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Silla, Aimee J. Dr.

Associate Research Fellow

  • Faculty of Science, Medicine and Health
  • School of Biological Sciences - 2021

Top Publications


    Year Title
    2018 Hormone-induced spawning of the critically endangered northern corroboree frog Pseudophryne pengilleyi
    Published in   Reproduction Fertility and Development
    2017 Sperm motility activation in the critically endangered booroolong frog: the effect of medium osmolality and phosphodiesterase inhibitors
    Published in   Reproduction Fertility and Development

Research Overview


  • I am a Reproductive Biologist primarily focussed on developing Assisted Reproductive Technologies (ART) for the conservation of anurans. ART encompass a range of techniques that manipulate gametes for the purpose of controlling reproduction and enhancing fertility. My research includes manipulating hormone profiles to induce gamete-release, short-term gamete-storage, sperm cryopreservation, and artificial reproduction. I am also interested in comparative studies investigating response patterns among species, in order to expedite the application of ART to novel species.

     

    My research also employs evolutionary theory to predict ART outcomes. In particular, I am interested in investigating phenotypic indicators of male fertility, gamete adaptation to localised fertilisation environments, and how parental genetic incompatibilities effect fertilisation.

Selected Publications


Impact Story


  • <p>Research led by Dr Aimee Silla and Dr Phillip Byrne at the University of Wollongong (UOW) has enabled the generation of hundreds of offspring of the critically endangered Northern Corroboree Frog, using hormone application to induce reproduction.</p><p> </p><p>Although the northern corroboree frog has been bred successfully in captivity for a number of years, captive populations display strong mating bias with less than a third of available males contributing to mating success annually. Over time, such captive mating biases may lead to a loss of genetic variation and adaptive potential that could compromise long-term re-introduction success. In an attempt to boost breeding success and increase the genetic diversity of offspring, reproductive biologists Silla and Byrne teamed up with Michael McFadden from Taronga Conservation Society Australia to trial the use of hormone-induced breeding protocols to assist the genetic management of the species.</p><p> </p><p>The reproductive hormone GnRH-a was administered to male and female Corroboree frogs prior to putting pairs in breeding tanks. The hormones help encourage the frogs to mate, getting them in the right ‘mood’ for courtship and reproduction. Overall, in excess of 800 viable eggs have generated using hormone-assisted breeding techniques over the past four years.  Offspring of different developmental stages (eggs, tadpoles and juvenile frogs) have been released into natural sites in the Northern Brindabella Ranges by herpetofauna experts from UOW and Taronga Zoo. The research has been conducted with the support of Senior Threatened Species Officer Dr David Hunter from NSW Office of Environment and Heritage (OEH), who oversees the recovery program for Corroboree frogs.  </p><p> </p><p>In a world first, our team has also effectively applied the reproductive hormones topically to the abdomen of the frogs. Amphibians have highly permeable skin, so we were able to administer the hormones non-invasively. Topical application of reproductive hormones eliminates the need for specialised training in amphibian injection, which has been one of the main reasons that reproductive technologies have not yet been widely adopted by captive facilities, particularly in developing countries. We hope that by developing user-friendly, cost-effective  methods for hormone application will lead to more captive facilities using hormone treatment to boost the breeding success of endangered frogs, particularly in developing countries within Neotropical, Afrotropical and Indomalayan regions (collectively harbouring >82% of rapidly declining amphibians).</p>

Potential Supervision Topics


    • Eating to fuel fertility: Investigating the influence of female nutrition on yolk provisioning, egg quality and offspring fitness in Australian myobatrachid frogs
    • Investigating sperm trait evolution, sperm-egg interactions and genetic incompatibility to improve artificial fertilisation success in Australian hylid frogs
    • Investigating whether frogs show local adaptation or phenotypic plasticity in sperm traits, and whether knowledge of these adaptions can improve the success of artificial fertilisation

Advisees


  • Graduate Advising Relationship

    Degree Research Title Advisee
    Doctor of Philosophy The evolutionary causes of sequential polyandry in terrestrial toadlets from the genus Pseudophryne O'Brien Jones, Daniel
    Doctor of Philosophy The influence of dietary carotenoids on the growth, development, colouration+ performance of the actually endangered Southern Corroboree frogs McInerney, Emma
    Doctor of Philosophy Understanding patterns of intersexual selection and individual behavioural variation to assist with the captive breeding and reintroduction of the critically endangered corroboree frog Kelleher, Shannon

Top Publications


    Year Title
    2018 Hormone-induced spawning of the critically endangered northern corroboree frog Pseudophryne pengilleyi
    Published in   Reproduction Fertility and Development
    2017 Sperm motility activation in the critically endangered booroolong frog: the effect of medium osmolality and phosphodiesterase inhibitors
    Published in   Reproduction Fertility and Development

Research Overview


  • I am a Reproductive Biologist primarily focussed on developing Assisted Reproductive Technologies (ART) for the conservation of anurans. ART encompass a range of techniques that manipulate gametes for the purpose of controlling reproduction and enhancing fertility. My research includes manipulating hormone profiles to induce gamete-release, short-term gamete-storage, sperm cryopreservation, and artificial reproduction. I am also interested in comparative studies investigating response patterns among species, in order to expedite the application of ART to novel species.

     

    My research also employs evolutionary theory to predict ART outcomes. In particular, I am interested in investigating phenotypic indicators of male fertility, gamete adaptation to localised fertilisation environments, and how parental genetic incompatibilities effect fertilisation.

Selected Publications


Impact Story


  • <p>Research led by Dr Aimee Silla and Dr Phillip Byrne at the University of Wollongong (UOW) has enabled the generation of hundreds of offspring of the critically endangered Northern Corroboree Frog, using hormone application to induce reproduction.</p><p> </p><p>Although the northern corroboree frog has been bred successfully in captivity for a number of years, captive populations display strong mating bias with less than a third of available males contributing to mating success annually. Over time, such captive mating biases may lead to a loss of genetic variation and adaptive potential that could compromise long-term re-introduction success. In an attempt to boost breeding success and increase the genetic diversity of offspring, reproductive biologists Silla and Byrne teamed up with Michael McFadden from Taronga Conservation Society Australia to trial the use of hormone-induced breeding protocols to assist the genetic management of the species.</p><p> </p><p>The reproductive hormone GnRH-a was administered to male and female Corroboree frogs prior to putting pairs in breeding tanks. The hormones help encourage the frogs to mate, getting them in the right ‘mood’ for courtship and reproduction. Overall, in excess of 800 viable eggs have generated using hormone-assisted breeding techniques over the past four years.  Offspring of different developmental stages (eggs, tadpoles and juvenile frogs) have been released into natural sites in the Northern Brindabella Ranges by herpetofauna experts from UOW and Taronga Zoo. The research has been conducted with the support of Senior Threatened Species Officer Dr David Hunter from NSW Office of Environment and Heritage (OEH), who oversees the recovery program for Corroboree frogs.  </p><p> </p><p>In a world first, our team has also effectively applied the reproductive hormones topically to the abdomen of the frogs. Amphibians have highly permeable skin, so we were able to administer the hormones non-invasively. Topical application of reproductive hormones eliminates the need for specialised training in amphibian injection, which has been one of the main reasons that reproductive technologies have not yet been widely adopted by captive facilities, particularly in developing countries. We hope that by developing user-friendly, cost-effective  methods for hormone application will lead to more captive facilities using hormone treatment to boost the breeding success of endangered frogs, particularly in developing countries within Neotropical, Afrotropical and Indomalayan regions (collectively harbouring >82% of rapidly declining amphibians).</p>

Potential Supervision Topics


    • Eating to fuel fertility: Investigating the influence of female nutrition on yolk provisioning, egg quality and offspring fitness in Australian myobatrachid frogs
    • Investigating sperm trait evolution, sperm-egg interactions and genetic incompatibility to improve artificial fertilisation success in Australian hylid frogs
    • Investigating whether frogs show local adaptation or phenotypic plasticity in sperm traits, and whether knowledge of these adaptions can improve the success of artificial fertilisation

Advisees


  • Graduate Advising Relationship

    Degree Research Title Advisee
    Doctor of Philosophy The evolutionary causes of sequential polyandry in terrestrial toadlets from the genus Pseudophryne O'Brien Jones, Daniel
    Doctor of Philosophy The influence of dietary carotenoids on the growth, development, colouration+ performance of the actually endangered Southern Corroboree frogs McInerney, Emma
    Doctor of Philosophy Understanding patterns of intersexual selection and individual behavioural variation to assist with the captive breeding and reintroduction of the critically endangered corroboree frog Kelleher, Shannon
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