title: The energetic costs of alternative male reproductive strategies in Xiphophorus nigrensis.
abstract: The coexistence of alternative male mating strategies depends on the balance between costs and benefits. Here we examine the short-term metabolic costs associated with distinct reproductive strategies in the genetically determined alternative male phenotypes of a northern swordtail, Xiphophorus nigrensis. In this species, large males court females, non-adorned small males chase females, and intermediate males exhibit both courtship and chase behaviors. Using intermittent flow respirometry, we measure oxygen consumption rates and behaviors of each size class in isolation and in the presence of a female. Changes in oxygen consumption between solitary and female presence trials (DeltaVO2) correlated significantly with standard length across all size classes (r = 0.42). Only the large male class exhibited a significant increase in oxygen consumption in female-present trials exhibiting a range of increase from 2 to 200% relative to solitary metabolic rates, but costs of specific courtship displays could not be demonstrated. Sword length explained 54-57% of the variation in oxygen consumption in large male solitary trials and 63-65% in the female-present trials independent of any behavioral correlation with sword length. Our results exhibit similarities to condition-dependent alternative mating systems where the female-favored phenotype has higher energetic costs.
authors.affiliation: Section of Integrative Biology, University of Texas, Austin, TX 787120, USA. mcummings@mail.utexas.edu
authors.forename: Molly Elizabeth
authors.initials: ME
authors.lastname: Cummings
authors.forename: Rose
authors.initials: R
authors.lastname: Gelineau-Kattner
mesh_terms: D000818:Animals; D049628:Body Size; D003532:Cyprinodontiformes / Q000235:genetics / Q000378:metabolism*; D004734:Energy Metabolism; D005260:Female; D005838:Genotype; D008297:Male; D010101:Oxygen Consumption; D010641:Phenotype; D012098:Reproduction; D012727:Sex Characteristics; D012726:Sexual Behavior, Animal; D013550:Swimming
references.citation: Proc Biol Sci. 2003 Aug 7;270(1524):1631-6
references.pmid: 12908985
references.citation: Evolution. 1989 Sep;43(6):1298-1307
references.pmid: 28564513
references.citation: J Exp Biol. 2001 Oct;204(Pt 19):3379-88
references.pmid: 11606611
references.citation: Anim Behav. 1998 Dec;56(6):1375-1382
references.pmid: 9933533
references.citation: Proc Biol Sci. 2003 Nov 7;270(1530):2271-7
references.pmid: 14613614
references.citation: Science. 1990 Nov 9;250(4982):808-10
references.pmid: 17759973
references.citation: Proc Biol Sci. 2003 May 7;270(1518):897-904
references.pmid: 12803903
references.citation: J Evol Biol. 2007 Mar;20(2):488-95
references.pmid: 17305814
references.citation: J Exp Biol. 2005 May;208(Pt 9):1621-5
references.pmid: 15855393
references.citation: Science. 1981 May 1;212(4494):563-4
references.pmid: 17737211
references.citation: Am Nat. 2001 Aug;158(2):146-54
references.pmid: 18707343
references.citation: Fish Physiol Biochem. 1989 Jan;6(1):49-59
references.pmid: 24226899
references.citation: Science. 2001 Feb 23;291(5508):1534-6
references.pmid: 11222856
references.citation: J Exp Biol. 2003 Mar;206(Pt 6):967-78
references.pmid: 12582139
references.citation: Nature. 2004 Dec 23;432(7020):1024-7
references.pmid: 15616562
references.citation: Evolution. 1989 Dec;43(8):1683-1698
references.pmid: 28564344
references.citation: Anim Behav. 1998 Aug;56(2):329-336
references.pmid: 9787023
references.citation: Zebrafish. 2006;3(1):91-100
references.pmid: 18248249
references.citation: Proc Biol Sci. 1998 Aug 7;265(1404):1417-21
references.pmid: 9721688
references.citation: Trends Ecol Evol. 1998 Jun 1;13(6):222-7
references.pmid: 21238275