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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.


Egg arrangement, described in 22 clutches of the water snake Natrix maura, varied significantly across clutches (χ222  = 120.28, P = 0.0001), ranging from 100% free eggs (i.e. no eggs were attached to each other) to 100% clustered eggs (in one, two or three distinct clusters).
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f1: Egg arrangement, described in 22 clutches of the water snake Natrix maura, varied significantly across clutches (χ222  = 120.28, P = 0.0001), ranging from 100% free eggs (i.e. no eggs were attached to each other) to 100% clustered eggs (in one, two or three distinct clusters).

Mentions: Egg arrangement varied significantly across clutches (χ222 = 120.28, P = 0.0001), ranging from 100% free eggs (i.e. no eggs were attached to each other) to 100% clustered eggs (in one, two or three distinct clusters—Fig. 1). Egg attachment occurred in 18 out of 22 clutches for which 76.9 ± 17.2% of the eggs within the clutch were attached. Larger clutches contained more attached eggs (Linear regression R = 0.88, F1, 16 = 54.55, P = 0.001).


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)

Egg arrangement, described in 22 clutches of the water snake Natrix maura, varied significantly across clutches (χ222  = 120.28, P = 0.0001), ranging from 100% free eggs (i.e. no eggs were attached to each other) to 100% clustered eggs (in one, two or three distinct clusters).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f1: Egg arrangement, described in 22 clutches of the water snake Natrix maura, varied significantly across clutches (χ222  = 120.28, P = 0.0001), ranging from 100% free eggs (i.e. no eggs were attached to each other) to 100% clustered eggs (in one, two or three distinct clusters).
Mentions: Egg arrangement varied significantly across clutches (χ222 = 120.28, P = 0.0001), ranging from 100% free eggs (i.e. no eggs were attached to each other) to 100% clustered eggs (in one, two or three distinct clusters—Fig. 1). Egg attachment occurred in 18 out of 22 clutches for which 76.9 ± 17.2% of the eggs within the clutch were attached. Larger clutches contained more attached eggs (Linear regression R = 0.88, F1, 16 = 54.55, P = 0.001).

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.