Arthropod-Plant Interactions最新文献

The Canadian Prairies are one of the major agricultural regions of the world in terms of cereal, oilseed and pulse crop production. With few exceptions, major insect pests like grasshoppers, flea beetles, Lygus bugs, wireworms and pea leaf weevils are controlled with insecticides. Wheat stem sawfly is managed through host plant resistance and endemic natural enemies, whereas cereal leaf beetle is managed through classical biological control. Large farms and short growing seasons in the region present logistical challenges to adopt time intensive pest management systems such as trap crops. Therefore, there is no adoption of trap crops even though some research has demonstrated their potential. In this article we present a brief overview of the pest status and management, and we summarize research on trap crops in the Prairies Ecozone and adjacent ecoregions. We conclude the review with some innovative research ideas to make trap cropping a more appealing pest management system in our quest to reduce dependency on chemical insecticides and increase the environmental resilience of Canadian agroecosystems.

Trap cropping has long been an important component of integrated pest management schemes in agricultural ecosystems. Spatial dispersion and the strength of attraction of trap crops relative to principal crops, along with insect movement behavior, may all moderate the efficacy of trap cropping in controlling pests. Here we employ a simple differential-equation patch model to explore the interplay of trap cropping and biological control. In particular, we vary attraction strength to trap crops along with predator foraging behavior (mobility and directedness) to determine the relative influences of these factors on herbivore suppression. Our results highlight the fact pest suppression is mediated by the relative palatability of trap crops to both pests and predators, and somewhat mediated by the spatial dispersion of trap crops. We discuss the potential for using trap crops in combination with natural enemies to boost pest suppression in annual cropping systems.

Trap crops and entomopathogenic fungi can provide partial solutions for integrated pest management, by attracting and killing insect pests, respectively, but both solutions have some limitations restricting their practical field applications. Both solutions have been tested against a major soil-borne pest of brassicaceous vegetables, the cabbage root fly Delia radicum. Chinese cabbage is very attractive to this pest, but it is also a high-quality host plant for developing larvae of D. radicum, which limits the application as a trap crop in the field. The entomopathogenic fungus Metarhizium brunneum can infect D. radicum larvae in the soil, but M. brunneum has not proved to be sufficiently effective in reducing damages caused by cabbage root fly. In the present work, we evaluated whether the entomopathogenic fungus M. brunneum can be used to regulate D. radicum populations together with trap crops by inoculating Chinese cabbage and broccoli plants at sowing with M. brunneum colonized rice grains before transplantation of small plants to field soil. The evaluation was performed under natural fly infestation. In both plant treatments, D. radicum infestations were high with no or only moderate effect of the fungus inoculation on the number of larvae and pupae recorded, despite evidence of successful fungal infections. On broccoli plants, our results clearly demonstrated that the M. brunneum application was inefficient in reducing number of D. radicum stages in the soil and resulting plant mortality. However, in the trap crop, Chinese cabbage, M. brunneum inoculation reduced the number of D. radicum imagos emerging from the plants by 36%. Hence, the strategy is likely to have effects on the next D. radicum generation. This result is the first to indicate complementarity between the ‘attract’ and ‘kill’ strategies to control pest development inside a favorable trap crop and prevent future pest population outbreaks. Also, from both plant inoculation treatments, some emerging D. radicum imagos developed M. brunneum infection, which may assist the transmission of the entomopathogenic fungus among adult populations.

Grain legumes, such as faba bean (Vicia faba L.), are crucial for protein supply and soil fertility enhancement through nitrogen fixation. However, faba bean cultivation is challenged by Lygus plant bugs (Hemiptera: Miridae), which cause significant crop damage and seed quality loss. This study aimed to evaluate Lygus preferences between faba bean and alternative crops to develop effective management strategies. We conducted choice bioassay experiments under laboratory conditions and field plot experiments. Laboratory results indicated sex-based host preferences, with males favoring faba beans and females preferring canola. Field studies showed that faba beans adjacent to canola had higher Lygus abundance and damage compared to those next to peas, flax, and safflower. Safflower and sunflower demonstrated potential as trap crops to reduce Lygus damage to faba beans. Our findings provide insights into Lygus behavior and suggest that a combination of trap cropping, and targeted insecticide use could mitigate the impact of Lygus infestations on faba bean cultivation.

Bee species interact differently with flowers, playing different roles in pollination. For gynodioecious plant populations, which consist of two sexes (female-non-pollen-producing flowers and hermaphroditic flowers), bee–flower interactions also have ecological implications, including the maintenance of females. We evaluated bee performance on a gynodioecious globose cactus, Coryphantha elephantidens, to determine how bees interact with different sexes and if they visit and pollinate them differently. We recorded videos of visits to both hermaphroditic and female flowers (n = 26 flowers of each sex). From these videos, we registered and analyzed bee visitation rate, handling time, and behavior using non-parametric models, generalized linear models, and chi-squared tests. Our findings revealed 15 species of visiting bees, with the most frequent being Augochlorines (59%), Ashmeadiella opuntiae (21%), and Apis mellifera (13%). Augochlorines were focused on collecting pollen and rarely touched stigmas, while A. mellifera promoted self-pollination, as they contacted stigmas after contacting the stamens. The solitary bee A. opuntiae emerged as the most effective pollinator, promoting cross-pollination by visiting both sexes with equal frequency. Since both sexes of C. elephantidens lack nectar and female flowers lack pollen, we suggest that female flowers are pollinated by deceit. This cactus species exhibits functional specialization, as only three bee species significantly contribute to pollination. Although the other remaining bees are not effective pollinators, their presence suggests this cactus is an important host for a wide variety of wild bees.

Arthropods are crucial for sustaining global cacao cultivation, contributing to diverse ecological functions within the cacao agroecosystem. Despite their importance, there’s a lack of comprehensive documentation on factors influencing arthropod presence, ecosystem services, impact, management, and conservation across cacao cultivation systems. To bridge this gap, our study aimed to consolidate existing knowledge by systematically mapping global scientific articles on arthropods associated with cacao cultivation. Using advanced text mining and structural topic modeling, we identified eight thematic categories in 552 articles, with 69.6% published between 2000 and 2023. Geographically, studies were concentrated in America (38.2%), Africa (34.6%), and Asia (20.8%). Publications showed a surge across most topics, providing updated insights into their distribution. Research in America focused on beetles, parasitoid hymenopterans, ants, pollinating dipterans, and arachnids. Conversely, substantial publications addressed pest arthropods, including hemipterans in Africa, the Cocoa Pod Borer in Asia, and other pests in America and Africa. Through our systematic analysis, we uncovered key topics shedding light on arthropod biology and ecological interactions, highlighting the importance of agroforestry systems for conserving diversity and promoting ecosystem services like pollination and biological control. The study outlines research trends and gaps within each topic, serving as a valuable resource for professionals and policymakers, facilitating further investigations into arthropods in the cacao agroecosystem.

Many Loasaceae are characterized by specialized androecium composed of complex nectar scales and bundles of fertile stamens that present pollen through one-by-one stamen movements to the flower center over several days. It is a challenge for pollen-seeking bees to predict when the small pollen packets will be presented during the days-long staminate phase. Narrow interactions with oligolectic bee pollinators that exhibit specialized pollen foraging are characteristic for flowers of Loasoideae. We investigated the pollination system of Blumenbachia catharinensis, an endemic to the Araucaria Forest of Brazil, with a specific focus on the role of the newly described oligolectic bee Rhophitulus ater (Andrenidae). We described the pollen presentation characteristics of B. catharinensis, analyzed the foraging strategy of R. ater and its role as pollinator and determined which bee species obtains the most pollen. Females of R. ater were the dominant flower visitors (> 90% of visits) and the first to remove the pollen from > 95% of the anthers, thus gaining almost the entire pollen content of B. catharinensis flowers. During foraging flights, females always approached and hovered at a short distance in front of flowers. After ~ 80% of floral approaches, they rejected visits, particularly when no pollen-carrying anther was available. Thus, this floral inspection is a constant behavioral trait of the pollen foraging strategy of R. ater. Curiously, in more than half of the visits to pistillate-phase flowers, females actively collected the deposited allochthonous pollen present on stigma and style. Therefore, they are both pollinators and antagonistic pollen thieves for B. catharinensis.

Euborellia annulipes, a nocturnal predatory earwig, has been found in association to fallen Myrtaceae fruits infested with fruit-fly larvae (Diptera: Tephritidae). Additionally, these fruits seem to serve as shelter for the earwigs, which deposit their eggs inside. Considering the importance of plant chemicals as cues for insects in their search for both prey and shelter, we hypothesized that volatiles from guava fruit (Psidium guajava) play these roles for the earwig E. annulipes. First, in arena tests, we investigated the role of guava fruits as shelters to earwigs by examining their preference for mechanically perforated guava fruits (MPF) or artificial fruits made from plastic (AF), as well as for MPF versus fruits infested with Ceratitis capitata larvae (IF), over a time course. Subsequently, we evaluated the earwigs’ attraction and preference for volatiles emitted from uninfested guavas (UF), MPF, or IF. The results of the arena tests showed that the earwigs preferred MPF over AF to shelter, but had no preference between MPF and IF up to 33 h; however, from 45 h after release, more females sheltered in MPF. The olfactory tests showed that the female earwigs recognized volatiles from MPF and IF, but preferred volatiles emitted by IF over those emitted by UF or MPF. Thus, our results suggest that females of E. annulipes use volatile chemical cues to locate guava fruits, which serve as shelter, and that despite being initially attracted by the odors of fruit-fly-infested guava fruits, they prefer to shelter in uninfested fruits after predation.

Co-flowering congeneric plant species may either experience competition for the services of shared pollinators or facilitation when together, they attract a higher number and diversity of pollinators. In this study, we evaluate whether temporal segregation in flowering time and temporal partition of shared pollinators operate among sympatric Anthurium species as mechanisms to reduce competition to attract potential pollinators. We investigated flowering phenology, the intra-e interspecific synchrony, and the composition of the flower visitor community of seven coexisting Anthurium species biweekly for a whole year in Native and Pine forests. We also analyzed the structure of Anthurium -flower visitor networks and the functional role of species. Flowering was continuous thorough the year for most Anthurium species, but their flowering peaks were segregated significantly in time. Although the flowering periods of these species overlapped, flower visitor communities were very dissimilar among Anthurium species, sharing only a tiny fraction of insects that function as connectors among species in the network. The partition of potential pollinators in a fine temporal scale occurred through the rewiring of shared flower visitors to the most abundant flowering Anthurium species. On the other hand, a high number of inflorescences attracted larger abundance and richness of insect visitors. Facilitation occurred almost throughout the year, while competition occurred during the flowering peak, where a particular species was the best competitor increasing the constancy of pollinators. This study highlights the role of facilitation and competition as mechanisms that together shape the use of potential pollinator resources between sympatric congeneric plant species.