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Questions Climate change is dramatically altering rainfall patterns and species distribution around the world. However, little is known about how rainfall reduction may affect plant–herbivore interactions that are crucial to the of input energy and nutrients into terrestrial ecosystems. Following Coley’s growth rate hypothesis, we assessed whether rainfall reduction in a seasonally dry tropical forest decreases community‐level herbivory owing to water shortage in drier areas. Location Catimbau National Park, Northeast Brazil. Methods We sampled 16 herb communities along a rainfall gradient (564–917 mm). Using digital photographs, we monitored for 3 weeks the frequency, magnitude and type (feeding guild) of insect damage on young, fully expanded, short‐lived leaves (lifespan <1 month). We related herbivory levels to local rainfall and examined potential confounding effects of herb abundance, richness and floristic composition on such relationships. Results We monitored 290 leaves from 202 plants belonging to 28 species. About one‐third of the leaves and six species escaped from herbivory. Leaf‐chewing insects were the most frequent herbivores, attacking 17 species, 44% ± 15% of the leaves and removing the same amount of foliar tissue as all the other insects combined removed (sap‐sucking, rasping, leaf‐mining and ‘unknown’). Contrary to expectations, foliar damage accumulated more in drier areas following the increase in the frequency of leaf‐chewing damage. In addition, frequency and magnitude of herbivory did not vary with herb abundance and richness and were weakly influenced by floristic composition. Conclusions Our findings suggest that rainfall underlies community‐level herbivory by mechanisms not related to plant availability, identity and diversity. Based on recent evidence that aridity favours leaf‐chewing proliferation in the study region, we hypothesize that rainfall reduction may weaken the top‐down control of herbivores, increasing folivory pressure on herbs. If prolonged droughts become more frequent in the coming decades, plant–herbivore interactions may be altered permanently.

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Recent decades have seen increased research interest in the processes and mechanisms related to insect gall richness and host plants. The data set provided here includes 968 records of interactions between galling insects and host plants for the Cerrado biome. The data set comprises 505 species of 222 genera and 67 families of host plants. The botanical families most represented in the data set are Asteraceae, Fabaceae, Myrtaceae, Malpighiaceae, and Melastomataceae, which account for ~48.5% of all records and 52% of the total number of species. The gall‐inducing insects listed in the data set include 48 species of Cecidomyiidae and one species of Tephritidae. This data set is the first to compile inventories of plant‐galling insect communities and information about the diversity and distribution of insect galls and their host plants in the Cerrado. The data set reveals knowledge gaps and opportunities for future research on patterns of diversity and distribution, and provides a basis for generating and testing new ecological hypotheses. Please cite this data paper when using the current data in publications and let us know how the data are used in the publications. There are no copyright restrictions.

Gall inducers use these structures as shelters and sources of nutrition. Consequently, they cause multiple physiological changes in host plants. We studied the impact caused by seed coat galls of a braconid wasp on the performance of fruits, seeds and seedlings of tree Inga laurina. We tested whether these seed galls are 'nutrient sinks' with respect to the fruit/seed of host plant, and so constrain the reproductive ability and reduce seedling longevity. We measured the influence of such galls on the secondary compounds, fruit and seed parameters, seed viability and germination and seedling performance. Inga laurina has indehiscent legumes with polyembryonic seeds surrounded by a fleshy sarcotesta rich in sugars. The galls formed inside the seed coat and galled tissues presented higher phenol concentrations, around 7-fold that of ungalled tissues. Galls caused a significant reduction in parameters such as fruit and seed size, seed weight and the number of embryos. Fluctuating asymmetry (a stress indicator) was 31% higher in leaves of galled seed plants in comparison to ungalled seed plants. However, the negative effects on fruit and seed parameters were not sufficient to reduce seed germination (except the synchronization index) or seedling performance (except leaf area and chlorophyll content). We attributed these results to the ability of I. laurina to tolerate gall attack on seeds without a marked influence on seedling performance. Moreover, because of the intensity of seed galling on host plant, we suggest that polyembryony may play a role in I. laurina reproduction increasing tolerance to seed damage.