Cryptic diversity, high host specificity and reproductive synchronization in army ant-associated Vatesus beetles

Army ants and their arthropod symbionts represent one of the most species-rich animal associations on Earth, and constitute a fascinating example of diverse host-symbiont interaction networks. However, despite decades of research, our knowledge of army ant symbionts remains fragmentary due to taxonomic ambiguity and the inability to study army ants in the lab. Here we present an integrative approach that allows us to reliably determine species boundaries, assess biodiversity, match different developmental stages and sexes, and to study the life cycles of army ant symbionts. This approach is based on a combination of community sampling, DNA barcoding, morphology and physiology. As a test case, we applied this approach to the staphylinid beetle genus Vatesus and its different Eciton army ant host species at La Selva Biological Station, Costa Rica. DNA barcoding led to the discovery of cryptic biodiversity and, in combination with extensive community sampling, revealed strict host partitio...