Smell those spots

two of the most widely cited models in biodiversity research; niche partitioning and adaptive radiation. Many Amazonian fish genera are represented by 10 or more species living together — cheek by jowl — in multi-species assemblages. Even the specialist can hardly tell them apart; they often have very similar shapes and sizes, diets and microhabitats. In the face of this exuberance arguments for competitive exclusion, or one species, one niche are hard to sustain. Further, recent molecular, biogeographic, and paleontological data suggest that most Amazonian fish genera are ancient, dating back tens of millions of years, to a time before the geological assembly of the modern Amazon basin. Phylogenetic analysis has shown that the closest relatives of floodplain species frequently inhabit non-floodplain streams and rivers. In other words, the coexistence of numerous ecologically similar species in floodplain floating meadows is the result of multiple independent invasions of this habitat, not in situ speciation. Niche partitioning and adaptive radiation may be real in Neotropical floodplains and, if so, the signals they yield are quickly overwhelmed by exceptionally high rates of other evolutionary phenomena. Amazonian floodplains extend over 180,000 km 2 , a little larger than the area of England and Wales combined, or about 2.6% of the 7 million km 2 area of the entire basin. I doubt that we as a community will fully document the species of this immense area within my professional lifetime, let alone that of the entire biosphere. But I dare say it is not impossible. An all-species survey will necessarily be a collective effort — on a scale of the NASA Mars program, or the Human Genome initiative. It will require a collaboration of traditional morphological and biogeographical approaches with novel bioinformatic, remote sensing and genetic technologies. What we most urgently need however is really just a great deal more of what we already have; more taxonomists, more students, more collaborations, more surveys, more museums, more work. We have a good idea of what such a determined effort will yield; pay-off in everything from resource management to basic scholarship. A widespread strategy among prey species unpalatable to their potential predators, is warning colouration advertising the fact. Research suggests that this has evolved because predators learn more quickly to avoid distinctively marked unpalatable prey than those which give out no such warnings. But interestingly, many species that carry warning colouration also have a second defence strategy: …