Competitive release leads to range expansion and rampant speciation in malagasy dung beetles.

摘要: Competition is often thought to promote ecological diversification and thereby facilitate the coexistence of competitors during evolutionary radiations. At large spatial scales, species may also coexist by having allopatric distributions, which raises question about role range expansion in proliferation Here, we integrate a well-sampled (50 out 74 species) timed phylogeny Nanos Apotolamprus dung beetles (Canthonini) Madagascar with data on species' geographical ranges, abundances, body sizes. There an overall decline lineage accumulation through time since colonization northern mid Miocene (24-13 Ma). A clade 24 extant (clade L) originating 6.0 Ma exhibits increase speciation rate, associated significant size strikingly distributions species. Large typically confers competitive advantage beetles, here reflected strong numerical dominance L local communities. We suggest that "key innovation" has allowed due release, created extensive opportunities for differentiation along environmental gradients. Most theories explain patterns rely modes speciation, but they fail how ancestral became widespread first place. The mechanism proposed here, involving following release via innovation", have operated other Malagasy taxa numbers small geographic ranges. [biodiversity hotspot; competition; Madagascar; microendemism; radiation.].