A Review of Shark Reproductive Ecology: Life History and Evolutionary Implications

2008 ◽  
pp. 449-484
1996 ◽  
Vol 19 (2) ◽  
pp. 209
Author(s):  
R. Delaney

Petrogale assimilis has a typical life history and reproductive ecology for a macropodid of its size. Both sexes are capable of reproducing continuously; gestation is about the same length as the oestrous cycle (approximately one month); a single young is born and, a post-partum oestrus and embryonic diapause probably occurs. The sex ratio of young is unbiased. Pouch young remain permanently attached to the teat until 110 - 143 days (n=11). Permanent exit from the pouch occurs at 180 - 231 days (mean=201 days, n=25), and weaning occurs between 267 - 387 days (n=5). Sexual maturity occurs at a minimum age of 17.5 months in females and 23 months in males.


2018 ◽  
Vol 32 (1) ◽  
pp. 34-50 ◽  
Author(s):  
Roy C. Averill-Murray ◽  
Terry E. Christopher ◽  
Brian T. Henen

2005 ◽  
Vol 53 (6) ◽  
pp. 353 ◽  
Author(s):  
DG Chapple

The life history and reproductive ecology of White’s skink, Egernia whitii, was examined in a population in the Australian Capital Territory using both field and genetic studies. Colour pattern polymorphism was evident within the population, with both patterned and plain-back morphs present. Lizards typically took 3 years to reach sexual maturity, with the size at maturity being ~75 mm snout–vent length (SVL) in both sexes. There was an even overall adult sex ratio, although a slight female-bias was evident in plain-back individuals. Sexual dimorphism was evident, with males having longer and wider heads, and females having larger body size. Females generally bred annually, with mating occurring in September–October and parturition in late January–February, although the litter was produced over several days (2–10 days, mean 4 days). Litter size ranged from one to four (mean of 2.5). There was a significant relationship between maternal SVL and both litter size and relative clutch mass, but these trends were not consistent between colour morphs. An inverse relationship between litter size and offspring size (SVL and mass) was found. Comparison of the results with previous investigations of E. whitii indicates substantial geographic variation in life-history traits that is presumably associated with latitudinal variation in climatic conditions.


2020 ◽  
Author(s):  
Janko Mileta Međedović

Mating patterns are crucial for understanding selection regimes in current populations and highly implicative for sexual selection and life history theory. However, empirical data on the relations between mating and fitness-related outcomes in contemporary humans are lacking. In the present research we examined the sexual selection on mating (with an emphasis on Bateman’s third parameter – the association between mating and reproductive success) and life history dynamics of mating by examining the relations between mating patterns and a comprehensive set of variables which determine human reproductive ecology. We conducted two studies (Study 1: N=398, Mage=31.03; Study 2: N=996, Mage=40.81, the sample was representative for participants’ sex, age, region, and settlement size). The findings from these studies were mutually congruent and complementary. In general, the data suggested that short-term mating was unrelated or even negatively related to reproductive success. Conversely, long-term mating was positively associated with reproductive success and there were indices that the beneficial role of long-term mating is more pronounced in males, which is in accordance with Bateman’s third principle. Observed age of first reproduction fully mediated the link between long-term mating and number of children but only in male participants. There were no clear indications of the position of the mating patterns in human life history trajectories; however, the obtained data suggested that long-term mating has some characteristics of fast life history dynamics. Findings are implicative for sexual selection and life history theory in humans.


2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Jeffrey P. Ethier ◽  
Aurore Fayard ◽  
Peter Soroye ◽  
Daeun Choi ◽  
Marc J. Mazerolle ◽  
...  

AbstractAmphibian biodiversity is declining globally, with over 40% of species being considered threatened to become extinct. Crucial to the success of conservation initiatives are a comprehensive understanding of life history and reproductive ecology of target species. Here we provide an overview of the Pseudacris genus, including breeding behaviour, reproduction, development, survival and longevity. We present an updated distribution map of the 18 species found throughout North America. We also summarize the conservation status at the national and subnational (state, provincial, and territorial) levels, in Canada, USA, and Mexico, to evaluate the relationship between life history traits and extinction risk. Results show a high degree of consistency in the life history traits of Pseudacris species considering their relative diversity and wide distribution in North America. However, data are lacking for several species, particularly in the Fat Frog and West Coast clades, causing some uncertainties and discrepancies in the literature. We also found that the most threatened populations of chorus frog were located in the east coast of the USA, potentially as a result of increased levels of anthropogenic disturbance. We suggest that the similarities in life history traits among chorus frog species provides an opportunity for collaboration and united efforts for the conservation of the genus.


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