Contribution to the knowledge of the nesting biology of Eumenine wasps (Hymenoptera, Vespidae) in the Brazilian Amazonia

Several recent studies have improved our knowledge on the biodiversity and evolution of Eumeninae wasps, yet many groups lack systematic reviews, and there are still many gaps regarding the nesting biology, with the rather fragmentary information dispersed in the literature. Eumeninae are solitary wasps and important predatory insects regulating arthropod populations and exhibiting remarkable nest-building behaviors. Nesting strategies include using preexisting cavities, making clay pots, or other exposed structures built with plant material, sometimes incorporating chewed leaves, cellulose pulp, or plant resins. Understanding the nesting biology of Eumeninae is important for elucidating the origins of group living and eusociality, as these species range from solitary to primitively social. However, there is a scarcity of information on behavior and nest architecture, hindering a comprehensive understanding of these subjects. In this study, we describe and illustrate for the first time the nest of Monobia funebris Gribodo, 1891 (Odynerini), the nest of Eumenes versicolor de Saussure, 1852 (Eumenini), and provide additional information on the nesting of Pachymenes ghilianii (Spinosa, 1851) (Eumenini) from nests collected in the Brazilian Amazonia. Our observations reveal new facts about nest architecture in Eumeninae and highlight the need for additional efforts to elucidate aspects of the nesting behavior of M. funebris and the continued presence of female P. ghilianii in the nest after its completion.