scholarly journals On the role of sexual selection in ecological divergence: a test of body-size assortative mating in the eastern newt Notophthalmus viridescens

2010 ◽  
Vol 101 (4) ◽  
pp. 884-897 ◽  
Author(s):  
MIZUKI K. TAKAHASHI ◽  
YUKIKO Y. TAKAHASHI ◽  
MATTHEW J. PARRIS
Keyword(s):  
Sexual Selection ◽  
Body Size ◽  
Assortative Mating ◽  
Notophthalmus Viridescens ◽  
Ecological Divergence ◽  
Eastern Newt

scholarly journals It is not always about body size: evidence of Rensch's rule in a male weapon

2021 ◽  
Vol 17 (6) ◽  
pp. 20210234
Author(s):  
Glauco Machado ◽  
Bruno A. Buzatto ◽  
Diogo S. M. Samia
Keyword(s):  
Sexual Selection ◽  
Body Size ◽  
Potential Role ◽  
Empirical Studies ◽  
Condition Dependence ◽  
Rensch’S Rule ◽  
Evolutionary Pattern ◽  
Rensch's Rule ◽  
Original Proposal

In many species, sexual dimorphism increases with body size when males are the larger sex but decreases when females are the larger sex, a macro-evolutionary pattern known as Rensch's rule (RR). Although empirical studies usually focus exclusively on body size, Rensch's original proposal included sexual differences in other traits, such as ornaments and weapons. Here, we used a clade of harvestmen to investigate whether two traits follow RR: body size and length of the fourth pair of legs (legs IV), which are used as weapons in male–male fights. We found that males were slightly smaller than females and body size did not follow RR, whereas legs IV were much longer in males and followed RR. We propose that sexual selection might be stronger on legs IV length than on body size in males, and we discuss the potential role of condition dependence in the emergence of RR.

scholarly journals Antagonistic selection on body size and sword length in a wild population of the swordtail fish, Xiphophorus multilineatus: potential for intralocus tactical conflict

2021 ◽  
Author(s):  
Melissa Liotta ◽  
Jessica Abbott ◽  
Molly Morris ◽  
Oscar Rios-Cardenas
Keyword(s):  
Sexual Selection ◽  
Body Size ◽  
Wild Population ◽  
Genetic Correlations ◽  
Reproductive Tactics ◽  
Swordtail Fish ◽  
The Arts ◽  
In The Wild ◽  
Life History Tradeoffs

Alternative reproductive tactics (ARTs) have provided valuable insights into how sexual selection and life history tradeoffs can lead to variation within a sex. However, the possibility that tactics may constrain evolution through intralocus tactical conflict (IATC) is rarely considered. In addition, when IATC has been considered, the focus has often been on the genetic correlations between the ARTs, while evidence that the ARTs have different optima for associated traits and that at least one of the tactics is not at its optima is often missing. Here we investigate selection on three traits associated with the ARTs in the swordtail fish Xiphophorus multilineatus; body size, body shape and the sexually selected trait for which these fishes were named, sword length (elongation of the caudal fin). All three traits are tactically dimorphic, with courter males being larger, deeper bodied and having longer swords, and the sneaker males being smaller, more fusiform and having shorter swords. Using measures of reproductive success in a wild population we calculated selection differentials, linear and quadratic gradients, demonstrate that the tactics have different optima and at least one of the tactics is not at its optima for body size and sword length. Our results provide the first evidence of selection in the wild on the sword, an iconic trait for sexual selection. In addition, given the high probability that these traits are genetically correlated to some extent between the two tactics, our study suggests that IATC is constraining both body size and the sword from reaching their phenotypic optima. We discuss the importance of considering the role of IATC in the evolution of tactical dimorphism, how this conflict can be present despite tactical dimorphism, and how it is important to consider this conflict when explaining not only variation within a species but differences across species as well.

scholarly journals Scent may signal fighting ability in male Iberian rock lizards

2007 ◽  
Vol 3 (2) ◽  
pp. 125-127 ◽  
Author(s):  
José Martín ◽  
Pilar López
Keyword(s):  
Sexual Selection ◽  
Body Size ◽  
Competitive Advantage ◽  
Intrasexual Competition ◽  
Chemical Signals ◽  
Lizard Species ◽  
Fighting Ability ◽  
Femoral Gland Secretions ◽  
Selection Of

Intrasexual competition favours the evolution of conspicuous fighting ability badges. However, in spite of the fact that chemoreception is important in sexual selection of many animals, such as lizards, the role of chemical signals in males' contests is relatively unknown. Here, we show that proportions of cholesterol in femoral gland secretions of male Iberian rock lizards were related to their body size (which confers a competitive advantage in fights). Males discriminated chemically and responded aggressively to cholesterol stimuli presented on swabs. Moreover, we experimentally increased cholesterol in the scent of males, and staged encounters in neutral cages between two unfamiliar and size-matched males. Focal males lost more agonisitic interactions against males manipulated with cholesterol than in control tests. We suggest that differences in scent composition may reliably signal fighting ability in many lizard species, which would help to avoid the costs of fighting.

Social behavior and sexual dimorphism in the Bonaire whiptail, Cnemidophorus murinus (Squamata: Teiidae): the role of sexual selection

2003 ◽  
Vol 81 (11) ◽  
pp. 1781-1790 ◽  
Author(s):  
Troy A Baird ◽  
Laurie J Vitt ◽  
Teresa D Baird ◽  
William E Cooper, Jr. ◽  
Janalee P Caldwell ◽  
...  
Keyword(s):  
Sexual Selection ◽  
Body Size ◽  
Sexual Dimorphism ◽  
Male Aggression ◽  
Body Dimensions ◽  
Light Blue ◽  
Ultimate Causation ◽  
Courtship Activity ◽  
Coloration Patterns

We measured body dimensions and coloration and quantified the behavior of females and males of two color phases in the Bonaire whiptail, Cnemidophorus murinus, to begin addressing the ultimate causation for sexual dimorphism in this species. Examination of size-adjusted body dimensions revealed that males have wider, longer, and deeper heads as well as somewhat longer forelegs and hind legs. Males were characterized by two distinct coloration patterns. Blue males displayed purple–blue dewlaps, blue–gray background coloration on the head and anterior torso, numerous light blue spots on the flanks, brown–orange coloration on the posterior torso, and a turquoise section on the proximal portion of the tail. By contrast, brown males were uniform olive–green to yellow–brown, with the exception of light blue spots on the lateral torso. Females were colored like brown males but lacked the blue spots. Testis length scaled with body size. Testes of only 26% of brown males were active, whereas all blue males had active testes. Blue males initiated aggressive encounters involving chases and displays directed toward other males much more frequently than females were aggressive with consexuals or with either type of male. Brown males were not observed to initiate aggression. Most blue male aggression was directed toward other blue males (70.6% of encounters), whereas 29.4% of encounters were with brown males. Blue males initiated 85.7% of the courtship encounters observed compared with only 7.1% initiated by brown males and 7.2% by females. Male-biased dimorphism in head and leg dimensions as well as coloration, together with higher rates of intrasexual aggression and courtship activity by blue males, are consistent with the hypothesis that sexual selection explains the evolution of sexual dimorphism in C. murinus.

The role of underestimating body size for self-esteem and self-efficacy among grade five children in Canada

2015 ◽  
Vol 25 (10) ◽  
pp. 753-759 ◽  
Author(s):  
Katerina Maximova ◽  
Mohammad K.A. Khan ◽  
S. Bryn Austin ◽  
Sara F.L. Kirk ◽  
Paul J. Veugelers
Keyword(s):  
Body Size ◽  
Self Efficacy ◽  
Self Esteem

Methyl mercury in zooplankton—the role of size, habitat, and food quality

2002 ◽  
Vol 59 (10) ◽  
pp. 1606-1615 ◽  
Author(s):  
Martin Kainz ◽  
Marc Lucotte ◽  
Christopher C Parrish
Keyword(s):  
Organic Matter ◽  
Fatty Acid ◽  
Body Size ◽  
Methyl Mercury ◽  
Size Fraction ◽  
Food Sources ◽  
Calanoid Copepods ◽  
Bacterial Food

Pathways of methyl mercury (MeHg) accumulation in zooplankton include ingestion of organic matter (OM). We analyzed fatty acid (FA) biomarkers in zooplankton to (i) investigate the effect of allochthonous and autochthonous OM ingestion on MeHg concentrations ([MeHg]) in zooplankton and (ii) examine how algal and bacterial food sources affect MeHg bioaccumulation. We partitioned bulk zooplankton samples (i.e., >500, 202, 100, and 53 μm) from Lake Lusignan (Québec) and measured [MeHg] and [FA] in each fraction. [MeHg] increased with increasing body size and was significantly higher in pelagic than in littoral macrozooplankton (>500 μm). The amount of the ingested terrestrial FA biomarker 24:0 indicated that less than 1% of the total FA in zooplankton was derived from allochthonous sources. More than 60% of the ingested FA originated from algal biomarkers and <10% from bacterial biomarkers. Relative amounts of algal-derived essential FA and bacterial FA were not associated with [MeHg] in any size fraction. In pelagic zones, the amount of MeHg in zooplankton related positively to the number of large organisms such as Calanoid copepods and Daphnia. We propose that the accumulation of MeHg in lacustrine zooplankton depends on the zooplankton habitat rather than on the quality of ingested food.

Accuracy of body size estimation: Role of biopsychosocial variables

Body Image ◽  
2006 ◽  
Vol 3 (2) ◽  
pp. 163-171 ◽  
Author(s):  
Marita P. McCabe ◽  
Lina A. Ricciardelli ◽  
Geeta Sitaram ◽  
Katherine Mikhail
Keyword(s):  
Body Size ◽  
Size Estimation ◽  
Body Size Estimation

Season of birth and subsequent body size: The potential role of prenatal vitamin D

2010 ◽  
Vol 23 (2) ◽  
pp. 190-200 ◽  
Author(s):  
Marta Krenz-Niedbała ◽  
Elżbieta A. Puch ◽  
Krzysztof Kościński
Keyword(s):  
Vitamin D ◽  
Body Size ◽  
Potential Role ◽  
Season Of Birth

Rapid Change in Life-Cycle Polyphenism across a Subspecies Boundary of the Eastern Newt, Notophthalmus viridescens

2011 ◽  
Vol 45 (3) ◽  
pp. 379-384 ◽  
Author(s):  
Mizuki K. Takahashi ◽  
Yukiko Y. Takahashi ◽  
Matthew J. Parris
Keyword(s):  
Life Cycle ◽  
Rapid Change ◽  
Notophthalmus Viridescens ◽  
Eastern Newt
Sign in / Sign up

Export Citation Format

Share Document