The evolution of polygamy in European reed warblers of the genusAcrocephalus: a comparative approach

Abstract

A comparative survey of mating systems in six European Acrocephalus species revealed that two of the species can be classified as polygamous and four monogamous. Several correlations were then found between mating system and various aspects of behaviour, ecology and morphology. Males of polygamous species invested little or nothing in parental care, whereas males of monogamous species shared it equally with females. Males of polygamous species defended large territories in high productivity marshland ecotones rich in arthropod food. Monogamous males defended smaller territories in less productive marshland. Females of polygamous species fed their young on larger prey collected within territory near the nest. In monogamous species, smaller prey was collected from longer flights often outside territory. Polygamous species also had larger bills as an adaptation to take larger prey. Males of polygamous species had short, simple songs used in territorial defense, whereas males of monogamous species had long, c...