Female choice linked to male dorsal fin height in a shortfin molly

Abstract

Sexual selection is a possible mechanism of speciation. This could be true even in systems where female mate choice has not been clearly observed, because pre-existing biases may be expressed if female decision-making results in male trait evolution. In some mollies, males have enlarged dorsal fins and courtship display is the prevailing mating process. In others, male dominance is thought to play a greater role. We tested females of a species in the latter group, Poecilia mexicana, for consistent preference related to dorsal fin morphology. We found that females were biased toward larger dorsal fins. This latent preference could be an important driver in trait evolution.

The effects of caudal fin loss and regeneration on the swimming performance of three cyprinid fish with different swimming capacities

“…Thus, the caudal fin size of the three selected fish species may not be the optimal fin area to sustain swimming. Fin size in many fish species is subject to sexual selection because fish with larger fins have greater success during reproduction (Warner and Schultz, 1992;Jordan et al, 2006;Wilson et al, 2010). Furthermore, the stronger unsustained swimming performance is expected to support a larger caudal fin (Langerhans, 2009).…”

“…However, the decreased caudal fin area will also result in a decrease in drag during swimming (Webb, 1973;Sinclair et al, 2011), making it easier for fish with damaged caudal fins to finish each tail beat. In addition, fin shape and size in many fish species is subject to sexual selection, either because females choose to mate with males that have larger fins or because males with larger fins gain access to more females through male-to-male competition (Warner and Schultz, 1992;Jordan et al, 2006;Wilson et al, 2010). Thus, for many fish species, the existing size of the caudal fin may not be best suited to sustainable swimming performance, but instead may be a response to sexual selection or a compromise with unsteady swimming performance, which come from the selective pressure of reproduction and escape, respectively (Sinclair et al, 2011).…”

Mating Preferences of the Gynogenetic Amazon Molly Differ Between Populations Sympatric with Different Host Species

“…In addition to body size, other male traits such as the size of the dorsal fin are also used by female mollies when selecting mates (Ptacek ; Jordan et al. ; Kozak et al. ).…”

“…Similar to females of both parent species, Amazon mollies prefer larger males (Marler & Ryan 1997;Ptacek & Travis 1997;Gabor 1999;Gabor et al 2011). In addition to body size, other male traits such as the size of the dorsal fin are also used by female mollies when selecting mates (Ptacek 1998;Jordan et al 2006;Kozak et al 2008). Male P. latipinna morphology is characterized by a large, sail-like dorsal fin but male P. mexicana are part of the short fin molly species complex that is characterized by a smaller dorsal fin (Ptacek & Breden 1998).…”

Fin-mutant female zebrafish (Danio rerio) exhibit differences in association preferences for male fin length

“…These exaggerated fins may be used in aggressive interactions between males (e.g. Betta splendens : Simpson, 1968; Cyathopharynx furcifer : Karino, 1997; Eviota prasina : Sekiya and Karino, 2004; Xiphophorus helleri : Benson and Basolo, 2006; Danio rerio : Itzkowitz and Iovine, 2007) or may be the target of female choice ( Poecilia reticulata : Bischoff et al, 1985; Karino and Kobayashi, 2005; X. helleri : Basolo, 1990a; P. mexicana : Jordan et al, 2006; but see X. birchmanni : Fisher and Rosenthal, 2007; X. helleri : MacLaren and Daniska, 2008). In some species, exaggerated fins may exploit existing female preferences for larger size ( X. helleri : Basolo, 1990b; Rosenthal and Evans, 1998; P. latipinna : MacLaren et al, 2004; P. mexicana : MacLaren and Rowland, 2006).…”