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Social insects have developed different nest defence strategies; for example, social wasps use nonaggressive mechanisms or aggressiveness, including stinging. This subject has been widely examined in the literature, and it may help improve our understanding of wasps' ecology. The nesting behaviour of some genera is still poorly known. In this paper, we report new information on the nesting behaviour of the species Clypearia in different Brazilian biomes. We observed six nesting events in natural and anthropic environments of the Amazon rainforest, Atlantic forest, and Cerrado domains, sporadically from 2004 to 2022. From our observations, we suggest that Clypearia nest defence includes (i) preference for nest camouflage rather than aggressive behaviour; (ii) selection of nesting sites close to water sources in natural or anthropic environments, and eventually obtaining food from the substrate; (iii) nesting association with ants for mutual protection against predators; and (iv) variations in the nests' height. Our records suggest nest camouflage and association with ants are strategies for nest defence. These may have influenced nest height in relation to the ground, which may also vary according to the environment explored by the species. [ABSTRACT FROM AUTHOR]

Overwintering insects are facing energetic challenges because of food shortage, low temperature, and desiccation stress. Paper wasps of the genus Polistes overwinter as mated adults (gynes) in hibernacula protecting them from predation, snow, and rain but barely from low environmental temperature. In different climates, they face differing overwintering temperature regimes, and therefore they may differ in their energy use. We investigated how much of energy resources built up until autumn is used during diapause dormancy in natural hibernacula by measuring lipid, glycogen, and free carbohydrate content in autumn and early spring in Polistes dominula from temperate European (Austrian) and warm Mediterranean (Italian) climate and Polistes gallicus from Mediterranean climate. Winter energy consumption amounted to ~ 339 and ~ 310 J per wasp in the Austrian and Italian Polistes dominula populations. The smaller Italian Polistes gallicus consumed ~ 247 J. This amounts to 2.62, 2.35, and 1.79 J per day. Of this, the energy demand was mainly fuelled by lipids (84%, 93%, and 90%, respectively), but glycogen stores contributed also considerably (16%, 6%, and 9%). Free carbohydrates decreased only by 0.7%, 1%, and 0.8%. While fat stores seem still sufficient in spring, the wasps depleted most of their carbohydrates. The energy reserves of 396, 400, and 147 J per wasp remaining in spring in the three populations seem sufficient to fuel rest or simple brood care activities for a whole summer but restrict foraging flights to a few hours (~ 3.5–6 h). Results suggest that energy supply might become challenging in expected future climate scenarios. [ABSTRACT FROM AUTHOR]

Mitochondrial (mtDNA) genes have served as widely utilised genetic loci for phylogenetic and phylogeographic studies of animals. However, the phylogenetic performance of many mtDNA genes has not been empirically evaluated across lineages within hymenopteran wasps. To address this question, we assembled and analysed mitogenomic data from social wasps, representing the four recognised tribes of Polistinae and all Epiponini genera. Additionally, we evaluated whether mtDNA gene order in Polistinae is congruent with its tribal classification. Using concatenation phylogenetic methods, we show phylogenetic congruence between mitogenomic and nuclear data. Statistically comparing the phylogenetic performance of individual mtDNA genes, we demonstrate that for social wasps the molecular markers COI, 16S, NAD5, and NAD2 perform best, while ATP6, COII, and 12S show the worst results. Finally, we verified that the tRNA cluster close to the noncoding region is a hotspot of genetic rearrangements in Vespidae and can be used as additional information for the systematics of this group. Together, these results indicate that mitogenomes contain robust phylogenetic signal to elucidate the evolutionary history of Vespidae. Moreover, our study identifies the best choice of mtDNA markers for systematic investigations of social wasps. [ABSTRACT FROM AUTHOR]