiders in the Chihuahuan Desert. In the Jornada del Muerto of southern New Mexico, we collected ca. 120 species of spiders in the past 30 years. We report four state records and five potential undescribed species. A comparison of our list of species with those from three other areas in the Chihuahuan Desert (White Sands National Monument and vicnity and Valley of near Carrizozo and vicinity, both in New Mexico, and an area near Big Bend, Texas) revealed low overlap, indicating that the regional spider fauna is still not fully known. Baseline knowledge of the spider fauna from several sites could serve as a criterion for assessing climatic change.

Food web studies often examine density and behaviourally mediated effects of predators on herbivores, but are less likely to assess the plant targeted by the herbivore. We conducted a study that incorporated four trophic levels examining the effect of two generalist predators (damsel bugs, Nabis kinbergii Reuter; and lynx spiders, Oxyopes molarius L. Koch) on damage to cotton bolls caused by green mirids ( Creontiades dilutus (Stål)). First we tested whether lynx spiders and damsel bugs could control mirid numbers and cotton boll damage in field cages. We found that in cages containing mirids and only lynx spiders, lynx spiders reduced both mirid numbers and boll damage. However, in cages which contained mirids and both predators (lynx spiders and damsel bugs) only mirid numbers were reduced. To explain the negative effect of damsel bugs on boll damage, we examined the interactions between lynx spiders, damsel bugs and mirids. We found that lynx spiders were better mirid predators than damsel bugs, and that lynx spiders attacked damsel bugs, but not vice versa. Behaviourally, mirids responded to increasing predator pressure regardless of whether the predators were lynx spiders or damsel bugs. However, damsel bugs seemed to alter the behaviour of lynx spiders because in their presence, a higher proportion of lynx spiders moved to the top of the plant, towards the damsel bugs but away from the bolls found lower on the plant. These results suggest that the most likely explanation for the increase in boll damage in the presence of damsel bugs was that lynx spiders moved to the top of the plant in the presence of damsel bugs, which then exposed the bolls lower down on the plant to mirid attack. This work emphasizes the importance of behaviourally mediated effects in food webs extending over four trophic levels.