scholarly journals Larger body size leads to greater female beluga whale ovarian reproductive activity at the southern periphery of their range

2021 ◽  
Author(s):  
Steven H. Ferguson ◽  
David J. Yurkowski ◽  
Justine M. Hudson ◽  
Tera Edkins ◽  
Cornelia Willing ◽  
...  
Keyword(s):  
Body Size ◽  
Reproductive Activity ◽  
Beluga Whale

scholarly journals Larger body size leads to greater female beluga whale reproductive activity at the southern periphery of their range

2021 ◽  
Author(s):  
Steven Ferguson ◽  
David Yurkowski ◽  
Justine Hudson ◽  
Tera Edkins ◽  
Cornelia Willing ◽  
...  
Keyword(s):  
Body Size ◽  
Body Length ◽  
Reproductive Activity ◽  
Food Competition ◽  
Beluga Whale ◽  
Delphinapterus Leucas ◽  
Hudson Bay ◽  
Beluga Whales ◽  
Future Challenges ◽  
Variation Explained

Identification of phenotypic characteristics in reproductively successful individuals provides important insights into the evolutionary processes that cause range shifts due to environmental change. Female beluga whales (Delphinapterus leucas) from the Baffin Bay region (BB) of the Canadian Arctic in the core area of the species’ geographic range have larger body size than their conspecifics at the southern range periphery in Hudson Bay (HB). We investigated the mechanism for this north and south divergence as it relates to reproductive activity (RA = total corpora) that combines morphometric data with ovarian corpora counted from female reproductive tracts. Based on the previous finding of reproductive senescence in older HB females, but not for BB whales, we compared RA patterns the of the two populations’ with age and body length. Female beluga whale RA increased more quickly with age (63% partial variation explained) in BB than in HB (41%). In contrast, body length in HB female beluga whale accounted for considerably more of the total variation (12 vs 1%) in RA compared to BB whales. We speculate that female HB beluga whale RA was more strongly linked with body length due to higher population density resulting in food competition that favors the energetic advantages of larger body size during seasonal food limitations. Understanding the evolutionary mechanism of how RA, and potentially fitness, varies across a species’ range will assist conservation efforts in anticipating and mitigating future challenges associated with a warming planet.

scholarly journals Larger body size leads to greater female beluga whale ovarian reproductive activity at the southern periphery of their range

2021 ◽  
Author(s):  
Steven Ferguson ◽  
David Yurkowski ◽  
Justine Hudson ◽  
Tera Edkins ◽  
Cornelia Willing ◽  
...  
Keyword(s):  
Body Size ◽  
Body Length ◽  
Reproductive Activity ◽  
Food Competition ◽  
Beluga Whale ◽  
Delphinapterus Leucas ◽  
Hudson Bay ◽  
Beluga Whales ◽  
Future Challenges ◽  
Variation Explained

Identification of phenotypic characteristics in reproductively successful individuals provides important insights into the evolutionary processes that cause range shifts due to environmental change. Female beluga whales (Delphinapterus leucas) from the Baffin Bay region (BB) of the Canadian Arctic in the core area of the species’ geographic range have larger body size than their conspecifics at the southern range periphery in Hudson Bay (HB). We investigated the mechanism for this north and south divergence as it relates to ovarian reproductive activity (ORA = total corpora) that combines morphometric data with ovarian corpora counted from female reproductive tracts. Based on the previous finding of reproductive senescence in older HB females, but not for BB whales, we compared ORA patterns of the two populations with age and body length. Female beluga whale ORA increased more quickly with age (63% partial variation explained) in BB than in HB (41%). In contrast, body length in HB female beluga whales accounted for considerably more of the total variation (12 vs 1%) in ORA compared to BB whales. We speculate that female HB beluga whale ORA was more strongly linked with body length due to higher population density resulting in food competition that favors the energetic advantages of larger body size during seasonal food limitations. Understanding the evolutionary mechanism of how ORA varies across a species’ range will assist conservation efforts in anticipating and mitigating future challenges associated with a warming planet.

Reproductive biology of the false coral snake Oxyrhopus guibei (Colubridae) from southeastern Brazil

2002 ◽  
Vol 23 (4) ◽  
pp. 495-504 ◽  
Author(s):  
Otavio Marques ◽  
Lígia Pizzatto
Keyword(s):  
Body Size ◽  
Reproductive Biology ◽  
Rainy Season ◽  
Reproductive Activity ◽  
Climatic Conditions ◽  
Southeastern Brazil ◽  
Coral Snake ◽  
Males And Females ◽  
Reproductive Cycles ◽  
Number Of Individuals

AbstractThe reproductive biology of the false coral snake, Oxyrhopus guibei, was studied through dissection of 496 specimens, combined with observations on captive individuals. Males mature with smaller body size than females, females attain much larger body size, and male-male combat is not expected. Clutch size ranged from 3 to 20, and was correlated with female length. Reproductive cycles in both males and females seem to be continuous, with vitellogenesis and spermatogenesis occurring throughout the year. Reproductive activity in both sexes decreased at the end of the rainy season possibly due to previous intense reproductive activity in more favorable climatic conditions. The smaller number of individuals collected at the end of the rainy season apparently occurs due to the decrease of reproductive activity of this snake.

scholarly journals Reproductive biology of the Amazon Lava Lizard (Tropidurus torquatus) from the Wet Chaco of Corrientes (Argentina): congeneric comparisons of ecotypic and interspecific variations

2014 ◽  
Vol 92 (7) ◽  
pp. 643-655 ◽  
Author(s):  
M.A. Ortiz ◽  
J.M. Boretto ◽  
C. Piantoni ◽  
B.B. Álvarez ◽  
N.R. Ibargüengoytía
Keyword(s):  
Body Size ◽  
Reproductive Biology ◽  
Fat Body ◽  
Tail Length ◽  
Reproductive Activity ◽  
Hatching Time ◽  
Fat Bodies ◽  
Reproductive Cycles ◽  
Lava Lizard ◽  
Clutch Mass

Herein we describe the reproductive biology of a population of the Amazon Lava Lizard (Tropidurus torquatus (Wied-Neuwied, 1820)) from Corrientes, northeastern Argentina (Wet Chaco). We describe the male and female reproductive cycles, minimum body size for adults, reproductive output, mean relative clutch mass, fat body cycles, and sexual dimorphism. Our results were compared with data on the reproductive biology of Brazilian populations of T. torquatus and congeneric species. In Corrientes, males of T. torquatus exhibited a continuous reproductive cycle, but with annual variation of testicular parameters associated with spermatogenic activity. In contrast, females were reproductive only from winter to summer (July–February), laying at least two clutches each of six eggs, on average, per reproductive season. The relative clutch mass and egg size values in Corrientes were the highest reported for the species. The annual cycle of energy storage (as fat bodies) was inversely correlated with reproductive activity in both sexes. Males differed from females in snout–vent length, head size, interlimb length, and tail length. We observed interpopulational differences in relative clutch mass, egg volume and mass, incubation period and hatching time, and the minimum body size for sexual maturity probably as a result of phenotypic plasticity or adaptation to local environmental conditions and likely both.

Body size of ectotherms constrains thermal requirements for reproductive activity in seasonal environments

2020 ◽  
Vol 98 (10) ◽  
pp. 651-659
Author(s):  
Jared W.H. Connoy ◽  
Jessica A. Leivesley ◽  
Ronald J. Brooks ◽  
Jacqueline D. Litzgus ◽  
Njal Rollinson
Keyword(s):  
Body Size ◽  
Thermal Inertia ◽  
Reproductive Activity ◽  
Time Of Day ◽  
Thermal Requirements ◽  
Heating And Cooling ◽  
Painted Turtles ◽  
Snapping Turtles ◽  
Nesting Behaviour ◽  
Preferred Body Temperature

Body size may influence ectotherm behaviour by influencing heating and cooling rates, thereby constraining the time of day that some individuals can be active. The time of day at which turtles nest, for instance, is hypothesized to vary with body size at both inter- and intra-specific levels because large individuals have greater thermal inertia, retaining preferred body temperatures for a longer period of time. We use decades of data on thousands of individual nests from Algonquin Park, Ontario, Canada, to explore how body size is associated with nesting behaviour in Painted Turtles (Chrysemys picta (Schneider, 1783); small bodied) and Snapping Turtles (Chelydra serpentina (Linnaeus, 1758); large bodied). We found that (i) between species, Painted Turtles nest earlier in the evening and at higher mean temperatures than Snapping Turtles, and (ii) within species, relatively large individuals of both species nest at cooler temperatures and that relatively larger Painted Turtles nest later in the evening compared with smaller Painted Turtles. Our data support the thermal inertia hypothesis and may help explain why turtles in general exhibit geographic clines in body size: northern environments experience more daily variation in temperature, and larger size may evolve, in part, for retention of preferred body temperature during terrestrial forays.

Visual signaling and reproductive biology in a nocturnal treefrog, genus Hyla (Anura: Hylidae)

2004 ◽  
Vol 25 (4) ◽  
pp. 395-406 ◽  
Author(s):  
Paulo Hartmann ◽  
Marília Hartmann ◽  
Célio Haddad
Keyword(s):  
Body Size ◽  
Unknown Function ◽  
Courtship Behavior ◽  
Reproductive Mode ◽  
Reproductive Activity ◽  
Call Structure ◽  
Larval Stages ◽  
Visual Signaling ◽  
Body Sizes ◽  
Behavioral Sequences

AbstractWe investigated reproductive activity, courtship behavior, call structure, body size, clutch size, oviposition site, and reproductive mode of Hyla sp. (aff. ehrhardti). Males called in all months, but showed a peak of activity during the rainy season. Three pair formations were observed and courtship involved stereotyped behavioral sequences, including visual signaling. Males emitted three different vocalization types: advertisement calls, courtship calls, and a vocalization of unknown function. Females attained larger body sizes than males and deposited an average of 74.5 unpigmented eggs per clutch. Early larval stages are aquatic but restricted to water in constructed subterranean nests; subsequent to flooding of nests, exotrophic tadpoles live in ponds or streams. Courtship behavior in Hyla sp. (aff. ehrhardti) is complex and the diverse repertoire of limb movements, exhibited by males, probably provide visual stimuli to females in this nocturnal treefrog. Hyla sp. (aff. ehrhardti) belongs to the H. albomarginata group. Considering the reproductive modes in this group, the complexes of H. albosignata and of H. albofrenata can be considered more close related to each other than to the H. albomarginata complex.

scholarly journals The Composition of the Blood of the Shore Crab, Carcinus Moenas (Pennant), in Relation to Sex and Body Size

1959 ◽  
Vol 36 (3) ◽  
pp. 495-500
Author(s):  
A. B. GILBERT
Keyword(s):  
Body Weight ◽  
Body Size ◽  
Frequency Distribution ◽  
Reproductive Activity ◽  
Ionic Concentration ◽  
Shore Crab ◽  
Protein Nitrogen ◽  
Body Weights ◽  
Total Ionic Concentration

1. The influence of sex and body weight on the concentration of the non-protein nitrogen (N.P.N.) in the blood of Carcinus moenas was investigated. 2. Blood N.P.N. decreased with body size in both sexes until a minimum was reached at a body weight of about 35 g. Thereafter it increased with increasing body weight. 3. For body weights less than 35 g. males had higher N.P.N. values than females; above this weight male values were lower. Statistically these differences were highly significant. 4. Frequency distribution of reproductive activity with body size showed peaks which correspond with those for total ionic concentration (Gilbert, 1959a, b) and with the troughs for N.P.N. 5. Results of the present work have been discussed in relation to those reported earlier for conductivity, total O.P., chloride and sulphate (Gilbert, 1959a, b).

A modelling-based perspective on the past, present, and future polychlorinated biphenyl contamination of the St. Lawrence beluga whale (Delphinapterus leucas) population

2000 ◽  
Vol 57 (S1) ◽  
pp. 101-112 ◽  
Author(s):  
Brendan E Hickie ◽  
Michael CS Kingsley ◽  
Peter V Hodson ◽  
Derek CG Muir ◽  
Pierre Béland ◽  
...  
Keyword(s):  
Polychlorinated Biphenyl ◽  
Sediment Cores ◽  
Reproductive Activity ◽  
Population Based ◽  
Beluga Whale ◽  
Delphinapterus Leucas ◽  
History Of ◽  
Beluga Whale Delphinapterus Leucas ◽  
American Eels ◽  
Good Agreement

Individual- and population-based models are presented that provide quantitative assessments of the accumulation of persistent organic pollutants over the lifetime of the beluga whale (Delphinapterus leucas) and consider all aspects of its life history. The models are used to examine the history of polychlorinated biphenyl (PCB) accumulation by the endangered St. Lawrence beluga population from 1950 to the present and to predict future trends based on likely contaminant loading scenarios. The hypothesis that migrating American eels (Anguilla rostrata) are a significant source of contaminants to the population is examined. The history of PCB exposure via the diet is reconstructed from existing data and from PCB profiles in dated sediment cores. The models adequately describe the effects of age, growth, sex, and reproductive activity on PCB concentrations in the beluga, and results show good agreement with observed concentrations when eels are included as 3% of the annual diet. PCB levels in the population appear to have peaked between 1967 and 1972. The model agrees with recent studies that have shown that PCB concentrations in the population are declining slowly.

Sexual dimorphism and evidence for intrasexual selection from quill impalements, injuries, and mate guarding in porcupines (Erethizon dorsatum)

1997 ◽  
Vol 75 (6) ◽  
pp. 847-854 ◽  
Author(s):  
Richard Alan Sweitzer ◽  
Joel Berger
Keyword(s):  
Sexual Selection ◽  
Body Size ◽  
Sexual Dimorphism ◽  
Mate Guarding ◽  
Reproductive Activity ◽  
Erethizon Dorsatum ◽  
Threshold Size ◽  
Guarding Behavior ◽  
Mating Opportunities ◽  
Foot Pad

Sexual selection is a commonly cited explanation for sexual size dimorphism. We examined patterns of sexual dimorphism in North American porcupines (Erethizon dorsatum) and used data on quill impalements, injuries, and guarding behavior to examine the intrasexual component of sexual selection among male porcupines. Results indicated that porcupines were sexually dimorphic for foot-pad length, body length, and body mass because males grew more rapidly and for longer periods than females. Quill impalements, injuries, and guarding episodes were restricted predominantly to older, larger males, intimating that only the largest porcupines were reproductively active. Regression analyses suggested that size was more important than age in predicting reproductive activity among males. Also, relatively few quill impalements and guarding episodes among younger, smaller animals suggest that there is a threshold size below which male porcupines do not attempt to compete for mate access. Although our data do not directly link larger body size in males with relatively high reproductive success, they suggest that sexual dimorphism in this species is at least partly the result of the intrasexual component of sexual selection. It is also possible that females select males on the basis of quill morphology or some other indicator of male quality. Thus, our understanding of sexual dimorphism in porcupines would benefit from additional research investigating the extent to which body size and patterns of quill number or size are advantageous to male porcupines in garnering mating opportunities and enhancing fitness.

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