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Myth busting? Effects of embryo positioning and egg turning on hatching success in the water snake Natrix maura.

Aubret F, Blanvillain G, Kok PJ - Sci Rep (2015)

Bottom Line: Here, we used 338 eggs from 32 clutches of the water snake Natrix maura to (1) thoroughly describe natural clutch arrangement, (2) experimentally assess the effects of natural embryo positioning and (3) egg turning on embryo metabolism, hatching success, and hatchling phenotype.Egg turning did not significantly influence egg development, hatching success or hatchling phenotypes.However, post-birth mortality was significantly higher in turned (37.5%) compared to unturned (4.5%) embryos, providing support to the common belief that eggs should not be moved from their natural position.

View Article: PubMed Central - PubMed

Affiliation: Station d'Ecologie Expérimentale de Moulis, CNRS, 09200 Moulis, France.

ABSTRACT
It is a common belief that reptile eggs should not be turned after oviposition once the embryo has attached itself to the inner membrane of the shell as it might kill developing embryos. Here, we used 338 eggs from 32 clutches of the water snake Natrix maura to (1) thoroughly describe natural clutch arrangement, (2) experimentally assess the effects of natural embryo positioning and (3) egg turning on embryo metabolism, hatching success, and hatchling phenotype. Clutches contained, on average, 59% of embryos located at the top, 28% at the bottom, and 14% on a side of the egg. Larger females laid larger clutches with higher proportion of top located embryos. Top embryos displayed higher metabolic rates (heart rates), shorter incubation time, and produced lighter and shorter snakes than bottom embryos. Egg turning did not significantly influence egg development, hatching success or hatchling phenotypes. However, post-birth mortality was significantly higher in turned (37.5%) compared to unturned (4.5%) embryos, providing support to the common belief that eggs should not be moved from their natural position.

No MeSH data available.


Eggs laid with embryos located at the top (N = 77) lost more mass towards throughout the incubation period than eggs laid with embryos located at the bottom (N = 32).A repeated measure factorial Anova with litter of origin and embryo position as factors, and egg mass as repeated measures over time yielded: global interaction term F39, 243 = 1.12; P = 0.30; effect of embryo location across time F3, 243 = 3.31; P = 0.021). Means + SE are given.
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f3: Eggs laid with embryos located at the top (N = 77) lost more mass towards throughout the incubation period than eggs laid with embryos located at the bottom (N = 32).A repeated measure factorial Anova with litter of origin and embryo position as factors, and egg mass as repeated measures over time yielded: global interaction term F39, 243 = 1.12; P = 0.30; effect of embryo location across time F3, 243 = 3.31; P = 0.021). Means + SE are given.

Mentions: Incubation time, body mass and snout-vent length at birth were significantly different between top and bottom embryos (see Table 3 for statistical results). There was a significant difference in egg mass evolution throughout the incubation period between top and bottom embryos: the latter lost significantly more mass throughout the incubation than the former (Fig. 3). Post-birth growth rates (without food) in body mass and snout-vent length did not significantly differ between the two groups (repeated measure factorial Anova; global interaction terms both P > 0.36; effects of embryo location both P < 0.017): young snakes born from bottom embryos tended to remain both heavier and longer in the first 3 weeks of life.


Myth busting? Effects of embryo positioning and egg turning on hatching success in the water snake Natrix maura.

Aubret F, Blanvillain G, Kok PJ - Sci Rep (2015)

Eggs laid with embryos located at the top (N = 77) lost more mass towards throughout the incubation period than eggs laid with embryos located at the bottom (N = 32).A repeated measure factorial Anova with litter of origin and embryo position as factors, and egg mass as repeated measures over time yielded: global interaction term F39, 243 = 1.12; P = 0.30; effect of embryo location across time F3, 243 = 3.31; P = 0.021). Means + SE are given.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4543940&req=5

f3: Eggs laid with embryos located at the top (N = 77) lost more mass towards throughout the incubation period than eggs laid with embryos located at the bottom (N = 32).A repeated measure factorial Anova with litter of origin and embryo position as factors, and egg mass as repeated measures over time yielded: global interaction term F39, 243 = 1.12; P = 0.30; effect of embryo location across time F3, 243 = 3.31; P = 0.021). Means + SE are given.
Mentions: Incubation time, body mass and snout-vent length at birth were significantly different between top and bottom embryos (see Table 3 for statistical results). There was a significant difference in egg mass evolution throughout the incubation period between top and bottom embryos: the latter lost significantly more mass throughout the incubation than the former (Fig. 3). Post-birth growth rates (without food) in body mass and snout-vent length did not significantly differ between the two groups (repeated measure factorial Anova; global interaction terms both P > 0.36; effects of embryo location both P < 0.017): young snakes born from bottom embryos tended to remain both heavier and longer in the first 3 weeks of life.

Bottom Line: Here, we used 338 eggs from 32 clutches of the water snake Natrix maura to (1) thoroughly describe natural clutch arrangement, (2) experimentally assess the effects of natural embryo positioning and (3) egg turning on embryo metabolism, hatching success, and hatchling phenotype.Egg turning did not significantly influence egg development, hatching success or hatchling phenotypes.However, post-birth mortality was significantly higher in turned (37.5%) compared to unturned (4.5%) embryos, providing support to the common belief that eggs should not be moved from their natural position.

View Article: PubMed Central - PubMed

Affiliation: Station d'Ecologie Expérimentale de Moulis, CNRS, 09200 Moulis, France.

ABSTRACT
It is a common belief that reptile eggs should not be turned after oviposition once the embryo has attached itself to the inner membrane of the shell as it might kill developing embryos. Here, we used 338 eggs from 32 clutches of the water snake Natrix maura to (1) thoroughly describe natural clutch arrangement, (2) experimentally assess the effects of natural embryo positioning and (3) egg turning on embryo metabolism, hatching success, and hatchling phenotype. Clutches contained, on average, 59% of embryos located at the top, 28% at the bottom, and 14% on a side of the egg. Larger females laid larger clutches with higher proportion of top located embryos. Top embryos displayed higher metabolic rates (heart rates), shorter incubation time, and produced lighter and shorter snakes than bottom embryos. Egg turning did not significantly influence egg development, hatching success or hatchling phenotypes. However, post-birth mortality was significantly higher in turned (37.5%) compared to unturned (4.5%) embryos, providing support to the common belief that eggs should not be moved from their natural position.

No MeSH data available.