Sexual dimorphism in size and shell shape, and dichromatism of spotted turtles (Clemmys guttata) in Southwestern Michigan

2012 ◽  
Vol 33 (3-4) ◽  
pp. 443-450 ◽  
Author(s):  
John W. Rowe ◽  
Jessica R. Gradel ◽  
Charles F. Bunce ◽  
David L. Clark
Keyword(s):  
Body Size ◽  
Shell Height ◽  
Mate Recognition ◽  
Shell Shape ◽  
Sexually Dimorphic ◽  
Aquatic Habitats ◽  
Uv Spectrum ◽  
Full Spectrum ◽  
Cryptic Coloration ◽  
Clemmys Guttata

Differences in pigmentation, morphometry, and body size between sexes within populations can imply inter-sexual differences in reproductive biology. We assessed variation in body size, morphometrics, and pigmentation in Spotted Turtles (Clemmys guttata) in a southwestern Michigan population. Clemmys guttata was not sexually dimorphic in body size but when compared to males, positive allometric increases in shell height resulted in relatively domed shells in females. Integumental reflectance was mostly limited to the visual spectrum 400-700 nm with little to no reflectance in the UV spectrum (340-700 nm). We found no intersexual differences in the intensity (brightness) of yellow spots or black ground color of the head and carapace, perhaps suggesting that such markings are involved in cryptic coloration. The orange-red stripes of the head and forelimbs, that were similar in intensity between the sexes, would look conspicuous in the full spectrum light of the shallow aquatic habitats of C. guttata and thus could be involved in mate recognition. Chins of males were darker than those of females suggesting that chin color is a sexually selected trait.

A geometric analysis of growth in gastropod shells, with particular reference to turbinate forms

1983 ◽  
Vol 63 (4) ◽  
pp. 777-797 ◽  
Author(s):  
S. U. K. Ekaratne ◽  
D. J. Crisp
Keyword(s):  
Conversion Factor ◽  
Shell Height ◽  
Geometric Analysis ◽  
Logarithmic Spiral ◽  
Maximum Growth ◽  
Relative Magnitude ◽  
Shell Shape ◽  
Growth Band ◽  
Apical Angle ◽  
Image Position

Nucella lapillus and Littorina littorea afford examples of turbinately coiled shells with no space between the columella and the inner face of the whorls. Three constants are sufficient to determine the form of such shells: λ, the ratio between diameters of successive whorls; β, the semi-apical angle and ρ, the ratio of aperture length and breadth in the apertural plane passing through the axis. The variation of these three constants with size was examined and shown to be relatively small and insignificant in Nucella, but in Littorina it was significant.For Nucella and Littorina these shell characteristics were used to relate for the nth whorl, the length along the shell spiral (ln) to the shell height (Hn), the latter being the measure usually employed in growth studies. This relation was derived mathematically and confirmed empirically aswhere α is the angle of the logarithmic spiral given by α = tan−1 2π sin β/loge λ. The increased resolution of the micro-growth band increments, which are measured along the shell spiral was directly related to the ln:Hn ratios.Since the formula for the ln/Hn ratio (= shell conversion factor) includes λ, β and ρ, the three constants necessary to determine shell form in turbinately coiled shells of the type described, the shell conversion factor may be a better index of shell shape than indices based on a single constant. In species where the shell grows isometrically this ratio will remain constant, whereas changes in shell shape with size will influence this ratio. Such changes in shell shape during growth can be quantified in terms of the shell constants and when included in calculating the shell conversion factor, will show the relative magnitude of shell shape changes brought about by growth. The shell conversion factor may also be used to study the effects of ecological variations on the geometry of the shell.The conical shell of the limpet, Patella vulgata, is geometrically a much simpler system in which direct shell measurements were used to relate length along the direction of maximum growth to the antero-posterior diameter of aperture.

scholarly journals Body size, female reproduction and sexual dimorphism in the lizard Ameiva ameiva (Teiidae) in a restinga of southeastern Brazil

2008 ◽  
Vol 25 (2) ◽  
pp. 370-372 ◽  
Author(s):  
Carlos Frederico Duarte Rocha
Keyword(s):  
Body Size ◽  
Sexual Dimorphism ◽  
Clutch Size ◽  
Reproductive Period ◽  
Southeastern Brazil ◽  
Head Width ◽  
Sexually Dimorphic ◽  
Female Reproduction ◽  
Female Body Size ◽  
Reproductive Body

In this study 57 specimens of the lizard Ameiva ameiva (Linnaeus, 1758) collected in the restinga at Barra de Maricá, in the state of Rio de Janeiro, southeastern Brazil, were analyzed to investigate size relations and reproduction (in females) and sexual dimorphism of this population. We answered the following questions: 1) what is the minimum reproductive body size in females? 2) what is the average clutch size and 3) how is clutch size related to body size? 4) Are body and head sizes sexually dimorphic? Mean clutch size was 6.7 ± 2.1 eggs and was positively correlated with female body size. Sexual dimorphism favoring males was found: adult mean snout-vent length was great in males (124.2 ± 17.8 mm) than females (96.5 ± 23.1 mm SVL), and males were larger with respect to head width and length, and body mass. Thus, despite the marked seasonality at Barra de Maricá, A. ameiva has an extended reproductive period. Also, intrasexual selection may have acted on females to produce larger clutches, and on males, favoring larger males.

Geographic variation in body size and sexual size dimorphism of North American Ratsnakes (Pantherophis spp. s.l.)

2018 ◽  
Vol 96 (11) ◽  
pp. 1196-1202 ◽  
Author(s):  
Brett A. DeGregorio ◽  
Gabriel Blouin-Demers ◽  
Gerardo L.F. Carfagno ◽  
J. Whitfield Gibbons ◽  
Stephen J. Mullin ◽  
...  
Keyword(s):  
Body Size ◽  
Large Scale ◽  
Sexual Size Dimorphism ◽  
Size Variation ◽  
Sexually Dimorphic ◽  
Male Body ◽  
Complex Species ◽  
Size Dimorphism ◽  
Body Size Variation ◽  
Female Body Size

Because body size affects nearly all facets of an organism’s life history, ecologists have long been interested in large-scale patterns of body-size variation, as well as why those large-scale patterns often differ between sexes. We explored body-size variation across the range of the sexually dimorphic Ratsnake complex (species of the genus Pantherophis Fitzinger, 1843 s.l.; formerly Elaphe obsoleta (Say in James, 1823)) in North America. We specifically explored whether variation in body size followed latitudinal patterns or varied with climatic variables. We found that body size did not conform to a climatic or latitudinal gradient, but instead, some of the populations with the largest snakes occurred near the core of the geographic range and some with the smallest occurred near the northern, western, and southern peripheries of the range. Males averaged 14% larger than females, although the degree of sexual size dimorphism varied between populations (range: 2%–25%). There was a weak trend for male body size to change in relation to temperature, whereas female body size did not. Our results indicate that relationships between climate and an ectotherm’s body size are more complicated than linear latitudinal clines and likely differ for males and females.

scholarly journals CO2-induced low pH in an eastern oyster (Crassostrea virginica) hatchery positively affects reproductive development and larval survival but negatively affects larval shape and size, with no intergenerational linkages

2020 ◽  
Author(s):  
Jeff C Clements ◽  
Claire E Carver ◽  
Martin A Mallet ◽  
Luc A Comeau ◽  
André L Mallet
Keyword(s):  
Crassostrea Virginica ◽  
Shell Height ◽  
Reproductive Development ◽  
Eastern Oyster ◽  
Larval Survival ◽  
Low Ph ◽  
Shell Shape ◽  
Biological Sex ◽  
Positive Effects ◽  
Ph Conditions

Abstract In North America, studies regarding effects of CO2-induced low pH in bivalve aquaculture are largely restricted to the US Pacific coast. Studies on species from the northwest Atlantic are lacking. Furthermore, information on the roles of intergenerational exposure and biological sex in bivalve responses to low pH, particularly in an aquaculture-specific context, is scant. We tested if short-term (1 month) exposure to CO2-induced reductions in pHNBS affected the reproductive development of male and female eastern oysters (Crassostrea virginica) during hatchery-specific reproductive conditioning and whether maternal and/or paternal exposure influenced larval responses. Reduced pH (7.5–7.7) increased the rate of reproductive development in both males and females. There was no indication of intergenerational effects; adult pH conditions did not affect early larval development. In contrast, low pH conditions experienced by gametes during spawning, fertilization, and embryo incubation (48 h) resulted in higher larval survival (+6–8% from control), reduced shell height (−2 to 3 µm), and increased deformities (abnormal shell shape; +3–5%). We suggest that local adaptation to acidic land runoff may account for the positive effects of low pH observed in this study. Bioeconomic assessments are now needed to understand the implications of reduced pH on aquaculture operations in these regions of Atlantic Canada.

The Detection of Near-Ultraviolet Light by Nonmigratory and Migratory Birds

The Auk ◽  
1984 ◽  
Vol 101 (1) ◽  
pp. 53-58 ◽  
Author(s):  
John W. Parrish ◽  
James A. Ptacek ◽  
Kevin L. Will
Keyword(s):  
Migratory Birds ◽  
Uv Light ◽  
Mate Recognition ◽  
Insectivorous Birds ◽  
Uv Spectrum ◽  
Near Ultraviolet ◽  
Ultraviolet Reflectance ◽  
Uv Reflectance ◽  
Uv Vision ◽  
First Time

Abstract Near-ultraviolet (UV) light reception was demonstrated for the first time in three species of nonmigratory emberizid and passerid birds. Behavioral data also established that eight additional alcedinid and emberizid birds can detect near-UV wavelengths. The finding that these more recently evolved species can see near-UV light implies that near-UV vision is probably an important visual capability in most, if not all, diurnal birds. Although the utility of near-UV reception for birds remains equivocal, the fact that nonmigratory as well as migratory birds can perceive UV suggests that birds may be able to utilize the UV spectrum for homing, orientation, and navigation, as do the UV-sensitive arthropods. It also can be inferred that UV vision may be especially useful to insectivorous birds for the detection of UV reflectance patterns, which many otherwise cryptic arthropods possess for mate recognition. Ultraviolet reflectance patterns also may be useful to frugivorous and nectarivorous birds for the detection of food items.

TO SYNCHRONISE OR NOT TO SYNCHRONISE: A DILEMMA FOR YOUNG BIGHORN MALES?

Behaviour ◽  
1999 ◽  
Vol 136 (6) ◽  
pp. 805-818 ◽  
Author(s):  
Keyword(s):  
Body Size ◽  
Age Groups ◽  
Young Male ◽  
Ovis Canadensis ◽  
Sexually Dimorphic ◽  
Group Type ◽  
Group Members ◽  
Mixed Groups ◽  
Mixed Age ◽  
Dimorphic Species

AbstractBighorn sheep (Ovis canadensis) are sexually dimorphic and live in nursery groups, bachelor or mixed groups. To remain in a group, individuals have to synchronise their activity according to the type of group they are in, which may incur a cost for individuals of different body size from the other group members. To test this hypothesis, I calculated the degree of synchrony of activities for each individual within a group. Animals in nursery or bachelor groups were highly synchronised with each other while mixed-age-sex groups had the lowest group synchronisation index. Two and three-year old bighorn males are intermediate in body size between the two adult sexes. Two-year-old males always adjusted their behaviour independent of group type, while three-year-old males synchronised their behaviour when with bachelor, but less so when in nursery groups. I suggest that two- and three-year-old males may face a conflict between synchronising their behaviour to stay in a group and the need to forage according to their own time budgets. I conclude that intermediate-sized young male ungulates of sexually dimorphic species may be better off forming same-sex-age groups.

Reproductive patterns of European pond turtles differ between sites: a small scale scenario

2015 ◽  
Vol 36 (4) ◽  
pp. 339-349
Author(s):  
Marco A.L. Zuffi ◽  
Elena Foschi
Keyword(s):  
Body Size ◽  
Egg Production ◽  
Shell Height ◽  
The Body ◽  
Small Scale ◽  
Central Mediterranean ◽  
Population Structures ◽  
Body Sizes ◽  
Reproductive Females ◽  
Similar Body

From 1996 to 2002, we studied the body size, measures of reproductive strategy (relative clutch mass and delayed reproduction at sexual maturity), and reproductive output (clutch frequency and annual egg production) of female European Pond turtles,Emys orbicularis, at two sites separated by 12 km in central Mediterranean Tuscany (San Rossore and Camp Darby, central northern Italy). Females did not reproduce at the first appearance of external sexual characters, but reproduced at larger sizes, probably as older turtles. Among years, reproductive females were more common than were non-reproductive females, yet both groups had similar body sizes. Body size (carapace length and width, plastron length and width, shell height and body mass) varied between localities and among years. Body size differed between reproductive and non reproductive females in Camp Darby, but not in San Rossore females. Shell volume did not vary among years, nor between localities, nor between reproductive status. Reproductive females had higher body condition indices (BCI) than did non-reproductive females, while BCI did not differ between females laying one clutch and females laying multiple clutches. Clutch size did not vary among years. One clutch per year was much more frequent than multiple clutches, and multiple clutches were more frequent in Camp Darby than in San Rossore females, likely due to differences in population structures between sites.

scholarly journals Sexual dimorphism in mud crabs: a tale of three sympatric Scylla species

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10936
Author(s):  
Hanafiah Fazhan ◽  
Khor Waiho ◽  
Yushinta Fujaya ◽  
Nita Rukminasari ◽  
Hongyu Ma ◽  
...  
Keyword(s):  
Body Size ◽  
Sexual Dimorphism ◽  
Discriminant Function ◽  
Discriminant Function Analysis ◽  
Function Analysis ◽  
Carapace Width ◽  
Sympatric Species ◽  
Sexually Dimorphic ◽  
Morphometric Characteristics ◽  
Mud Crabs

Sexual dimorphism is a common phenomenon in the animal kingdom. To test the consistency of sexual dimorphism patterns among sympatric species of the same genus, ten morphometric characteristics of mud crabs Scylla olivacea, S. tranquebarica and S. paramamosain were measured and compared using Discriminant Function Analysis (DFA). The descriptive analysis revealed that in all three species, body size dimensions and cheliped dimensions were significantly larger in males whereas the abdomen width was female-biased. Also, we described a morphological variation (carapace width, CW ≤ CW at spine 8, 8CW) that is unique to S. olivacea. Discriminant function analysis revealed that all nine morphometric characteristics were sexually dimorphic in S. olivacea, S. tranquebarica (except right cheliped’s merus length, ML) and S. paramamosain (except 8CW). The obtained discriminant functions based on the morphometric ratios (with CW as divisor) correctly classified 100% of adults of known sex of all three species. Further, based on the selected body traits, DFA was able to almost completely distinguish males (94%), but not females (74%), among the three Scylla species. This study highlights that congeneric species of portunids (e.g., Scylla spp.) show similar sexually dimorphic characteristics (body size and secondary sexual characteristics).

scholarly journals Description of the male of fossil <i>Calomicrus eocenicus</i> Bukejs et Bezděk (Coleoptera: Chrysomelidae: Galerucinae) from Eocene Baltic amber using X-ray microtomography

Fossil Record ◽  
2020 ◽  
Vol 23 (1) ◽  
pp. 105-115 ◽  
Author(s):  
Andris Bukejs ◽  
Jan Bezděk ◽  
Vitalii I. Alekseev ◽  
Kristaps Kairišs ◽  
Ryan C. McKellar
Keyword(s):  
Body Size ◽  
Body Cavity ◽  
The Body ◽  
Baltic Amber ◽  
Sexually Dimorphic ◽  
Apical Margin ◽  
Fossil Species ◽  
X Ray ◽  
Total Body ◽  
First Time

Abstract. A male representative of the extinct species Calomicrus eocenicus Bukejs et Bezděk, 2014 (Chrysomelidae: Galerucinae) is found and described for the first time from Eocene Baltic amber using X-ray microtomography. The aedeagus is well preserved within the body cavity of the specimen, and it is illustrated in detail. This fossil species exhibits distinct sexual dimorphism: the male has a smaller total body size, as well as a copula-adapted modification in abdominal ventrite 5 (apical margin deeply trilobed, with round medial fovea present); meanwhile the female is larger in body size and has a simple abdominal ventrite 5 (without fovea, non-incised and widely rounded apically). Similar sexually dimorphic characters are typical for extant members of the tribe Luperini, and this report is the first time that they are described in an Eocene species. The known sexually dimorphic characters present in Coleoptera within Eocene Baltic amber are briefly discussed.

scholarly journals Performance Surface Analysis Identifies Consistent Functional Patterns across 10 Morphologically Divergent Terrestrial Turtle Lineages

2019 ◽  
Vol 59 (2) ◽  
pp. 346-357 ◽  
Author(s):  
C Tristan Stayton
Keyword(s):  
Functional Performance ◽  
Morphological Changes ◽  
Shell Height ◽  
Model Systems ◽  
Hydrodynamic Performance ◽  
Shell Shape ◽  
Test Case ◽  
Evolutionary Diversification ◽  
And Performance ◽  
Performance Surface

Abstract Newly-developed methods for utilizing performance surfaces—multivariate representations of the relationship between phenotype and functional performance—allow researchers to test hypotheses about adaptive landscapes and evolutionary diversification with explicit attention to functional factors. Here, information from performance surfaces of three turtle shell functions—shell strength, hydrodynamics, and self-righting—is used to test the hypothesis that turtle lineages transitioning from aquatic to terrestrial habitats show patterns of shell shape evolution consistent with decreased importance of hydrodynamic performance. Turtle shells are excellent model systems for evolutionary functional analysis. The evolution of terrestriality is an interesting test case for the efficacy of these methods because terrestrial turtles do not show a straightforward pattern of morphological convergence in shell shape: many terrestrial lineages show increased shell height, typically assumed to decrease hydrodynamic performance, but there are also several lineages where the evolution of terrestriality was accompanied by shell flattening. Performance surface analyses allow exploration of these complex patterns and explicit quantitative analysis of the functional implications of changes in shell shape. Ten lineages were examined. Nearly all terrestrial lineages, including those which experienced decreased shell height, are associated with morphological changes consistent with a decrease in the importance of shell hydrodynamics. This implies a common selective pattern across lineages showing divergent morphological patterns. Performance studies such as these hold great potential for integrating adaptive and performance data in macroevolutionary studies.

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