Sökning: "PaternAl"

Visar resultat 1 - 5 av 127 avhandlingar innehållade ordet PaternAl.

  1. 1. Egg size evolution and paternal care in pipefishes

    Författare :Inês Braga Gonçalves; Göteborgs universitet; Göteborgs universitet; Gothenburg University; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Egg size; embryo development; embryo survival; hypoxia; male quality; mate choice; mating constraints; oxygen; parental care; parental effects; paternal care; reproductive compensation; sex-role reversal; sexual conflict; Syngnathidae; Syngnathus typhle;

    Sammanfattning : In this thesis I explore how sexual selection, sexual conflicts, coevolution with parental care and an environmental selective agent (hypoxia) affect the evolution of different egg characteristics and embryo survival and size in pipefishes (Syngnathidae). In the broad-nosed pipefish, Syngnathus typhle Linnaeus, both sexes prefer to mate with large partners; large females produce more and larger eggs and large males can care for more young, and, as shown in this thesis, invest more per embryo and provide better oxygenation during brooding. LÄS MER

  2. 2. Sexual selection in Pomatoschistus – nests, sperm competition, and paternal care

    Författare :Ola Svensson; Charlotta Kvarnemo; Sigal Balshine; Stockholms universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Female choice; Filial cannibaism; Gobiidae; Nests; Paternal care; Pomatoschistus microps; Pomatoschistus minutus; Sexual selection; Sperm competition; Teleostei; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi;

    Sammanfattning : Sexual selection arises through variation in reproductive success. This thesis investigates different aspects important in sexual selection, namely nest building, sperm competition, paternity and paternal care, and their mutual interrelationships. LÄS MER

  3. 3. Female choice and paternal care in the fifteen-spined stickleback, Spinachia spinachia

    Författare :Sara Östlund-Nilsson; Uppsala universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Developmental biology; fifteen-spined stickleback; spinachia spinachia; female choice; paternal care; nest building; ornament; fanning; Utvecklingsbiologi; Developmental biology; Utvecklingsbiologi; Animal Ecology; zooekologi;

    Sammanfattning : In the fifteen-spined stickleback, Spinachia spinachia, males provide females with direct benefits by fanning, cleaning and guarding the offspring. Males announce their parental skills through intense body shakes during courtship. Females preferred to mate with more intensely shaking males. LÄS MER

  4. 4. Paternal care and brood reduction in a pipefish

    Författare :Gry Sagebakken; Göteborgs universitet; Göteborgs universitet; Gothenburg University; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Parental care; brood reduction; embryo survival; parental condition; filial cannibalism; post-mating sexual selection; HSI; sexual conflicts; Syngnathus typhle; male brooding;

    Sammanfattning : From an evolutionary and adaptive perspective, the occurrence and extent of parental care in animals (investment in offspring beyond the genetic contribution) is expected to depend on an optimal (fitness-maximizing) balance of its costs and benefits. Males of the sex-role reversed broad-nosed pipefish, Syngnathus typhle, which care for eggs and embryos and may perform brood reduction, are particularly interesting in this respect. LÄS MER

  5. 5. Teenage parenthood : paternal characteristics and child health outcomes

    Författare :Cecilia Ekéus; Karolinska Institutet; Karolinska Institutet; []

    Sammanfattning : This thesis had two general aims. The first was to describe and compare the social-economic and reproductive characteristics and involvement in pregnancy and childbirth of fathers of children born to teenage mothers in Stockholm (Papers I and II). LÄS MER