On clutch size and hatching success of the South American turtles Podocnemis expansa (Schweigger, 1812) and P. unifilis Troschel, 1848 (Testudines, Podocnemididae)

On clutch size and hatching success of the South American turtles Podocnemis expansa (Schweigger, 1812) and P. unifilis Troschel, 1848 (Testudines, Podocnemididae)

Data on clutch size and hatching success of P. expansa were gathered for seven beaches traditionally used by the species and re-analyzed statistically by means of regression analysis, of the number of eggs on the number of females (or nests) and of the number of young on the number of eggs. All regressions were linear, passed through the origin and had excellent fits. Average clutch size varied from 75 to 123, and presented geographic differentiation: (i) Rio Orinoco, (ii) Rio Trombetas + Rio Branco and (iii) Rio Juruá + Rio Purus. Average hatching success was ca. 83%. In P. unifilis there was also geographic variation in clutch size, the Iquitos area showing the highest values. Hatching success of P. unifilis was uniformly high: only one sample, from Iquitos, had less than 90% success. The outstanding fit of the clutch size regressions leads one to consider egg volume variability, which was found to be high in both species, in contradiction with current optimal egg size theory.

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Main Author: Vanzolini,Paulo Emilio
Format: Digital revista
Language:English
Published: Academia Brasileira de Ciências 2003
Online Access:http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652003000400002
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spelling oai:scielo:S0001-376520030004000022003-10-30On clutch size and hatching success of the South American turtles Podocnemis expansa (Schweigger, 1812) and P. unifilis Troschel, 1848 (Testudines, Podocnemididae)Vanzolini,Paulo Emilio turtle reproduction hatching success clutch size optimal egg-size theory Podocnemis expansa Podocnemis unifilis Data on clutch size and hatching success of P. expansa were gathered for seven beaches traditionally used by the species and re-analyzed statistically by means of regression analysis, of the number of eggs on the number of females (or nests) and of the number of young on the number of eggs. All regressions were linear, passed through the origin and had excellent fits. Average clutch size varied from 75 to 123, and presented geographic differentiation: (i) Rio Orinoco, (ii) Rio Trombetas + Rio Branco and (iii) Rio Juruá + Rio Purus. Average hatching success was ca. 83%. In P. unifilis there was also geographic variation in clutch size, the Iquitos area showing the highest values. Hatching success of P. unifilis was uniformly high: only one sample, from Iquitos, had less than 90% success. The outstanding fit of the clutch size regressions leads one to consider egg volume variability, which was found to be high in both species, in contradiction with current optimal egg size theory.info:eu-repo/semantics/openAccessAcademia Brasileira de CiênciasAnais da Academia Brasileira de Ciências v.75 n.4 20032003-12-01info:eu-repo/semantics/articletext/htmlhttp://old.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652003000400002en10.1590/S0001-37652003000400002
institution SCIELO
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country Brasil
countrycode BR
component Revista
access En linea
databasecode rev-scielo-br
tag revista
region America del Sur
libraryname SciELO
language English
format Digital
author Vanzolini,Paulo Emilio
spellingShingle Vanzolini,Paulo Emilio
On clutch size and hatching success of the South American turtles Podocnemis expansa (Schweigger, 1812) and P. unifilis Troschel, 1848 (Testudines, Podocnemididae)
author_facet Vanzolini,Paulo Emilio
author_sort Vanzolini,Paulo Emilio
title On clutch size and hatching success of the South American turtles Podocnemis expansa (Schweigger, 1812) and P. unifilis Troschel, 1848 (Testudines, Podocnemididae)
title_short On clutch size and hatching success of the South American turtles Podocnemis expansa (Schweigger, 1812) and P. unifilis Troschel, 1848 (Testudines, Podocnemididae)
title_full On clutch size and hatching success of the South American turtles Podocnemis expansa (Schweigger, 1812) and P. unifilis Troschel, 1848 (Testudines, Podocnemididae)
title_fullStr On clutch size and hatching success of the South American turtles Podocnemis expansa (Schweigger, 1812) and P. unifilis Troschel, 1848 (Testudines, Podocnemididae)
title_full_unstemmed On clutch size and hatching success of the South American turtles Podocnemis expansa (Schweigger, 1812) and P. unifilis Troschel, 1848 (Testudines, Podocnemididae)
title_sort on clutch size and hatching success of the south american turtles podocnemis expansa (schweigger, 1812) and p. unifilis troschel, 1848 (testudines, podocnemididae)
description Data on clutch size and hatching success of P. expansa were gathered for seven beaches traditionally used by the species and re-analyzed statistically by means of regression analysis, of the number of eggs on the number of females (or nests) and of the number of young on the number of eggs. All regressions were linear, passed through the origin and had excellent fits. Average clutch size varied from 75 to 123, and presented geographic differentiation: (i) Rio Orinoco, (ii) Rio Trombetas + Rio Branco and (iii) Rio Juruá + Rio Purus. Average hatching success was ca. 83%. In P. unifilis there was also geographic variation in clutch size, the Iquitos area showing the highest values. Hatching success of P. unifilis was uniformly high: only one sample, from Iquitos, had less than 90% success. The outstanding fit of the clutch size regressions leads one to consider egg volume variability, which was found to be high in both species, in contradiction with current optimal egg size theory.
publisher Academia Brasileira de Ciências
publishDate 2003
url http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652003000400002
work_keys_str_mv AT vanzolinipauloemilio onclutchsizeandhatchingsuccessofthesouthamericanturtlespodocnemisexpansaschweigger1812andpunifilistroschel1848testudinespodocnemididae
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