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Over the past few years, our knowledge of how ecological interactions shape the structure and dynamics of natural communities has rapidly advanced. Plant chemical traits play key roles in these processes because they mediate a diverse range of direct and indirect interactions in a community-wide context. Many chemically mediated interactions have been extensively studied in industrial cropping systems, and thus have focused on simplified, pairwise and linear interactions that rarely incorporate a community perspective. A contrasting approach considers the agroecosystem as a functioning whole, in which food production occurs. It offers an opportunity to better understand how plant chemical traits mediate complex interactions which can enhance or hinder ecosystem functions. In this paper, we argue that studying chemically mediated interactions in agroecosystems is essential to comprehend how agroecosystem services emerge and how they can be guaranteed through ecosystem management. First, we discuss how plant chemical traits affect and are affected by ecological interactions. We then explore research questions and future directions on how studying chemical mediation in complex agroecosystems can help us understand the emergence and management of ecosystem services, specifically biological control and pollination.

ABSTRACT. Richness and composition of Arctiinae (Lepidoptera, Erebidae) in five Conservation Units in the Cerrado biome. The Cerrado biome contains about 50% of the Brazilian Arctiinae moths. However, northern region of the Cerrado is under-sampled for these insects, where there are more preserved areas. Here, we described the richness, composition, abundance, and beta diversity of Arctiinae in different vegetation types in five Protected Areas in the Cerrado northeast. We found 83 species, almost 78% of them occurred in one Protected Area. Less preserved localities had higher species richness. This result can be explained as a response to frequent intermediate disturbances in the landscape of these places. Forested areas were richer in species, supporting the environmental heterogeneity hypothesis. Compositional similarity was low among protected areas and among vegetation types. More complete inventories are required to assess which factors are influencing species richness and composition patterns of Arctiinae moths in these localities and thus guide future conservation actions. KEYWORDS. Protected Areas, inventories, moths.RESUMO. Cerca de 50% da diversidade de mariposas Arctiinae do Brasil está no Cerrado. Contudo, a fauna desses insetos é extremamente subamostrada na região norte do bioma, onde localizam-se as áreas de vegetação mais preservadas. Diante disso, este trabalho teve como objetivos descrever a riqueza, abundância, composição e diversidade beta de Arctiinae em diferentes fitofisionomias de cinco Unidades de Conservação localizadas no nordeste do Cerrado. Foram amostradas 83 espécies, das quais quase 78% ocorreram em apenas uma Unidade de Conservação. As localidades com menor grau de preservação apresentaram maior riqueza de espécies, o que pode ser explicado como uma resposta a distúrbios intermediários na paisagem destes locais. As fitofisionomias florestais foram mais ricas em espécies, corroborando a hipótese da heterogeneidade ambiental. De maneira geral, a similaridade da fauna foi baixa tanto entre as Unidades de Conservação quanto entre as fitofisionomias. Inventários mais completos precisam ser feitos a fim de avaliarmos que fatores estão influenciando os padrões de riqueza e composição de Arctiinae nestas localidades de Cerrado e, assim, subsidiar futuras ações de conservação. PALAVRAS-CHAVE.Áreas protegidas, inventários, mariposas.

Encounters between flowers and invertebrates are key events for the functioning of tropical forests. Assessing the structure of networks composed of the interactions between those partners leads to a better understanding of ecosystem functioning and the effects of environmental factors on ecological processes. Gathering such data is, however, costly and time‐consuming, especially in the highly diverse tropics. We aimed to provide a comprehensive repository of available flower–invertebrate interaction information for the Atlantic Forest, a South American tropical forest domain. Data were obtained from published works and “gray literature,” such as theses and dissertations, as well as self‐reports by co‐authors. The data set has ~18,000 interaction records forming 482 networks, each containing between one and 1061 interaction links. Each network was sampled for about 200 h or less, with few exceptions. A total of 641 plant genera within 136 different families and 39 orders were reported, with the most abundant and rich families being Asteraceae, Fabaceae, and Rubiaceae. Invertebrates interacting with these plants were all arthropods from 10 orders, 129 families, and 581 genera, comprising 2419 morphotypes (including 988 named species). Hymenoptera was the most abundant and diverse order, with at least six times more records than the second‐ranked order (Lepidoptera). The complete data set shows Hymenoptera interacting with all plant orders and also shows Diptera, Lepidoptera, Coleoptera, and Hemiptera to be important nodes. Among plants, Asterales and Fabales had the highest number of interactions. The best sampled environment was forest (~8000 records), followed by pastures and crops. Savanna, grasslands, and urban environments (among others) were also reported, indicating a wide range of approaches dedicated to collecting flower–invertebrate interaction data in the Atlantic Forest domain. Nevertheless, most reported data were from forest understory or lower strata, indicating a knowledge gap about flower–invertebrate interactions at the canopy. Also, access to remote regions remains a limitation, generating sampling bias across the geographical range of the Atlantic Forest. Future studies in these continuous and hard‐to‐access forested areas will yield important new information regarding the interactions between flowers and invertebrates in the Atlantic Forest. There are no copyright restrictions on the data set. Please cite this data paper if the data are used in publications and teaching events.

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Herbivory may affect important plant traits that mediate the interaction with floral visitors and potential pollinators with consequences to fruit and seed production. These may occur through varied mechanisms, ranging from a trade-off in resource allocation for defense and reproduction, to pleiotropic effects in the biosynthesis of secondary compounds for plant defense and floral attractiveness. The subject has been receiving attention and is leading to new perspectives in the study of ecology and evolution of insect-plant interactions. Here our main goal is to briefly review the scientific literature and discuss theoretical aspects of plant mediation of interactions between herbivores and pollinators. We conducted an extensive but non-systematic search for literature on the main theme "effects of herbivory on floral visitors and pollination". We found experimental studies and reviews reporting that foliar and floral herbivory usually change floral traits that mediate plant-pollinator interactions. The effect of herbivores on floral visitation tend to be neutral or negative, and does not always lead to negative impacts on seed production. These results open a path for new hypotheses on how plants may avoid or compensate for possible ecological costs of herbivory. We suggest that future studies should explore finer mechanisms through which herbivory affects pollination by considering natural history, pollination effectiveness, and the chemical background upon which flowers are presented to pollinators. Such studies will improve our understanding of how indirect effects structure ecological communities and their role in the evolution of plant-animal interactions.

The efficiency of different plant defenses is expected to vary depending on the combination and abundance of herbivores. Effectiveness of ant-mediated defenses can also depend on ant activity and local ant assemblage, which can vary due to human activities such as intensive grazing. We used the plant Crotalaria pallida (Fabaceae), its two pod-boring herbivores and the ants that visit the extrafloral nectaries (EFNs) to understand how chemical defense and ant-plant associations affect plant damage. We hypothesized causal relationships between plant chemical defense, ant presence on plants and herbivore damage in scenarios of constitutive and induced plant defenses and tested the different possible relationships using path analysis. The constitutive model explained the data more adequately, and each plant defense had different effects on each herbivore species. First, chemical defense significantly reduced damage by the generalist pod borer Etiella zinckenella but not by the specialist Utetheisa ornatrix. Second, ant presence reduced damage by the generalist, but had no effect on damage by the specialist. Third, a larger number of pods on the plant increased ant presence, as expected since more pods results in more EFNs. Finally, we show that these density-dependent responses by ants mediate indirect cascades on herbivory and generate context-specific responses reducing damage by E. zinckenella in sites with cattle grazing. In synthesis, we highlight that plant defenses have distinct effects on co-occurring herbivores and that indirect defenses can mediate ecological cascades that generate context dependency in the efficiency of different defenses.