scholarly journals SEXUAL SELECTION, GENETIC ARCHITECTURE, AND THE CONDITION DEPENDENCE OF BODY SHAPE IN THE SEXUALLY DIMORPHIC FLY PROCHYLIZA XANTHOSTOMA (PIOPHILIDAE)

Evolution ◽  
2005 ◽  
Vol 59 (1) ◽  
pp. 138-151 ◽  
Author(s):  
Russell Bonduriansky ◽  
Locke Rowe
Keyword(s):  
Sexual Selection ◽  
Genetic Architecture ◽  
Body Shape ◽  
Condition Dependence ◽  
Sexually Dimorphic

Is body shape of mangrove-dwelling monitor lizards (Varanus indicus; Varanidae) sexually dimorphic?

2011 ◽  
Vol 32 (1) ◽  
pp. 27-37 ◽  
Author(s):  
Jan Hnízdo ◽  
Veronika Cikánová ◽  
Olga Šimková ◽  
Daniel Frynta ◽  
Petr Velenský ◽  
...  
Keyword(s):  
Sexual Selection ◽  
Body Shape ◽  
Sexually Dimorphic ◽  
Evolutionary Explanation ◽  
Body Measurements ◽  
Male And Female ◽  
Fecundity Selection ◽  
Selective Forces ◽  
Monitor Lizards

AbstractIn monitor lizards, males are typically larger than conspecific females, but body shape is usually quite similar in both sexes. This not only represents a puzzle worthy of evolutionary explanation, but also makes field sex determination of monitor lizards difficult. We asked whether subtle differences in body shape follow the same pattern as in other sexually dimorphic lizard taxa and thus can be explained by the same selective forces. We tested the hypotheses that (1) females have a longer abdomen due to fecundity selection and (2) males possess bigger heads due to intrasexual selection. We also hypothesised that (3) male monitors show a wider chests and longer upper fore-limbs to win male-male wrestling matches. We monitored ontogeny in 35 mangrove-dwelling monitors (Varanus indicus). Seventeen body measurements were taken every three months up to the age of 24-34 months. Sex was determined by an ultrasonographic imaging. We employed multiple approaches to remove the effect of size and used both confirmation and exploratory statistics. The results revealed that sexual differences in body shape were small and emerged after maturity. Females have a relatively longer abdomen while males wider chest and longer upper fore-limbs. Thus, the differences in body shape between male and female varanid lizards may be attributed to both fecundity and sexual selection.

scholarly journals Heightened condition dependent expression of structural colouration in the faces, but not wings, of male and female flies

2021 ◽  
Author(s):  
Thomas E White ◽  
Amy Locke ◽  
Tanya Latty
Keyword(s):  
Mate Choice ◽  
Condition Dependence ◽  
Sexually Dimorphic ◽  
Male And Female ◽  
Honest Signals ◽  
Mutual Mate Choice ◽  
Close Range ◽  
Males And Females ◽  
Structural Colouration

Abstract Structurally coloured sexual signals are a conspicuous and widespread class of ornament used in mate choice, though the extent to which they encode information on the quality of their bearers is not fully resolved. Theory predicts that signalling traits under strong sexual selection as honest indicators should evolve to be more developmentally integrated and exaggerated than nonsexual traits, thereby leading to heightened condition dependence. Here we test this prediction through examination of the sexually dimorphic faces and wings of the cursorial fly Lispe cana. Males and females possess structural UV-white and golden faces, respectively, and males present their faces and wings to females during close-range, ground-based courtship displays, thereby creating the opportunity for mutual inspection. Across a field-collected sample of individuals, we found that the appearance of the faces of both sexes scaled positively with individual condition, though along separate axes. Males in better condition expressed brighter faces as modelled according to conspecific flies, whereas condition scaled with facial saturation in females. We found no such relationships for their wing interference pattern nor abdomens, with the latter included as a nonsexual control. Our results suggest that the structurally coloured faces, but not the iridescent wings, of male and female Lispe cana are reliable guides to individual quality and support the broader potential for structural colours as honest signals. They also highlight the potential for mutual mate choice in this system, while arguing for one of several alternate signalling roles for wing interferences patterns among the myriad taxa which bear them.

scholarly journals Sex differences in the genetic architecture of aggressiveness in a sexually dimorphic spider

2019 ◽  
Vol 9 (18) ◽  
pp. 10758-10766 ◽  
Author(s):  
Simona Kralj‐Fišer ◽  
Kate L. Laskowski ◽  
Francisco Garcia‐Gonzalez
Keyword(s):  
Sex Differences ◽  
Genetic Architecture ◽  
Sexually Dimorphic

scholarly journals Variation in Chin and Mandibular Symphysis Size and Shape in Males and Females: A CT-Based Study

2020 ◽  
Vol 17 (12) ◽  
pp. 4249
Author(s):  
Tatiana Sella Tunis ◽  
Israel Hershkovitz ◽  
Hila May ◽  
Alexander Dan Vardimon ◽  
Rachel Sarig ◽  
...  
Keyword(s):  
Sexual Selection ◽  
Anatomical Landmark ◽  
Anatomical Structure ◽  
Sexually Dimorphic ◽  
Selection Theory ◽  
Size And Shape ◽  
Size Index ◽  
Sexual Selection Theory ◽  
Males And Females ◽  
Anthropological Literature

The chin is a unique anatomical landmark of modern humans. Its size and shape play an important role from the esthetic perspective. However, disagreement exists in the dental and anthropological literature regarding the sex differences in chin and symphysis morphometrics. The “sexual selection” theory is presented as a possible reason for chin formation in our species; however, many other contradictory theories also exist. This study’s aims were therefore to determine how chin and symphysis size and shape vary with sex, and to discuss “sexual selection” theory as a reason for its formation. Head and neck computed tomography (CT) scans of 419 adults were utilized to measure chin and symphysis sizes and shapes. The chin and symphysis measures were compared between the sexes using an independent-samples t-test, a Mann–Whitney test, and the F-statistic. The chin width was significantly greater in males than in females (p < 0.001), whereas the chin height, area, and size index were significantly greater in females (p < 0.001). Symphysis measures did not differ significantly between the sexes. Size accounted for 2–14% of the chin variance and between 24–33% of the symphysis variance. Overall, the chin was found to be a more heterogeneous anatomical structure than the symphysis, as well as more sexually dimorphic.

scholarly journals Sexual selection favours good or bad genes for pathogen resistance depending on males' pathogen exposure

2019 ◽  
Vol 286 (1902) ◽  
pp. 20190226 ◽  
Author(s):  
Patrick Joye ◽  
Tadeusz J. Kawecki
Keyword(s):  
Drosophila Melanogaster ◽  
Sexual Selection ◽  
Female Choice ◽  
Experimental Studies ◽  
Pathogen Resistance ◽  
Condition Dependence ◽  
Indirect Benefit ◽  
Intestinal Pathogen ◽  
Sexual Traits ◽  
Pathogen Exposure

Resistance to pathogens is often invoked as an indirect benefit of female choice, but experimental evidence for links between father's sexual success and offspring resistance is scarce and equivocal. Two proposed mechanisms might generate such links. Under the first, heritable resistance to diverse pathogens depends on general immunocompetence; owing to shared condition dependence, male sexual traits indicate immunocompetence independently of the male's pathogen exposure. By contrast, other hypotheses (e.g. Hamilton–Zuk) assume that sexual traits only reveal heritable resistance if the males have been exposed to the pathogen. The distinction between the two mechanisms has been neglected by experimental studies. We show that Drosophila melanogaster males that are successful in mating contests (one female with two males) sire sons that are substantially more resistant to the intestinal pathogen Pseudomonas entomophila —but only if the males have themselves been exposed to the pathogen before the mating contest. By contrast, sons of males sexually successful in the absence of pathogen exposure are less resistant than sons of unsuccessful males. We detected no differences in daughters’ resistance. Thus, while sexual selection may have considerable consequences for offspring resistance, these consequences may be sex-specific. Furthermore, contrary to the ‘general immunocompetence’ hypothesis, these consequences can be positive or negative depending on the epidemiological context under which sexual selection operates.

scholarly journals Macroevolutionary consequences of sexual conflict

2018 ◽  
Vol 14 (6) ◽  
pp. 20180186
Author(s):  
Jo S. Hermansen ◽  
Jostein Starrfelt ◽  
Kjetil L. Voje ◽  
Nils C. Stenseth
Keyword(s):  
Sexual Selection ◽  
Genetic Architecture ◽  
Time Frame ◽  
Sexual Conflicts ◽  
Males And Females ◽  
Selection For ◽  
Evolutionary Consequences ◽  
Future Work ◽  
Shared Genetic

Intralocus sexual conflicts arise whenever the fitness optima for a trait expressed in both males and females differ between the sexes and shared genetic architecture constrains the sexes from evolving independently towards their respective optima. Such sexual conflicts are commonplace in nature, yet their long-term evolutionary consequences remain unexplored. Using a Bayesian phylogenetic comparative framework, we studied the macroevolutionary dynamics of intersexual trait integration in stalk-eyed flies (Diopsidae) spanning a time frame of more than 25 Myr. We report that increased intensity of sexual selection on male eyestalks is associated with reduced intersexual eyestalk integration, as well as sex-specific rates of eyestalk evolution. Despite this, lineages where males have been under strong sexual selection for millions of years still exhibit high levels of intersexual trait integration. This low level of decoupling between the sexes may indicate that exaggerated female eyestalks are in fact adaptive—or alternatively, that there are strong constraints on reducing trait integration between the sexes. Future work should seek to clarify the relative roles of constraints and selection in contributing to the varying levels of intersexual trait integration in stalk-eyed flies, and in this way clarify whether sexual conflicts can act as constraints on adaptive evolution even on macroevolutionary time scales.

Adult morphology of Paramorganiella adventurosa Tonnoir (Diptera: Mycetophilidae: Sciophilinae), including a description of the unique maxillary palpi

Zootaxa ◽  
2010 ◽  
Vol 2559 (1) ◽  
pp. 36 ◽  
Author(s):  
MATHIAS JASCHHOF ◽  
STEPHAN M. BLANK ◽  
Uwe Kallweit
Keyword(s):  
Sexual Selection ◽  
Male Genitalia ◽  
Maxillary Palpus ◽  
Sexually Dimorphic ◽  
Adult Morphology ◽  
New Material ◽  
Mechanical Tool ◽  
First Time

The adult morphology of male Paramorganiella adventurosa Tonnoir is redescribed on the basis of new material from Tasmania. Details of the male genitalia are described and figured for the first time. The female is described for the first time. Special attention is paid to the clypeus and maxillary palpus, both sexually dimorphic, of which the anatomy is extensively illustrated and discussed with respect to possible function and in the context of palpal modifications found in other Mycetophilidae. Anatomy suggests the palpi of males function as a mechanical tool rather than a probing organ, which is unique among Mycetophilidae and Diptera. Various functional hypotheses are discussed in the context of sexual selection.

Sign in / Sign up

Export Citation Format

Share Document