A recent study aimed to determine whether insects possess facial recognition abilities similar to humans. The research found that honeybees and wasps can learn to recognize human faces and Navon-like parameterized-stimuli with experience and apply holistic processes similar to humans. Holistic processing is a cognitive mechanism that enables humans to recognize faces by treating them as unique stimuli that combine various visual features: functionally, this facilitates the ability to differentiate between highly similar visual stimuli. The research found that the bees and wasps could learn to recognize similar faces from standard human face recognition tests and could transfer that learning to new images. The study highlights that sophisticated visual processing abilities may be far more common in the animal kingdom than previously recognized. The results of the study were consistent with the concept of holistic processing as we understand it in terms of human facial recognition. The study suggests that holistic processing, which relies on the combining of visual features, is not unique to humans but is also present in insects.

The ability of invertebrates to form associations between stimuli is important to understanding cognitive abilities in animals. Invertebrates have fewer neural networks than vertebrates, making their behavior a valuable tool for studying the underlying mechanisms of cognitive abilities. While bees and wasps have been shown to have visual memory, it was not expected that crayfish would have similar abilities, because they do not interact in strong social groups. However, the researchers found that crayfish are able to visually recognize individuals, with facial features being learned during face-to-face fights. They also found that the type of variability in cues used is important, and that the learning is context-dependent. The study also looked at the ability of crayfish to differentiate between twin opponents and whether false identifications could be engineered. Overall, the study suggests that invertebrates such as crayfish have more complex cognitive abilities than previously thought, and that their behavior can provide important insights into the mechanisms involved in recognition and memory.

Researchers have found that individual face recognition varies between nest-founding queens and workers in Polistes fuscatus paper wasps. The ability to recognise individuals is often assumed to be species-typical, but the researchers found that it could vary within species. Three previously published experiments showed that foundresses benefit from advertising their identity with distinctive facial patterns that facilitate recognition, have robust memories of individuals, and rapidly learn to distinguish between face images. However, worker dominance interactions were found to be muted. The researchers found that workers with unique faces did not receive any more aggression than workers with common faces and lacked robust memories for individuals. Workers were also slower to distinguish between facial images than foundresses. The recognition differences between foundresses and workers are notable because Polistes lack discrete castes; foundresses and workers are morphologically similar, and workers can take over as queens. The study highlights the surprising plasticity of social benefits and receiver capacity for individual recognition.

New research has found that the small brain of the paper wasp possesses specialized face processing capabilities, whereas it was previously thought that this ability required a large mammalian brain. In addition, honeybees have been found to rely on configurational learning for extensive visual learning, leading researchers to posit that honeybees may also be able to recognize human faces due to their foraging lifestyle of visiting and memorizing many flowers. Researchers then investigated the visual capacities of the wasp Vespula vulgaris, which is unlikely to have any specialization for face processing, but found that wasps in fact perform well in distinguishing between similar human face images. The study concludes that a general visual system can likely solve complex recognition tasks, the first stage to evolving a visual expertise system for face recognition, even in the absence of neurobiological or behavioral specialization. This research has important implications for understanding the evolution of visual processing in the natural world, and could also have potential applications in fields such as facial recognition technology.

New research suggests that paper wasps use "holistic processing" to recognize individual faces. Holistic processing, which is different from typical feature-based recognition, involves facial features being bound together into a gestalt that is more than the sum of its parts. In the study, two related paper wasp species were tested: Polistes fuscatus, which use facial patterns to identify conspecifics, and Polistes dominula, which do not show individual recognition. The results showed that P. fuscatus uses holistic processing to distinguish between their own face images but not those of P. dominula. However, P. dominula does not use holistic processing to identify either conspecific or heterospecific face images. The study suggests that wasps have evolved holistic face processing, but this ability is highly specific and influenced by species-specific and stimulus-specific selective pressures. Holistic processing may be a universal adaptive strategy for expertise in face recognition, exemplified by the convergence in primates and wasps and divergence in closely related wasp species.

Researchers have found that female parasitoid wasps do not recognise the sex ratios produced by other females and adjust their laying sex ratios accordingly. Sex allocation theories predict that in cases where the interaction between ovipositing females is restricted and their offspring mate within the local patch, more female-biased (cooperative) sex ratios are expected. The female-biased sex ratio reduces competition among male offspring and increases overall reproductive productivity. The theory also suggests that females will respond to more even (noncooperative) sex ratios by producing a less female-biased sex ratio to avoid exploitation by defectors. However, the research demonstrated that female Melittobia australica did not change their offspring sex ratios based on those produced by other females using a sterile male technique, indicating this hypothesis to be invalid. Further research looking into the conditions needed for the evolution of reciprocity linked to recognition ability was discussed. The results of the meta-analysis of studies examining sex recognition ability in parasitoid wasps also did not support the predicted pattern of relevant sex ratio adjustment, suggesting that parasitoid females do not possess this ability.

A total of 81 genera and 2,999 extant species are recognized as valid, including 36 nominal species that are currently considered as species inquirendae. Based on ratios of Lepidoptera and Microgastrinae species from several areas, the actual world diversity of Microgastrinae is expected to be between 30,000-50,000 species; although these ratios were mostly based on data from temperate areas and thus must be treated with caution, the single tropical area included had a similar ratio to the temperate ones.

Hummingbirds adjust their feeding behavior in the presence of wasps at food sources, exhibiting vigilance and risk-avoidance behaviors rather than engaging in direct competition. This was found in a study of Ruby-throated Hummingbirds foraging at artificial feeders with and without visual obstruction in the presence and absence of three species of wasps, which caused hummingbirds to spend a greater proportion of their visit being vigilant. Aggressive competitive interactions at feeders were asymmetric, with hummingbirds avoiding feeders with wasps and switching between available feeders more often, and never pursuing wasps away from the feeder. The hummingbirds were either chased by wasps or avoided foraging from feeders when they were present. Changes in hummingbird vigilance patterns in response to wasp aggression match those of other avian species, suggesting that hummingbirds perceive wasps as a potential threat and not solely as competitors. While interference competition inevitably occurs, vigilance patterns indicate a perceived risk from wasps. The study highlights the importance of understanding complex ecological interactions in order to effectively conserve biodiversity.

Research has found that female Melittobia wasps adjust their offspring sex ratios in response to other females and whether they have dispersed. In natural populations, females lay eggs with close relatives when they have not dispersed, maintaining high levels of local mate competition and being selected to produce consistently female-biased sex ratios. However, when they disperse and interact with non-relatives, they adjust their sex ratio depending on the number of females laying eggs. The study has solved the puzzle of the sex ratio behavior of Melittobia wasps that has long posed questions in the field of sex allocation. The influence of dispersal can be predicted for a range of cooperative traits, including parasite virulence. The findings demonstrate that females use dispersal status as an indirect cue of relatedness to determine whether they should adjust their sex ratio in response to the number of females laying eggs on the patch. The study concludes that the offspring sex ratios produced by Melittobia wasps may have implications for other scenarios where cooperative behavior and relatedness are relevant.

Two new genera, Bohartodynerus and Parkerodynerus, have been created for three species of North American eumenine wasps from the Odynerus group. The bionomics of each species in the new genera are discussed, including reports of nectar robbing by wasps in the genus Bohartodynerus at specific flowers. It is speculated that the nectar is used to bond the gravel during nest construction. However, Parkerodynerus erythrogaster apparently does not use liquid for nest construction. The cocoon of P. erythrogaster is described in detail, and similar structures are found in other genera in the Odynerus group, albeit in a different location. Overall, it is concluded that neither Bohartodynerus nor Parkerodynerus can be considered members of the genus Odynerus due to their differing ethology and the observable differences between the newly created taxa. The creation of these new genera expands our understanding of the diversity of eumenine wasps in North America.