scholarly journals Habitat, Sexual and Allometric Influences on Morphological Traits of Intertidal Crabs

2020 ◽  
Author(s):  
P. Vermeiren ◽  
C. Lennard ◽  
C. Trave
Keyword(s):  
Sexual Selection ◽  
Sexual Dimorphism ◽  
Morphological Variation ◽  
Morphological Traits ◽  
Low Cost ◽  
Habitat Preferences ◽  
Mangrove Crab ◽  
Habitat Factors ◽  
Specific Factors ◽  
Claw Shape

Abstract Intertidal crabs display distinct morphological traits that allow differential interactions with biotic and abiotic features of the intertidal landscape, but are also influenced by allometry and sexual selection. This study aimed to explore the influence of sexual, allometric and habitat factors on morphological variation in the intertidal mangrove crab assemblage. A standardized photographic protocol was developed using readily available, low-cost technology to capture the morphology of carapaces and claws as sets of Cartesian landmarks. Digitization errors were 1 to 2 orders of magnitude smaller than the variation among individuals. In Tubuca seismella and Tubuca signata (superfamily Ocypodoidea), species that have traditionally been studied for sexual dimorphism, standardized major claw sizes were 2.8 and 3.7, respectively, times larger for males than females. Sexual dimorphism in claw size was also observed for Metopograpsus frontalis and Parasesarma longicristatum (superfamily Grapsoidea), with the largest claw in males being 15% and 33%, respectively, larger than in females. In contrast to size, claw shape did not relate to sex, except for T. seismella. Carapace shape, although variable among individuals and displaying asymmetry, was unrelated to sex. Claw and carapace shapes displayed high correlations, with values around 0.78. Carapace shapes grouped into taxonomic families and linked to habitat preferences, while claw shapes varied along a taxonomic gradient. These results complement studies on crab morphology that focus on specific factors or species, and stress the importance of multiple, interacting factors including sexual, allometric and habitat influences as drivers of morphological trait variability.

Heads or tails? Sexual dimorphism in helodermatid lizards

2007 ◽  
Vol 85 (1) ◽  
pp. 92-98 ◽  
Author(s):  
C.M. Gienger ◽  
Daniel D. Beck
Keyword(s):  
Sexual Selection ◽  
Body Size ◽  
Sexual Dimorphism ◽  
Morphological Traits ◽  
Tail Length ◽  
Repeated Sequences ◽  
Analysis Of Covariance ◽  
Head Size ◽  
Heloderma Suspectum

We tested the hypothesis that helodermatid lizards (Gila monsters, Heloderma suspectum Cope, 1869, and beaded lizards, H. horridum (Wiegmann, 1829)) show sexual dimorphism in morphological traits related to male–male agonistic behaviors. Male–male combat in helodermatid lizards involves repeated sequences of ritualized grappling. Male Gila monsters use their heads in attempts to gain or maintain a superior position during repeated combat bouts that may last for hours. Pairs of fighting male beaded lizards form spectacular body arches, with abdomens adpressed and snouts, forelimbs, and tail tips contacting the ground. We measured body size, head size, and tail length in 208 preserved H. suspectum, and body size and tail length (but not head size) in 79 live H. horridum, then tested for sexual dimorphism using analysis of covariance. Male Gila monsters had proportionately larger heads than females but did not differ in tail length or body size. Male beaded lizards had proportionately longer tails than females and were larger in body size only when the largest individuals were included in the analysis. Differences in head dimensions (in H. suspectum) and tail length (in H. horridum) are likely the result of sexual selection acting through male–male agonistic behaviors in this unique lizard taxon.

scholarly journals Sexual behaviour and morphological variation in the millipede Megaphyllum bosniense (Verhoeff, 1897)

2018 ◽  
Vol 87 (3) ◽  
pp. 133-148
Author(s):  
Vukica Vujić ◽  
Bojan Ilić ◽  
Zvezdana Jovanović ◽  
Sofija Pavković-Lučić ◽  
Sara Selaković ◽  
...  
Keyword(s):  
Sexual Selection ◽  
Sexual Behaviour ◽  
Morphological Variation ◽  
Morphological Traits ◽  
Morphological Evolution ◽  
Random Mating ◽  
Mate Preferences ◽  
Linear Measurements ◽  
Time Duration ◽  
Sexual Selection Theory

Sexual selection can be a major driving force that favours morphological evolution at the intraspecific level. According to the sexual selection theory, morphological variation may accompany non-random mating or fertilization. Here both variation of linear measurements and variation in the shape of certain structures can significantly influence mate choice in different organisms. In the present work, we quantified sexual behaviour of the millipede Megaphyllum bosniense (Verhoeff, 1897) as characterized by several sequences. These are: mating latency, duration of copulation, contact to copulation time, duration of contact without copulation, time from entrance (time-point when individuals were placed in boxes in which tests occurred) to contact with copulation, and time from entrance to contact without copulation. Further, we analysed the influence of morphological variation (both variation of linear measurements and variation in the shape of several structures) on mating success. Variation of body length, antennal length, length of the walking legs, trunk width, and trunk height was analysed by traditional morphometrics, while variation in size and shape of the antennae, walking legs, head, and gonopods (promeres, opisthomeres) was analysed using geometric morphometrics. More than half of all physical contacts detected among the millipedes resulted in copulation. Based on the value of sexual selection coefficients, preferences toward the previous partner were found to be prevalent in both female and male choice tests. Individuals with different mating status significantly differed in some morphological traits (body mass, head centroid size, head shape, and promere shape). Our study yielded new information about the sexual behaviour of millipedes and variation of morphological traits as a potential basis for mate preferences.

scholarly journals Sexual Dimorphism in Bite Performance Drives Morphological Variation in Chameleons

PLoS ONE ◽  
2014 ◽  
Vol 9 (1) ◽  
pp. e86846 ◽  
Author(s):  
Jessica M. da Silva ◽  
Anthony Herrel ◽  
G. John Measey ◽  
Krystal A. Tolley
Keyword(s):  
Sexual Dimorphism ◽  
Morphological Variation

Sexual Selection and Sexual Dimorphism in Mottled Sculpins

Evolution ◽  
1983 ◽  
Vol 37 (1) ◽  
pp. 96 ◽  
Author(s):  
Jerry F. Downhower ◽  
Luther Brown ◽  
Ronald Pederson ◽  
Gloria Staples
Keyword(s):  
Sexual Selection ◽  
Sexual Dimorphism

scholarly journals Peak shifts and extinction under sex-specific selection

2021 ◽  
Author(s):  
Stephen P. De Lisle
Keyword(s):  
Sexual Selection ◽  
Sexual Dimorphism ◽  
Peak Shift ◽  
Adaptive Landscape ◽  
Population Estimates ◽  
Sexual Antagonism ◽  
Adaptive Landscapes ◽  
Quantitative Genetic ◽  
Complex Adaptive ◽  
The Face

AbstractA well-known property of sexual selection combined with a cross sex genetic correlation (rmf), is that it can facilitate a peak shift on the adaptive landscape. How do these diversifying effects of sexual selection +rmf balance with the constraints imposed by such sexual antagonism, to affect macroevolution of sexual dimorphism? Here, I extend existing quantitative genetic models of evolution on complex adaptive landscapes. Beyond recovering classical predictions for the conditions promoting a peak shift, I show that when rmf is moderate to strong, relatively weak sexual selection is required to induce a peak shift in males only. Increasing the strength of sexual leads to a sexually-concordant peak shift, suggesting that macroevolutionary rates of sexual dimorphism may be largely decoupled from the strength of within-population sexual selection. Accounting explicitly for demography further reveals that sex-specific peak shifts may be more likely to be successful than concordant shifts in the face of extinction, especially when natural selection is strong. An overarching conclusion is that macroevolutionary patterns of sexual dimorphism are unlikely to be readily explained by within-population estimates of selection or constraint alone.

Cryptic Diversity and Sexual Selection

2020 ◽  
pp. 447-471
Author(s):  
Matthias Galipaud ◽  
Loïc Bollache ◽  
Clément Lagrue
Keyword(s):  
Sexual Selection ◽  
Morphological Traits ◽  
Character Displacement ◽  
Secondary Contact ◽  
Cryptic Diversity ◽  
Reproductive Character Displacement ◽  
Behavioral Traits ◽  
Genetic Techniques ◽  
Existing Data

Recent advances in molecular and genetic techniques have revealed tremendous hidden genetic diversity in plants and animals. Crustaceans are no exception and, in fact, present one of the highest levels of cryptic diversity among the metazoans. Beyond the importance of such discovery and its multiple implications for taxonomy and ecology, it is now timely to investigate the potential causes of cryptic diversity. This chapter reviews the theoretical and experimental literature, seeking evidences for a relationship between sexual selection and cryptic diversity in crustaceans. It proposes three scenarios for the role of sexual selection on the origin and maintenance of pre-mating isolation and genetic divergence among crustacean populations, and suggests ways to discriminate among them experimentally or using existing data. Assuming that taxonomic identification is largely based on differences in sexually selected morphological traits, it also reviews evidence for a cryptic action of sexual selection on crustacean phenotypes. Specifically, if sexual selection acts primarily on chemical, visual, or behavioral traits, it is likely that allopatric crustacean populations remain morphologically similar even when they are reproductively isolated. This review shows that the strength of sexual selection likely differs among allopatric populations but does not seem to consistently induce pre-mating isolation (e.g. as in copepods and amphipods). Research is now needed to try to identify general patterns and determine the role of sexual selection on pre-mating isolation after secondary contact between populations, through reinforcement and reproductive character displacement.

scholarly journals Sex ratio and sexual selection in wormshrimps (Crustacea, Amphipoda, Ingolfiellidea)

2006 ◽  
Vol 75 (03-04) ◽  
pp. 189-194 ◽  
Author(s):  
Ronald Vonk ◽  
Vincent Nijman
Keyword(s):  
Sexual Selection ◽  
Sexual Dimorphism ◽  
Sex Ratio ◽  
Habitat Use ◽  
Individual Species ◽  
Small Populations ◽  
Secondary Sexual Characters ◽  
Elusive Species ◽  
The Individual ◽  
Secondary Sexual

Small populations of several species of the groundwater dwelling amphipod genus Ingolfiella are found in caves, wells, seabottoms, beaches and riverbed interstitial habitats. To gain insight in the socio-ecology of these elusive species, we used data from collected specimens to explore the relationships between sexratios, display of secondary sexual characters and other morphological features, and habitat use. We extracted data on the sex ratios and the presence-absence of secondary sexual characters of 13 species from the literature and through examination of museum material. We found a clearly skewed sex ratio with a preponderance of females, both in the individual species as in the genus as a whole. However, sex ratio and the display of secondary sexual characters were not correlated, nor did these characters correlate with the amount of sexual dimorphism. It remains unknown why so many ingolfiellids have evolved these costly features.

scholarly journals Exploitation of Diversity for Morphological Traits in Lilium tsingtauense under Different Habitats

2014 ◽  
Vol 6 (2) ◽  
pp. 178-184 ◽  
Author(s):  
KiByung LIM ◽  
Adnan YOUNIS ◽  
Jong TAEK PARK ◽  
Yoon JUNG HWANG
Keyword(s):  
Morphological Variation ◽  
Morphological Traits ◽  
Morphological Analysis ◽  
Flower Color ◽  
Cut Flower ◽  
Light Yellow ◽  
Fundamental Information ◽  
Color Fading ◽  
Young Leaves

In this study naturally growing morphological variation of Lilium tsingtauense (Korean wheel lily), from southern Chung San Island to northern Mount Seorak, was investigated in 16 habitats around the country. Morphological analysis revealed that this species had its own unique characteristics in different habitats. Flowers with luster are in actinomorphic form, with shades of orange, each plant having an average of 2.4 flowers that blossom upward. The shape of flower petals was from oval to oblong. The width of the petals, which determines the shape of the flower, significantly varied among regions. Flower petals showed purple spots and its occurrence greatly varied among plants from almost none to 300 spots per flower. In addition, when the number of spots increased, the flower color was more vivid. Leaves were typically one-tiered verticillate and most of the leaves were long, oval and some were lanceolate. Young leaves showed definitive patterns that faded during growth. Starting from the verticillate leaves, stems below the leaves were smooth, although 81% of all stems, above the verticillate leaves, showed rough micro-protrusions. Bulb shapes were long and vertically elliptical. The ramentum was light yellow in color and the base was darker, with the color fading toward the upper region of the plant. The shape of the ramentum was long, with a pointy end, and its adhesiveness was weak. This study offers basic fundamental information for the effective exploitation and recognition of L. tsingtauense resources as a potential cut flower and potting plant in floral trade worldwide.

Sign in / Sign up

Export Citation Format

Share Document