Sexual selection in hermaphrodites, sperm and broadcast spawners, plants and fungi.
Darwin was the first to recognize that sexual selection is a strong evolutionary force. Exaggerated traits allow same-sex individuals to compete over access to mates and provide a mechanism by which mates are selected. It is relatively easy to appreciate how inter- and intrasexual selection work in organisms with the sensory capabilities to perceive physical or behavioural traits that signal mate quality or mate compatibility, and to assess the relative quality of competitors. It is therefore not surprising that most studies of sexual selection have focused on animals with separate sexes and obvious adaptations that function in the context of reproductive competition. Yet, many sexual organisms are both male and female at the same time, often lack sexual dimorphism and never come into direct contact at mating. How does sexual selection act in such species, and what can we learn from them? Here, we address these questions by exploring the potential for sexual selection in simultaneous hermaphrodites, sperm- and broadcast spawners, plants and fungi. Our review reveals a range of mechanisms of sexual selection, operating primarily after gametes have been released, which are common in many of these groups and also quite possibly in more familiar (internally fertilizing and sexually dimorphic) organisms.This article is part of the themed issue 'Weird sex: the underappreciated diversity of sexual reproduction'.
School of Life and Environmental Sciences, University of Sydney, 2006 New South Wales, Australia madeleine.beekman@sydney.edu.au.
Madeleine
0000-0002-9040-3756
M
Beekman
Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, 75236 Uppsala, Sweden.
Bart
0000-0001-8159-4784
B
Nieuwenhuis
School of Biological Sciences, University of Queensland, St Lucia, Queensland, Australia.
Daniel
D
Ortiz-Barrientos
Centre for Evolutionary Biology, School of Animal Biology, University of Western Australia, 6009 Western Australia, Australia.
Jonathan P
0000-0002-2603-6832
JP
Evans
D000818:Animals; D005658:Fungi / Q000502:physiology*; D057850:Hermaphroditic Organisms / Q000502:physiology; D007448:Invertebrates / Q000502:physiology*; D052586:Mating Preference, Animal; D018521:Plant Physiological Phenomena; D012098:Reproduction; D012641:Selection, Genetic; D012723:Sex; D014714:Vertebrates / Q000502:physiology*
anisogamy; hermaphroditism; pollination; sexual conflict; sexual selection; sperm competition