Mating systems (1) were first discussed in evolutionary terms by Darwin (2). Since then,
major developments in genetic theory have allowed a better understanding of sex ratios …

Nectar from flowers provides nourishment for animals ranging in size from mites (to man.
However, few of the organisms that can use these food resources are pollinators. One of the …

Nine hummingbird—pollinated species of Heliconia occur together at Finca La Selva, in the
wet Caribbean lowlands of Costa Rica. In forest habitats, Heliconia clumps (clones) are …

The overall objective is to compare the ecological impact of bird-flower coevolution in
different geographical areas. However, it is first necessary to define the parameters of such …

Fourteen months' observations on hummingbird foraging patterns in successional habitats at
Monteverde, Costa Rica, showed that one territorial species (Amazilia saucerottei) …

Computer simulations of a pollinator foraging in a mixture of two species were used to
explore how plant reproduction can be influenced by interspecific pollination movements …

(1) We studied the ecological organization of a four-species hummingbird community in the
highlands of Costa Rica, Central America.(2) Three of the four bird species (Colibri …

Charles Darwin (1871) introduced the concept of sexual selection with illus trations of birds
that display in leks. He viewed sexual selection as a proces evolutionary change that is …

Migrant Rufous Hummingbirds (Selasphorus rufus) arrive in eastern Arizona in late summer
and establish feeding territories from which other hummingbirds are excluded. Territories …

SYNOPSIS. When a population may be characterized by interference competition for
resources, variation in fighting ability among individuals, and repeated confrontations …