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Colony breeding systems and dispersal strategies of eusocial insects shape the genetic structure at the colony, but also at the population level. Most of the few molecular studies dedicated to termites suggest that winged reproductives disperse far enough to secure the formation of outbred founding pairs. However, these studies almost exclusively focused on wood-feeding termites and knowledge about the dispersal potential of winged reproductives is missing for soil-feeding termites. We investigated the dispersal and mating strategies of Embiratermes neotenicus and Silvestritermes minutus (Termitidae, Syntermitinae), two very abundant soil-feeding species from the Neotropics. In both species, analysis of microsatellite markers indicated low genetic similarity between closely located colonies and low genetic differentiation between populations separated by less than 10 km. Each of the 39 E. neotenicus colonies originated from a single pair of primary reproductives and the mean inbreeding coefficient of sterile castes was only slightly different from that expected in offspring of an outbred pair. Most S. minutus colonies (34/41) were consistent with outbred biparental foundation. In three mature colonies, the genotypes of sterile castes suggested their origin by mixing of multiple related reproductives. Finally, four colonies in late stage of the colony life cycle contained sterile populations originating from multiple unrelated reproductives. We conclude that long-distance flights resulting in outbred reproduction are common in these soil-feeding species in pristine habitats but that other factors, such as mating preferences, could increase relatedness between founders., SCOPUS: ar.j, info:eu-repo/semantics/published

Termite soldiers often combine mechanical adaptations with defensive chemicals secreted from the frontal gland. Amongst the most remarkable strategies for mechanical defence, symmetrical and asymmetrical snapping mandibles evolved in several lineages of the diversified subfamily Termitinae (Termitidae). The contribution of the frontal chemical weapon to defence in snapping soldiers has long been doubted and the subfamily Termitinae overlooked with respect to soldier-produced chemicals. We recently reported an active frontal gland secreting unique defensive chemicals in the symmetrically snapping soldiers of Cavitermes tuberosus. The aim of the present study was a larger-scale comparison of chemical defence in symmetrically snapping soldiers. We studied the anatomy of the frontal gland and the chemistry of its secretion in five additional Neotropical species and mapped our observations on a de novo constructed molecular phylogeny of the target group. We show that the soldiers of all studied species possess a functional frontal gland, housed in part in the frontal projections on their heads. Phylogenetic reconstruction groups the studied taxa into two well-defined clades, supported by fundamental differences in defensive chemicals, either arising exclusively from the lipogenic pathway or containing also the products of the isoprenoid pathway. Our results also identify a new genus of symmetrical snappers, related to the genus Cavitermes, incorrectly classified in several previous studies., SCOPUS: ar.j, info:eu-repo/semantics/published

Mixed modes of reproduction, combining sexual processes with thelytokous parthenogenesis, occur in all major clades of social insects. In several species of termites, queens maximize their genetic input into nondispersing replacement queens through parthenogenesis, while maintaining genetically diverse sterile offspring and dispersing reproductives via sexual reproduction. This so-called asexual queen succession (AQS) has multiple independent origins and its presumed advantages are diverse as well, ranging from multiplication of colony reproductive potential to extension of its lifespan beyond that of the foundress. However, how AQS shapes colony life cycles under natural conditions remains poorly known. The neotropical termite Silvestritermes minutus inhabits small but conspicuous nests, offering a unique opportunity to investigate the impact of AQS on life history. We report on its breeding system, life cycle and sex allocation using social structure census in 137 nests and genotyping of 12 colonies at 12 microsatellite loci. We show that colonies are established by an outbred pair of primary reproductives. In less than 2 years, the foundress is replaced by multiple neotenic queens, arising mostly through automixis with central fusion. Sterile castes, male and most (93%) female dispersers are produced sexually. Colony reproduction is usually restricted to a single dispersal of alates with unbiased sex ratio, taking place after 3 years. We conclude that S. minutus benefits from AQS to maximize colony growth rate and alate production within a very short life cycle rather than to extend colony lifespan. This highlights the versatile role of AQS in different cases of its polyphyletic origin., SCOPUS: ar.j, info:eu-repo/semantics/published