Project Summary

Terrestrial arthropods make up a large fraction of global biodiversity but are among the least known of multicellular organisms. In the American tropics, Costa Rica has been a focus for inventory effort on a wide variety of arthropods (INBio, Project ALAS), but we remain ignorant of biodiversity patterns at larger spatial scales. In particular we know very little of species richness, degrees of endemism, and patterns of faunal turnover across the rest of Mesoamerica, a region scientists have long recognized as one of the most biogeographically interesting and imperiled landscapes on the planet. LLAMA is a program of arthropod sampling that builds on Costa Rican knowledge and extends it from Nicaragua to southern Mexico, in both lowland and highland areas. The sampling from highland areas is particularly important since these are known to be conservation priorities because of high endemism levels and vulnerability to global warming.

LLAMA focusses on two signature taxa - ants (Formicidae) and weevils (Curculionidae) - and one subcomponent of tropical forest ecosystems - the leaf litter layer of the forest floor. Ants and weevils are diverse, are important in ecosystem-level processes, represent different trophic guilds, have a well-developed taxonomic infrastructure on which to build, and have a large user community among ecologists and evolutionary biologists. Forest floor leaf litter is an easily sampled zone of concentrated biodiversity. Over 60% of total ant diversity and numerous poorly-known but diverse radiations of weevils live in this thin layer at the interface of soil and vegetation. It is an important zone for carbon movement, where carbon is either respired or stored in the soil, and litter arthropods play an important role in litter decomposition and dynamics.

Following reconnaissance and initial taxonomic work in year 1, LLAMA sampled four regions over four years: southern Mexico, Guatemala, Honduras, and Nicaragua. Each year the project sampled a range of sites at a range of elevations. Each site was sampled with a combination of quantitative methods that allow diversity analysis and non-quantitative methods that maximized species capture. Each year there was a 6-week field season, followed by 10 days of sample processing at a Latin American host institution. Field crews were composed of graduate and undergraduate students from both PI and host institutions. All ants and weevils were sorted and non-focal taxa were distributed to collaborating taxonomists.

All specimen data are electronically available. Each year all species and morphospecies of Formicidae are reported on-line, complete with Automontage images. For ants, special emphasis is placed on the systematics of the hyperdiverse genus Pheidole and a thorough revision and molecular phylogenetic analysis of Mesoamerican Stenamma. For weevils the focus is on members of the Lymantini, including descriptions of a number of known new generic lineages, and a thorough revision and phylogenetic analysis of the cryptorhynchine genus Tylodinus.

Broader impacts of the project are in education, international collaboration and development, and biodiversity conservation. Each year an international team of students was immersed in a field experience with taxonomists, encouraging their development through training, inspiration, guidance, and social networks. PhD candidate Michael Branstetter received support and training for his research program. PI's Longino and Anderson and project students, in conjunction with collaborators from Latin American host institutions, delivered lectures each year during the sample processing time, fostering international scientific ties that will greatly benefit global biodiversity science. The scientific research carried out in biological reserves and remaining forest patches will raise their status as sites that can attract economic activity, and the results on species turnover and endemism will inform conservation decisions and highlight the biotic importance of Mesoamerican wet forests.