Arthropod-Plant Interactions最新文献

Climate change is a threat to agriculture and humankind. Sustainable cropping systems can enhance the resistance of crops against extreme weather events. The effects of drought stress on flower traits of insect-pollinated crops grown in sole stands and intercrops have rarely been studied, though. In this field study, we investigated how drought stress alters plant and flower traits of faba beans and the resulting pollinator behavior in faba bean sole crops and in faba bean–wheat intercrops. Plant height was reduced by drought stress and in intercrops (vs. sole crops). The number of open flowers per plant was unaffected by drought stress but reduced in intercrops. Drought stress increased the nectar sugar concentration but did not alter nectar volume and pollen production. Faba beans grown in intercrops produced higher nectar, sugar, and pollen grain amounts compared to sole crops. Drought stress effects on plant and flower traits were not affected by intercropping. Drought stress reduced the plant and flower visitation frequency by bumblebees. Although intercropping plots were visited less frequently, the individual flowers were visited more frequently than flowers in sole crops. The bumblebees’ nectar robbing activity increased with plant height and flower sugar amount. Our study shows that drought stress reduces crop plant growth and reduces pollinator visitation to crop flowers. Faba bean flowers in intercrops seem to be more attractive to bumblebees than flowers in sole crops, potentially enhancing pollination. The potential of intercropping should further be investigated in terms of mitigating detrimental effects of climate change on crop plants.

The predatory ring-legged earwig, Euborellia annulipes (Lucas, 1847) (Dermaptera: Anisolabididae), exhibits omnivorous feeding habits, enabling it to incorporate non-prey items into its diet. This behavior is thought to offer additional needed benefits from the occasional consumption of plant material. This study examined the hypothesis that herbivory of E. annulipes on various species of cultivated Brassica has a positive effect on its biological traits and is influenced by the availability of essential food sources. The provisioned plant material (pieces of leaf) consisted of the following Brassica species: pak choi cabbage, Portuguese cabbage, cabbage, and radish did not improve the biological performance of the earwig when compared to a diet without plant material. Nevertheless, 66.0% of the second instar nymphs developed successfully when fed only pak choi cabbage, and 43.3% did so when fed solely on Portuguese cabbage. Herbivory by E. annulipes on brassicas occurred in the presence and absence of a diet, although it was significantly more pronounced when no other food sources were available. Among the four Brassica species studied, pak choi cabbage exhibited the highest feeding frequency and consumption rate. Additionally, pak choi cabbage grown under controlled conditions and exposed to routine releases of earwigs showed no reduction in productivity. These findings indicate that E. annulipes can consume brassica leaves, demonstrating species-specific variations in this consumption. However, conditions of food scarcity lead to increased consumption of plant material, while repeated releases of earwigs do not affect the growth and yield of pak choi cabbage plants.

In tomato production, yield reduction is often caused by both abiotic and biotic stresses, particularly the threat of herbivorous insects. However, tomato trichomes and secondary metabolites play a crucial role in the resistance of tomatoes against external threats. This study aimed to assess the effect of agricultural practices on the development of trichomes and their importance in the defense of tomato plants against insect herbivores, specifically the pest Zonocerus variegatus. A survey was conducted in two major tomato production areas in Southern Benin, presenting different agricultural practices that could influence the development of trichomes. Samples from 200 tomato plants were collected from various tomato fields and trichomes on leaf and stem samples were counted using an optical microscope. Additionally, to understand the responses of specific tomato varieties to attacks by insect herbivores, experiments were conducted on the varieties Akikon, Tounvi, and Thorgal cultivated in pots and then subjected to biotic stress by Z. variegatus, with both control and experimental batches. Three weeks later, leaf and stem samples were taken and the trichomes were observed and also counted. Subsequently, phytochemical screenings and quantification of secondary metabolites were performed on the experimental and control plants. Structural Equation Models analysis revealed a significant positive effect of cropping systems and fertilization methods on trichome density, but a significant negative effect of soil type and biopesticide use. The experiment results showed an increase in trichome density in response to pest attacks. Phytochemical screenings revealed considerable production of polyphenols and flavonoids in all three varieties. The rate of insect damage was highest in the Tounvi tomato variety, followed by the Akikon variety and finally the Thorgal variety which released more flavonoids and polyphenols. These findings underscore the vital function of trichomes in protecting tomato plants against herbivore insects. This study provides a theoretical and practical basis for advancing and integrating the roles of trichomes in controlling insect herbivores and improve tomato production.

Floral traits can influence sex reproduction and population persistence in non-native areas like in crop systems. Lagenaria siceraia, native to Africa and cultivated globally for its economic and cultural significance, attracts diverse floral visitors. Through analyses of floral biology, reproductive traits, nectar dynamics, and pollinator records, this study aimed to characterize the pollination ecology of this species in a crop field in Southern Brazil. Nectar is produced only by staminate flowers and is available throughout anthesis. The main floral visitors included hawkmoths, bees, and hummingbirds. Of the total visits, 43% occurred at night by three sphingid species. We recorded a higher visitor preference for staminate flowers, and this result indicates that unrewarding pistillate flowers mimic rewarding staminate flowers. Despite the abundance of diurnal flower visits, fruits could be produced only from nocturnal visits, corroborating the role of hawkmoths in pollination of L. siceraria. However, significant pollen limitation was observed in the studied population. The species maintains a specialized pollination niche in cultivated areas outside its natural range.

Pinguicula (Lentibulariaceae) is the most diverse genus of carnivorous plants in Mexico; however, prey capture patterns of most of its species remain unexplored. Here, we analyzed the spatial and temporal variation in prey capture across four populations of Pinguicula crenatiloba, one of the smallest species in the genus. A total of 122 fully developed individuals were sampled and examined for prey items during November 2022 and 2023. Despite its minute size (5–10 mm rosette diameter), P. crenatiloba captures a number of prey comparable to that of larger congeneric species. We recorded a total of 744 prey specimens representing eight arthropod taxa, with Collembola and Acari as the most abundant prey across populations and years. Prey number and composition differed significantly among populations and years. Despite overall compositional overlap, prey assemblages differed across populations and years. Diversity estimates based on Hill numbers showed significant variation, reflecting differences in both prey richness and dominance. Our findings suggest that prey capture in P. crenatiloba is influenced by both environmental factors and morphological constraints, with interannual variation in rainfall and temperature potentially affecting prey retention. This is the first study to document prey capture in P. crenatiloba, and one of the few to explore spatio-temporal variation in the feeding ecology of Mexican carnivorous plants.

Ant-plant interactions are diverse and complex, with their effects on plants largely determined by the species involved and the ecological context. Most ants are omnivorous, preying on arthropods (e.g., pests) for protein, while deriving carbohydrates from plant-based sources and honeydew from hemipterans. Ants can benefit plants by preying on pests, but when they interact with honeydew-producing pests and start to defend these pests (e.g., attacking natural enemies), ants may become detrimental. In this study, we investigated the role of ants as predators in erva-mate, a key crop in Southern Brazil, and studied how fruit presence and the honeydew-producing pest Gyropsylla spegazziniana, influenced ant densities and predation. Using sticky barriers to exclude ants and termites as prey models, we found that termite survival was significantly lower in branches with ants, suggesting an important role of ants as predators in erva-mate plants. Plants infested by G. spegazziniana and plants containing fruits, exhibited higher ant densities. Additionally, survival of termites was significantly lower in plants with the pest. As no evidence for ant predation on G. spegazziniana was observed, we suggest that ants visit colonies of G. spegazziniana on erva-mate plants to collect honeydew, and in doing so, they prey more aggressively on termites and possibly other arthropods that either, compete for honeydew or threaten G. spegazziniana. Despite our study was conducted in a single erva-mate plantation, the observed ant—G. spegazziniana interactions revel clear ecological and potential biocontrol implications for erva-mate cultivation.

Mustard aphid, Lipaphis erysimi (Kaltenbach), is a major pest of Brassica juncea (L.) Czern. & Coss, causing significant losses to seed yield and quality. Plant-aphid interactions are influenced by various plant defense enzymes, which play a crucial role in defending the host plant against biotic stresses. The study assessed constitutive and aphid-induced enzymatic variation in 30 B. juncea genotypes, and their effect on the host preference and developmental biology of L. erysimi. Significant variations were observed in the host preference and biological parameters of L. erysimi across different plant parts of B. juncea genotypes. The activity of plant defense enzymes was significantly higher in healthy and L. erysimi-infested plant parts of B. juncea genotypes viz., RBJ 49, Pusa 119-1-2, GP 454, TS 18–5124, and NPJ 50. Elevated levels of ascorbate oxidase and ascorbate peroxidase activities in healthy and L. erysimi-infested buds of B. juncea genotypes were negatively associated with aphid survival, while both enzymes showed a positive correlation with the percentage of nymphs recovered. Conversely, higher catalase and myrosinase activities in buds were positively associated with nymph recovery and fecundity, respectively. In siliquae, ascorbate oxidase activity was negatively correlated with fecundity, which exhibited adverse effect on the developmental biology and reproductive performance of L. erysimi. Genotypes such as RBJ 11, RBJ 77, and RBJ 49 demonstrated a balanced defensive response; PDZ 6, Pusa 119-1-3, and PM 26 exhibited a strong multilayered defense; EC 62-46-1, Pusa 119-1-2, and Pusa Tarak exhibited elevated catalase activity. These findings underscore the complex interactions between plant defense enzymes and aphid development, highlighting the critical role of ascorbate oxidase, ascorbate peroxidase, catalase and myrosinase, in modulating aphid survival and reproduction. Aforesaid genotypes hold significant potential for use in Brassica breeding program aimed at developing aphid-resistant varieties of Indian mustard.

Among the various plant–animal antagonistic interactions, florivory stands out due to its numerous direct and indirect negative effects on plant reproduction. However, some interfaces of this relationship are still poorly understood, especially which floral traits of certain species are affected by florivory. This study aimed to delimit the florivore guild of Senna aversiflora (Herb.) H. S. Irwin & Barneby and examine the natural patterns of florivory and the possible floral traits that influence florivory in the species. We evaluated seventeen flowering individuals of S. aversiflora, considering the floral development stage, floral display, and floral whorls, besides the corolla size. Florivorous organisms included individuals of the orders Coleoptera, Hymenoptera, Blattodea, Lepidoptera, and Hemiptera. Floral display positively affected the number of flowers and buds damaged by florivory. On the other hand, florivores showed no preference for a particular floral development stage. The gynoecium was the least consumed whorl. In the corolla, damage was caused continuously and discontinuously at the base and apex of the petals. Corolla size had no relation with the proportions of florivory in the whorls, the locations of the damage in the petals, forms of florivory, and the amount of tissue consumed in the petals. We conclude that some traits such as floral development stage and corolla size do not determine florivory in S. aversiflora, but floral display and floral whorls were traits that responded to the pressure by florivores on S. aversiflora and allowed us to gather relevant information about the ecological relationship between this species and its florivores.

The mirid bug Helopeltis bakeri Poppius feeds on a wide range of host plants including economically important crops, like cocoa (Theobroma cacao) and sweetpotato (Ipomea batatas), yet little is known about its complex interactions with its host plants. Here, we assessed the response of sweetpotato to feeding by H. bakeri. Headspace volatiles from healthy and infested sweetpotato cuttings were collected and compared. Feeding resulted in the production of a new headspace constituent, the terpene squalene, and an increase in the emission of other volatiles, including several terpenes and terpenoids and a green leaf volatile [(Z)-3-hexenyl acetate]. Electroantennographic and behavioral analyses confirmed that squalene is not electrophysiologically and behaviorally active toward H. bakeri, which suggests that squalene might have other ecological functions. The results provide important baseline information on the interactions of H. bakeri with its host plant, but the role of these volatile compounds in multitrophic interactions cannot be assessed yet since the natural enemies (e.g., parasitoids) of H. bakeri have not yet been identified.

Graphical Abstract

Adaptation to siliceous versus carbonate substrates is thought to be an important driver of speciation in the alpine flora. The role of the pollination system in the formation and maintenance of such species is presently unclear. Here, we chose three species pairs in the genera Gentiana, Primula, and Rhododendron which often occur in geographic proximity or even sympatry to study the existence of pollination barriers in these lineages. Using remote camera and direct observation approaches, scent and color analyses, we tested the hypothesis whether divergent pollinator communities exist that could help to maintain genetic separation of plant populations adapted to different soil types. We found differences in frequency, diurnal activity and to some extent also community composition of flower visitors in edaphic vicarious species pairs. Floral traits like color and scent as well as flower visitor co-distributions indicate that our study species have divergent but overlapping pollination systems. Our results do not suggest a strong reproductive barrier function of the pollination system. While adaptation to different soils still seems to be the main force keeping edaphic vicarious alpine plants genetically separated, pollinators might mediate hybridization in contact areas.