Influence of pregnancy on oxygen consumption, heart rate and hematology in the garter snake: Implications for the “cost of reproduction” in live bearing reptiles

Birchard, Geoffrey F.; Black, Craig Patrick; Schuett, Gordon W.; Black, Virginia D.

doi:10.1016/0300-9629(84)90221-4

Cited by 76 publications

(69 citation statements)

References 16 publications

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“…The evolution of reptilian viviparity requires the formation of a placenta for gas and/or water exchange (Weekes, 1935;Guillette, 1982a;Guillette & Jones, 1985). That is, oxygen consumption increases slightly during early gravidity in oviparous lizards (Sceloporus aeneus: Guillette, 1982c) but increases significantly in viviparous lizards and snakes (Clausen, 1936;Guillette, 1982c;Birchard et al, 1984 Guillette & Jones, 1985;Yaron, 1985). Maximal capillary density occurred during gravidity in all 3 species and the mean density achieved was essentially the same; that is, about 30-35 capillaries/mm2.…”

Section: Discussionmentioning

confidence: 99%

Changes in oviducal vascularity during the reproductive cycle of three oviparous lizards (Eumeces obsoletus, Sceloporus undulatus and Crotaphytus collaris)

Masson¹,

Guillette²

1987

Reproduction

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Section: Discussionmentioning

confidence: 99%

Changes in oviducal vascularity during the reproductive cycle of three oviparous lizards (Eumeces obsoletus, Sceloporus undulatus and Crotaphytus collaris)

Masson¹,

Guillette²

1987

Reproduction

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“…An increase in the metabolic rate of females during reproduction has been documented in a variety of oviparous and viviparous amniotes (Hytten and Leitch, 1971;Hoversland et al, 1974;Pernoll et al, 1975;Guillette, 1982;Birchard et al, 1984;Beuchat and Vleck, 1990;Beaupre and Duvall, 1998;Angilletta and Sears, 2000;Robert and Thompson, 2000;Nilsson and Raberg, 2001;Vézina and Williams, 2002;Schultz et al, 2008;Van Dyke and Beaupre, 2011;Yue et al, 2012). Available data suggest that metabolic changes during the pre-ovulation period vary among species depending on the extent of lecithotrophic energy provisioning (i.e.…”

Section: Introductionmentioning

confidence: 99%

Influence of reproductive mode on metabolic costs of reproduction: insight from the bimodal lizard Zootoca vivipara

Foucart

Lourdais

DeNardo

et al. 2014

Journal of Experimental Biology

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Examination of the selective forces behind the transition from oviparity to viviparity in vertebrates must include an understanding of the relative energy costs of the two reproductive modes. However, interspecific comparisons of reproductive mode are confounded by numerous other inherent differences among the species. Therefore, we compared oxygen consumption, as a reflection of energy costs, during reproduction in oviparous and viviparous females of the reproductively bimodal lizard Zootoca vivipara (Jaquin 1787). Female oxygen consumption progressively increased over the course of reproduction, peaking just prior to parition when it was 46% (oviparous form) and 82% (viviparous form) higher than it was at the pre-reproductive stage. Total increase in oxygen consumption (TIOC) during the pre-ovulation period was not different between the reproductive modes. Conversely, post-ovulation TIOC was more than three times higher in viviparous females, reflecting a dramatic increase in embryonic metabolism as well as maternal metabolic costs of pregnancy (MCP). MCP accounted for 22% of total metabolism in viviparous females, whereas it was negligible in oviparous females. Our results demonstrate that egg retention through the first third of development, as is typical of most oviparous squamates, entails minimal maternal energy demand, while extending retention imposes much greater metabolic constraints. Selection for transition from oviparity to viviparity must therefore provide benefits that outweigh not only the added burden associated with prolonged embryonic retention, but also the substantial additional energy costs that are incurred.

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“…With three separate experiments using three different methods, we show that copulatory plug production alone, sans spermatogenesis, generates increased metabolic rates similar to those induced during pregnancy in this species. The average RMR of gravid female garter snakes during late pregnancy (Thamnophis sirtalis: V˙O 2 =0.0023 ml g −1 min −1 ; recalculated into common units from Birchard et al, 1984) is similar to the post-activity RMRs of males that engaged in courtship (V˙O 2 =0.0025 ml g −1 min −1 ). Furthermore, we demonstrate that mating males have even higher energetic expenditures than males engaged only in courtship, especially for small males.…”

Section: Discussionmentioning

confidence: 99%

Size dependence in non-sperm ejaculate production is reflected in daily energy expenditure and resting metabolic rate

Friesen

Powers

Copenhaver

et al. 2015

Journal of Experimental Biology

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A number of minor errors were published in J. Exp. Biol. 218, 1410-1418 The corrected sections are reproduced below, with changes highlighted in bold. These changes do not affect the conclusions of the paper. RESULTS Metabolic substrates: respiratory quotientMean respiratory quotient (RQ=VĊ O2 /VȮ 2 , where VĊ O2 is the rate of CO 2 production and VȮ 2 is the rate of O 2 consumption) across treatments and size classes was 0.743. Mean RQ of the mating males (median=0.71) was significantly lower than that of the courting males (median=0.76) [Kruskal-Wallis test, K 1 =24.091 (where the subscript 1 indicates d.f.), P<0.001]. A non-parametric test was used because these data failed a normality test (Shapiro-Wilk, P<0.05). This difference in RQ between courting and mating males was driven by small courting males having a significantly higher RQ than small mating males (Kruskal-Wallis test, K 3 =31.394, P<0.001; multiple comparisons using Dunn's method; Fig. 5). This suggests that small, mating males were using different metabolic substrates after mating from those used by the small, courting males. The shift in RQ, seen only in small males (Fig. 5), provides support for the hypothesis that smaller males are investing in plug production, as a shift in the substrates used in metabolism could be due to shunting resources to plug production from muscular activity (i.e. mate searching and courtship).The authors apologise for any inconvenience this may have caused. ABSTRACTThe non-sperm components of an ejaculate, such as copulatory plugs, can be essential to male reproductive success. But the costs of these ejaculate components are often considered trivial. In polyandrous species, males are predicted to increase energy allocation to the production of non-sperm components, but this allocation is often condition dependent and the energetic costs of their production have never been quantified. Red-sided garter snakes (Thamnophis sirtalis parietalis) are an excellent model with which to quantify the energetic costs of non-sperm components of the ejaculate as they exhibit a dissociated reproductive pattern in which sperm production is temporally disjunct from copulatory plug production, mating and plug deposition. We estimated the daily energy expenditure and resting metabolic rate of males after courtship and mating, and used bomb calorimetry to estimate the energy content of copulatory plugs. We found that both daily energy expenditure and resting metabolic rate were significantly higher in small mating males than in courting males, and a single copulatory plug without sperm constitutes 5-18% of daily energy expenditure. To our knowledge, this is the first study to quantify the energetic expense of size-dependent ejaculate strategies in any species.

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Influence of pregnancy on oxygen consumption, heart rate and hematology in the garter snake: Implications for the “cost of reproduction” in live bearing reptiles

Cited by 76 publications

References 16 publications

Changes in oviducal vascularity during the reproductive cycle of three oviparous lizards (Eumeces obsoletus, Sceloporus undulatus and Crotaphytus collaris)

Changes in oviducal vascularity during the reproductive cycle of three oviparous lizards (Eumeces obsoletus, Sceloporus undulatus and Crotaphytus collaris)

Influence of reproductive mode on metabolic costs of reproduction: insight from the bimodal lizard Zootoca vivipara

Size dependence in non-sperm ejaculate production is reflected in daily energy expenditure and resting metabolic rate

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