2024-03-28T13:52:07Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/1108192020-05-21T12:16:22Zcom_10261_132com_10261_8col_10261_385
00925njm 22002777a 4500
dc
Traveset, Anna
author
Willson, Mary F.
author
1998
Although some studies have focused on the colour polymorphisms of flowers and fruits, little is known of their ecological and evolutionary significance. We investigated the potential contribution of several factors to the maintenance of fruit-colour polymorphism in Rubus spectabilis, a common shrub in the temperate rainforests of southeast Alaska. Fruits occur in two colours (red and orange), whose frequencies vary geographically. The two colour morphs have similar size, weight, seed load and nutrient composition. Colour preferences of avian frugivores, in the aviary and in the field, varied among individuals, but the majority favoured red fruits. Seed predators (mostly rodents) did not discriminate between seeds from different morphs. The effect of seed passage through the digestive tract of frugivores (birds and bears) on germination was similar for both morphs, although there were significant differences among frugivores. The type of soil on which the seeds are deposited influenced their germination behaviour, suggesting that some soils could favour one morph over the other. Such differences may contribute to the regional differences in frequencies of the two morphs. This study emphasizes the need to investigate fruit and seed characteristics that correlate with fruit colour; the colour preferences of consumers is only one of several selection pressures that determine the frequency distribution of fruit colours.
Evolutionary Ecology 12(3): 331-345 (1998)
http://hdl.handle.net/10261/110819
10.1023/A:1006504317585
Colour preferences
Avian seed dispersal
Southeast Alaska
Seed germination
Fruit polymorphism
Ecology of the fruit-colour polymorphism in Rubus spectabilis