Silla, Aimee J.

Research Areas

0699 - OTHER BIOLOGICAL SCIENCES

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

Journal Article

Year	Title
2018	Animal personality and behavioral syndromes in amphibians: a review of the evidence, experimental approaches, and implications for conservation Published In Behavioral Ecology and Sociobiology Volume 72 Pages 79-1 - 79-26 ISSN 0340-5443 Altmetric
2018	Dose and life stage-dependent effects of dietary beta-carotene supplementation on the growth and development of the Booroolong frog Published In Conservation Physiology Volume 6 Pages 1 - 10 Altmetric
2018	Effect of long-term dietary beta-carotene supplementation on sperm concentration and motility in an endangered amphibian Published In Animal Reproduction Science Volume 195 Pages 259 - 265 ISSN 0378-4320 Altmetric
2018	Hormone-induced spawning of the critically endangered northern corroboree frog Pseudophryne pengilleyi Published In Reproduction Fertility and Development Volume Online First Pages A - G ISSN 1448-5990 Altmetric
2018	The unexpected genetic mating system of the red-backed toadlet (Pseudophryne coriacea): A species with prolonged terrestrial breeding and cryptic reproductive behaviour Published In Molecular Ecology Volume 27 Pages 3001 - 3015 ISSN 0962-1083 Altmetric
2017	Body size predicts between-individual differences in exploration behaviour in the southern corroboree frog Published In Animal Behaviour Volume 129 Pages 161 - 170 ISSN 0003-3472 Altmetric
2017	Dietary carotenoid supplementation enhances the cutaneous bacterial communities of the critically endangered southern corroboree frog (Pseudophryne corroboree) Published In Microbial Ecology: an international journal Volume 73 Pages 435 - 444 ISSN 0095-3628 Altmetric
2017	Sperm motility activation in the critically endangered booroolong frog: the effect of medium osmolality and phosphodiesterase inhibitors Published In Reproduction Fertility and Development Volume 29 Pages 2277 - 2283 ISSN 1448-5990 Altmetric
2017	Testing the effect of dietary carotenoids on larval survival, growth and development in the critically endangered southern corroboree frog Published In Zoo Biology Volume 36 Pages 161 - 169 ISSN 0733-3188 Altmetric
2017	The effect of antioxidants on sperm motility activation in the Booroolong frog Published In Animal Reproduction Science Volume 183 Pages 126 - 131 ISSN 0378-4320 Altmetric
2017	The effect of dietary antioxidants and exercise training on the escape performance of Southern Corroboree frogs Published In Behavioural Processes Volume 144 Pages 46 - 50 ISSN 0376-6357 Altmetric
2017	The effect of gentamicin on sperm motility and bacterial abundance during chilled sperm storage in the Booroolong frog Published In General and Comparative Endocrinology Volume 243 Pages 51 - 59 ISSN 0016-6480 Altmetric
2016	Dietary carotenoid supplementation improves the escape performance of the southern corroboree frog Published In Animal Behaviour Volume 112 Pages 213 - 220 ISSN 0003-3472 Altmetric
2016	Dietary carotenoids change the colour of Southern corroboree frogs Published In Biological Journal of the Linnean Society Volume 119 Pages 436 - 444 ISSN 0024-4066 Altmetric
2016	Planning for ex situ conservation in the face of uncertainty Published In Conservation Biology Volume 30 Pages 599 - 609 ISSN 1523-1739 Altmetric
2016	The influence of carotenoid supplementation at different life-stages on the foraging performance of the Southern Corroboree frog (Pseudophryne corroboree): a test of the Silver Spoon and Environmental Matching Hypotheses Published In Behavioural Processes Volume 125 Pages 26 - 33 ISSN 0376-6357 Altmetric
2015	Antibiotics and oxygen availability affect the short-term storage of spermatozoa from the critically endangered booroolong frog, Litoria booroolongensis Published In Reproduction Fertility and Development Volume 27 Pages 1147 - 1153 ISSN 1448-5990 Altmetric
2015	Environmental osmolality influences sperm motility activation in an anuran amphibian Published In Journal of Evolutionary Biology Volume 28 Pages 521 - 534 ISSN 1010-061X Altmetric
2013	Artificial fertilisation in a terrestrial toadlet (Pseudophryne guentheri): effect of medium osmolality, sperm concentration and gamete storage Published In Reproduction Fertility and Development Volume 25 Pages 1134 - 1141 ISSN 1448-5990 Altmetric
2013	Emerging trends for biobanking amphibian genetic resources: the hope, reality and challenges for the next decade Published In Biological Conservation Volume 164 Pages 10 - 21 ISSN 0006-3207 Altmetric
2012	Investigating patterns in the spermiation response of eight Australian frogs administered human chorionic gonadotropin (hCG) and luteinizing hormone-releasing hormone (LHRHa) Published In General and Comparative Endocrinology Volume 179 Pages 128 - 136 ISSN 0016-6480 Altmetric
2011	Effect of priming injections of luteinizing hormone-releasing hormone on spermiation and ovulation in Gϋnther's Toadlet, Pseudophryne guentheri Published In Reproductive Biology and Endocrinology Volume 9 Pages 68-1 - 68-9 ISSN 1477-7827 Altmetric
2010	Effects of luteinizing hormone-releasing hormone and arginine-vasotocin on the sperm-release response of Günther's Toadlet, Pseudophryne guentheri Published In Reproductive Biology and Endocrinology Volume 8 Pages 139-1 - 139-9 ISSN 1477-7827 Altmetric
2010	Hormone induction of gamete release and In-vitro fertilization in the critically endangered corroboree frog Published In Reproductive Biology and Endocrinology Volume 8 Pages 1 - 13 ISSN 1477-7827 Altmetric

Investigator On

Year	Title
2017 - 2020	Let them eat Carotenoids: boosting corroboree frog immunity Awarded by: NSW Environmental Trust Funding Scheme: Environmental Research Program
2012	Assisted reproductive technologies (ART) for frog conservation Awarded by: NSW Environmental Trust Funding Scheme: Environmental Research Program

Impact Story

Using assisted reproductive technologies to conserve Australia's endangered amphibians
Summary
Environmental change is responsible for unprecedented rates of species extinction for all vertebrate classes, and amphibians have been most severely affected. Current estimates indicate that over 34 per cent of amphibian species globally are now threatened with extinction. The emerging methods being developed here at UOW integrate sophisticated Assisted Reproductive Technologies (ART) with traditional captive breeding methods to enhance the propagation and genetic management of threatened frog species.This project began when UOW biologists Dr Phillip Byrne and Dr Aimee Silla were approached by the NSW Department of Environment and Heritage to develop ART for one of Australia’s most critically engendered vertebrates, the Southern Corroboree frog (Pseudophryne corroboree). Our research team has since developed ART for a number of model frog species as well as other species of high conservation value, including the critically endangered Booroolong frog (Litoria booroolongensis) and the Northern Corroboree frog (Pseudophryne pengilleyi).Taronga Conservation Society Australia have adopted ART protocols developed by the researchers to hormonally induce spawning to enhance the captive breeding and release program for the Northern Corroboree frog. Overall, in excess of 800 viable eggs have been generated using ART over the past 3-years, and these eggs have been reintroduced into their natural environment by the NSW Office of Environment and Heritage, contributing significantly to the on-ground conservation efforts for this species. Our research team has also recently completed experiments at Taronga Zoo to develop protocols for the topical application of hormones to induce breeding so that ART technologies can be more widely adopted by global amphibian captive breeding facilities, without the need for specialist training in administering animal injections.Our partner organisations have pledged additional funding over the next three years to further support these important avenues of research for improving endangered species captive breeding and reintroduction programs and ultimately, species recovery in the wild.

Detail View

Detail View Summary View
Detail of Impact
An insurance colony was established for the northern corroboree frog at Tidbinbilla Nature Reserve in the ACT, following the annual collection of fertilised eggs from wild populations between 2003 and 2008. Since then, a substantial number of animals have been transferred to Taronga Zoo and a collaborative captive breeding and reintroduction program has been established from a partnership between the two captive institutions and the NSW Office of Environment and Heritage (OEH) (<a href="#_ENREF_6" target="_blank" rel="noopener">McFadden et al., 2016</a>). Captive breeding protocols have been established for the northern corroboree frog, with the first viable clutch of eggs laid in captivity in 2008. As with its sister species the southern corroboree frog (Pseudophryne corroboree) key requirements for achieving successful breeding of this species include adequate temperature cycling that incorporates a winter cooling period prior breeding, and the provision of large breeding tanks containing multiple males to allow for female mate-choice (<a href="#_ENREF_5" target="_blank" rel="noopener">McFadden et al., 2013</a>). Incorporating assisted reproductive technologiesAlthough 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. The natural mating system of this species has similarly been shown to exhibit strong mating bias toward a small number of male individuals, so this mating pattern is not unique among captive populations. However, over time, such captive mating biases may lead to a loss of genetic variation in the offspring generated for re-introduction. Between 2014 and 2016, experimental trials were conducted as part of a strategic research collaboration between the University of Wollongong and Taronga Conservation Society Australia, employing hormone-induced spawning protocols to assist the genetic management of the species. Hypothalamic hormones, administered via a single injection, were used to induce spawning in isolated male-female pairs housed together in small aquaria. Hormone administration significantly improved the number of pairs producing viable embryos and total egg number (Silla AJ, McFadden M & Byrne PG, unpublished data). Overall, in excess of 800 viable eggs (from 37 clutches) were generated using ART between 2014 and 2016, which were subsequently released into natural sites in the Northern Brindabella Ranges. Following on from initial experiments, in 2017 our research team developed successful techniques for the topical application of reproductive hormones to induce breeding in the northern corroboree frog in order to further improve animal welfare, and allow ART technologies to be more widely adopted by amphibian captive breeding facilities nationally. Incorporating ARTs into existing conservation breeding programs has a number of potential benefits, including: 1) enhanced species propagation, 2) synchronisation of breeding events, 3) increased genetic diversity and adaptive potential of the offspring generated, and 4) better control over breeding designs, including an opportunity for selective breeding of particular genotypes. As a result, ARTs are being increasingly employed by captive facilities to compliment traditional breeding methods and enhance species recovery.
Field of Research
Countries / Regions
Beneficiaries

Beneficiary Quantification Description
External Partners
Evidence of Impact

Evidence Description
UOW Centres / Programs
UOW Researchers / Collaborators

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

Research Areas

0699 - OTHER BIOLOGICAL SCIENCES

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

Journal Article

Year	Title
2018	Animal personality and behavioral syndromes in amphibians: a review of the evidence, experimental approaches, and implications for conservation Published In Behavioral Ecology and Sociobiology Volume 72 Pages 79-1 - 79-26 ISSN 0340-5443 Altmetric
2018	Dose and life stage-dependent effects of dietary beta-carotene supplementation on the growth and development of the Booroolong frog Published In Conservation Physiology Volume 6 Pages 1 - 10 Altmetric
2018	Effect of long-term dietary beta-carotene supplementation on sperm concentration and motility in an endangered amphibian Published In Animal Reproduction Science Volume 195 Pages 259 - 265 ISSN 0378-4320 Altmetric
2018	Hormone-induced spawning of the critically endangered northern corroboree frog Pseudophryne pengilleyi Published In Reproduction Fertility and Development Volume Online First Pages A - G ISSN 1448-5990 Altmetric
2018	The unexpected genetic mating system of the red-backed toadlet (Pseudophryne coriacea): A species with prolonged terrestrial breeding and cryptic reproductive behaviour Published In Molecular Ecology Volume 27 Pages 3001 - 3015 ISSN 0962-1083 Altmetric
2017	Body size predicts between-individual differences in exploration behaviour in the southern corroboree frog Published In Animal Behaviour Volume 129 Pages 161 - 170 ISSN 0003-3472 Altmetric
2017	Dietary carotenoid supplementation enhances the cutaneous bacterial communities of the critically endangered southern corroboree frog (Pseudophryne corroboree) Published In Microbial Ecology: an international journal Volume 73 Pages 435 - 444 ISSN 0095-3628 Altmetric
2017	Sperm motility activation in the critically endangered booroolong frog: the effect of medium osmolality and phosphodiesterase inhibitors Published In Reproduction Fertility and Development Volume 29 Pages 2277 - 2283 ISSN 1448-5990 Altmetric
2017	Testing the effect of dietary carotenoids on larval survival, growth and development in the critically endangered southern corroboree frog Published In Zoo Biology Volume 36 Pages 161 - 169 ISSN 0733-3188 Altmetric
2017	The effect of antioxidants on sperm motility activation in the Booroolong frog Published In Animal Reproduction Science Volume 183 Pages 126 - 131 ISSN 0378-4320 Altmetric
2017	The effect of dietary antioxidants and exercise training on the escape performance of Southern Corroboree frogs Published In Behavioural Processes Volume 144 Pages 46 - 50 ISSN 0376-6357 Altmetric
2017	The effect of gentamicin on sperm motility and bacterial abundance during chilled sperm storage in the Booroolong frog Published In General and Comparative Endocrinology Volume 243 Pages 51 - 59 ISSN 0016-6480 Altmetric
2016	Dietary carotenoid supplementation improves the escape performance of the southern corroboree frog Published In Animal Behaviour Volume 112 Pages 213 - 220 ISSN 0003-3472 Altmetric
2016	Dietary carotenoids change the colour of Southern corroboree frogs Published In Biological Journal of the Linnean Society Volume 119 Pages 436 - 444 ISSN 0024-4066 Altmetric
2016	Planning for ex situ conservation in the face of uncertainty Published In Conservation Biology Volume 30 Pages 599 - 609 ISSN 1523-1739 Altmetric
2016	The influence of carotenoid supplementation at different life-stages on the foraging performance of the Southern Corroboree frog (Pseudophryne corroboree): a test of the Silver Spoon and Environmental Matching Hypotheses Published In Behavioural Processes Volume 125 Pages 26 - 33 ISSN 0376-6357 Altmetric
2015	Antibiotics and oxygen availability affect the short-term storage of spermatozoa from the critically endangered booroolong frog, Litoria booroolongensis Published In Reproduction Fertility and Development Volume 27 Pages 1147 - 1153 ISSN 1448-5990 Altmetric
2015	Environmental osmolality influences sperm motility activation in an anuran amphibian Published In Journal of Evolutionary Biology Volume 28 Pages 521 - 534 ISSN 1010-061X Altmetric
2013	Artificial fertilisation in a terrestrial toadlet (Pseudophryne guentheri): effect of medium osmolality, sperm concentration and gamete storage Published In Reproduction Fertility and Development Volume 25 Pages 1134 - 1141 ISSN 1448-5990 Altmetric
2013	Emerging trends for biobanking amphibian genetic resources: the hope, reality and challenges for the next decade Published In Biological Conservation Volume 164 Pages 10 - 21 ISSN 0006-3207 Altmetric
2012	Investigating patterns in the spermiation response of eight Australian frogs administered human chorionic gonadotropin (hCG) and luteinizing hormone-releasing hormone (LHRHa) Published In General and Comparative Endocrinology Volume 179 Pages 128 - 136 ISSN 0016-6480 Altmetric
2011	Effect of priming injections of luteinizing hormone-releasing hormone on spermiation and ovulation in Gϋnther's Toadlet, Pseudophryne guentheri Published In Reproductive Biology and Endocrinology Volume 9 Pages 68-1 - 68-9 ISSN 1477-7827 Altmetric
2010	Effects of luteinizing hormone-releasing hormone and arginine-vasotocin on the sperm-release response of Günther's Toadlet, Pseudophryne guentheri Published In Reproductive Biology and Endocrinology Volume 8 Pages 139-1 - 139-9 ISSN 1477-7827 Altmetric
2010	Hormone induction of gamete release and In-vitro fertilization in the critically endangered corroboree frog Published In Reproductive Biology and Endocrinology Volume 8 Pages 1 - 13 ISSN 1477-7827 Altmetric

Investigator On

Year	Title
2017 - 2020	Let them eat Carotenoids: boosting corroboree frog immunity Awarded by: NSW Environmental Trust Funding Scheme: Environmental Research Program
2012	Assisted reproductive technologies (ART) for frog conservation Awarded by: NSW Environmental Trust Funding Scheme: Environmental Research Program

Impact Story

Using assisted reproductive technologies to conserve Australia's endangered amphibians
Summary
Environmental change is responsible for unprecedented rates of species extinction for all vertebrate classes, and amphibians have been most severely affected. Current estimates indicate that over 34 per cent of amphibian species globally are now threatened with extinction. The emerging methods being developed here at UOW integrate sophisticated Assisted Reproductive Technologies (ART) with traditional captive breeding methods to enhance the propagation and genetic management of threatened frog species.This project began when UOW biologists Dr Phillip Byrne and Dr Aimee Silla were approached by the NSW Department of Environment and Heritage to develop ART for one of Australia’s most critically engendered vertebrates, the Southern Corroboree frog (Pseudophryne corroboree). Our research team has since developed ART for a number of model frog species as well as other species of high conservation value, including the critically endangered Booroolong frog (Litoria booroolongensis) and the Northern Corroboree frog (Pseudophryne pengilleyi).Taronga Conservation Society Australia have adopted ART protocols developed by the researchers to hormonally induce spawning to enhance the captive breeding and release program for the Northern Corroboree frog. Overall, in excess of 800 viable eggs have been generated using ART over the past 3-years, and these eggs have been reintroduced into their natural environment by the NSW Office of Environment and Heritage, contributing significantly to the on-ground conservation efforts for this species. Our research team has also recently completed experiments at Taronga Zoo to develop protocols for the topical application of hormones to induce breeding so that ART technologies can be more widely adopted by global amphibian captive breeding facilities, without the need for specialist training in administering animal injections.Our partner organisations have pledged additional funding over the next three years to further support these important avenues of research for improving endangered species captive breeding and reintroduction programs and ultimately, species recovery in the wild.

Detail View

Detail View Summary View
Detail of Impact
An insurance colony was established for the northern corroboree frog at Tidbinbilla Nature Reserve in the ACT, following the annual collection of fertilised eggs from wild populations between 2003 and 2008. Since then, a substantial number of animals have been transferred to Taronga Zoo and a collaborative captive breeding and reintroduction program has been established from a partnership between the two captive institutions and the NSW Office of Environment and Heritage (OEH) (<a href="#_ENREF_6" target="_blank" rel="noopener">McFadden et al., 2016</a>). Captive breeding protocols have been established for the northern corroboree frog, with the first viable clutch of eggs laid in captivity in 2008. As with its sister species the southern corroboree frog (Pseudophryne corroboree) key requirements for achieving successful breeding of this species include adequate temperature cycling that incorporates a winter cooling period prior breeding, and the provision of large breeding tanks containing multiple males to allow for female mate-choice (<a href="#_ENREF_5" target="_blank" rel="noopener">McFadden et al., 2013</a>). Incorporating assisted reproductive technologiesAlthough 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. The natural mating system of this species has similarly been shown to exhibit strong mating bias toward a small number of male individuals, so this mating pattern is not unique among captive populations. However, over time, such captive mating biases may lead to a loss of genetic variation in the offspring generated for re-introduction. Between 2014 and 2016, experimental trials were conducted as part of a strategic research collaboration between the University of Wollongong and Taronga Conservation Society Australia, employing hormone-induced spawning protocols to assist the genetic management of the species. Hypothalamic hormones, administered via a single injection, were used to induce spawning in isolated male-female pairs housed together in small aquaria. Hormone administration significantly improved the number of pairs producing viable embryos and total egg number (Silla AJ, McFadden M & Byrne PG, unpublished data). Overall, in excess of 800 viable eggs (from 37 clutches) were generated using ART between 2014 and 2016, which were subsequently released into natural sites in the Northern Brindabella Ranges. Following on from initial experiments, in 2017 our research team developed successful techniques for the topical application of reproductive hormones to induce breeding in the northern corroboree frog in order to further improve animal welfare, and allow ART technologies to be more widely adopted by amphibian captive breeding facilities nationally. Incorporating ARTs into existing conservation breeding programs has a number of potential benefits, including: 1) enhanced species propagation, 2) synchronisation of breeding events, 3) increased genetic diversity and adaptive potential of the offspring generated, and 4) better control over breeding designs, including an opportunity for selective breeding of particular genotypes. As a result, ARTs are being increasingly employed by captive facilities to compliment traditional breeding methods and enhance species recovery.
Field of Research
Countries / Regions
Beneficiaries

Beneficiary Quantification Description
External Partners
Evidence of Impact

Evidence Description
UOW Centres / Programs
UOW Researchers / Collaborators

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

Silla, Aimee J. Dr.

Postdoctoral Research Fellow

Overview

Research Areas

Research Overview

Publications

Selected Publications

Journal Article

Funding

Investigator On

Impact

Impact Story

Using assisted reproductive technologies to conserve Australia's endangered amphibians

Supervision

Advisees

Graduate Advising Relationship

Overview

Research Areas

Research Overview

Publications

Selected Publications

Journal Article

Funding

Investigator On

Impact

Impact Story

Using assisted reproductive technologies to conserve Australia's endangered amphibians

Supervision

Advisees

Graduate Advising Relationship

Visualisations

Research Areas