scholarly journals Geometric morphometrics reveals sex-differential shape allometry in a spider

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3617 ◽  
Author(s):  
Carmen Fernández-Montraveta ◽  
Jesús Marugán-Lobón
Keyword(s):  
Sex Differences ◽  
Geometric Morphometrics ◽  
Sexual Size Dimorphism ◽  
Egg Load ◽  
Male Size ◽  
Size Dimorphism ◽  
Life Styles ◽  
Reverse Pattern ◽  
Sexual Shape Dimorphism ◽  
First Time

Common scientific wisdom assumes that spider sexual dimorphism (SD) mostly results from sexual selection operating on males. However, testing predictions from this hypothesis, particularly male size hyperallometry, has been restricted by methodological constraints. Here, using geometric morphometrics (GMM) we studied for the first time sex-differential shape allometry in a spider (Donacosa merlini, Araneae: Lycosidae) known to exhibit the reverse pattern (i.e., male-biased) of spider sexual size dimorphism. GMM reveals previously undetected sex-differential shape allometry and sex-related shape differences that are size independent (i.e., associated to the y-intercept, and not to size scaling). Sexual shape dimorphism affects both the relative carapace-to-opisthosoma size and the carapace geometry, arguably resulting from sex differences in both reproductive roles (female egg load and male competition) and life styles (wandering males and burrowing females). Our results demonstrate that body portions may vary modularly in response to different selection pressures, giving rise to sex differences in shape, which reconciles previously considered mutually exclusive interpretations about the origins of spider SD.

Sexual Size Dimorphism and Survival of Male and Female Blackbirds (Icteridae)

The Auk ◽  
1981 ◽  
Vol 98 (3) ◽  
pp. 457-465 ◽  
Author(s):  
William A. Searcy ◽  
Ken Yasukawa
Keyword(s):  
Sexual Size Dimorphism ◽  
Relative Survival ◽  
Female Size ◽  
Male Size ◽  
Size Dimorphism ◽  
Large Size ◽  
Survival Selection ◽  
Female Survival ◽  
Positive Correlations ◽  
Dimorphic Species

Abstract In a between-species comparison of icterids, male survival decreases relative to female survival as the degree of sexual size dimorphism increases. This result is consistent with the hypothesis that male size is limited by survival selection in icterids; the degree of size dimorphism is known to correlate with the degree of polygyny in icterids, however, so the decreased relative survival of males in dimorphic species may be caused by some correlate of polygyny other than large size. Survival estimates based on records of recovery of dead birds show positive correlations between male size and male survival and between female size and female survival, but survival estimates based on recaptures of live birds fail to show such relationships.

Egg size, prey size, and sexual size dimorphism in digger wasps (Hymenoptera: Sphecidae)

1985 ◽  
Vol 63 (9) ◽  
pp. 2187-2193 ◽  
Author(s):  
Kevin M. O'Neill
Keyword(s):  
Body Size ◽  
Selection Pressure ◽  
Sexual Size Dimorphism ◽  
Species Selection ◽  
Male Size ◽  
Size Dimorphism ◽  
Female Body Size ◽  
Mean Size ◽  
Males And Females ◽  
Apparent Association

Female digger wasps invest substantially in each of their offspring, laying relatively few, large eggs and providing the young with the insect prey on which they depend for food. In a study of six species in the genera Philanthus, Bembecinus, and Bembix, it was found that within each species, there is a positive correlation between female body size and both the size of their ovarial eggs and the size of the prey they provision. In five of the six species, females were larger than males on average. It is suggested that the apparent association between body size and certain aspects of parental investment by females may provide the directional selection pressure that results in the evolution of sexual size dimorphism in digger wasps. In one species, males and females have the same mean size, probably because, in this species, selection pressure on male size is similar to that on females.

Sexual dimorphism in a freshwater atyid shrimp (Decapoda: Caridea) with direct development: a geometric morphometrics approach

Zootaxa ◽  
2016 ◽  
Vol 4196 (1) ◽  
pp. 120 ◽  
Author(s):  
DANIELA ELIANA SGANGA ◽  
LUCAS RAUL FERNANDEZ PIANA ◽  
LAURA SUSANA LÓPEZ GRECO
Keyword(s):  
Sexual Dimorphism ◽  
Geometric Morphometrics ◽  
Mating System ◽  
Abdominal Segment ◽  
Sexual Size Dimorphism ◽  
Centroid Size ◽  
Caridean Shrimp ◽  
Size Dimorphism ◽  
Adult Females ◽  
Ornamental Species

Neocaridina davidi is a caridean shrimp that has gained popularity in recent years as an ornamental species. Using geometric morphometrics, we investigated sexual dimorphism in carapace and second abdominal segment shape of N. davidi. Adult females displayed a more elongated carapace and a longer rostrum than males. However, male carapace shape was similar to that of juvenile females. The second abdominal pleura was more elongated and wider in adult females than in males. Significant differences were found in centroid size for the carapace and the second abdominal segment between sexes, which is consistent with sexual size dimorphism. These results support the hypothesis of a “pure search” mating system in N. davidi, where small males search actively for receptive females, and after insemination they continue searching. 

Using effects of parasitoid size on fitness to test a host quality model assumption with the parasitoid wasp Spalangia endius

2006 ◽  
Vol 84 (11) ◽  
pp. 1678-1682 ◽  
Author(s):  
B.H. King ◽  
M.E. Napoleon
Keyword(s):  
Sexual Size Dimorphism ◽  
Parasitoid Wasp ◽  
Host Size ◽  
Female Size ◽  
Host Quality ◽  
Quality Model ◽  
Male Size ◽  
Model Assumption ◽  
Size Dimorphism ◽  
Spalangia Endius

How body size affects fitness of males relative to females is relevant to understanding the evolution of sexual size dimorphism and maternal sex-ratio manipulation. In most parasitoid wasps, mothers oviposit a greater proportion of daughters in larger hosts. The host-quality model describes how this may be adaptive. A major assumption of the model is that host size has a greater effect on the fitness of daughters than of sons. The assumption has often been tested indirectly by examining the effects of parasitoid size on fitness, because a parasitoid’s size generally increases with the size of the host on which it develops. The validity of this indirect method is examined here for the parasitoid wasp Spalangia endius Walker, 1839 parasitizing Musca domestica L., 1758. If the method is valid, effects of parasitoid size on fitness should match the effects of host size on fitness that were shown in a previous study. The effects matched in that both parasitoid size and host size affected the fitness of females but not of males. However, the aspects of female fitness that were affected differed. That female size but not male size affected fitness was consistent with the female-biased sexual size dimorphism of S. endius.

scholarly journals Male size predicts extrapair paternity in a socially monogamous bird with extreme sexual size dimorphism

2014 ◽  
Vol 26 (1) ◽  
pp. 200-206 ◽  
Author(s):  
Sarah J. Wells ◽  
Weihong Ji ◽  
James Dale ◽  
Beatrix Jones ◽  
Dianne Gleeson
Keyword(s):  
Sexual Size Dimorphism ◽  
Male Size ◽  
Extrapair Paternity ◽  
Size Dimorphism ◽  
Socially Monogamous

scholarly journals Comparative Transcriptome Analysis of Female and Male Fine-Patterned Puffer: Identification of Candidate Genes Associated with Growth and Sex Differentiation

Fishes ◽  
2021 ◽  
Vol 6 (4) ◽  
pp. 79
Author(s):  
Binbin Shan ◽  
Yan Liu ◽  
Changping Yang ◽  
Yuan Li ◽  
Liangming Wang ◽  
...  
Keyword(s):  
Transcriptome Analysis ◽  
Sexual Size Dimorphism ◽  
Sex Differentiation ◽  
Complex Phenomenon ◽  
Common Phenomenon ◽  
Comparative Transcriptome ◽  
Comparison Analysis ◽  
Size Dimorphism ◽  
First Time ◽  
Simple Sequence

Sexual growth dimorphism is a common phenomenon in teleost fish. However, the mechanism of this complex phenomenon remains unclear. The fine-patterned puffer (Takifugu poecilonotus; Temminck and Schlegel, 1850) exhibits female-biased sexual size dimorphism similar to other pufferfish. In this study, the transcriptomes of female and male T. poecilonotus were sequenced, 285.95 million raw read pairs were generated from sequence libraries. After identification and assembly, a total of 149,814 nonredundant unigenes were obtained with an N50 length of 3538 bp. Of these candidates, 122,719 unigenes (81.91% of the total) were successfully annotated with multiple public databases. The comparison analysis revealed 10,385 unigenes (2034 in females and 8351 in males) were differentially expressed between different sexes of T. poecilonotus. Then, we identified many candidate growth- and sex-related genes, including Dmrt1, Sox3, Spatas, Prl/Prlr, fabps, Ghr, and Igf1r. In addition to these well-known genes, Fabp4 was identified for the first time in fish. Furthermore, 68,281 simple sequence repeats (SSRs) loci were screened and identified in the transcriptome sequence of T. poecilonotus. The results of our study could provide valuable information on growth- and sex-associated genes and facilitate further exploration of the molecular mechanism of sexual growth dimorphism.

scholarly journals Mass-mediated sex differences in climbing patterns support the gravity hypothesis of sexual size dimorphism

Web Ecology ◽  
2007 ◽  
Vol 7 (1) ◽  
pp. 106-112 ◽  
Author(s):  
J. Moya-Laraño ◽  
D. Vinković ◽  
C. M. Allard ◽  
M. W. Foellmer
Keyword(s):  
Sex Differences ◽  
Body Size ◽  
Sexual Size Dimorphism ◽  
Negative Relationship ◽  
Simulated Data ◽  
Statistical Efficiency ◽  
Data Set ◽  
Size Dimorphism ◽  
Significant Negative Relationship ◽  
Gravity Hypothesis

Abstract. The gravity hypothesis of sexual size dimorphism can explain the patterns of extreme sexual size dimorphism in spiders (males smaller than females) because small males climb faster and therefore may be better at reaching females that live in high habitats. Recently, the main prediction of a negative relationship between climbing speed and body size in spiders has been called into question. Here we induced males and females of the spider Leucauge venusta (Tetragnathidae) to run on vertical surfaces and found partial support for the gravity hypothesis. As predicted, males climb faster than females and we demonstrated that this effect is an indirect effect mediated by the negative relationship between body mass and climbing speed. We validate our results using simulated data showing that there is enough statistical efficiency in our data set to support our conclusions. We distinguished between direct and indirect effects (through mass) on sex differences in climbing speed by means of path analysis. Thus, we provide empirical evidence that by being smaller, males are able to climb faster than females. However, we found only a barely significant negative relationship between climbing speed and body size when only males were considered. Reasons for such results are discussed within the text.

scholarly journals Proximate Causes of Rensch’s Rule: Does Sexual Size Dimorphism in Arthropods Result from Sex Differences in Development Time?

2007 ◽  
Vol 169 (2) ◽  
pp. 245-257 ◽  
Author(s):  
Wolf U. Blanckenhorn ◽  
Anthony F. G. Dixon ◽  
Daphne J. Fairbairn ◽  
Matthias W. Foellmer ◽  
Patricia Gibert ◽  
...  
Keyword(s):  
Sex Differences ◽  
Development Time ◽  
Sexual Size Dimorphism ◽  
Rensch’S Rule ◽  
Size Dimorphism ◽  
Rensch's Rule ◽  
Proximate Causes

Revision of the Litoria watjulumensis (Anura: Pelodryadidae) group from the Australian monsoonal tropics, including the resurrection of L. spaldingi

Zootaxa ◽  
2021 ◽  
Vol 4933 (2) ◽  
pp. 211-240
Author(s):  
STEPHEN C. DONNELLAN ◽  
SARAH R. CATALANO ◽  
STEPHEN PEDERSON ◽  
KIEREN J. MITCHELL ◽  
AIDAN SUHENDRAN ◽  
...  
Keyword(s):  
Gene Locus ◽  
Sexual Size Dimorphism ◽  
Nuclear Gene ◽  
River System ◽  
Northern Territory ◽  
Discrete Distributions ◽  
Advertisement Call ◽  
Size Dimorphism ◽  
First Time ◽  
North Western

We show that the Wotjulum frog, Litoria watjulumensis (Copland, 1957), comprises two deeply divergent mitochondrial DNA lineages that are also reciprocally monophyletic for a nuclear gene locus and have discrete distributions. The taxa are differentiated in multivariate analysis of shape but show no appreciable differences in colour and pattern. The two taxa differ substantially in the degree of female biased sexual size dimorphism, with the western taxon showing considerably more pronounced dimorphism. We subsequently resurrect Litoria (Hyla) spaldingi (Hosmer, 1964) for populations from east of the Daly River system in the Northern Territory through to western Queensland and restrict L. watjulumensis to populations from the Kimberley region of north-western Australia and the Victoria River system of the western Northern Territory. The complex advertisement call of L. spaldingi is described for the first time. 

Sex biases in parasitism of neotropical bats by bat flies (Diptera: Streblidae)

2008 ◽  
Vol 24 (4) ◽  
pp. 387-396 ◽  
Author(s):  
Bruce D. Patterson ◽  
Carl W. Dick ◽  
Katharina Dittmar
Keyword(s):  
Sex Differences ◽  
Sexual Size Dimorphism ◽  
Species Level ◽  
Male And Female ◽  
Size Dimorphism ◽  
Bat Flies ◽  
Neotropical Bats ◽  
Males And Females ◽  
Heavy Loads ◽  
Sex Biases

AbstractWe describe levels of parasitism of ectoparasitic bat flies (Hippoboscoidea: Streblidae) on male and female bats from an extensive Neotropical survey. The collection resulted from coordinated vertebrate-parasite surveys undertaken by the Smithsonian Venezuelan Project (SVP) from 1965–1968, which sexed 24 978 bats of 130 species. Streblid parasites were recovered from 6935 individuals of 87 bat species, but only 47 species were captured frequently enough (≥ 20 infested individuals) to permit reliable estimates of streblid parasitism on males and females. Well-sampled species included 39 phyllostomids, four mormoopids, two noctilionids, one natalid and one molossid. Prevalence of streblid parasitism (proportion of individuals infested) of male and female bats was generally not significantly different, and averaged 0.34 across infested species. In species-level analyses assessed against captures, significant sex differences in infestation levels were noted in six species; all had mean prevalence below 0.5 and females were parasitized disproportionately in each. Sex differences in total numbers of flies were noted in 21 species, and in 16 of these, females carried disproportionately heavy loads. Sex differences were also found for eight species of bat in the number of fly species infesting an individual; seven of eight showed heavier female parasitism. In analyses weighted by infestation levels, sex differences in total number of flies were found in only 12 species, with seven showing excessive parasitism of females, and no species showed sex differences in the number of fly species infesting them. These significant biases were not associated with sexual size dimorphism among the bat species. Generally higher levels of parasitism among female bats accords with theory, given their generally higher survivorship and enhanced probabilities of lateral and vertical transmission of host-specific parasites, but contrasts with patterns shown by many other parasitic arthropods. Future analyses should target social groupings of bats, not passively sampled foragers, to better address the mechanisms responsible for this pattern.

Sign in / Sign up

Export Citation Format

Share Document