Aspectos ecológicos da determinação sexual em tartarugas

Abstract

ResumoOs aspectos ecológicos relacionados à reprodução das tartarugas e de outros répteis que apresentam determinação sexual dependente da temperatura de incubação desempenham um papel crucial no equilíbrio das populações. Nestas espécies a razão sexual dos filhotes é controlada pela temperatura a que os ovos são submetidos durante a incubação. Entender como as características do local da desova afetam a temperatura da incubação é essencial para que se possa argüir sobre os fatores que controlam a ecologia, a reprodução e a distribuição geográfica das tartarugas. Este trabalho de revisão aborda o modo de reprodução das tartarugas e a maneira como a reprodução é afetada pelo meio físico.PalavRas-chave: quelônio, reprodução, nidificação, incubação, sedimento Ecological aspects of turtle sex determination abstRactThe ecological aspects related to the reproduction of turtles and other reptiles, which present incubation temperature-dependent sex determination, play a crucial role in their population equilibrium. For such species, the sex ratio of hatchlings is controlled by the nest temperature during incubation. To understand how the nest site characteristics affect temperature is essential for considering the factors which control the ecology, reproduction and distribution of turtles. In this paper, we have made a review on the way turtles reproduce and how the physical environment affects reproduction.

Impacto do consumo de quelônios no perímetro urbano de Cruzeiro do Sul - Acre - Brasil.

“…Diversos estudos demonstram que as espécies do gênero Podocnemis são as que apresentam maior predileção alimentar pelas populações amazônicas (Martins e Molina 2008;Vogt 2008;Ferreira Júnior 2009). Entretanto, o presente estudo demonstra que na região estudada o jabuti é a espécie mais impactada pelas ações antrópicas associadas ao consumo.…”

NESTING HABITAT OF THE ‘CUPISO’ Podocnemis sextuberculata (TESTUDINES: PODOCNEMIDIDAE) IN EREPECU LAKE (PARÁ-BRAZIL)

“…Podocnemis expansa and P. unifilis have a clear preference by specific nesting substrates (Ferreira-Junior, 2009). Although no significant relationship was found between the number of nests and the type of substrate, it was noticeable that beaches with coarser grained substrates (large-sand grain) did not contain nests, while beaches with mid-sized sand grain substrate recorded more nests.…”

“…Temperature has been shown to be the main environmental variable that affects directly the sexual determination of most species of freshwater, marine, and terrestrial turtles (Bull and Vogt, 1979;Janzen and Paukstis, 1991;Ferreira-Junior, 2009). However in all the species of the familes Chelidae and Trionychidae, as well as in some species of Emydidae and Kinosternidae, the sex is genetically determined.…”

“…Every species requires specific habitat characteristics; likewise, every habitat represents various combinations of physicochemical and biotic factors that have an effect on the species (Ojasti, 2002). For instance, in large freshwater turtles (for example genus Podocnemis) the vegetation structure, amplitude and river depth, light, sand grain size, moisture and amount of food, are positively related to their distribution and abundance, and when found together, indicate suitable habitat for the species (Flaherty and Bider, 1984;Vogt and Bull, 1984;Shively and Jackson, 1985;Morrison et al, 1998;Roosenburg et al, 1999;FerreiraJunior andCastro, 2003, Arzola, 2007;Ferreira-Junior, 2009;González-Zarate et al, 2011).…”

Management and relocation of nests of Podocnemis expansa (Schweigger, 1812) (Testudines, Podocnemididae) on the Crixás-Açu river, Brazil

“…The nesting environment, as well as its physical and climatic characteristics determine the temperature inside nests, which reveals the crucial importance of choosing appropriate oviposition sites to the reproductive success of the species (Ferreira Júnior, 2009). The reproductive cycle of Podocnemis and hydrological cycles are synchronously related.…”