Arthropod-Plant Interactions最新文献

Plants and ants engage in diverse mutualistic interactions that contribute to their adaptive fitness. However, the presence of ants in flowers can generate conflicts between plants and pollinators. These interactions are little studied in temperate grasslands, despite the ubiquitous interactions between ants and plants in this region. In this study, we investigated how the presence and mobility of Camponotus termitarius (Emery) ants on Eryngium chamissonis Urb. affect the frequency of insect visitation on the flowers of this plant. We constructed contrasts and tested using generalized linear mixed models (I) whether the presence of any organism in the inflorescences decreases insect visitation, (II) whether it is really the presence of ants that decreases visitor interaction, and (III) whether the ant behavior has a greater effect on potentially reducing visits. We showed that the interaction of ants with E. chamissonis affected the number of visits to flowers, mainly reducing the frequency of the two main groups, bees and flies. These effects were consistent regardless of the ants' behavior, indicating that the mere presence of these insects on flowers can alter the frequencies of floral visitors. Our work is one of the first to report the effects of the interaction between ants and flowers in temperate grasslands in southern South America. The observed effects may go beyond the simple risk of predation and competition for resources, involving broader ecological implications for this ant–plant interaction, including a negative impact on the reproduction of E. chamissonis.

Plant-pollinator interactions play a vital role in the maintenance of biodiversity and ecosystem function. Geographical variation in environmental factors can influence the diversity of pollinators and thus, affect the structure of pollination networks. Given the current global climate change, understanding the variation of pollination network structure along environmental gradients is vital to predict how global change will affect the ecological interaction processes. Here, we used a global plant-pollinator interaction data collection by the same sampling method at the same period to explore the effects of elevation, latitude, and plant richness on the structure and robustness of pollination networks. We analyzed a total of 87 networks of plant-pollinator interactions on 47 sites from 14 countries. We conducted a piecewise structural equation model to examine the direct and indirect effects of elevation, latitude, and plant richness on the network robustness and analyzed the function of network structure in elucidating the relationship between robustness and these gradients. We found that plant richness had both positive effects on robustness under random and specialist-first scenarios. Elevation, latitude, and plant richness affected network connectance and modularity, and ultimately affected network robustness which were mediated by nestedness under specialist-first and random scenarios, and by connectance under the generalist-first scenario. This study reveals the indirect effects of elevation, latitude, and plant richness on pollination network robustness were mediated by nestedness or connectance depended on the order of species extinctions, implying that communities with different pollination network structures can resist different extinction scenarios.

The geographic mosaic model of plant–herbivore coevolution asserts that interactions between a plant species and an herbivore species vary in intensity among populations across the plant’s geographic range. Despite this model’s intuitive appeal, data to investigate its implications for the type of complex, multiple-herbivore communities that occur in nature are scant. This paper reports on the results of 2 years of field surveys of damage by five leaf herbivores and one stem herbivore in four Solanum carolinense (horsenettle) populations, combined with results of a common-garden study quantifying the mean resistance levels of the plants from each field against each of the six herbivores. The relative amounts of damage caused by each species (representing the “herbivore-community structure”) differed significantly among the four fields. The plants were much more heavily damaged in the 2nd year than in the first, but the herbivore-community structure remained stable within each field between years. Overall, the amount of damage by species of herbivores in a field tended to be positively correlated with the plants’ levels of resistance that were measured in the common garden (r = 0.40, P = 0.05). Specifically, for five of the six herbivores, greater damage in the field was associated with greater plant resistance. This result suggests that horsenettle’s evolution of resistance against specific herbivores can occur rather quickly within fields, creating a local-scale mosaic of populations specifically adapted to the particular structure of the herbivore community that they are facing, but that herbivore-community structure is not strongly determined by plant resistance.

The structure of the community of insect herbivores in a plant can be determined by plant traits and also by interactions with consumers. We studied the herbivores associated with the tropical plant Andira nitida (Fabaceae), aiming to understand the temporal co-occurrence of herbivore insects from different guilds. We monitored and quantified the temporal sequence of appearance and leaf consumption of three herbivore guilds (leaf miners, gall-formers and chewers) at weekly intervals for 23 weeks (between September 2021 and March 2022), testing whether functional leaf traits (leaf area, leaf dry matter content, specific leaf area and leaf age) influence herbivory incidence and intensity. Leaves of A. nitida showed simultaneous damage by miners, chewers and six gall species. We found a temporal sequence in the establishment of leaf herbivores and a preference for young leaves. However, null model analysis indicated independent patterns of association between herbivores, and there was no evidence of co-occurrence or repulsion between herbivores or herbivore guilds. We found that leaf age is a determinant functional trait for the occurrence of all guilds and types of herbivores in A. nitida. However most of the physical characteristics of the leaf did not show a clear effect on the herbivore community. We showed that interactions among herbivores partially explained the organization of herbivorous insects in A. nitida and that patterns of occurrence depend more on the life history of herbivores than on aspects associated with plant functional traits. We suggest that there is differential leaf use by herbivores in time, which leads to the formation of different pairs of co-occurring herbivores.

Pollination plays a vital role in maintaining ecological functioning of ecosystems, and bees are the main pollinating insects in natural and agricultural areas. Identification of bee food sources can be carried out directly by observing their visits to flowers, or indirectly by analyzing the pollen they carry. Pollen analysis is employed to determine the breadth of the bees’ dietary niche and understand the relationship between flower traits, pollen grains, and floral resources. While Exomalopsis females were previously recorded as pollinators of Solanaceae species, information regarding their trophic niche in agricultural areas remains limited but is essential for the management of these wild pollinators. In this study we accessed the floral resources used by two Exomalopsis species (E. analis and E. auropilosa) through pollen analysis in their scopae, using cultivated Capsicum cultivars (Solanaceae) as target plants. Pollen samples from 56 Exomalopsis females (21 from E. analis and 35 from E. auropilosa) revealed 58 pollen types belonging to 24 botanical families, with the highest values found for Fabaceae, Asteraceae, Euphorbiaceae, and Rubiaceae. E. auropilosa showed greater pollen type richness (46) with 3–10 types per bee, while E. analis had 43 types with 3–13 types per individual. Capsicum, a pollen, and nectar source constituted approximately 77% of the pollen loads. Most of other plant species identified were arboreal and provided nectar to these pollinators. Trophic niche overlap between Exomalopsis species was low. The conservation of wildflowers surrounding pepper cultivations is essential for maintaining these two important pollinators in agricultural areas. Additionally, areas with bare soil can contribute to the persistence of Exomalopsis populations.

The range of the breeding hosts of 59 species of the Lixus genus includes the plants of 11 dicot families. Host range of 22 species was identified or confirmed during original observations. Hosts of six species firstly recorded. Therefore, reliable data on the larval trophic links of Palaearctic species are summarized. The greatest numbers of species of Lixus are linked with Apiaceae (33.9%), Asteraceae (20.0%), and Amaranthaceae (18.6%). All species except L. pulverulentus are oligophagous. Each of two Lixus subgenera is associated with the sole plant family: all Callistolixus develop in Apiaceae, and Epimeces—in Asteraceae. Almost all Lixus are associated with herbaceous plants. The majority of hosts are herbs which occur in ruderal habitats. The dispersal of Lixus and their hosts are discussed and feeding specialization of Lixus and Larinus Dejean are compared as well. The synoptical list of Lixus and their breeding hosts added as an Appendix. This review summarizes more than 130 sources in the biological literature, published from the 1880s till now, which contain valid information on the host plants of the Lixus species. Some long-term field observations by the author are included as well.

Seed dispersal by ants plays a major role globally in plant dynamics for many angiosperms and can be influenced by multiple factors. One of those factors is competition between ants and other organisms for gaining access to seeds. A habitat with high abundance of potential competitors for ants is forests in marine coast ecosystem, where there is a high abundance of terrestrial crabs that functionally act as seed predators. In a coastal forest on Coiba Island, Panama, we measured seed removal rates at increasing intervals from the coast towards the interior of the forest, representing a decreasing gradient in ant–crab competition. We found that seed removal was dominated by hermit crabs near the coast, and while ants moved more seeds as the distance from the coast increased. We expect that this differential removal should generate varying levels of seed predation and seedling establishment, with crabs acting mainly as seed and seedling predators. This study provides insights into how ant–crab dynamics may play a role in maintaining the vegetation gradients in coastal ecosystems.

Spodoptera litura is a destructive lepidopteran generalist pest widespread in tropical and subtropical regions and causes huge yield loss by gregarious feeding on crop plants. During co-evolution, Zea mays (Var. African tall) has attained a well-crafted defence mechanism and can demote the performance of its invaders. When an insect feeds on a host/non-host plant, its digestive system needs to upregulate the first line of defence against a broad spectrum of antifeedants and toxins of host origin. To understand the molecular mechanisms underlying insect response to plant resistance factors, a comparative midgut transcriptome of Spodoptera litura fed on maize and control plants was investigated, which identified a total of 712 differentially expressed genes (DEGs), including 232 up-regulating and 480 down-regulating genes. Gene ontology, gene enrichment and pathway analysis revealed that upregulated genes are involved in carbohydrate metabolism, detoxification, defence, lipid metabolism, digestion, and signal transduction. In contrast, down-regulated genes were primarily linked to cytoskeleton, transport, signalling, carbohydrate and lipid metabolism, growth and developmental processes. The above results indicate an antinutritional stress on S. litura, which leads to a compensatory mechanism in the insect by enhanced digestibility and detoxification at the cost of growth and development. This study provides an overall understanding of the transcriptomic response of S. litura upon feeding on a suboptimal host. Nevertheless, our study forms the basis for future molecular studies on S. litura adaptation and may widen the scope for their management.

Myrmecochory is a common mutualism between ants and plants benefiting both partners: ants obtain a nutrient-rich food source, while plants enjoy a host of benefits ranging from enhanced dispersal to protected germination sites. However, this mutualism can be exploited by invasive myrmecochores, where native ants spread invasive plant seeds, possibly to the detriment of native plant assemblages. With the recent introduction of a potentially invasive myrmecochorous plant (Thesium ramosum) in Alberta, Canada, we tested ant interest in T. ramosum. To evaluate both general interest in T. ramosum as a food source, and preference for T. ramosum over other food sources, we collected colonies of four commonly occurring native Formica species and conducted seed removal trials and food preference trials. We then evaluated interest in and preference for T. ramosum seeds through assessing mean rate of seed removal and food item removal, total number of seeds and food items removed, and trends in seed and food item removal through time. We found that while all ant species tested showed interest in T. ramosum, interest level varied among species, and additional factors such as colony size and presence of host species in socially parasitic species influenced interest in T. ramosum. Considering native ant interest in T. ramosum as a food source, it seems plausible that Formica species may act as a dispersal vector for T. ramosum, potentially enhancing its invasiveness.

Implementation of IPM in arable crops requires affordable monitoring tools. YATLORf traps baited with a synthetic pheromone lure for a target species have proven to be effective for monitoring Europe’s most harmful soil pests: Agriotes spp. After the suitable lure position for each of the main Agriotes species was ascertained, different combinations of lures in the same trap were studied in various European countries. Trials were carried out between 2001 and 2007, with the traps being arranged in blocks. Each block contained one trap per treatment under study (i.e., traps baited with a single species lure and traps baited with combinations of two or more different species lures). Unlike most of the research outputs on sex pheromone lures (e.g., on Lepidoptera species), the results of this research have clearly shown that lures for many Agriotes species can be combined in the same trap without loss of performance against most species. Two clear exceptions were A. sputator and A. rufipalpis, which were sensitive to the presence of the geranyl octanoate in lures for other species. It was possible to multi-bait a trap, i.e., use up to four different lures (A. brevis, A. sordidus, A. litigiosus, and A. ustulatus) with good results, thus demonstrating for the first time that important soil pest species belonging to the same genus can be monitored with multi-baited sex pheromone traps. Multi-baiting the same trap resulted in significantly reduced monitoring costs.