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

Barron, James N.; Andraso, Gregory M.

doi:10.2307/1565971

Cited by 11 publications

(5 citation statements)

References 14 publications

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“…As an alternative to ovulation, yolk‐filled follicles can undergo atresia, in which the yolk materials are resorbed by the body. This has been hypothesised to allow reptiles to mediate the combination of capital‐ and income‐breeding, by beginning vitellogenesis in many follicles and allowing some of those follicles to undergo atresia if spring feeding conditions are poor (Shine, ; Méndez‐de la Cruz, Guillette & Villagran‐Santa Cruz, ; Barron & Andraso, ; Lourdais et al., ). Atresia may occur by ‘bursting’, in which yolk escapes into the abdominal cavity, or by ‘non‐bursting’ atresia.…”

Section: Lipid Metabolism During Vitellogenesismentioning

confidence: 99%

The physiology of lipid storage and use in reptiles

Price

2016

Biological Reviews

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Lipid metabolism is central to understanding whole-animal energetics. Reptiles store most excess energy in lipid form, mobilise those lipids when needed to meet energetic demands, and invest lipids in eggs to provide the primary source of energy to developing embryos. Here, I review the mechanisms by which non-avian reptiles store, transport, and use lipids. Many aspects of lipid absorption, transport, and storage appear to be similar to birds, including the hepatic synthesis of lipids from glucose substrates, the transport of triglycerides in lipoproteins, and the storage of lipids in adipose tissue, although adipose tissue in non-avian reptiles is usually concentrated in abdominal fat bodies or the tail. Seasonal changes in fat stores suggest that lipid storage is primarily for reproduction in most species, rather than for maintenance during aphagic periods. The effects of fasting on plasma lipid metabolites can differ from mammals and birds due to the ability of non-avian reptiles to reduce their metabolism drastically during extended fasts. The effect of fasting on levels of plasma ketones is species specific: β-hydroxybutyrate concentration may rise or fall during fasting. I also describe the process by which the bulk of lipids are deposited into oocytes during vitellogenesis. Although this process is sometimes ascribed to vitellogenin-based transport in reptiles, the majority of lipid deposition occurs via triglycerides packaged in very-low-density lipoproteins (VLDLs), based on physiological, histological, biochemical, comparative, and genomic evidence. I also discuss the evidence for non-avian reptiles using 'yolk-targeted' VLDLs during vitellogenesis. The major physiological states - feeding, fasting, and vitellogenesis - have different effects on plasma lipid metabolites, and I discuss the possibilities and potential problems of using plasma metabolites to diagnose feeding condition in non-avian reptiles.

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Section: Lipid Metabolism During Vitellogenesismentioning

confidence: 99%

The physiology of lipid storage and use in reptiles

Price

2016

Biological Reviews

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“…In vertebrates, evidence for body condition thresholds for reproduction is largely limited to within‐species correlations between body condition and either the likelihood of reproduction (Weimerskirch, 1992; Chastel, Weimerskirch & Jouventin, 1995; Naulleau & Bonnet, 1996; Meijer & Drent, 1999; Aubret et al ., 2002; Reading, 2004; Lewis & Kappeler, 2005; Santos et al ., 2005) or reproductive output (Drent & Daan, 1980; Madsen & Shine, 1999; Barron & Andraso, 2001; Lourdais et al ., 2003; Telemeco & Baird, 2011). However, we are unaware of any studies that have identified the physiological mechanisms that: (1) identify body condition ‘state’; (2) transmit body condition ‘state’ to the hypothalamic‐pituitary‐gonadal axis; and (3) decide, based on body condition ‘state’, whether to initiate reproduction via activation of the hypothalamic‐pituitary‐gonadal axis.…”

Section: Introductionmentioning

confidence: 99%

Snakes allocate amino acids acquired during vitellogenesis to offspring: are capital and income breeding consequences of variable foraging success?

Dyke

Beaupré

Kreider

2012

Biological Journal of the Linnean Society

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Reproductive allocation strategies have been historically described as lying on a continuum between capital and income breeding. Capital breeders have been defined as species that allocate stored reserves to reproduction, whereas income breeders have been defined as species that allocate relatively recently‐ingested food resources to reproduction. Snakes are considered capital breeders because they efficiently store large amounts of nutrients and energy, potentially enough to support an entire reproductive bout without feeding. We examined the abilities of five viviparous snake species to allocate income to follicles during vitellogenesis. We fed 15N‐labelled L‐leucine to experimental females of each species during vitellogenesis, whereas control females were fed unlabelled meals. After ovulation, we measured yolk 15N p.p.m. using mass spectrometry. Maternal scale samples taken before labelling were used to estimate endogenous 15N concentrations, which should represent ‘capital’. Scale samples taken at ovulation were used to determine whether snakes assimilated 15N‐labelled‐leucine from labelled diets. Yolks and post‐ovulatory scales of labelled females were significantly more enriched in 15N than those of unlabelled females in all species, indicating significant assimilation and allocation of income‐derived amino acids to the yolk during vitellogenesis. The lack of among‐species differences suggests that all species allocated income amino acids to vitellogenesis. The results obtained in the present study suggest that proportional utilization of income or capital depends on the frequency and timing of foraging success during reproductive events. Therefore, capital and income breeding may be consequences of both life‐history and environmental constraints on foraging success, rather than strategies of reproductive allocation. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 106, 390–404.

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“…Snakes have been popular subjects for research on this trade‐off (Andrén & Nilson 1983; Brodie & Ducey 1989; Ford & Seigel 1989; Seigel & Ford 1991, 1992; King 1993; Gregory & Skebo 1998; Bronikowski & Arnold 1999; Weatherhead et al . 1999; Barron & Andraso 2001). Essential to understanding why a trade‐off results in offspring of a particular size is knowledge of how neonatal size, and traits associated with size, affect survival.…”

Section: Introductionmentioning

confidence: 99%

Phenotypic effects on survival of neonatal northern watersnakes Nerodia sipedon

Kissner

2005

Journal of Animal Ecology

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Summary 1.Understanding the trade-off females make between offspring size and number requires knowing how neonatal size, and traits associated with size, affect survival. 2. We studied neonatal survival in the northern watersnake Nerodia sipedon in outdoor enclosures with artificial hibernation sites. 3. From a total of 950 neonates from 77 litters collected over 3 years, we found a survival rate of 65% between birth and hibernation and 47% during hibernation. Estimated survival from birth to the end of hibernation was 31%, comparable with indirect estimates for free-living watersnakes. 4. Consistent with the 'bigger is better' hypothesis, larger neonates and neonates heavier relative to their body length were more likely to survive both the pre-hibernation and hibernation periods. 5. Survival in the pre-hibernation period also decreased with the duration of that period and varied among years. 6. Survival during hibernation was higher in warmer winters. Mass change prior to hibernation did not affect survival during hibernation. 7. These results suggest that an optimal reproductive strategy should exist for female watersnakes, producing a 'consensus' among females on the optimal size for offspring. This expectation stands in stark contrast to the pronounced variation in offspring size observed both within and among litters.

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

Cited by 11 publications

References 14 publications

The physiology of lipid storage and use in reptiles

The physiology of lipid storage and use in reptiles

Snakes allocate amino acids acquired during vitellogenesis to offspring: are capital and income breeding consequences of variable foraging success?

Phenotypic effects on survival of neonatal northern watersnakes Nerodia sipedon

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