Joint environmental and social benefits from diversified agriculture.

Agricultural simplification continues to expand at the expense of more diverse forms of agriculture. This simplification, for example, in the form of intensively managed monocultures, poses a risk to keeping the world within safe and just Earth system boundaries. Here, we estimated how agricultural diversification simultaneously affects social and environmental outcomes. Drawing from 24 studies in 11 countries across 2655 farms, we show how five diversification strategies focusing on livestock, crops, soils, noncrop plantings, and water conservation benefit social (e.g., human well-being, yields, and food security) and environmental (e.g., biodiversity, ecosystem services, and reduced environmental externalities) outcomes. We found that applying multiple diversification strategies creates more positive outcomes than individual management strategies alone. To realize these benefits, well-designed policies are needed to incentivize the adoption of multiple diversification strategies in unison.

Effects of Soil Rhizobia Abundance on Interactions between a Vector, Pathogen, and Legume Plant Host.

Soil rhizobia promote nitrogen fixation in legume hosts, maximizing their tolerance to different biotic stressors, plant biomass, crop growth, and yield. While the presence of soil rhizobia is considered beneficial for plants, few studies have assessed whether variation in rhizobia abundance affects the tolerance of legumes to stressors. To address this, we assessed the effects of variable soil rhizobia inoculum concentrations on interactions between a legume host (Pisum sativum), a vector insect (Acyrthosiphon pisum), and a virus (Pea enation mosaic virus, PEMV). We showed that increased rhizobia abundance reduces the inhibitory effects of PEMV on the nodule formation and root growth in 2-week-old plants. However, these trends were reversed in 4-week-old plants. Rhizobia abundance did not affect shoot growth or virus prevalence in 2- or 4-week-old plants. Our results show that rhizobia abundance may indirectly affect legume tolerance to a virus, but effects varied based on plant age. To assess the mechanisms that mediated interactions between rhizobia, plants, aphids, and PEMV, we measured the relative expression of gene transcripts related to plant defense signaling. Rhizobia concentrations did not strongly affect the expression of defense genes associated with phytohormone signaling. Our study shows that an abundance of soil rhizobia may impact a plant's ability to tolerate stressors such as vector-borne pathogens, as well as aid in developing sustainable pest and pathogen management systems for legume crops. More broadly, understanding how variable rhizobia concentrations can optimize legume-rhizobia symbiosis may enhance the productivity of legume crops.

Global change influences scavenging and carrion decomposition.

Carrion decomposition is fundamental to nutrient cycling in terrestrial ecosystems because it provides a high-quality resource to diverse organisms. A conceptual framework incorporating all phases of carrion decomposition with the full community of scavengers is needed to predict the effects of global change on core ecosystem processes. Because global change can differentially impact scavenger guilds and rates of carrion decomposition, our framework explicitly incorporates complex interactions among microbial, invertebrate, and vertebrate scavenger communities across three distinct phases of carcass decomposition. We hypothesize that carrion decomposition rates will be the most impacted when global change affects carcass discovery rates and the foraging behavior of competing scavenger guilds.

A high-throughput plate method for nucleic acid extraction from beet leafhopper (Hemiptera: Cicadellidae) and potato psyllid (Hemiptera: Triozidae) for pathogen detection.

Plant pathogens that are transmitted by insect vectors cause considerable damage to crops when pests or pathogens are not detected early in the season and populations are not controlled. Knowledge of pathogen prevalence in insect pest populations can aid growers in their insect pest management decisions but requires the timely dissemination of results. This process requires that specimen capture, identification, nucleic acid extraction, and molecular detection of a pathogen(s) occur alongside a platform for sharing results. The potato psyllid (Bactericera cockerelli, Sulc; Hemiptera: Triozidae) and beet leafhopper (Circulifer tenellus, Baker; Hemiptera: Cicadellidae) transmit pathogens to potato and other vegetable or seed crops each season in the northwestern United States. While the potato psyllid has been tested for pathogen occurrence for the past decade, testing of the beet leafhopper is a new endeavor and substantially increases the specimen number that must be tested by our laboratories each season. To aid in the rapid processing of individual insect specimens, we optimized and validated a new high-throughput 96-well plate nucleic acid extraction method for use in place of a standard 1.5-ml single-tube extraction method. Processing efficiency, in terms of total specimens processed over a 2-day period, improved 2.5-fold, and the cost associated with processing a single sample was nearly cut in half with this newly developed plate nucleic acid extraction method. Overall, this method has proven to be an excellent tool for the rapid testing of large numbers of small, individual insect vectors to enable timely dissemination of data on pathogen prevalence to growers.

Potential distribution and spread of Japanese beetle in Washington State.

The Japanese beetle, Popillia japonica (Newman, 1841) (Coleoptera: Scarabaeidae), was first detected in southern Washington State in 2020. Widespread trapping efforts ensued, and over 23,000 individuals were collected in both 2021 and 2022 in this region known for specialty crop production. The invasion of Japanese beetle is of major concern as it feeds on over 300 plant species and has shown an ability to spread across landscapes. Here, we created a habitat suitability model for Japanese beetle in Washington and used dispersal models to forecast invasion scenarios. Our models predict that the area of current establishment occurs in a region with highly suitable habitat. Moreover, vast areas of habitat that are likely highly suitable for Japanese beetle occur in coastal areas of western Washington, with medium to highly suitable habitat in central and eastern Washington. Dispersal models suggested that the beetle could spread throughout Washington within 20 years without management, which justifies quarantine and eradication measures. Timely map-based predictions can be useful tools to guide management of invasive species while also increasing citizen engagement to invaders.

Integrating Community Ecology into Models of Vector-Borne Virus Transmission.

Vector-borne plant viruses are a diverse and dynamic threat to agriculture with hundreds of economically damaging viruses and insect vector species. Mathematical models have greatly increased our understanding of how alterations of vector life history and host-vector-pathogen interactions can affect virus transmission. However, insect vectors also interact with species such as predators and competitors in food webs, and these interactions affect vector population size and behaviors in ways that mediate virus transmission. Studies assessing how species' interactions affect vector-borne pathogen transmission are limited in both number and scale, hampering the development of models that appropriately capture community-level effects on virus prevalence. Here, we review vector traits and community factors that affect virus transmission, explore the existing models of vector-borne virus transmission and areas where the principles of community ecology could improve the models and management, and finally evaluate virus transmission in agricultural systems. We conclude that models have expanded our understanding of disease dynamics through simulations of transmission but are limited in their ability to reflect the complexity of ecological interactions in real systems. We also document a need for experiments in agroecosystems, where the high availability of historical and remote-sensing data could serve to validate and improve vector-borne virus transmission models.

Drought stress affects interactions between potato plants, psyllid vectors, and a bacterial pathogen.

Transmission of insect-borne pathogens is mediated by interactions between insects and plants across variable environments. Water stress, for example, affects the physiology, defense, chemistry, and nutritional balance of plants in ways that alter their tolerance to herbivores and pathogens. However, few studies have explored interactions between water stress and insect-borne pathogens as well as the molecular mechanisms mediating these interactions. Here, we address these knowledge gaps by assessing effects of plant water stress on the transmission of a bacterial pathogen, Candidatus Liberibacter solanacearum (CLs), by the vector Bactericera cockerelli Sulc (potato psyllid). We hypothesized that plant water stress would promote pathogen transmission by inducing plant gene transcripts and phytohormones involved in defense. Our results showed water stress was associated with decreased CLs titer with two psyllid haplotypes. Our analysis of plant gene transcripts suggested water stress affected phytohormone pathways in ways that altered plant tolerance to the CLs pathogen. Our study shows that abiotic stressors like drought may mediate the spread of plant pathogens by altering plant signaling pathways in ways that affect pathogen transmission.

Alternative prey mediate intraguild predation in the open field.

BACKGROUND: Generalist predators that kill and eat other natural enemies can weaken biological control. However, pest suppression can be disrupted even if actual intraguild predation is infrequent, if predators reduce their foraging to lower their risk of being killed. In turn, predator-predator interference might be frequent when few other prey are available, but less common when herbivorous and detritus-feeding prey are plentiful. We used molecular gut-content analysis to track consumption of the predatory bug Geocoris sp. by the larger intraguild predator Nabis sp., in organic and conventional potato (Solanum tuberosum) fields. RESULTS: We found that higher densities of both aphids and thrips, two common herbivores, correlated with higher probability of detecting intraguild predation. Perhaps, Nabis foraging for these herbivores also encountered and ate more Geocoris. Surprisingly, likelihood of intraguild predation was not strongly linked to densities of either Nabis or Geocoris, or farming system, suggesting a greater importance for prey than predator community structure. Intriguingly, we found evidence that Geocoris fed more often on the detritus-feeding fly Scaptomyza pallida with increasing predator evenness. This would be consistent with Geocoris shifting to greater foraging on the ground, where S. pallida would be relatively abundant, in the face of greater risk of intraguild predation. CONCLUSION: Overall, our findings suggest that while herbivorous prey may heighten intraguild predation of Geocoris in the foliage, detritivores might support a shift to safer foraging on the ground. This provides further evidence that prey abundance and diversity can act to either heighten or relax predator-predator interference, depending on prey species identity and predator behavior. © 2022 Society of Chemical Industry.

Alternative prey and farming system mediate predation of Colorado potato beetles by generalists.

BACKGROUND: Biological control by generalist predators can be mediated by the abundance and biodiversity of alternative prey. When alternative prey draw predator attacks away from the control target, they can weaken pest suppression. In other cases, a diverse prey base can promote predator abundance and biodiversity, reduce predator-predator interference, and benefit biocontrol. Here, we used molecular gut-content analysis to assess how community composition altered predation of Colorado potato beetle (Leptinotarsa decemlineata (Say)) by Nabis sp. and Geocoris sp. Predators were collected from organic or conventional potato (Solanum tuberosum L.) fields, encouraging differences in arthropod community composition. RESULTS: In organic fields, Nabis predation of potato beetles decreased with increasing arthropod richness and predator abundance. This is consistent with Nabis predators switching to other prey species when available and with growing predator-predator interference. In conventional fields these patterns were reversed, however, with potato beetle predation by Nabis increasing with greater arthropod richness and predator abundance. For Geocoris, Colorado potato beetle predation was more frequent in organic than in conventional fields. However, Geocoris predation of beetles was less frequent in fields with higher abundance of the detritus-feeding fly Scaptomyza pallida Zetterstedt, or of all arthropods, consistent with predators choosing other prey when available. CONCLUSION: Alternative prey generally dampened predation of potato beetles, suggesting these pests were less-preferred prey. Nabis and Geocoris differed in which alternative prey were most disruptive to feeding on potato beetles, and in the effects of farm management on predation, consistent with the two predator species occupying complementary feeding niches. © 2021 Society of Chemical Industry.

Factors affecting virus prevalence in honey bees in the Pacific-Northwest, USA.

Global efforts to assess honey bee health show viruses are major stressors that undermine colony performance. Identifying factors that affect virus incidence, such as management practices and landscape context, could aid in slowing virus transmission. Here we surveyed viruses in honey bees from 86 sites in the Pacific Northwest, USA, and tested effects of regional bee density, movement associated with commercial pollination, julian date, and hive management on virus prevalence. We also explored patterns of virus co-occurrence and spatial autocorrelation to identify whether local transmission was a primary driver of pathogen distribution. Our surveys found widespread prevalence of Deformed wing virus (DWV), Sacbrood virus (SBV), and Black queen cell virus (BQCV). BQCV and SBV were most prolific in commercial apiaries, while Chronic bee paralysis virus (CPBV) was more common in hobbyist apiaries than commercial apiaries. DWV was most common in urban landscapes and was best predicted by mite prevalence and julian date, while the incidence of both SBV and BQCV were best predicted by regional apiary density. We did not find evidence of additional spatial autocorrelation for any viruses, although high co-occurrence suggests parallel transmission patterns. Our results support the importance of mite management in slowing virus spread and suggest that greater bee density increases transmission. Our study provides support that viruses are widespread in honey bees and connects known mechanisms of virus transmission to the distribution of pathogens observed across the Pacific Northwest.

Documenting pollinators, floral hosts, and plant-pollinator interactions in U.S. Pacific Northwest agroecosystems.

The abundance and diversity of pollinator populations are in global decline. Managed pollinator species, like honey bees, and wild species are key ecosystem service providers in both natural and managed agroecosystems. However, relatively few studies have exhaustively characterized pollinator populations in diverse agroecosystems over multiple years, while also thoroughly documenting plant-pollinator interactions. Yet, such studies are needed to fulfill the national pollinator protection plans that have been released by the United States and other nations. Our research is among the first studies to respond to these directives by systematically documenting bee and plant biodiversity, bee-plant interactions, and bee-mediated pollen movement in farming systems of the Pacific Northwest, USA. Our data provides insight into the processes mediating pollinator and plant community assembly, persistence, and resilience across landscapes with variable crop and landscape diversity and agroecosystem management practices. These data will also contribute to the development of a United States pollinator database, supporting the United States' plan to promote pollinators. With few publicly available data sets that systematically take account of agroecosystem practices, plant populations, and pollinators, our research will provide future users the means to conduct synesthetic studies of pollinators and ecosystem function in a period of rapid and global pollinator declines. There are no copyright or proprietary restrictions for research or teaching purposes. Usage of the data set must be cited.

Responses of pea plants to multiple antagonists are mediated by order of attack and phytohormone crosstalk.

Plants are often attacked by multiple antagonists and traits of the attacking organisms and their order of arrival onto hosts may affect plant defences. However, few studies have assessed how multiple antagonists, and varying attack order, affect plant defence or nutrition. To address this, we assessed defensive and nutritional responses of Pisum sativum plants after attack by a vector herbivore (Acrythosiphon pisum), a nonvector herbivore (Sitona lineatus), and a pathogen (Pea enation mosaic virus, PEMV). We show viruliferous A. pisum induced several antipathogen plant defence signals, but these defences were inhibited by S. lineatus feeding on peas infected with PEMV. In contrast, S. lineatus feeding induced antiherbivore defence signals, and these plant defences were enhanced by PEMV. Sitona lineatus also increased abundance of plant amino acids, but only when they attacked after viruliferous A. pisum. Our results suggest that diverse communities of biotic antagonists alter defence and nutritional traits of plants through complex pathways that depend on the identity of attackers and their order of arrival onto hosts. Moreover, we show interactions among a group of biotic stressors can vary along a spectrum from antagonism to enhancement/synergism based on the identity and order of attackers, and these interactions are mediated by a multitude of phytohormone pathways.

Responses to predation risk cues and alarm pheromones affect plant virus transmission by an aphid vector.

Herbivores assess predation risk in their environment by identifying visual, chemical, and tactile predator cues. Detection of predator cues can induce risk-avoidance behaviors in herbivores that affect feeding, dispersal, and host selection in ways that minimize mortality and reproductive costs. For herbivores that transmit plant pathogens, including many aphids, changes in herbivore behavior in response to predator cues may also affect pathogen spread. However, few studies have assessed how aphid behavioral responses to different types of predator cues affect pathogen transmission. Here, we conducted greenhouse experiments to assess whether responses of pea aphids (Acyrthosiphon pisum) to predation risk and alarm pheromone (E-ß-Farnesene), an aphid alarm signal released in response to predation risk, affected transmission of Pea enation mosaic virus (PEMV). We exposed A. pisum individuals to risk cues, and quantified viral titer in aphids and pea (Pisum sativum) host plants across several time periods. We also assessed how A. pisum responses to risk cues affected aphid nutrition, reproduction, and host selection. We show that exposure to predator cues and alarm pheromone significantly reduced PEMV acquisition and inoculation. Although vectors avoided hosts with predator cues, predator cues did not alter vector reproduction or reduce nutrient acquisition. Overall, these results suggest that non-consumptive effects of predators may indirectly decrease the spread of plant pathogens by altering vector behavior in ways that reduce vector competence and pathogen transmission efficiency.

Vector-borne plant pathogens modify top-down and bottom-up effects on insect herbivores.

Ecological theory predicts that host-plant traits affect herbivore population growth rates, which in turn modulates predator-prey interactions. However, while vector-borne plant pathogens often alter traits of both host plants and vectors, a few studies have assessed how pathogens may act as interaction modifiers within tri-trophic food webs. By applying a food web motif framework, we assessed how a vector-borne plant pathogen (Pea-enation mosaic virus, PEMV) modified both bottom-up (plant-herbivore) and top-down (predator-prey) interactions. Specifically, we assessed trophic interactions with PEMV-infectious Acyrthosiphon pisum (pea aphid) vectors compared to non-infectious aphids in a factorial experiment that manipulated predator and plant communities. We show that PEMV altered bi-trophic relationships, whereby on certain plant species, PEMV reduced vector performance but also increased their susceptibility to predators. However, on other plant species, PEMV weakened top-down control or increased vector performance. Our results suggest that vector-borne plant pathogens are important interaction modifiers for plant-herbivore-predator dynamics: host-plant response to viruses can decrease herbivore abundance by reducing herbivore performance, but also increase herbivore abundance by weakening top-down control. Broadly speaking, trophic interactions that regulate herbivore outbreaks appear to be modified for herbivores actively transmitting viruses to host plants. Consequently, management and monitoring of outbreaking herbivores should consider the infection status of focal populations.

Efficacy of Naturally Occurring and Commercial Entomopathogenic Nematodes Against Sugar Beet Wireworm (Coleoptera: Elateridae).

Wireworms are the larval stage of click beetles (Coleoptera: Elateridae), and some of their species are serious pests of many crops. In the present study, we evaluated the efficacy of naturally occurring and commercial entomopathogenic nematode species against the sugar beet wireworm, Limonius californicus (Mannerheim), in the laboratory. First, efficacies of Steinernema feltiae (Filipjev) (Rhabditida: Steinernematidae) collected from an irrigated (S. feltiae-SSK) and a dryland (S. feltiae-SSC) field and the two commercial entomopathogenic nematode species, S. carpocapsae (Weiser) (Rhabditida: Steinernematidae) and Heterorhabditis bacteriophora Poinar (Rhabditida: Heterorhabditidae), were examined. Efficacies of the two field-collected S. feltiae isolates were also compared against a commercial S. feltiae strain. In the first bioassay, S. feltiae-SSK caused 63.3% wireworm mortality, followed by 30% caused by S. carpocapsae, 23.3% by S. feltiae-SSC, and 6.7% by H.bacteriophora. In the second assay, S. feltiae-SSK killed 56.7% of the wireworms, ≈2.1- and ≈5.7-fold higher than S. feltiae-SSC and the commercial isolate, respectively.

Effects of Agronomic Practices on Lygus spp. (Hemiptera: Miridae) Population Dynamics in Quinoa.

Crop diversification often promotes farm sustainability. However, proper management of newly introduced crops is difficult when pests are unknown. Characterizing herbivore dynamics on new crops, and how they respond to agronomic factors, is crucial for integrated pest management. Here we explored factors affecting Lygus spp. (Hemiptera: Miridae) herbivores in quinoa crops of Washington State. Quinoa is a newly introduced crop for North America that has multiple varieties and a range of agronomic practices used for cultivation. Through arthropod surveys and discussions with growers, we determined that Lygus spp. was the most abundant insect herbivore and likely contributed to low quinoa yields in previous seasons. We assessed how different varieties (Pison and QQ74), irrigation regimes (present and not), and planting methods (direct-seeded and transplanted) affected Lygus population dynamics. Lygus phenology was correlated with timing of quinoa seed-set in July and August, corresponding to a period when quinoa is most susceptible to Lygus. Both irrigation and planting manipulations had significant effects on Lygus abundance. Irrigation reduced Lygus abundance compared with nonirrigated plots in 2018. Planting method had a significant effect on Lygus populations in both 2017 and 2018, but effects differed among years. Variety had a significant effect on Lygus abundance, but only in nonirrigated plots. Overall, our study shows that Lygus is a common insect herbivore in quinoa, and careful selection of variety, planting method, and irrigation regime may be key components of effective control in seasons where Lygus abundance is high.

Ants of the Palouse Prairie: diversity and species composition in an endangered grassland.

Grasslands are globally imperilled ecosystems due to widespread conversion to agriculture and there is a concerted effort to catalogue arthropod diversity in grasslands to guide conservation decisions. The Palouse Prairie is one such endangered grassland; a mid-elevation habitat found in Washington and Idaho, United States. Ants (Formicidae) are useful indicators of biodiversity and historical ecological disturbance, but there has been no structured sampling of ants in the Palouse Prairie. To fill this gap, we employed a rapid inventory sampling approach using pitfall traps to capture peak ant activity in five habitat fragments. We complemented our survey with a systemic review of field studies for the ant species found in Palouse Prairie. Our field inventory yielded 17 ant species across 10 genera and our models estimate the total ant species pool to be 27. The highest ant diversity was found in an actively-managed ecological trust in Latah County, Idaho, suggesting that restoration efforts may increase biodiversity. We also report two rarely-collected ants in the Pacific Northwest and a microgyne that may represent an undescribed species related to Brachymyrmex depilis. Our score-counting review revealed that grassland ants in Palouse Prairie have rarely been studied previously and that more ant surveys in temperate grasslands have lagged behind sampling efforts of other global biomes.

Orchard Management and Landscape Context Mediate the Pear Floral Microbiome.

Crop-associated microbiota are a key factor affecting host health and productivity. Most crops are grown within heterogeneous landscapes, and interactions between management practices and landscape context often affect plant and animal biodiversity in agroecosystems. However, whether these same factors typically affect crop-associated microbiota is less clear. Here, we assessed whether orchard management strategies and landscape context affected bacterial and fungal communities in pear (Pyrus communis) flowers. We found that bacteria and fungi responded differently to management schemes. Organically certified orchards had higher fungal diversity in flowers than conventional or bio-based integrated pest management (IPM) orchards, but organic orchards had the lowest bacterial diversity. Orchard management scheme also best predicted the distribution of several important bacterial and fungal genera that either cause or suppress disease; organic and bio-based IPM best explained the distributions of bacterial and fungal genera, respectively. Moreover, patterns of bacterial and fungal diversity were affected by interactions between management, landscape context, and climate. When examining the similarity of bacterial and fungal communities across sites, both abundance- and taxon-related turnovers were mediated primarily by orchard management scheme and landscape context and, specifically, the amount of land in cultivation. Our study reveals local- and landscape-level drivers of floral microbiome structure in a major fruit crop, providing insights that can inform microbiome management to promote host health and high-yielding quality fruit. IMPORTANCE Proper crop management during bloom is essential for producing disease-free tree fruit. Tree fruits are often grown in heterogeneous landscapes; however, few studies have assessed whether landscape context and crop management affect the floral microbiome, which plays a critical role in shaping plant health and disease tolerance. Such work is key for identification of tactics and/or contexts where beneficial microbes proliferate and pathogenic microbes are limited. Here, we characterize the floral microbiome of pear crops in Washington State, where major production occurs in intermountain valleys and basins with variable elevation and microclimates. Our results show that both local-level (crop management) and landscape-level (habitat types and climate) factors affect floral microbiota but in disparate ways for each kingdom. More broadly, these findings can potentially inform microbiome management in orchards for promotion of host health and high-quality yields.

Primacy of plants in driving the response of arthropod communities to drought.

Drought threatens arthropod communities worldwide. Water limitation affects the quantity and quality of plants available to herbivores as food, and can also affect higher trophic-level consumers through variability in prey quality and reduced availability of suitable habitats. Our study assessed the response of an arthropod community to water limited wheat (Triticum aestivum L.) in a field setting. We used rainout shelters to exclude precipitation, irrigated raised bed plots to create three levels of water availability, and monitored arthropod community development over 8 weeks. First, we compared arthropod communities in habitats with different levels of water limitation and found that community composition was reliant on the magnitude of the water stress. This difference was largely due to the loss of piercing-sucking herbivores and predators in high-stress environments. Next, we focused on aphids and their natural enemies to investigate the underlying mechanisms driving community responses using structural equation modeling (SEM). Aphid abundance was negatively affected by water limitation, and this response was primarily associated with stress-induced plant physiological changes and not plant biomass or natural enemy abundance. Natural enemy abundance was also reduced in water-limited habitats, but natural enemies responded to plant biomass and not prey availability. These effects were exacerbated as water stress increased. The absence of natural enemy effects on aphids indicates that top-down predation effects were dampened by strong bottom-up effects of plant water limitation. This study revealed the importance of considering water stress intensity when predicting outcomes of droughts for arthropod communities.

Insect alarm pheromones in response to predators: Ecological trade-offs and molecular mechanisms.

Insect alarm pheromones are chemical substances that are synthesized and released in response to predators to reduce predation risk. Alarm pheromones can also be perceived by predators, who take advantage of alarm cues to locate prey. While selection favors evolution of alarm pheromone signals that are not easily detectable by predators, predator evolution selects for better prey detection ability. Here, we review the diversity of alarm signals, and consider the behavioral and ecological conditions under which they have evolved. We show that components of alarm pheromones are similar across many insects, although aphids exhibit different behavioral responses to alarm cues compared to social insects. The effects of alarm pheromones on prey behavior depend on factors such as the concentration of pheromones and the density of conspecifics. We also discuss the molecular mechanisms of alarm pheromone perception underlying the evolutionary arms race between predators and prey, and the function of olfactory proteins and receptors in particular. Our review provides a novel synthesis of the diversity and function of insect alarm pheromones, while suggesting avenues that might better allow researchers to exploit population-level responses to alarm signaling for the sustainable management of pests and vector-borne pathogens.