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.

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.

scholarly journals Selection for increased male size predicts variation in sexual size dimorphism among fish species

2020 ◽  
Vol 287 (1918) ◽  
pp. 20192640 ◽  
Author(s):  
Curtis R. Horne ◽  
Andrew G. Hirst ◽  
David Atkinson
Keyword(s):  
Sexual Selection ◽  
Fish Species ◽  
Sexual Size Dimorphism ◽  
Male Competition ◽  
Energy Output ◽  
Female Size ◽  
Male Size ◽  
Size Dimorphism ◽  
Fecundity Selection ◽  
Selection For

Variation in the degree of sexual size dimorphism (SSD) among taxa is generally considered to arise from differences in the relative intensity of male–male competition and fecundity selection. One might predict, therefore, that SSD will vary systematically with (1) the intensity of sexual selection for increased male size, and (2) the intensity of fecundity selection for increased female size. To test these two fundamental hypotheses, we conducted a phylogenetic comparative analysis of SSD in fish. Specifically, using records of body length at first sexual maturity from FishBase, we quantified variation in the magnitude and direction of SSD in more than 600 diverse freshwater and marine fish species, from sticklebacks to sharks. Although female-biased SSD was common, and thought to be driven primarily by fecundity selection, variation in SSD was not dependent on either the allometric scaling of reproductive energy output or fecundity in female fish. Instead, systematic patterns based on habitat and life-history characteristics associated with varying degrees of male–male competition and paternal care strongly suggest that adaptive variation in SSD is driven by the intensity of sexual selection for increased male size.

Sexual size dimorphism in the viviparous caecilian amphibian Geotrypetes seraphini seraphini (Gymnophiona: Dermophiidae) including an updated overview of sexual dimorphism in caecilian amphibians

2016 ◽  
Vol 37 (3) ◽  
pp. 291-299 ◽  
Author(s):  
Markus Maerker ◽  
Sandy Reinhard ◽  
Peter Pogoda ◽  
Alexander Kupfer
Keyword(s):  
Sexual Dimorphism ◽  
Body Length ◽  
Sexual Size Dimorphism ◽  
Molecular Ecology ◽  
Female Size ◽  
Sexually Dimorphic ◽  
Size Dimorphism ◽  
Mating System Evolution ◽  
Accurate Comparison ◽  
Widespread Phenomenon

Sexual size dimorphism (SSD) describing intersexual size differences of a given taxon is a widespread phenomenon in the animal kingdom. SSD plays a significant role in understanding life history and mating system evolution. The snakelike morphology of limbless caecilian amphibians lacking obvious secondary sexual characters (in contrast to frogs and salamanders) impedes an accurate comparison between sexes.Here, the phylogenetically derived teresomatan and viviparous caecilianGeotrypetes seraphini seraphiniwas analysed for patterns of sexual dimorphism. In terms of body size females were the larger sex, but when body length was adjusted male-biased intersexual differences in cloacal shape appeared. The larger female size is likely explained by fecundity selection as clutch size was positively correlated to female body length. Unexpectedly a cryptic, ontogeny related variation of the nuchal collars was found. An overview of SSD in caecilians including data for 27 species of nine out of ten existing families revealed a quite high number of taxa showing sexually dimorphic head size dimensions exclusively present among phylogenetically derived teresomatan caecilians. Still further research including insights into the behavioural ecology and molecular ecology of mating systems is warranted to better understand the evolution of sexual size dimorphism of caecilian amphibians.

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.

Egg-laying site, fecundity and degree of sexual size dimorphism in frogs

2020 ◽  
Vol 131 (3) ◽  
pp. 600-610
Author(s):  
Nelson Rodrigues Silva ◽  
Bianca V M Berneck ◽  
Helio R da Silva ◽  
Célio F B Haddad ◽  
Kelly R Zamudio ◽  
...  
Keyword(s):  
Sexual Size Dimorphism ◽  
Egg Laying ◽  
Female Size ◽  
Selective Force ◽  
Size Dimorphism ◽  
Body Sizes ◽  
Space Limitation ◽  
Males And Females ◽  
Similar Body ◽  
Oviposition Sites

Abstract Female fecundity is an important selective force leading to female-biased sexual size dimorphism (SSD) in frogs. Because anurans exhibit diverse reproductive modes, we investigated whether variation in SSD and fecundity are related with oviposition site. We asked whether arboreal breeding species show pronounced female-biased SSD and if, paradoxically, females have lower fecundity because of the costs of carrying oocytes and amplectant males. Conversely, we tested whether species that deposit eggs in concealed sites show less pronounced SSD, because females do not carry males and space limitation may reduce female size and fecundity. Our results showed that, in general, males were approximately 20% smaller than females. However, for species with hidden oviposition sites, males and females exhibited more similar body sizes and arboreal hylids showed more pronounced female-biased SSD. Overall, fecundity was higher in aquatic breeders, as expected, but in hylids, fecundity was smaller in arboreal breeders, which suggests that arboreality may impose restrictions on fecundity. By analysing SSD in a broader and more specific lineage (Hylidae), we found that reproductive microhabitat may also influence female size and fecundity, playing an important role in the evolution of SSD in frogs at different evolutionary scales.

Reproduction of Psammodromus algirus in coastal sandy areas of NE Spain

1997 ◽  
Vol 18 (4) ◽  
pp. 369-382 ◽  
Author(s):  
Miguel A. Carretero ◽  
Gustavo A. Llorente
Keyword(s):  
Ecological Niche ◽  
Sexual Size Dimorphism ◽  
Reproductive Traits ◽  
Reproductive Season ◽  
Breeding Period ◽  
Female Size ◽  
Size Dimorphism ◽  
Common Trend ◽  
Psammodromus Algirus ◽  
Ne Spain

AbstractThe variation in the reproductive cycle of three populations of the lizard Psammodromus algirus living in coastal sandy areas of NE Spain was analyzed. In contrast with those in continental climates, they showed evidence of reproductive stress: the reproductive season began sooner and was longer. Moreover, body size was smaller and sexual size dimorphism did not arise. Only the end of the breeding period was relatively constant. Nevertheless, these different reproductive traits seem to follow a common trend. In general, no important reproductive differences were found among the three coastal areas. Females laying two clutches have been detected in one locality. Clutch size was correlated with female size. The high phenological plasticity of this species is associated with its wide ecological niche.

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

Sexual selection on male size drives the evolution of male-biased sexual size dimorphism via the prolongation of male development

Evolution ◽  
2016 ◽  
Vol 70 (6) ◽  
pp. 1189-1199 ◽  
Author(s):  
Patrick T. Rohner ◽  
Wolf U. Blanckenhorn ◽  
Nalini Puniamoorthy
Keyword(s):  
Sexual Selection ◽  
Sexual Size Dimorphism ◽  
Male Size ◽  
Size Dimorphism ◽  
Male Development

scholarly journals Golden Orbweavers Ignore Biological Rules: Phylogenomic and Comparative Analyses Unravel a Complex Evolution of Sexual Size Dimorphism

2018 ◽  
Author(s):  
Matjaž Kuntner ◽  
Chris A. Hamilton ◽  
Cheng Ren-Chung ◽  
Matjaž Gregorič ◽  
Nik Lupše ◽  
...  
Keyword(s):  
Body Size ◽  
Female Body ◽  
Sexual Size Dimorphism ◽  
Female Size ◽  
Male And Female ◽  
Size Dimorphism ◽  
Female Body Size ◽  
Size Evolution ◽  
Web Size ◽  
Cope’S Rule

AbstractInstances of sexual size dimorphism (SSD) provide the context for rigorous tests of biological rules of size evolution, such as Cope’s Rule (phyletic size increase), Rensch’s Rule (allometric patterns of male and female size), as well as male and female body size optima. In certain spider groups, such as the golden orbweavers (Nephilidae), extreme female-biased SSD (eSSD, female:male body length ≥ 2) is the norm. Nephilid genera construct webs of exaggerated proportions which can be aerial, arboricolous, or intermediate (hybrid). First, we established the backbone phylogeny of Nephilidae using 367 Anchored Hybrid Enrichment (AHE) markers, then combined these data with classical markers for a reference species-level phylogeny. Second, we used the phylogeny to test Cope and Rensch’s Rules, sex specific size optima, and the coevolution of web size, type, and features with female and male body size and their ratio, SSD. Male, but not female, size increases significantly over time, and refutes Cope’s Rule. Allometric analyses reject the converse, Rensch’s Rule. Male and female body sizes are uncorrelated. Female size evolution is random, but males evolve towards an optimum size (3.2–4.9 mm). Overall, female body size correlates positively with absolute web size. However, intermediate sized females build the largest webs (of the hybrid type), giant female Nephila and Trichonephila build smaller webs (of the aerial type), and the smallest females build the smallest webs (of the arboricolous type). We propose taxonomic changes based on the criteria of clade age, monophyly and exclusivity, classification information content, diagnosability, and arachnological community practice. We resurrect the family Nephilidae Simon 1894 that contains Clitaetra Simon 1889, the Cretaceous Geratonephila Poinar & Buckley 2012, Herennia Thorell 1877, Indoetra Kuntner 2006, new rank, Nephila Leach 1815, Nephilengys L. Koch 1872, Nephilingis Kuntner 2013, and Trichonephila Dahl 1911, new rank. We propose the new clade Orbipurae to contain Araneidae Clerck 1757, Phonognathidae Simon 1894, new rank, and Nephilidae. Nephilid female gigantism is a phylogenetically-ancient phenotype (over 100 ma), as is eSSD, though their magnitudes vary by lineage and, to some extent, biogeographically.

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