The Influence of Fall Foraging Success on Follicle Number in the Northern Water Snake, Nerodia sipedon

2001 ◽  
Vol 35 (3) ◽  
pp. 504 ◽  
Author(s):  
James N. Barron ◽  
Gregory M. Andraso
Keyword(s):  
Foraging Success ◽  
Nerodia Sipedon ◽  
Water Snake ◽  
Northern Water Snake

Variation in offspring sex ratios in the northern water snake (Nerodia sipedon)

1998 ◽  
Vol 76 (12) ◽  
pp. 2200-2206 ◽  
Author(s):  
Patrick J Weatherhead ◽  
Gregory P Brown ◽  
Melanie R Prosser ◽  
Kelley J Kissner
Keyword(s):  
Sex Ratio ◽  
Sex Ratios ◽  
Birth Date ◽  
Nerodia Sipedon ◽  
Water Snake ◽  
In Captivity ◽  
Northern Water Snake ◽  
Northern Water Snakes ◽  
Gravid Females ◽  
Water Snakes

We used data from 88 litters of northern water snakes (Nerodia sipedon) to test predictions about how mothers would adaptively vary the sex ratios of their offspring. Larger mothers produced significantly more daughters (r2 = 0.04, P = 0.05), and mothers producing larger offspring produced significantly more daughters (r2 = 0.06, P = 0.02). Because neonate size did not vary with maternal size, these sex-ratio patterns were independent of each other. These patterns were more pronounced for wild females than for females maintained in captivity while gravid, but rearing conditions did not have a significant effect on sex ratio. Also, because sex ratios were similar between captive and free-living females despite captive females giving birth 16 days earlier, on average, and because sex ratios did not vary with birth date within the two groups of females, gestation appeared not to affect sex ratio. If females vary sex ratios adaptively, only the relationship between sex ratio and neonate size was consistent with our predictions. Limited evidence from other snake species also indicates variation in neonatal sex ratios that is nonrandom but not necessarily adaptive. A better understanding of these patterns will require information on the factors that affect the fitness of male and female neonates differently. An unexpected sex-ratio pattern that we found was that 14 of 19 stillborn young were male. We speculate that this pattern could be a result of male embryonic sensitivity to temperature. Thus, the need for gravid females to maintain a high body temperature so that their young are born with enough time to find hibernation sites may conflict with the need for embryos to develop at a safe temperature.

Sex ratios, mating behavior and sexual size dimorphism of the northern water snake, Nerodia sipedon

1995 ◽  
Vol 36 (5) ◽  
pp. 301-311 ◽  
Author(s):  
Patrick J. Weatherhead ◽  
Frances E. Barry ◽  
Gregory P. Brown ◽  
Mark R. L. Forbes
Keyword(s):  
Mating Behavior ◽  
Sexual Size Dimorphism ◽  
Sex Ratios ◽  
Nerodia Sipedon ◽  
Size Dimorphism ◽  
Water Snake ◽  
Northern Water Snake

Sex ratios, mating behavior and sexual size dimorphism of the northern water snake, Nerodia sipedon

1995 ◽  
Vol 36 (5) ◽  
pp. 301-311 ◽  
Author(s):  
P. J. Weatherhead ◽  
Frances E. Barry ◽  
Gregory P. Brown ◽  
M. R. L. Forbes
Keyword(s):  
Mating Behavior ◽  
Sexual Size Dimorphism ◽  
Sex Ratios ◽  
Nerodia Sipedon ◽  
Size Dimorphism ◽  
Water Snake ◽  
Northern Water Snake

Effects of Maternally-Transferred Methylmercury on Stress Physiology in Northern Water Snake (Nerodia sipedon) Neonates

2016 ◽  
Vol 96 (6) ◽  
pp. 725-731 ◽  
Author(s):  
J. Patrick W. Cusaac ◽  
Victoria Kremer ◽  
Raymond Wright ◽  
Cassandra Henry ◽  
Ryan R. Otter ◽  
...  
Keyword(s):  
Stress Physiology ◽  
Nerodia Sipedon ◽  
Water Snake ◽  
Northern Water Snake

Variation in offspring sex ratios in the northern water snake (Nerodia sipedon)

1998 ◽  
Vol 76 (12) ◽  
pp. 2200-2206 ◽  
Author(s):  
Patrick J. Weatherhead ◽  
Gregory P. Brown ◽  
Melanie R. Prosser ◽  
Kelley J. Kissner
Keyword(s):  
Sex Ratios ◽  
Nerodia Sipedon ◽  
Water Snake ◽  
Offspring Sex ◽  
Northern Water Snake

The ultrastructure of the spermatozoon of the northern water snake, Nerodia sipedon (Colubridae, Serpentes), with phylogenetic considerations

1994 ◽  
Vol 72 (9) ◽  
pp. 1648-1652 ◽  
Author(s):  
B. G. M. Jamieson ◽  
L. Koehler
Keyword(s):  
Base Plate ◽  
Mature Spermatozoon ◽  
Boiga Irregularis ◽  
Nerodia Sipedon ◽  
Fibrous Sheath ◽  
Dense Bodies ◽  
Water Snake ◽  
Northern Water Snake ◽  
Distal Centriole ◽  
Electron Lucent

The ultrastructure of the spermatozoon of Nerodia sipedon conforms closely to that of other described snake sperm: it is filiform; the acrosome vesicle is in the form of a hollow, concentrically zoned cone that basally overlies a subacrosomal cone which invests the tapered anterior end of the nucleus; the putative perforatorium is a slender rod extending anteriorly from the subacrosomal cone; the midpiece contains dense bodies and mitochondria; the axonemal fibrous sheath extends anteriorly into the midpiece (squamate autapomorphy); 9 peripheral dense fibres surround the distal centriole and the axoneme in the midpiece, of which fibres adjacent to 3 and 8 are enlarged; and the endpiece lacks peripheral fibres and the fibrous sheath. The midpiece is very long (a synapomorphy of the Serpentes) and is surrounded by a multilaminar membrane (an autapomorphy). In the squamates, only snakes, including N. sipedon, retain microtubules external to the plasma membrane of the mature spermatozoon. Helically arranged zigzag mitochondria are shared (probably homoplasically) with iguanid sperm. A poorly developed "stopperlike" putative perforatorial base plate in N. sipedon, unknown in other snakes, is questionably homologous with that of gekkonids. An electron-lucent space caps the nuclear point, as in the snakes Boiga irregularis and Stegonotus cucullatus and in some other squamate orders.

scholarly journals SPLENOPANCREATIC DUCTAL ADENOCARCINOMA WITH MULTIORGAN METASTASIS IN A NORTHERN WATER SNAKE (NERODIA SIPEDON)

2014 ◽  
Vol 45 (2) ◽  
pp. 437-440 ◽  
Author(s):  
Mary Ellen Matthews ◽  
David Eshar ◽  
Katie W. Delk ◽  
Lisa Pohlman ◽  
Gordon Andrews
Keyword(s):  
Ductal Adenocarcinoma ◽  
Nerodia Sipedon ◽  
Water Snake ◽  
Northern Water Snake
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