摘要:

Rapa Island in SE Polynesia hosts a remarkable adaptive radiation of small, flightless weevils in the genusMiocalles. Sixty‐seven species are known at present, of which 26 are described as new. One new name, two new combinations, and two new synonyms are established. The paradoxical occurrence of a large adaptive radiation on a small (40 km2), isolated, oceanic island is analysed in its evolutionary and ecological aspects: how did so many species of weevils evolve, and how is such a diversity of weevils maintained? Most of the speciation has taken place on Rapa itself. Two principal methods of intra‐island isolation of weevil populations have led to speciation: between high mountain ranges, and between Rapa and its satellite islets. Glacial sea level fluctuations aided in speciation by connecting the satellite islets to Rapa at times, and by the downward extension, and connection of high‐altitude cloud forests. Some speciational events may have taken place in 15000–150 000 years. Close relatives of Rapan weevils are known from nearby Marotiri, an almost sunken island, and from the neighbouring Austral archipelago, with which some inter‐island speciation has taken place. The weevil species are almost all host‐plant specific. There are often several species occupying the same host plant, in which case they may inhabit different parts of it. Some plants with a longer history on Rapa host more weevil species than new

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1985.tb01554.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Between 1848 and 1895 the melanic form fcarbonariaof the peppered moth increased in Manchester from 0 to 98%. The reverse process is now occurring in one locality in Memyside where a year‐to‐year survey has shown that the pale form f.typicahas increased from 6 to 30% between 1959 and 1984. Supporting information also comes from two studies in N Wales. The Clean Air Acts and the consequent decline in air pollution levels are probably responsible but there are many ill–understood problems, not the least being how, and the extent to which, non‐visual selection o

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1985.tb01555.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY