Arthropod-Plant Interactions最新文献

We studied the vertical distribution of ant species in the rainforest of Akok, part of the “Campo Ma’an National Park”, Cameroon. We gathered entire colonies whenever possible for ground-dwelling species. Nests in the understory were collected from shrubs, mostly myrmecophytes, or by climbing the base of large trees to look for ants sheltering under their bark. We climbed trees to find nests of non-dominant species associated with epiphytes and hemi-epiphytes. For those living in the crowns of the sub-canopy, we used airborne access methods (i.e., the “canopy sledge” and “canopy raft”) also used in the upper canopy to collect samples of territorially dominant arboreal ants (TDAAs) with large colonies. Ants on a forest path were also recorded. We identified 153 ant species from eight subfamilies and 46 genera; the sampling coverage for each strata and the forest path, above 0.9, indicated high sampling completeness. A non-metric multidimensional scaling (NMDS) followed by a “complete clustering” showed that most species can be found in clusters. The upper canopy was characterized by the overwhelming presence of the TDAA Crematogaster depressa Santschi that occupied 87.65% of 170 trees and whose lack of aggressiveness was noted between workers gathered at a distance of 500 m. This species, which lives on trees several centuries old, is likely typical for this National Park known for a high level of endemism. This study, conducted in the early 1990s, provides a baseline for studying diversity changes in the future.

Insect galls represent highly specialized plant–insect interactions whose temporal dynamics are strongly influenced by environmental conditions and host plant physiology. However, the relationship between seasonal variation in gall communities and phytochemical responses of host plants remains poorly understood. This study investigated the temporal dynamics of insect gall morphotypes associated with Miconia prasina and evaluated phytochemical differences between galled and non-galled leaves in an Atlantic Forest fragment in northeastern Brazil. Sampling was conducted bimonthly between November 2022 and September 2023. Gall diversity, community composition, and their relationships with climatic variables were analyzed using ecological indices and multivariate analyses. Total phenolic compounds and alkaloids were evaluated through qualitative and quantitative phytochemical analyses. Six gall morphotypes were recorded throughout the sampling period. Gall morphotype richness remained stable, whereas community composition varied among sampling campaigns. Minimum temperature was the environmental variable most strongly associated with temporal variation in gall community composition, while precipitation showed no significant independent effect. Leaves bearing galls exhibited higher concentrations of total phenolic compounds than non-galled leaves, together with stronger qualitative reactions for alkaloids. These findings demonstrate that temporal variation in gall communities is primarily associated with minimum temperature and that gall induction is accompanied by marked changes in host plant secondary metabolism. The study contributes to a better understanding of the ecological and chemical mechanisms underlying plant–gall interactions in Atlantic Forest ecosystems.

Synopsis

This study analyzes the temporal dynamics of entomogenous galls on Miconia prasina and their association with phenolic compounds, highlighting environmental influences on plant-insect interactions in the Atlantic Forest.

Oak gall wasps (Hymenoptera: Cynipidae: Cynipini) are among the most diverse and host-specific insect groups associated with oak forests, yet patterns of their diversity and community composition in Anatolian oak ecosystems remain poorly documented. This study examined patterns of oak gall wasp diversity and community composition in pure and mixed oak forests on the northern slopes of the Sultan Mountains (Afyonkarahisar, Türkiye). A total of 40 sampling plots (400 m² each) were established between 1068 and 1951 m a.s.l. in pure and mixed oak forests dominated by Quercus cerris, Q. infectoria subsp. boissieri, and the endemic Q. vulcanica. In total, 6102 galls representing 51 gall wasp species were recorded. Species richness was similar between pure and mixed oak forests; however, Shannon and Simpson diversity indices were significantly higher in pure oak stands. Community composition also differed between forest types. Indicator species analysis identified seven species significantly associated with forest type, five with pure oak forests, and two with mixed oak forests; further indicating differences in gall wasp assemblages between the two forest types. Overall, the results indicate that differences among gall wasp communities were more evident in species composition than in local species richness or total gall abundance. These findings provide new baseline information on oak gall wasp diversity and community composition observed in pure and mixed oak forest plots in the Sultan Mountains, Türkiye.

The remarkable habits of gall-inducing insects make them valuable subjects for ecological and evolutionary research. However, comparative studies across regions are often constrained by uneven sampling efforts, both spatially and temporally. To overcome this limitation, we developed a new sampling methodology, the “Target Host Sampling Strategy” (THSS), which leverages insect-host plant associations derived from ecological networks in neighboring zoogeographical regions to guide systematic sampling in the focal areas. We validated the THSS through a case study of gall-inducing insects associated with Asteraceae in Taiwan, where species diversity has likely been underestimated due to inconsistent survey efforts. In total, we documented 53 gall morphotypes on 23 plant species, of which approximately 53% (28 morphotypes) represent new records. We identified 25 previously recorded gall morphotypes, and 64% (16 morphotypes) of them were updated with new biological information. These findings demonstrate that THSS is a powerful approach for uncovering previously overlooked gall-inducing insects, especially those forming inconspicuous galls on herbaceous hosts. Four orders of gall-inducing insects are recognized in this study, i.e., Diptera (Cecidomyiidae and Tephritidae), Hemiptera (Triozidae and Aphidoidea), Lepidoptera and Hymenoptera. To support future taxonomic and ecological studies, we also provided an updated checklist of gall morphotypes on Taiwanese Asteraceae.

Successful production of cultivated sunflower (Helianthus annuus, Asteraceae) depends on wild and managed bee pollination. Of special importance are the oligolectic bees Melissodes agilis and M. trinodis, which are among the most frequent sunflower visitors and have been shown to increase seed yield, providing significant economic benefits to sunflower production. In this study, we used pollen metabarcoding (two barcodes, ITS2 and trnL) to identify non-Helianthus plants visited by female M. agilis and M. trinodis and to determine whether pollen diversity and composition varied by year, bee species, and site. We collected pollen from 112 bees in two locations in North Dakota (agricultural and urban) during 2019 and 2020. Our results show that both species foraged mostly on sunflowers but also visit other Asteraceae and plants from other families like Fabaceae and Poaceae. ITS2 identified plants representing 36 genera and 17 families, while trnL identified 31 genera within 9 families. The two barcode regions shared 22 genera (61–71% overlap), but each recovered unique taxa, demonstrating the value of combining markers to characterize bee pollen loads. Pollen richness and diversity differed by year (ITS2 and trnL) and site (ITS2 only), but not by bee species. Pollen composition differed by year, site, and bee species for both ITS2 and trnL. Identifying the non-Helianthus floral resources used by Melissodes may help guide the management of field margins and other surrounding vegetation to support wild pollinator populations.

Land cover change and biological invasions alter pollinator communities and the distribution of floral resources, but how these changes influence specific bee–plant interactions across different landscapes and time often remains unclear. We reconstructed bee–plant interaction networks from New Zealand using 2,266 interactions extracted from digitised natural history collections and compared interaction patterns between land cover dominated by native or exotic vegetation. Native bees accounted for most recorded interactions across all land cover types. Bee and plant biostatus showed strong non-random associations, with native bees interacting mainly with native plants and exotic bees interacting more frequently with exotic plants. Network-level specialisation was moderate and varied little among land cover types (H2′ = 0.63–0.68), although species-level specialisation differed substantially among bee species. Preference indices showed that most native bee species exhibited neutral or negative preferences for exotic plants, whereas several exotic bee species preferentially visited exotic plants. Temporal analyses further showed that native bees increasingly incorporated exotic plants into their interactions through time, while exotic bees showed increased use of native plants. Our results suggest that changes to land cover influences bee–plant interaction patterns while native and exotic bees differ in their use of floral resources.

Plant-pollinator interactions are shaped not only by environmental conditions but also by biotic interactions such as predation. Predators influence prey through direct consumption and non-consumptive effects (NCEs) arising from perceived predation risk altering prey traits such as foraging behaviour. Emergent freshwater macrophytes such as the yellow water lily (Nuphar lutea) create a shared interface where predators and pollinators co-occur. Yet, NCEs of predation risk on pollinators and their consequences for plant-pollinator interactions remain severely understudied, especially at aquatic-terrestrial transition zones. Therefore, we experimentally tested how artificial dragonflies, as standardised visual predation cues, shape the foraging behaviour of pollinators on N. lutea and assessed whether these behaviours were related to natural variation in odonate abundance. We quantified visitation rates and visit durations under artificial dragonfly, neutral object, and control treatments, and related visit duration to natural odonate abundance. Our results showed that artificial dragonfly-like cues reduced visitation rates by up to 50% and visit durations by up to 18 s per visit, across pollinator taxa. Moreover, visit duration showed a negative association with natural odonate abundance. Structural equation models revealed that pollinator behaviour was indirectly associated with environmental conditions (i.e., wind and overcast weather) via their negative effects on odonate abundance. Consequently, our findings demonstrate that predator-mediated NCEs can play a substantial role in shaping pollinator foraging on N. lutea, highlighting that plant-pollinator interactions at freshwater-land ecotones may depend on dynamic predation risks and underlying environmental drivers. These insights are particularly important for understanding macrophyte-insect interactions because communities at aquatic-terrestrial interfaces are especially vulnerable to shifts in environmental conditions on land and water.

Bumble bees are important pollinators of wild and crop plants, among them the Styrian oil pumpkin (Cucurbita pepo subsp. pepo var. styriaca Greb.). The flowers of this economically important crop species release strong scents, dominated by 1,4-dimethoxybenzene, which are believed to be involved in the attraction of the bumble bees to the flowers. To determine the volatiles that elicit physiological responses in the antennae of Bombus terrestris, the most important bumble bee pollinator species of Styrian oil pumpkin in Europe, we performed gas chromatography-electroantennographic detection (GC-EAD) analyses using both natural floral scent samples and synthetic blends. The synthetic blend contained a mixture of 21 volatile compounds in similar amounts, independent of whether they have been dominant or minor compounds in the natural samples. From the measurements with natural samples, we found that compounds such as 1,4-dimethoxybenzene, (R)-linalool, 4-vinylanisole and 4-oxoisophorone elicited antennal responses. However, in the measurements with the synthetic blends, most of the 21 compounds including terpenoids and aromatic compounds, elicited responses in the antennae of the bumble bees. This study demonstrates that the antennae of bumble bees respond to a high number of floral scent compounds of pumpkin, which all have the potential to attract pollinators and thus contribute to fruit set of this commercially important crop. The compounds identified as being EAD-active in the present study can be used in future studies to determine the effects of these compounds, as a mixture and as individual compounds, in attracting bumble bee pollinators to pumpkin flowers.

The cycad aulacaspis scale, Aulacaspis yasumatsui Takagi (Hemiptera: Diaspididae), is an invasive armored scale insect that causes severe cycad mortality worldwide. However, safe, contained, and reproducible laboratory rearing systems for this species remain limited. We developed a simplified rearing method using detached Cycas revoluta leaf fragments inserted into standard 15 mL centrifuge tubes. Leaf longevity was assessed under various cutting and hydration treatments, and the most effective approach—longitudinally splitting the midrib and maintaining fragments in distilled water—was incorporated into the final system. The optimized method preserved leaf viability for at least 63 days, sufficient for complete A. yasumatsui development. Survival from the second instar to adult emergence was 69% and 100% in females and males, respectively, with mean egg hatchability reaching 96%. Although fecundity on leaf fragments was lower than that reported for whole-plant systems, the developed method consistently supported successive generations under controlled conditions. This simplified system provides a practical, low-risk platform for biological studies and evaluation of biological and chemical control agents without the hazards of maintaining whole cycad plants.

Varietal mixtures, which refer to the cultivation of multiple genetically distinct varieties of the same crop species within a farming system, have emerged as a scientifically grounded strategy within Integrated Pest Management (IPM). By creating a heterogeneous host environment, varietal mixtures can disrupt pest establishment, restrict disease spread and strengthen the abundance and effectiveness of natural enemies. Multitrophic interactions can be further strengthened through genotype-specific herbivore-induced plant volatiles (HIPVs) that improve predator and parasitoid activity, while phytobiome-mediated mechanisms, including induced systemic resistance and microbial modulation of plant secondary metabolites, contribute additional layers of pest suppression. However, if the varieties are not selected and combined properly, this approach may also lead to pest outbreaks between varieties, differences in susceptibility and added complexity in crop management. This review examines how intraspecific genetic diversity shapes pest population dynamics, evolutionary adaptation, behavioural responses, host-associated differentiation, multitrophic interactions and phytobiome-mediated defence pathways. It highlights the challenges of integrating varietal diversity into IPM frameworks, including seed system barriers, context-dependent outcomes, and knowledge gaps that currently limit adoption. It also emphasizes that the pest suppressive potential of varietal diversity depends upon the deliberate selection and spatial arrangement of cultivars and their incorporation within IPM. When strategically implemented, varietal diversity can impede pest colonization, enhance the activity of natural enemies and retard evolutionary adaptation in pest populations, thereby constituting a robust ecological approach to achieving durable, resilient and sustainable crop protection.