Small-bodied males invest in larger testes when highly ornamented.

Sperm competition and male mating rate are two non-mutually exclusive key evolutionary pressures selecting for larger testes within and across animal taxa. A few studies have tried to test the role of mating rate in the absence of sperm competition. Under the mating rate hypothesis, particular phenotypes of a given population that are expected to gain more mates (e.

A mixture of mesotrione and atrazine harms adults and larvae of the predatory wasp Polistes satan.

Herbicides have been intensively used for weed control, raising concerns about their potentially adverse effects on non-target organisms. Research on the effects of these common agrochemicals on beneficial insects and the ecosystem services they provide (e.g.

A predatory social wasp does not avoid nestmates contaminated with a fungal biopesticide.

Fungus-based biopesticides have been used worldwide for crop pest control as a safer alternative to chemical pesticides such as neonicotinoids. Both agrochemicals can be lethal and may also trigger side effects on the behavioral traits of non-target social insects, which play a crucial role in providing essential biological pest control services in agroecosystems. Here, we evaluated whether a commercial formulation of the entomopathogenic fungus Beauveria bassiana or the neonicotinoid imidacloprid causes mortality in foragers of Mischocyttarus metathoracicus.

Sex recognition does not modulate aggression toward nest intruders in a paper wasp.

During social interactions, the behavior of an individual often depends on the sex of its social partner. Many animal societies have males and females that play very different behavioral roles, although they coexist and interact non-sexually. At specific phases of the colony cycle, social wasp females and males are contemporaries within a nest, they often interact, although mating occurs mostly off the nest, therefore providing an opportunity to test sex discrimination in contexts other than classical sexual ones.

Chronic exposure to a common biopesticide is detrimental to individuals and colonies of the paper wasp Polistes versicolor.

Risk assessments of agrochemicals on non-target insects are biased in studies with surrogate groups, such as pollinators. In social insects, such investigations are generally restricted to lethal tests with adults maintained individually, simulating a non-realistic scenario. Here, we performed a holistic approach to resemble a chronic field exposure of Polistes versicolor (Hymenoptera: Vespidae) to a common biopesticide.

Paper wasps are darker at high elevation.

High mountains are harsh environments in which colder temperatures and higher levels of UV-B radiation are common. These abiotic conditions strongly affect animals' biology, often constraining their survival and reproduction. As a result, adaptations to live in such habitats are expected to evolve.

WASPnest: a worldwide assessment of social Polistine nesting behavior.

Cooperative breeding decreases the direct reproductive output of subordinate individuals, but cooperation can be evolutionarily favored when there are challenges or constraints to breeding independently. Environmental factors, including temperature, precipitation, latitude, high seasonality, and environmental harshness have been hypothesized to correlate with the presence of cooperative breeding. However, to test the relationship between cooperation and ecological constraints requires comparative data on the frequency and variation of cooperative breeding across differing environments, ideally replicated across multiple species.

Sexual ornaments reveal the strength of melanization immune response and longevity of male paper wasps.

It has been recently suggested that female mate choice, based on sexually selected ornaments, is an important component of social wasps' reproductive biology. The correlates of male ornaments that could be of a female's interest, however, remain to be investigated. Males of the Neotropical paper wasp Polistes simillimus have sexually dimorphic melanin-based black spots on their faces.

Ontogenic Caste Differences in the Van der Vecht Organ of Primitively Eusocial Neotropical Paper Wasps.

Recent studies have reported incipient morphological caste dimorphism in the Van der Vecht organ size of some temperate Polistes paper wasps. Whether species other than the temperate ones show a similar pattern remains elusive. Here, we have studied some Neotropical Polistes species.

Sexy faces in a male paper wasp.

Sexually selected signals are common in many animals, though little reported in social insects. We investigated the occurrence of male visual signals mediating the dominance relationships among males and female choice of sexual partner in the paper wasp Polistes simillimus. Males have three conspicuous, variable and sexually dimorphic traits: black pigmentation on the head, a pair of yellow abdominal spots and body size differences.