Open AccessMale mating success in a N orth A merican pitviper: influence of body size, testosterone, and spatial metrics
Author(s) -
Smith Charles F.,
Schuett Gordon W.,
Amarello Melissa
Publication year - 2015
Publication title -
biological journal of the linnean society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.906
H-Index - 112
eISSN - 1095-8312
pISSN - 0024-4066
DOI - 10.1111/bij.12490
Subject(s) - biology , sexual selection , mating , reproductive success , mating system , zoology , seasonal breeder , mate choice , akaike information criterion , population , testosterone (patch) , ecology , range (aeronautics) , reproduction , assortative mating , demography , statistics , genetics , mathematics , materials science , sociology , composite material
Males with enhanced traits relative to conspecifics often show increased mating and reproductive success and thus have a fitness advantage. The opportunity or potential for sexual selection is predicted to occur under these conditions. Here, we investigated proximate determinants of mating success in male copperhead snakes ( Agkistrodon contortrix ), a medium‐sized pitviper of N orth A merica. Specifically, we investigated the relationships of body size (snout‐vent length, body mass), body condition index, spatial metrics (total distance moved, home range size), and plasma testosterone concentration on mating success in males. The single mating season lasts from A ugust through S eptember. We compared a set of candidate linear mixed models and selected the best‐fitting one using the adjusted A kaike Information Criterion ( AIC c). The AIC c‐selected model (model 2), with testosterone, body condition index, and home range size as predictor variables, showed that male mating success was positively correlated with testosterone. To our knowledge, this is the first report to show the relationship of testosterone and individual mating success in any snake species. A parallel study conducted on male fitness in A. contortrix of the same population used microsatellite markers to assign parentage of fathers (known mothers). Unlike our study, they found that snout‐vent length was positively correlated with reproductive success and that males were experiencing greater sexual selection. This relationship has been detected under natural conditions in other species of snakes. Although behavioural data are important in any mating system analysis, they should not stand alone to infer parentage, relationships or selection metrics (e.g. B ateman gradients). Long‐term sperm storage by females, female cryptic choice, and other factors contribute to the complexity of mating success of males. Accordingly, we thus conclude that estimates of reproductive success and fitness in cryptic species, such as copperheads and other snakes, require robust molecular methods to draw accurate conclusions regarding proximate and evolutionary responses. © 2015 The Linnean Society of London, Biological Journal of the Linnean Society , 2015, 115 , 185–194.