Global models of ant diversity suggest regions where new discoveries are most likely are under disproportionate deforestation threat

Abstract

Most of the described and probably undescribed species on Earth are insects. Global models of species diversity rarely focus on insects and none attempt to address unknown, undescribed diversity. We assembled a database representing about 13,000 records for ant generic distribution from over 350 regions that cover much of the globe. Based on two models of diversity and endemicity, we identified regions where our knowledge of ant diversity is most limited, regions we have called "hotspots of discovery." A priori, such regions might be expected to be remote and untouched. Instead, we found that the hotspots of discovery are also the regions in which biodiversity is the most threatened by habitat destruction. Our results not only highlight the immediate need for conservation of the remaining natural habitats in these regions, but also the extent to which, by focusing on wellknown groups such as vertebrates, we may fail to conserve the far greater diversity of the smaller species yet to be found.biogeography | Formicidae T he global biodiversity crisis has made description and mapping of biological diversity a priority (1-4). Fortunately, distribution maps are available globally for vascular plants (5, 6) and terrestrial vertebrate animals (7, 8), helping target conservation plans for diversity hotspots (2, 9). Despite the fact that most species on Earth are insects (10) and that insects account for many ecosystem services (11) and disservices (12), no global maps of distribution or diversity exist for any major insect taxon. Understanding the patterns of distribution and diversity of even a single, diverse insect taxon would be disproportionately valuable.The central challenge to modeling global diversity of insects is that even the "best-known" taxa and regions are known incompletely. A solution to this challenge is to model and map both what is known and what is unknown and, in doing so identify regions for both exploration and conservation. Here we describe the known diversity patterns of ants, model-predicted diversity patterns, and then use the difference between model predictions and empirical estimates of ant diversity as a measure of our ignorance. We model spatial patterns of diversity in two ways. First, we use an "interpolation" approach in which presences are conservatively interpolated. Second, we model climate-diversity relationships. Although the global diversity pattern of ants is similar to that of other taxa (e.g., vascular plants), many regions, which we designate "hotspots of discovery," have much lower recorded diversity than expected given their climate and neighboring regions. Unfortunately, these hotspots of discovery are also the regions where deforestation is proceeding most quickly.

Arboreal Ant Colonies as ‘Hot-Points’ of Cryptic Diversity for Myrmecophiles: The Weaver Ant Camponotus sp. aff. textor and Its Interaction Network with Its Associates

“…Natural tropical and Neotropical habitats exhibit exceptionally high invertebrate diversity [19] but are also subject to a high risk of degradation [20], [53]. Despite this state of affairs, performing a global inventory remains a difficult task.…”

“…Thus, several species of social parasites of ants involved in highly specific relationships with their hosts are already considered endangered because of their high vulnerability to habitat change [55], [56], and this situation is even more obvious for the specific parasitoids of these parasites [30]. Recent evidence has suggested that, similar to many other arboreal ant species found in ‘hotspots of discovery’ [53], C. sp. aff.…”

New distribution records of the savanna specialist fungus-farming ant Cyatta Sosa-Calvo et al. (Hymenoptera: Formicidae: Myrmicinae)

“…It is essential to improve our knowledge about the natural history and geographic distribution of life forms to develop relevant conservation strategies for ants (Guenard et al 2012). This is especially true in ecosystems were the presence of endemic species is threatened due to the rapid loss of habitat resulting from unsustainable human exploitation, i.e.…”

Ectaheteromorph ants also host highly diverse parasitic communities: a review of parasitoids of the Neotropical genus Ectatomma

“…Essentially, these figures emphasize the lack of knowledge on the exact relations that exist inside numerous communities of ants and the need to carry out exhaustive studies on their associated fauna. Considering the drastic changes suffered by numerous habitats and the dramatic loss of biodiversity in different zones of the Neotropics cataloged as biodiversity 'hot-spots' (Guénard et al 2012;Lachaud et al 2012b), there is an urgent need to conduct thorough surveys on the diversity of different ant communities which are still poorly known. This is particularly the case for most ectaheteromorphs and poneromorphs, but also for all the arboreal species and some other species found in very restricted habitats (e.g.…”