Sperm traits in relation to male quality in colonial spawning bluegill

Abstract

Sperm traits (morphology, motility and concentration within ejaculates) and various correlates of male quality (age, body condition, spawning location and timing) were studied in bluegill Lepomis macrochirus, breeding in both the interior and periphery of six colonies in Lake Opinicon, Ontario, Canada. Sperm traits varied significantly more among than within males suggesting that some aspect of male phenotype might influence sperm morphology and behaviour. No measures of male body condition or size were correlated with any sperm or ejaculate traits, when controlling statistically for confounding variables. Sperm swimming speed increased significantly with male age and varied significantly among spawning bouts (controlling for sperm tail length) suggesting that some unknown aspects of male quality might influence the fertilization capacity of spermatozoa. Sperm concentration in ejaculates was significantly higher in males nesting in the interior rather than the periphery of a colony suggesting that those males might also have higher fertilization capacity correlated with their superior dominance status or the lower risk of sperm competition. Thus, older males nesting in the interior of a colony during the first spawning bout of the season are expected to be the best sperm competitors in this population, but the physiological reasons for this increased fertilization capacity remain unknown. # 2004 The Fisheries Society of the British Isles

Intraspecific variation in ejaculate traits of the northern watersnake (Nerodia sipedon)

“…Our sample sizes ( n =16–26 males) are comparable to other studies that have found significant relations between ejaculate traits and indices of size and condition (e.g. Uglem et al , 2001; Casselman & Montgomerie, 2004; Schulte‐Hostedde & Millar, 2004). Our estimates of condition in northern watersnakes were based on haematocrit and size‐corrected mass (which is correlated with energy reserves; Weatherhead & Brown, 1996), indices that may be coarse estimators of physiological condition.…”

Multivariate cluster analysis to study motility activation of Solea senegalensis spermatozoa: a model for marine teleosts

“…Furthermore, CASA has been frequently used only to obtain mean values for each parameter, ignoring the variability and multimodality of semen samples. Nonetheless, the results of studies in which the spermatozoa were considered individually indicate that there is an inherent within-sample variability (Toth et al 1997, Cosson et al 2000, Casselman & Montgomerie 2004. Our study seems to confirm that within-sample variability, one of our starting hypotheses, exists in S. senegalensis semen.…”

The genetic basis of traits regulating sperm competition and polyandry: can selection favour the evolution of good- and sexy-sperm?

“…Similarly, in the red deer Cervus elaphus, the size and complexity of male antlers is associated with relative testes mass and sperm velocity (Malo et al 2005). However, the influence of male body condition on primary sex traits is not universal and no evidence for condition dependence was found for ejaculate traits in the northern watersnake Nerodia sipedon (Schulte-Hostedde and Montgomerie 2006) and the fish Lepomis macrochirus (Casselman and Montgomerie 2004), or on ejaculate size in the grasshopper Chorthippus parallelus (Reinhardt 2001).…”