Density-dependent selection, which promotes contrasting patterns of trait means at different
population densities, has a long history in population genetics and ecology. The unifying …

Males in many species invest substantially in structures that are used in combat with rivals
over access to females. These weapons can attain extreme proportions and have diversified …

DOPAMINE receptors belong to the family of G protein-coupled receptors. On the basis of
the homology between these receptors, three different dopamine receptors (D1, D2, D3) …

Organisms compete for various resources in the course of sexual reproduction. First, there is
intrasexual competition for obtaining mates. Then, there is the need to exclude reproductive …

Among vertebrates, fish show by far the greatest variability of alternative reproductive tactics
(ARTs). Usually, males attempting to monopolize access to females or fertilizations are …

THREE genetically discrete male morphs coexist in Paracerceis sculpta, a Gulf of California
marine isopod1–5. The large α males defend harems within intertidal sponges, the smaller β …

Impressive examples of male ornamentation occur in horned beetles. Many beetle species
are characterized by substantial amounts of phenotypic variation in horn length, and in some …

We propose a practical concept that distinguishes the particular kind of weaponry that has
evolved to be used in combat between individuals of the same species and sex, which we …

The crustacean order Isopoda (excluding Asellota, crustacean symbionts and freshwater
taxa) comprise 3154 described marine species in 379 genera in 37 families according to the …

Discrete variation where one sex has more than one means of achieving the same
functional end, such as mating or nesting (alternative strategies and tactics), requires an …