Crystal Kelehear

Crystal Kelehear

PhD student 2008-2012

Current Email: crystal.kelehear@hotmail.com


Past Research

Tail autotomy in Velvet Geckos

Crystal

I first came to the Shine lab as an undergraduate in 2005 to carry out research on tail autotomy in Velvet Geckos (Oedura lesueurii) with Dr Jonathan Webb.

Tail autotomy is an important anti-predatory strategy employed by greater than 50% of all lizard families. When successful, tail autotomy affords the obvious benefit of immediate survival, however there are many associated costs that may compromise long-term survival, an important one being the loss of the tail as a future means of predator evasion. In response to the loss of this resource, it is expected that tailless lizards will compensate by investing in alternative anti-predator strategies. My studies on the Velvet Gecko concluded that tailless geckos did not increase their sprint speeds nor did they alter their anti-predator strategies in the presence of a predator cue following tail autotomy. These findings suggest that locomotor costs associated with tail autotomy are minor in the Velvet Gecko. Further, since Velvet Geckos do not compensate behaviourally for tail loss by investing in alternative anti-predator strategies, autotomised lizards may be more vulnerable to predation.

Nematodes versus cane toads

Metamorph cane toad
Metamorph cane toad

In 2006 I returned to the Shine lab to complete my Honours degree investigating the influence of a parasitic lung nematode (Rhabdias pseudosphaerocephala) on the fitness of metamorph cane toads (Bufo marinus). This lung nematode is a parasite of the toad’s native range and was presumably brought to Australia with the toad. This parasite readily achieves up to 90% prevalence in wild toad populations and has been found at an intensity of up to 300 adult worms per host – yet the effects of this parasite on its host were unknown prior to my honours research. The results of my honours research revealed a negative impact of laboratory induced infection on toad metamorph survival, growth, locomotor performance and feeding rate. Yet this in itself is perplexing: yes the parasite is common, yes it has a negative effect on its toad host… yet toads are still charging across the continent at an alarming pace.

The Endangered Blue Iguana

Blue Iguana
Blue Iguana

In the aftermath of my exciting yet confusing Honours results I took some time to ponder their meaning and the directions in which they may take me. During this pondering time I volunteered with the International Reptile Conservation Foundation and joined “Team Blue” in the Cayman Islands to carry out field research aimed at conserving the most endangered iguana in the world, the Blue Iguana. The Blue Iguana was considered functionally extinct in 2005 with less than 20 adults remaining in the wild – their survival threatened by habitat destruction, introduced species and road kill. Since 2005 a rigorous captive breeding program has bought wild animal numbers back to around 300 with a minimum of 1000 wild animals being the ultimate aim to bring the species back from the brink of extinction.

Current research

The results of my previous laboratory based studies hold promise for new avenues of toad control – however, the natural dynamics of host-parasite interactions in this system have not been established. The aim of my current research is to determine the impact of Rhabdias pseudosphaerocephala on wild cane toad populations and how this host-parasite relationship varies spatially and temporally – with a particular focus on parasite life history and the interaction between parasites and host reproductive investment.

Adult male cane toad Mature R. pseudosphaerocephala with eggs Infective R. pseudosphaerocephala
Adult male cane toad Mature R. pseudosphaerocephala with eggs Infective R. pseudosphaerocephala

Tertiary education

 Year  Details
 2008-2012 Doctorate of Philosophy in Biology. The University of Sydney
Thesis: Host-parasite interactions during a biological invasion
Advisors: Professor Richard Shine, Dr Gregory P. Brown
 2006-2007 First Class Honours (91%) in Biology. The University of Sydney
Thesis: The effects of lung nematodes (Rhabdias cf. hylae) on metamorph cane toads (Chaunus marinus), and implications for biological control.
Advisors: Professor Richard Shine, Dr Jonathan Webb
 2003-2005 Bachelor of Advanced Science. The University of Sydney

Peer-reviewed publications

#  Publication details
16. Pizzatto, L., Kelehear, C., and R. Shine. (2013). Seasonal dynamics of the lungworm, Rhabdias pseudosphaerocephala, in recently colonised cane toad populations in tropical Australia.  International Journal for Parasitology 43:753-761.
15. Brown, G. P., Kelehear, C. & Shine, R. (2013). The early toad gets the worm: cane toads at an invasion front benefit from higher prey availability. Journal of Animal Ecology 82:854-862.
14. Kelehear, C., Brown, G. P. & Shine, R. (2013). Invasive parasites in multiple invasive hosts: the arrival of a new host revives a stalled prior parasite invasion. Oikos 122:1317-1324.
13. Pizzatto, L., Kelehear, C., Dubey, S., Barton, D. & Shine, R. (2012). Host-parasite relationships during a biological invasion: 75 years post-invasion, cane toads and sympatric Australian frogs retain separate lungworm fauna. Journal of Wildlife Diseases 48: 951-961.
12. Kelehear, C., Cabrera-Guzmán, E. & Shine, R. (2012). Inadvertent consequences of community-based efforts to control invasive species. Conservation Letters 5:360-365.
11. Kelehear, C., Brown, G. P. & Shine, R. (2012). Size and sex matter: infection dynamics of an invading parasite (the pentastome Raillietiella frenatus) in an invading host (the cane toad Rhinella marina). Parasitology 139:1596-1604.
10. Graham, S. P., Kelehear, C., Brown, G. P. & Shine, R. (2012). Corticosterone-immune interactions during captive stress in invading Australian cane toads (Rhinella marina). Hormones & Behavior 62:146-153.
9. Kelehear, C., Brown, G. P. & Shine, R. (2012). Rapid evolution of parasite life history traits on an expanding range-edge. Ecology Letters 15: 329-337.
8. Kelehear, C., Webb, J. K., Hagman, M. & Shine, R. (2011). Interactions between infective helminth larvae and their anuran host. Herpetologica 64:378-385.
7. Brown, G. P., Kelehear, C. & Shine, R. (2011). Effects of seasonal aridity on the ecology and behaviour of invasive cane toads (Rhinella marina) in the Australian wet-dry tropics. Functional Ecology 25:1339-1347.
6. Kelehear, C., Spratt, D. M., Dubey, S., Brown, G. P. & Shine, R. (2011). Using combined morphological, allometric and molecular approaches to identify species of the genus Raillietiella (Pentastomida). PLoS ONE 6:e24936.
5. Kelehear, C., Brown, G. P. & Shine, R. (2011). Influence of lung parasites (Rhabdias pseudosphaerocephala) on growth rates of free-ranging and captive adult cane toads (Bufo marinus). Oecologia 165:585-592.
4. Kelehear, C. & Jones, H. I. (2010). Nematode larvae (Order Spirurida) in gastric tissues of Australian anurans: a comparison between the introduced cane toad and sympatric native frogs. Journal of Wildlife Diseases 46:1126-1140.
3. Phillips, B. L., Kelehear, C., Pizzatto, L., Brown, G. P., Barton, D. & Shine, R. (2010). Parasites and pathogens lag behind their host during periods of host range-advance. Ecology 91:872-881.
2. Kelehear, C., Webb, J. K. & Shine, R. (2009). Rhabdias pseudosphaerocephala infection in Bufo marinus: Lung nematodes reduce viability of metamorph cane toads. Parasitology 136:919-927.
1. Kelehear, C. & Webb, J. K. (2006). Effects of tail autotomy on anti-predator behavior and locomotor performance in a nocturnal gecko. Copeia 2006(4):803-809.

Popular articles

#
Article details
1.
Kelehear, C. (2009). Nematodes versus toads: investigating the potential for parasites to lessen the impact of the cane toad invasion. Australian Wildlife 4:35.

Awards and scholarships

Year Grants, awards, scholarships
2011 Honorable Mention: Best PhD Student Presentation, Annual Meeting of the Australian Society of Herpetologists
2011 Chief Executive Officer’s Prize for Achievement as a Student in the Invasive Animals Cooperative Research Centre ($3,000)
2011 Finalist: Biological Sciences Postgraduate Excellence Award
2011 People’s Choice Award for Best Student Presentation: Annual Meeting of the Invasive Animals Cooperative Research Centre
2011 Postgraduate Research Support Scheme: Graduate Student Grant ($260)
2010 Finalist: ANZANG Nature and Landscape Photographer of the Year
 2010 ARC/NHMRC Research Network for Parasitology: Research Exchange Award ($2,500)
2010 Invasive Animals CRC Student Travel Grant ($2,000)
2010 Australian Society for Parasitology Student Travel Grant ($590)
2010 G.H.S. & I.R. Lightoller Scholarship ($2,200)
2010 Frog and Tadpole Study Group of New South Wales Student Grant ($800)
2010 Postgraduate Research Support Scheme: Graduate Student Grant ($1,000)
2009 Wildlife Preservation Society of Australia Student Grant ($1,000)
2009 Postgraduate Research Support Scheme: Graduate Student Grant ($850)
2008- The University of Sydney Postgraduate Award ($20,000pa)
2008- The Invasive Animals Cooperative Research Centre Top-up Scholarship ($11,000pa)
2003-07 The University of Sydney Undergraduate Award ($5,000 pa)

Presentations

Year Title
2012 Invited seminar: Tales of invasion and evolution: cane toads and their parasites. Centre for Infectious Disease Dynamics, Pennsylvania State University, USA
2012 Oral presentation: Rapid evolution of parasite life history traits on an expanding range-edge. World Congress of Herpetology, Canada
2011 Oral presentation: Rapid evolution of parasite life-history traits at an expanding range edge. Annual Meeting of the Australian Society of Herpetologists, Australia
2011 Oral presentation: Rapid evolution of parasite life-history traits at an expanding range edge. Biological Sciences – Postgraduate Excellence Award, The University of Sydney, Australia
2011 Oral presentation: Influence of lung parasites on growth rates of adult cane toads. Annual Meeting of the Invasive Animals Cooperative Research Centre, Australia
2010 Oral presentation: Toads and nematodes – masters of invasion. Biological Sciences, Auburn University, United States of America
2010 Poster presentation: Parasites adjust life history traits in response to shifting population dynamics in an invading host. International Congress for Parasitology, Australia
2010 Oral presentation: Pentastomids in cane toads of the Northern Territory. Emerging Amphibian Diseases International Conference, Australia
2010 Oral presentation: Life-history adaptations in an invading parasite. Annual Meeting and Review of the Invasive Animals Cooperative Research Centre, Australia
2009 Postgraduate seminar: Host-parasite interactions during a biological invasion. Biological Sciences, The University of Sydney, Australia
2009 Oral presentation: Host-parasite interactions during a biological invasion. Annual Meeting of the Invasive Animals Cooperative Research Centre, Australia

Professional affiliations

  • Australian Society of Herpetologists
  • Australian Society for Parasitology
  • Australian Wildlife Health Network
  • Frog and Tadpole Study Group of New South Wales
  • International Reptile Conservation Foundation
  • Invasive Animals Cooperative Research Centre
  • Wildlife Disease Association
  • Wildlife Preservation Society of Australia