Cintia Akemi Oi

Belonogaster is an African genus of primitively eusocial wasps. They are widespread and conspicuous across sub-Saharan Africa and yet are among the least studied groups of social wasps. Here, we present the first high-quality, chromosome-level genome assembly for a representative of this genus, Belonogaster juncea, complemented by an RNA-seq analysis of brain transcription among individuals representing reproductive and non-reproductive castes. The assembled genome spans 315.8 Mb with a scaffold N50 of 7.91 Mb. The annotation contained 15,159 protein-coding genes and 20,046 isoforms, with Benchmarking Universal Single-Copy Orthologs (BUSCO) completeness of 98.0% for the genome and 97.8% for the annotation. Using this new assembly, we show that the B. juncea genome differs notably from other social wasp genomes: a single satellite repeat makes up a fifth of its chromosome-scale sequence, it has the highest putative chromosome number in a sequenced wasp genome to date, and it shows high levels of syntenic breaks. We find caste neuro-transcription differences between queens and workers, revealing 573 differentially expressed genes (341 worker biased, 232 queen biased), with significant overlap in caste-specific genes when compared to Polistes dominula and Liostenogaster flavolineata. This genomic resource provides a foundation for understanding the molecular mechanisms underlying primitive eusociality and social evolution in wasps, and opens up new research opportunities for a genus of little-studied insects from the Global South.

Gene family expansion and contraction analysis is a commonly used approach in evolutionary comparative genomics to identify lineage-specific evolutionary pressures on gene copy/family number. CAFE is one of the most popular tools to measure changes in gene family size, but requires a high level of bioinformatics expertise, manual parameter tuning and preprocessing. Here we present EXCON, an automated, Eco-Flow community-developed Nextflow pipeline that integrates NCBI genome download, annotation quality and format pre-processing, orthologous gene family identification (Orthofinder), ultrametric tree formatting, birth-death modelling (CAFE), and GO enrichment analysis (eggNOG-mapper/TopGO) into a single, portable workflow. EXCON accepts genome assemblies and annotations, supports local, HPC and cloud-based computing environments, and requires minimal user configuration. The pipeline auto-selects appropriate CAFE lambda and error models, and separates high variance orthogroups for separate treatment. Applied to a 24-species primate dataset spanning Catarrhini, Platyrrhini and Strepsirrhini, the pipeline identified 358 rapidly evolving gene families, including a DUX (double homeobox) gene showing repeated, independent copy-number turnover across multiple lineages, consistent with the known instability of the D4Z4 macrosatellite repeat it resides in. EXCON is freely available at https://github.com/Eco-Flow/excon .

Learning, memory and brain plasticity are thought to play an important role in regulating behavioural roles in social insects, as workers perform different tasks as nurses, builders, foragers and defenders. However, it remains challenging to disentangle whether neural changes regulate behaviour or arise as a consequence of it. While cognition has been extensively studied, especially in honeybees, the variation of cognitive traits remains poorly understood in social wasps. Here, we investigated age-related changes in learning, memory and neuroanatomy in workers of the common wasp, Vespula vulgaris. We developed a Y-maze to test differential conditioning and memory of wasps and later visualised the brains using a high-resolution micro-computed tomography imaging. We found that younger individuals exhibited slower decision making yet made more accurate decisions compared with older individuals, revealing a pronounced speed–accuracy trade-off. Short-term memory showed only a slight decline with age. Neuroanatomical image analysis revealed that, despite a reduction in overall brain volume, key major neuropils involved in sensory processing and learning, such as mushroom bodies, optic lobes and antennal lobes, increased in relative volume with age. These findings corroborate with studies in bees and provide novel insights into how ageing influences cognitive function and brain structure in wasps.

The decline of insect populations worldwide has raised concerns about the negative impact on ecosystem services, particularly pollination. Among the vital pollinators, bees play a central role, with wild and solitary species often receiving less attention compared to commercially managed bees. In this study, we focused on investigating the genetic and morphometric variation found across urban populations of the solitary oil‐collecting bee Centris ( Heterocentris ) analis . We collected and examined 361 individuals (259 males, 102 females) from 26 different locations in Brazil between 2012 and 2018. First, we developed a model to identify potential climatic habitats for this species, which revealed its distribution ranging from Mexico and North America to southern Brazil and other countries in South America. Second, to assess the interpopulational genetic differentiation, we genotyped 266 individuals from 25 locations at 16 species‐specific microsatellite loci. Our analysis indicated no genetic structuring. Third, a geometric morphometrics analysis of the wings from 361 individuals showed a clear sexual size dimorphism, with centroid size (CS) of males bigger than CS of females, but low differentiation among samples from four phytogeographical regions (Amazonian Forest, Cerrado, Caatinga, and Atlantic Forest). Intranidal sociogenetic structure was assessed through microsatellite genotyping, confirming a monogyny‐monandry mating system. Our findings emphasise the importance of studying both male and female solitary bees in the wild and urban areas to better comprehend the impacts of human‐dominated habitats on insect population genetics, a critical step for proposing effective conservation and management strategies to preserve them. Understanding the population genetics of these species is a critical step in developing effective conservation and management strategies to preserve them. Moreover, C. analis is a vital pollinator of various plant families, and identifying the plant species most frequently visited by these pollinators and promoting their cultivation in urban landscapes are valuable initiatives to support conservation efforts.

Insects are the most diverse group on earth, providing a vast array of essential functions for people and nature. Yet, our appreciation of their contributions is biased towards a few economically important taxa, especially pollinating insects like honeybees. Other taxa are less well appreciated despite the important roles they play, and these taxa are rarely (if ever) the focus of conservation initiatives. Here, we explore the role that scientists play through their interactions with the media in shaping our attitudes towards one of the least appreciated insects—the aculeate (stinging) wasps. Vespine wasps are an excellent taxonomic group for such a study as they are important predators in native ecosystems (e.g., the Northern Hemisphere—in Europe and North America) but ecologically devastating as invasive species in many regions of the Southern Hemisphere (e.g., New Zealand, Australia, South America). Despite this, global media coverage of wasps invariably focuses on and emotively exaggerates the negative defensive stinging behaviour of wasps, and almost entirely overlooks their beneficial positive roles (as pest controllers and pollinators). Wasp and bee scientists from around the world were surveyed about their interactions with the media and how they considered these interactions to influence public perceptions and insect conservation. Our surveys capture the negative-wasp and positive-bee biases experienced by scientists through their interactions with the media. We consider the implications of such biases on wasp populations, their conservation and management, and make recommendations for a more balanced portrayal of this important and diverse group of insects.

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.

Chemical communication plays a major role in regulating social dynamics in social insect colonies. The most studied class of chemical compounds are the cuticular hydrocarbons (CHCs), compounds with high molecular weight that cover the insect body. CHCs are used in nestmate recognition and to signal reproductive status. Brood, in the form of larvae and eggs, is known to participate in chemical communication and social dynamics by performing hunger behaviour and inducing interaction with adults and conferring nest and maternity identity. CHCs of adults and egg surface compounds are similar in composition in social insect species. The main source of egg compounds is proposed to be Dufour’s gland, an accessory reproductive gland found in several Hymenoptera females. There is still a lack of information about the level of similarity among CHCs, compounds of egg surface and Dufour’s gland for several wasp species, which could provide correlational evidence about the origins of egg-marking compounds. Thus, we investigated whether egg surface compounds were more similar to CHCs or Dufour’s gland secretions in two Neotropical primitively eusocial wasp species, Polistes versicolor (Olivier) and Mischocyttarus metathoracicus (de Saussure, 1854). As expected, there was a higher chemical similarity between eggs and Dufour’s gland secretions in both studied species, supporting the hypothesis that this gland is the source of chemical compounds found over the eggs in these two primitively eusocial species.