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
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.
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.
The brown marmorated stink bug, Halyomorpha halys (Stål), is an invasive, polyphagous pest insect with a broad host range of various cultivated plants, including several legumes such as green bean (Phaseolus vulgaris). The bugs feed on the bean pods and cause visible damages to the plant tissue. The feeding-induced chemical changes in fruits, including potential alterations in resource quality and volatile emissions, and their impact on insect’s behaviour, remain unclear. In this study, bush bean pods were used as a model system to investigate these effects after a three – day bug feeding period. Macronutrient analyses revealed a reduction in sugars and lipids after bug infestation, while protein content was not affected. Different sugars and sugar derivates, organic acids, and amino acids decreased due to the feeding activity. Furthermore, these nutrient changes were associated with significant quantitative and qualitative changes in the VOC profiles of infested beans. In addition, the bugs’ preference for the differently treated beans and for beans presented together with synthetic volatiles was assessed. The bugs showed a preference for uninfested beans over infested beans. The addition of β-cedrene, a compound that was induced by the feeding of H. halys, led to an avoidance of beans presented with this compound. These results suggest that feeding-induced changes in bean chemistry, including volatile emission may provide cues that enable insects to detect and avoid infested food sources. This study enhances our understanding of insect-plant interactions and host selection mechanisms in a polyphagous insect.
Euplatypus parallelus is an invasive ambrosia beetle causing severe economic damage to rubber plantations across tropical southern China. However, an integrated trapping system combining effective attractants and optimised deployment remains lacking. In a field programme in Danzhou, Hainan, China, we screened seven volatile compounds across eight concentrations in 75
