Denise Araujo Alves

Aim: Stingless bees are the most species‐rich group of eusocial bees, predominantly found in tropical and subtropical regions of the world. However, despite their diversity and importance, significant gaps remain in our understanding of their distribution patterns and the factors driving them, as these aspects have yet to be thoroughly investigated on a global scale. In this study, we aimed to fill this gap by mapping global habitat suitability for stingless bees. Location: Global. Taxon: Stingless bees (Apidae:Apinae:Meliponini). Method: We compiled over half a million spatiotemporal occurrence records from 361 species of stingless bees at an unprecedented scale from both public and private databases optimised using a recently published data‐cleaning workflow. Through a species distribution model approach, we assessed the relationship between stingless bee distribution, diversity, and environmental factors, ultimately characterising their ecological niche and producing the first habitat suitability maps for the bee tribe Meliponini. Results: Our results reveal significant discrepancies in occurrence records across the Neotropical, the Afrotropical, and the Indo‐Malayan, Papuasian, and Australian regions, as well as among taxa. Habitat suitability hotspots were identified in tropical forests and were associated with relatively high temperatures and humidity throughout the year. Projection maps further suggested that some temperate, xeric, and savannah regions could also be suitable habitats for stingless bees. Our results rescale the known environmental niche of stingless bees, demonstrating that suitable habitats exist well beyond the tropical and subtropical boundaries typically described in the literature. Main Conclusion: This study presents a novel, model‐based assessment of stingless bee distribution, revealing that it extends beyond tropical forests into drier, colder, and temperate regions more broadly than previously recognised. These findings highlight substantial gaps in ecological and distributional data, emphasising the need for taxonomic revision, targeted fieldwork, digitisation of collections, and foundational research on stingless bee ecology and evolution. Addressing these gaps will improve predictions of species responses to environmental change, inform conservation strategies, and advance understanding of stingless bees as essential providers of ecosystem services.

Bees are essential for ecosystem functioning, pollinating many wild and crop plant species. Predicting which species are most vulnerable to global changes, and how their loss may impact ecosystems and human well-being, is critical. Comprehensive information on bee response and effect traits is fundamental to these assessments. However, the Raunkiærian shortfall—insufficient trait data—remains significant for bees, particularly in the Neotropics. Moreover, it remains uncertain whether conservation strategies based on functional diversity from temperate regions can be generalized to the Neotropics. To address this gap, we compiled a comprehensive and validated dataset on Brazilian bee traits, covering 24 traits related to sociality (100% of the species with some information), nesting (88%), body size (71%), and buzzing capacity (42%) on 2,066 Brazilian bee species. The trait data here presented is a crucial resource for evaluating bee species' pollination effectiveness and susceptibility to global change. Comparative analysis with regions with ample trait data—USA, Europe, and China—revealed notable differences. Brazilian bees exhibited a higher prevalence of aboveground nesting species, especially compared to Europe. The proportion of eusocial species was also greater than in Europe and the United States, and more similar to China. Differently from other regions, Brazilian eusocial bees were significantly smaller than their non-eusocial counterparts. These cross-regional comparisons highlight the importance of geographically tailored conservation strategies and underscore the need for extensive trait data to accurately predict regional vulnerabilities and ecological impacts in a rapidly changing world.

Social inequality among individuals is a common cause of conflict in the animal kingdom. In eusocial insects, such as ants, bees, wasps, and termites, for example, the large differences in reproductive potential between castes result in conflicts over caste fate during development. Here, we present the first comprehensive review on caste fate conflict, drawing on data from diverse taxa and recent theoretical advances. In many eusocial species, caste fate is determined by differential feeding, which results in caste fate being socially controlled, thereby aligning larval development with the collective needs of the colony. However, in some taxa, mechanisms of individual self‐determination disrupt this balance, leading to overproduction of reproductive individuals at the expense of workers, with significant costs to colony fitness. Such conflicts are particularly pronounced in some stingless bees and lower termites, where larvae can bypass social control to determine their own caste fate. Indications of caste conflict can also be found in other groups, such as in some parasitic ants and in ant hybrid zones. Overall, the observed dynamics illustrate how conflicts in biological systems can be resolved in favour of either individual or collective interests, and how this affects the functioning of higher levels of organisation.

Using managed pollinators to supplement the contributions of wild pollinators is a promising means to increase crop production and rural livelihoods sustainably. However, evidence of the efficacy of managed pollinators must be provided for many crops, especially in tropical regions. Herein, we introduced managed colonies, including Africanized honey bees (Apis mellifera) and native stingless bees (Scaptotrigona spp.), in 23 coffee fields across a gradient of native forest cover in southeastern Brazil. We found coffee yield per bush increased by 16 % in coffee fields near managed colonies compared to more distant control fields. We detected positive effects for both managed bee species, though with higher variability for the native bee species due to low replication. Our study provides robust evidence that supplementing coffee farms with managed bee colonies can increase coffee yields and should stimulate further research and investment in bee supplementation.

The integration of managed pollinators into agricultural systems represents a practical strategy for boosting crop production, optimising sustainable farming practices, and improving rural livelihoods. However, the use of managed bees to supplement the contribution of wild pollinators still faces challenges, such as over-reliance on pesticides in intensively managed agroecosystems. Here, we placed managed bee colonies on conventional farms to assess their impact on arabica coffee yield, quality and market value, while also to evaluate colony health in coffee fields treated with field rates of thiamethoxam-based products. We show that supplementing farms with managed bees increased farmer income by enhancing coffee yield and beverage quality, which is rewarded by specialty coffee markets. Moreover, our field-based study reveals that, even when exposed to field-realistic levels of the neonicotinoid thiamethoxam, managed bee colonies exhibited no significant adverse effects on their health within coffee fields. Our results underline that pollination is a key input on intensively managed coffee farms, and that agricultural production and environmental conservation interact synergically to maximize profitability, which is fundamental to encourage farmers to be good stewards of their croplands by adopting nature-positive practices.

In the field of social evolution, inclusive fitness theory has been successful in making a wide range of qualitative predictions on expected patterns of cooperation and conflict. Nevertheless, outside of sex ratio theory, inclusive fitness models that make accurate quantitative predictions remain relatively rare. Past models dealing with caste fate conflict in insect societies, for example, successfully predicted that if female larvae can control their own caste fate, an excess should opt to selfishly develop as queens. Available models, however, were unable to accurately predict levels of queen production observed in Melipona bees—a genus of stingless bees where caste is self-determined—as empirically observed levels of queen production are approximately two times lower than the theoretically predicted ones. Here, we show that this discrepancy can be resolved by explicitly deriving the colony-level cost of queen overproduction from a dynamic model of colony growth, requiring the incorporation of parameters of colony growth and demography, such as the per-capita rate at which new brood cells are built and provisioned, the percentage of the queen’s eggs that are female, costs linked with worker reproduction and worker mortality. Our revised model predicts queen overproduction to more severely impact colony productivity, resulting in an evolutionarily stable strategy that is approximately half that of the original model, and is shown to accurately predict actual levels of queen overproduction observed in different Melipona species. Altogether, this shows how inclusive fitness models can provide accurate quantitative predictions, provided that costs and benefits are modeled in sufficient detail and are measured precisely. Bee societies have a strict reproductive division of labor between reproductively active queens and mostly sterile workers. In honeybees and also in most tropical stingless bees, who gets to become a queen is decided by nutrition: only larvae that receive enough high-quality food can make it into a queen. In one particular group of Melipona stingless bees, however, developing larvae themselves have been found to have the power to determine their own caste fate. Under such circumstances, the question becomes what processes prevent most from selfishly opting to become queens. The present article uses an inclusive fitness model to show that the proportion that develops as a queen (ca. 10%) is such that the individual reproductive benefit of developing as a queen exactly balances with the collective, indirect fitness costs caused by decreased swarm and male production. This is the first time that such an accurate match between theoretically predicted and empirically observed levels of queen production is obtained, which was possible thanks to the use of a dynamic model that determined how overproducing queens would reduce the success of the colony as a whole. Model predictions were further validated by comparison with other bee species where caste is nutritionally determined, and where queens were shown to be produced in line with colony needs, at a rate that was two orders of magnitude lower than in Melipona. Overall, this analysis demonstrates the power of inclusive fitness theory in being able to make accurate quantitative predictions in the field of social evolution and shows how conflicts between individual and collective interests play out in animal societies.

Communication is a fundamental feature of animal societies and helps their members to solve the challenges they encounter, from exploiting food sources to fighting enemies or finding a new home. Eusocial bees inhabit a wide range of environments and they have evolved a multitude of communication signals that help them exploit resources in their environment efficiently. We highlight recent advances in our understanding of bee communication strategies and discuss how variation in social biology, such as colony size or nesting habits, and ecological conditions are important drivers of variation in communication strategies. Anthropogenic factors, such as habitat conversion, climate change, or the use of agrochemicals, are changing the world bees inhabit, and it is becoming clear that this affects communication both directly and indirectly, for example by affecting food source availability, social interactions among nestmates, and cognitive functions. Whether and how bees adapt their foraging and communication strategies to these changes represents a new frontier in bee behavioral and conservation research.

Queens play an essential role in the colonies of stingless bees. Typically, only one queen occurs in a colony at any time, and she dominates the egg laying. Their presence maintains colony cohesion and ensures the development and survivorship of these matriarchal societies. Yet there remain significant gaps in our knowledge of queen life cycles as compared to their daughters, the workers. In this review, we follow chronologically the life of queens from pre-emergence inside brood cells (caste determination), to their interaction with workers (queen selection) and males (sexual selection), and up to adulthood. Stingless bee queens can be determined either trophically or genetically. After emergence, the virgin queens undergo a selection process whereby many are executed by workers. The body size, pheromones, age and behaviour of virgin queens may play a role in queen selection. Queens then leave the nest on a nuptial flight during which they mate just once. After mating, queens are still susceptible to workers’ harassment. For example, if they produce diploid males they are killed by workers. Previous studies have successfully in vitro reared and mated virgin queens under laboratory conditions, which have revealed new insights of queen development time, the threshold of minimum and maximum provided food to larvae developing into queens, and lethal and sublethal effects of agrochemical substances. These new techniques have also provided new information about queen physiology. However, the daily routine of queens inside colonies demands further well-designed experiments to capture other patterns of behaviour which remain poorly understood, including their interactions with other queens, workers and even males.