Aim The standard latitudinal diversity gradient (LDG), in which species richness decreases from equator to pole, is a pervasive pattern observed in most organisms. Some lineages, however, exhibit inverse LDGs. Seemingly problematic, documenting and studying contrarian groups can advance understanding of LDGs generally. Here, we identify one such contrarian clade and use a historical approach to evaluate alternative hypotheses...

Leafcutter ants propagate co‐evolving fungi for food. The nearly 50 species of leafcutter ants ( Atta , Acromyrmex ) range from Argentina to the United States, with the greatest species diversity in southern South America. We elucidate the biogeography of fungi cultivated by leafcutter ants using DNA sequence and microsatellite‐marker analyses of 474 cultivars collected across the leafcutter range. Fungal cultivars belong to t...

Evolution may improve the invasiveness of populations, but it often remains unclear whether key adaptation events occur after introduction into the recipient habitat (i.e. post‐introduction adaptation scenario), or before introduction within the native range (i.e. prior‐adaptation scenario) or at a primary site of invasion (i.e. bridgehead scenario). We used a multidisciplinary approach to determine which of these three scenar...