Uncovering hidden tropical biodiversity: taxonomic revision of the diverse genus Apiomerus

Biodiversity is vital for human survivorship. Nonetheless, human activities have put a heavy toll on different elements of this biodiversity directly threatening humanity as whole. Taxonomy is a scientific endeavor that allow researchers and other people to precisely communicate among them information about this biodiversity. Being able to adequately transfer knowledge on biodiversity using high quality taxonomy is necessary to generate policies directed towards its conservation. A large proportion of this biodiversity is represented by insects, most of them still largely unknown or without adequate scientific documentation. The true bugs, or Hemiptera, are the fifth most diverse group of insects. True bugs of the genus Apiomerus, the so-called bee killers, are one of the most commonly collected assassin bugs in the New World. With 105 described species and an estimate of 170 actual species, it is one of the largest genera of assassin bugs. The genus Apiomerus exhibits an interesting natural history, and some of its species might have potential use in biological control of insect pests. Despite these appealing evolutionary or applied aspects of the group, placing names on its species is still challenging given its confusing taxonomy. The goal of this research is to revise the diverse genus Apiomerus, producing a high quality taxonomic monograph to help overcome this impediment.Insects comprise most of the biodiversity of the planet. Within Hemiptera, with more than 6,600 described species, Reduviidae ¿ assassin bugs ¿ are morphologically and ecologically one of the most diverse groups. They demonstrate an exceptional array of specialized adaptations to capture prey. Reduviidae also comprise medically important vectors of Chagas disease and economically relevant species used in biological control. The key to understanding this diversity is a sound systematic framework ranging from species-level taxonomic revisions to high level evolutionary hypotheses.Species of the genus Apiomerus Hahn, 1831 (Harpactorinae: Apiomerini), the charismatic bee killers, are among the most commonly encountered and easily collected Reduviidae in the New World. With 105 described species and an estimate of 170 actual species, it is one of the largest genera of assassin bugs. The tribe Apiomerini is restricted to the New World, with species of the genus Apiomerus occurring from Argentina to the northern USA. Bee assassins are commonly seen on flowering vegetation, employ a prey capture strategy known as ¿sticky trap predation¿, and exhibit maternal care. Despite their common name, species of Apiomerus may be important as natural enemies for crop pests. Bee killers show one of the most remarkable predation techniques among Reduviidae and combine it with an intriguing type of maternal care. Species in the harpactorine tribes Apiomerini, Ectinoderini, and Diaspidini - the ¿resin bugs¿ - apply plant resins to their legs and use this ¿sticky trap¿ to catch prey insects. In addition, females of Apiomerus collect resin and store it on the ventral surface of the abdomen in a sexually dimorphic patch of setae, scrape it off during ovipostion, and use it to cover their egg masses (Forero et al., 2011). Females possess unique glands on the ventral surface of the abdomen that may prevent the resin from polymerizing. The secretions protect the eggs from desiccation and egg predators, but then are scraped off the eggs by early instar nymphs and used as a sticky trap to catch their first meals. The unusual natural history of the bee assassins accounts for the substantial number of published natural history papers compared to other predatory Reduviidae. Among them are publications on prey capture, interactions with stingless bees, predation on honey bees, harvester ants and termites, life cycle studies, and studies on the use of resins for prey capture and as an egg predator deterrent. Some Apiomerini target stingless bees at their nests, an association that may date back at least 35-40 million years to the origins of Dominican amber in the Oligocene and Eocene (Forero & Weirauch, 2017).Other papers evaluate the potential of bee killers as natural enemies in agricultural systems. Species of Apiomerus feed on a range of crop pests, among them the cotton boll weevil, and the lagriid beetle, Lagria villosa, which is a coffee pest in Brazil. They are also common in tobacco fields in Brazil, and methods for mass rearing have been explored. Species of Apiomerus are expected to be of economic importance as natural enemies. Revisionary taxonomic work, resulting in the accurate description of the diversity of Apiomerus, and the production of publicly available species pages, and online identification keys, offers a powerful internet-based model for promoting the study on this remarkable group of assassin bugs and to foster the exploration of their potential for pest management.The conspicuousness of the bee killers is also mirrored in the large number of specimens housed in natural history museums. Due to a lack of published, modern taxonomic revisions and workable keys, more than half of these specimens remained poorly identified, posing a significant impediment to the use of this extensive reservoir of information for the study of biological and analytic problems within the group as well as for curation of collections. This project will be the first attempt to solve systematic problems in a very speciose genus of Reduviidae, and thus serve as a model for future taxonomic revisions of genera in the family.The resulting taxonomic monograph is the starting point for subsequent analyses such as phylogenetic and biogeographic ones. Only with a clear delimitation of the taxa involved, other areas of inquiry will advance towards a meaningful implementation.