Thermal characteristics and sex determination in field nests of the pig-nosed turtle, carettochelys insculpta (Chelonia

Carettochelydidae), from Northern Australia

    Research output: Contribution to journalArticle

    46 Citations (Scopus)

    Abstract

    Carettochelys insculpta lays its eggs in shallow nests constructed in clean fine sand adjacent to water. Six nests had the following thermal characteristics: (1) core temperatures ranging from 26.1 to 33.7°C early in September, from 30.0 to 38.7°C early in October and from 28.4 to 36.8°C early in November; (2) a pronounced daily cycle in core temperatures of up to 6.4°C in amplitude, with the minimum occurring after sunrise in mid.morning and the maximum occurring in the evening; (3) a difference in the temperatures experienced by the top and bottom eggs in a single nest of up to 3.5°C at any one time. Nest heating and the maximum temperatures achieved were principally driven by solar irradiation, not ambient air temperatures. Hot nests produced females exclusively, nests intermediate in temperature produced a mixture of sexes, and the sole cool nest produced males exclusively. In nests that produced both sexes, males emerged from the deepest coolest eggs whereas females emerged from the shallowest eggs. Hence, field nests may yield both sexes either because egg temperatures are on the sex.determining threshold or because thermal gradients in nests span both male. and female.producing temperatures.

    Original languageEnglish
    Pages (from-to)453-476
    Number of pages24
    JournalAustralian Journal of Zoology
    Volume40
    Issue number5
    DOIs
    Publication statusPublished - 1 Jan 1992

    Fingerprint

    Chelonia
    sex determination
    turtle
    pig
    nest
    nests
    heat
    gender
    egg
    temperature
    Carettochelys insculpta
    temperature profiles
    ambient air
    ambient temperature
    air temperature
    irradiation
    solar radiation

    Cite this

    @article{bed6babb60a24b74a10b96c462979640,
    title = "Thermal characteristics and sex determination in field nests of the pig-nosed turtle, carettochelys insculpta (Chelonia: Carettochelydidae), from Northern Australia",
    abstract = "Carettochelys insculpta lays its eggs in shallow nests constructed in clean fine sand adjacent to water. Six nests had the following thermal characteristics: (1) core temperatures ranging from 26.1 to 33.7°C early in September, from 30.0 to 38.7°C early in October and from 28.4 to 36.8°C early in November; (2) a pronounced daily cycle in core temperatures of up to 6.4°C in amplitude, with the minimum occurring after sunrise in mid.morning and the maximum occurring in the evening; (3) a difference in the temperatures experienced by the top and bottom eggs in a single nest of up to 3.5°C at any one time. Nest heating and the maximum temperatures achieved were principally driven by solar irradiation, not ambient air temperatures. Hot nests produced females exclusively, nests intermediate in temperature produced a mixture of sexes, and the sole cool nest produced males exclusively. In nests that produced both sexes, males emerged from the deepest coolest eggs whereas females emerged from the shallowest eggs. Hence, field nests may yield both sexes either because egg temperatures are on the sex.determining threshold or because thermal gradients in nests span both male. and female.producing temperatures.",
    author = "A. Georges",
    note = "cited By 44",
    year = "1992",
    month = "1",
    day = "1",
    doi = "10.1071/ZO9920511",
    language = "English",
    volume = "40",
    pages = "453--476",
    journal = "Australian Journal of Zoology",
    issn = "0004-959X",
    publisher = "CSIRO",
    number = "5",

    }

    TY - JOUR

    T1 - Thermal characteristics and sex determination in field nests of the pig-nosed turtle, carettochelys insculpta (Chelonia

    T2 - Carettochelydidae), from Northern Australia

    AU - Georges, A.

    N1 - cited By 44

    PY - 1992/1/1

    Y1 - 1992/1/1

    N2 - Carettochelys insculpta lays its eggs in shallow nests constructed in clean fine sand adjacent to water. Six nests had the following thermal characteristics: (1) core temperatures ranging from 26.1 to 33.7°C early in September, from 30.0 to 38.7°C early in October and from 28.4 to 36.8°C early in November; (2) a pronounced daily cycle in core temperatures of up to 6.4°C in amplitude, with the minimum occurring after sunrise in mid.morning and the maximum occurring in the evening; (3) a difference in the temperatures experienced by the top and bottom eggs in a single nest of up to 3.5°C at any one time. Nest heating and the maximum temperatures achieved were principally driven by solar irradiation, not ambient air temperatures. Hot nests produced females exclusively, nests intermediate in temperature produced a mixture of sexes, and the sole cool nest produced males exclusively. In nests that produced both sexes, males emerged from the deepest coolest eggs whereas females emerged from the shallowest eggs. Hence, field nests may yield both sexes either because egg temperatures are on the sex.determining threshold or because thermal gradients in nests span both male. and female.producing temperatures.

    AB - Carettochelys insculpta lays its eggs in shallow nests constructed in clean fine sand adjacent to water. Six nests had the following thermal characteristics: (1) core temperatures ranging from 26.1 to 33.7°C early in September, from 30.0 to 38.7°C early in October and from 28.4 to 36.8°C early in November; (2) a pronounced daily cycle in core temperatures of up to 6.4°C in amplitude, with the minimum occurring after sunrise in mid.morning and the maximum occurring in the evening; (3) a difference in the temperatures experienced by the top and bottom eggs in a single nest of up to 3.5°C at any one time. Nest heating and the maximum temperatures achieved were principally driven by solar irradiation, not ambient air temperatures. Hot nests produced females exclusively, nests intermediate in temperature produced a mixture of sexes, and the sole cool nest produced males exclusively. In nests that produced both sexes, males emerged from the deepest coolest eggs whereas females emerged from the shallowest eggs. Hence, field nests may yield both sexes either because egg temperatures are on the sex.determining threshold or because thermal gradients in nests span both male. and female.producing temperatures.

    UR - http://www.scopus.com/inward/record.url?scp=84971056434&partnerID=8YFLogxK

    U2 - 10.1071/ZO9920511

    DO - 10.1071/ZO9920511

    M3 - Article

    VL - 40

    SP - 453

    EP - 476

    JO - Australian Journal of Zoology

    JF - Australian Journal of Zoology

    SN - 0004-959X

    IS - 5

    ER -