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Summary Historically, ferns have been described as underutilized by insects. However, studies have shown a diversity of insects interacting with ferns, although the evolutionary and ecological drivers of these interactions are still to be untangled. To fill these gaps, we compiled more than 100 yr of global data on insect–fern interactions from the literature comprising 374 fern and 649 insect species. With this database we assessed how fern trophic specialization, phylogenetic relationships and climate have shaped their interactions with insects. Our findings showed that interactions between ferns and insects can be explained by the phylogenetic relations among them. We observed that insect orders part of the Endopterygota clade tend to interact with similar fern species, which might be a result of the inheritance of Endopterygota ancestors probably due to phylogenetic niche conservationism. Under an ecological context, fern specialization increased with temperature, precipitation, and climatic stability. Our results show that climate might be one of the main factors explaining the spatial variation of insect–fern interactions, postulate also supported by the observed phylogenetic clustering of the studied ferns species. Our study highlights the intricate and multifaceted nature of insect–fern interactions, where evolutionary history and ecological factors converge to shape these relationships. [ABSTRACT FROM AUTHOR]

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Environmental impacts of conventional agriculture have generated interest in sustainable agriculture. Biological pest control is a fundamental tool, and ants are key players providing ecological services, as well as some disservices. We have used a meta-analytical approach to investigate the contribution of ants to biological control, considering their effects on pest and natural enemy abundance, plant damage and crop yield. We also evaluated whether the effects of ants are modulated by traits of ants, pests and other natural enemies, as well as by field size, crop system and experiment duration. Overall (considering all meta-analyses), from 52 studies on 17 different crops, we found that ants decrease the abundance of non-honeydew-producing pests, decrease plant damage and increase crop yield (services). In addition, ants decrease the abundance of natural enemies, mainly the generalist ones, and increase honeydew-producing pest abundance (disservices). We show that the pest control and plant protection provided by ants are boosted in shaded crops compared to monocultures. Furthermore, ants increase crop yield in shaded crops, and this effect increases with time. Finally, we bring new insights such as the importance of shaded crops to ant services, providing a good tool for farmers and stakeholders considering sustainable farming practices. [ABSTRACT FROM AUTHOR]

The conversion of natural areas into agricultural systems and silviculture is the greatest threat to biodiversity in tropical ecosystems such as the Brazilian savanna (Cerrado). This landscape transformation could lead to the loss of native species, including ants that cannot tolerate the new environment dominated by exotic plant species, such as Eucalyptus spp. The present study aims to investigate ant diversity and their functional groups to verify which vegetation and landscape variables explain their changes in a neglected formation of Cerrado (Campos Murundus) surrounded by Eucalyptus forests planted. We sampled ants in 29 sites, which presented a gradient of richness, average plant heights, and distances from Eucalyptus plantations and permanent protected areas (PPAs). We found 83 ant species from six functional guilds (arboreal, Camponotini, epigeic omnivorous, higher Attini, lower Attini and specialist predators). Plant richness best explained the diversity of ants. Higher distance from Eucalyptus plantations also positively explained the frequency of functional groups, whereas higher distance from the PPAs negatively explained the frequency of Camponotini species. Our study showed that vegetation (plant richness) and landscape variables help to understand ant diversity in a Eucalyptus‐dominated landscape. This reaffirms the importance of preserving the vegetation and their associate fauna in Campos Murundus by increasing the extent of conservation of this threatened biome. [ABSTRACT FROM AUTHOR]

Understanding the impacts of edge effects on ecological interactions plays an integral role in planning ecosystem recovery from human perturbations, as well as conservation of habitats. Edge effects related to forest fragmentation cause changes in species diversity that can disrupt ecological networks. Here, we evaluated how the diversity of, and interactions between, herbivorous insects associated with individuals of a pioneer plant species, Mabea fistulifera (Euphorbiaceae) are affected by the disturbances related to edge effects. We addressed two specific questions: (i) How do the forest edges affect species richness, abundance and composition of herbivorous interacting with M. fistulifera? (ii) Do different disturbances related to edge effects affect the topology of individual‐based plant‐herbivorous networks? Herbivorous insects were sampled from three population patches of M. fistulifera in Brazilian Atlantic forest areas: two areas were subjected to distinct intensities of anthropogenic disturbances (firebreak and park access road, considered edges of low‐ and high‐impact, respectively), and one in the forest interior (control). We expected a lower species richness and abundance of herbivorous interacting with plants in forest edges than in the forest interior apart from to differences in the species composition. Therefore, based on these predictions, we expected that the various disturbances related to edge effects may change the topology of individual‐based plant‐herbivorous networks. We observed that species richness and abundance of herbivorous in high‐impact environments decreased in relation to forest interior, as well the species composition differed between these areas. Disturbance jeopardised network specialisation but did not change the topology of individual‐based networks, which presented a modular pattern. Edges affected herbivorous diversity and decreased the interaction overlap as individual‐based networks became highly specialised with increasing disturbance. These results enhance the understanding of edge effects and resilience of plant‐herbivorous interactions in regularly disturbed tropical environments. [ABSTRACT FROM AUTHOR]

1. Harvester ants are major seed predators in arid environments. However, given that many harvester ants are partly omnivorous and therefore potentially attracted to the elaiosomes of myrmecochorous seeds, it is unclear if these ants act as predators or dispersers when removing myrmecochorous seeds. 2. We describe the outcomes of interactions between the harvester ant, Pogonomyrmex naegelii, and myrmecochorous plant, Microstachys serrulata, in a Brazilian savanna. We: (i) evaluated the role of elaiosome in seed removal by P. naegelii; (ii) investigated the fate and viability of removed seeds; (iii) tested if soils associated with P. naegelii nests are nutrient‐enriched; (iv) compared seedling survival; and (v) the density of seedling and adult M. serrulata nearby to P. naegelii nests compared with those away from these nests (i.e. controls). 3. Rates of removal of M. serrulata seeds were two‐fold higher with elaiosomes than without. The ant attractant oleic acid was the dominant fatty acid in elaiosomes, but it was absent from seeds. Removed seeds are taken into nests, and Tetrazolium tests indicated that 95% of seeds remain viable. Soils associated with P. naegelii nests were not nutrient‐enriched, and seedling survival was similar nearby to P. naegelii nests compared with control areas. However, densities of both seedling and adult M. serrulata were higher nearby to P. naegelii nests than in control areas. 4. Our findings show that P. naegelii switches its role from seed predator for most plant species to be the dominant seed disperser for M. serrulata, playing a key role in the distribution of adult plants. [ABSTRACT FROM AUTHOR]

Diaspore (e.g. seeds, fruits) dispersal is pivotal for plant communities and often involves several steps and different dispersing agents. Most studies focusing on diaspore dispersal by animals have highlighted the role of vertebrates, neglecting the role of ants in the diaspore dispersal of non‐myrmecochorous plants. Diaspore dispersal by ants is especially relevant in the current scenario of declining of vertebrate populations and, consequently, collapse of the dispersal system of large‐seeded plants. Although ants can never compensate for the dispersal service provided by vertebrates, they can mitigate the impact of vertebrate decline via removal of diaspores deposited on the ground. We have used a meta‐analytical approach to investigate the contribution of ants in the removal of non‐myrmecochorous diaspores (through vertebrate exclusion experiments). We considered the number of diaspore removal as effect size and factors such as plant growth forms, diaspore and ant size, habitat type as moderators. In addition, we investigated the role of such factors on the diaspore removal distance by ants. Ants played complementary role to non‐myrmecochorous diaspore removal services provided by vertebrates (mean Hedges' g of −0.30). The ant diaspore removal was 69% higher for diaspores from shrubs than that of tree diaspores and removal of small‐sized diaspores were 69% and 70% higher in comparison to medium‐ and large‐sized diaspores, respectively. Regarding the diaspore removal distance by ants, those of tree species were removed 32% farther than those of shrub species, and diaspores were removed three‐ times farther in the savanna than in rainforest ecosystems. Our results highlight the shrubs and small‐sized diaspores. Regarding the diaspore removal distance, the ants can be crucial for the dispersal of tree diaspores and in the savanna ecosystems. Finally, considering the biodiversity crisis, the ants may play an even more important role than appreciated in diaspores dispersal. [ABSTRACT FROM AUTHOR]

1. Harvester ants perform important ecological functions, such as seed predation and redistribution of nutrients in the soil, through a complex of ecological interactions. Most studies are static descriptions of network structure, while their temporal organisations and the factors that modulate it have been neglected. 2. This study describes the temporal organisation and the influence of climatic variables (e.g. temperature and rainfall) on network structure between a harvester ant species and its food resources (seeds and invertebrates) in the Brazilian savanna over a 1‐year period. In addition, considering the ant–seed networks, the relationship between the size of seeds collected by ants and the distance travelled was examined, as well as how this relationship behaves over time. 3. For all network types (ant–seed, ant–invertebrate, and combined) there was great structural variation throughout the year. Among climatic variables, only rainfall influenced the properties of ant–invertebrate networks, presenting a positive influence on diversity of interactions and a negative influence on network specialisation. Finally, this study shows that harvester ants tend to collect larger seeds in the vicinity of the nest (< 5 m) and smaller seeds at greater distances, and this relationship appears to be constant over time. 4. This study highlights that ecological networks are useful tools with which to understand the temporal organisation of ecological functions. In addition, climatic changes, mainly in the rainfall regime, may interfere directly in the availability of resources and ultimately in the interactions between harvester ants and their food resources. [ABSTRACT FROM AUTHOR]

Plants bearing extrafloral nectaries ( EFNs) vary the secretion of nectar between day and night, which creates turnover in the composition of interacting ant species. Daily variation in the composition of ant species foraging on vegetation is commonly observed, but its mechanisms are poorly understood. We evaluated the daily variation in nectar availability and interspecific aggressiveness between ants as possible regulatory mechanisms of the turnover in ant-plant interactions. We hypothesized that (i) plants would interact with more ant species during periods of higher secretion of nectar and that (ii) aggressive ant species would compete for nectar, creating a daily turnover of species collecting nectar. We tested this hypothesis by measuring the production of nectar during the day and night and by experimentally removing EFNs of Bionia coriacea (= Camptosema coriaceum) (Nees & Mart.) Benth. (Fabaceae: Faboideae) plants in a Brazilian savanna (Cerrado). We then compared the abundance and composition of ant species between those treatments and during the day. Our results indicate that more ant workers forage on plants during the day, when nectar was sugary, while more ant species forage at night, when aggressiveness between ant species was lower. We also detected a day/night turnover in ant species composition. Ant species foraging for nectar during the day were not the same at night, and this turnover did not occur on plants without EFNs. Both dominant ant species, diurnal Camponotus crassus (Hymenoptera: Formicidae) and nocturnal Camponotus rufipes (Hymenoptera: Formicidae), were the most aggressive species, attacking other ants in their specific periods of forage while also being very aggressive toward each other. However, this aggressiveness did not occur in the absence of nectar, which allowed non-aggressive nocturnal ant species to forage only during the daytime, disrupting the turnover. We conclude that extrafloral-nectar presence and interspecific aggressiveness between ants, along with other environmental factors, are important mechanisms creating turnovers in ants foraging on plants. [ABSTRACT FROM AUTHOR]