RESUMEN
Ants that resemble Camponotus maculatus (Fabricius, 1782) present an opportunity to test the hypothesis that the origin of the Pacific island fauna was primarily New Guinea, the Philippines, and the Indo-Malay archipelago (collectively known as Malesia). We sequenced two mitochondrial and four nuclear markers from 146 specimens from Pacific islands, Australia, and Malesia. We also added 211 specimens representing a larger worldwide sample and performed a series of phylogenetic analyses and ancestral area reconstructions. Results indicate that the Pacific members of this group comprise several robust clades that have distinctly different biogeographical histories, and they suggest an important role for Australia as a source of Pacific colonizations. Malesian areas were recovered mostly in derived positions, and one lineage appears to be Neotropical. Phylogenetic hypotheses indicate that the orange, pan-Pacific form commonly identified as C. chloroticus Emery 1897 actually consists of two distantly related lineages. Also, the lineage on Hawai'i, which has been called C. variegatus (Smith, 1858), appears to be closely related to C. tortuganus Emery, 1895 in Florida and other lineages in the New World. In Micronesia and Polynesia the C. chloroticus-like species support predictions of the taxon-cycle hypothesis and could be candidates for human-mediated dispersal.
RESUMEN
Big, beautiful organisms are useful for biological education, increasing evolution literacy, and biodiversity conservation. But if educators gloss over the ubiquity of streamlined and miniaturized organisms, they unwittingly leave students and the public vulnerable to the idea that the primary evolutionary plot of every metazoan lineage is "progressive" and "favors" complexity. We show that simple, small, and intriguingly repulsive invertebrate animals provide a counterpoint to misconceptions about evolution. Our examples can be immediately deployed in biology courses and outreach. This context emphasizes that chordates are not the pinnacle of evolution. Rather, in the evolution of animals, miniaturization, trait loss, and lack of perfection are at least as frequent as their opposites. Teaching about invertebrate animals in a "tree thinking" context uproots evolution misconceptions (for students and the public alike), provides a mental scaffold for understanding all animals, and helps to cultivate future ambassadors and experts on these little-known, weird, and fascinating taxa.
RESUMEN
Growing evidence for lineage diversification that occurs without strong ecological divergence (i.e., nonadaptive radiation) challenges assumptions about the buildup and maintenance of species in evolutionary radiations, particularly when ecologically similar and thus potentially competing species co-occur. Understanding nonadaptive radiations involves identifying conditions conducive to both the nonecological generation of species and the maintenance of co-occurring ecologically similar species. To borrow MacArthur's [1] (Challenging Biological Problems 1972;253-259) form of inquiry, the ecology of nonadaptive radiations can be understood as follows: for species of type A, in environments of type B, nonadaptive radiations may emerge. We review purported cases of nonadaptive radiation and suggest properties of organisms, resources, and landscapes that might be conducive to their origin and maintenance. These properties include poor dispersal ability and the ephemerality and patchiness of resources.