Mattias Hagman

Mattias Hagman

Position: PhD student, Post-Doc
Year: 2004 - 2007, 2007 - 2008
Phone: N/A
Fax: N/A
Location: Department of Zoology, Stockholm University, 106 91 Stockholm, Sweden

Research Interests

For as long as I can remember, reptiles and amphibians have fascinated me. This interest has had a great influence on my life and it has taken me from my home country, Sweden, to various places in the world. One of my favourite trips was a visit to the Komodo Islands, home of the famous Komodo dragon (Varanus komodoensis, below).



The colourful and highly toxic poison frogs (Dendrobatidae, below) of Central- and South America are also long time favourites and I have been to the rainforests of Costa Rica, Panama and Peru to study them. These frogs have some interesting aspects of life-history. Many species, for example, have evolved higly specialised reproduction strategies. The most obvious thing about them however, is their extremely potent skin toxins and conspicuous colouration. The vivid colouration presumably serves as a signal that warns potential predators about their toxicity. Experimental studies have shown that the avoidance inducing effect of conspicuous prey colouration increases with increasing size of pattern elements and with increasing body size. In collaboration with Professor Anders Forsman I used poison frogs to test predictions from these findings, i.e., that conspicuous colouration will evolve in tandem with body size. The results from our study were consistent with this hypothesis.

In the first quarter of 2004 I was in the rainforests of north-eastern Peru researching a flesh fly (Sarcophagidae) whose parasitic larvae prey on poison frogs from the family Epipedobates. The invasion of fly larvae in vertebrate tissues is a phenomenon commonly refered to as myiasis. The phenomenon is well documented in many animals, predominantly mammals and birds. Amphibians worldwide are also parasitised by numerous fly species. This however, is a poorly studied area of amphibian biology. In collaboration with Dr Thomas Pape and Rainer Schulte, I provided the first evidence of flies causing myiasis on frogs from Peru as well as the first evidence of fly larvae parasitising poison frogs. Some of the papers I published on poison frogs are available as PDF files from my list of publications.

poison dart frogsvine

Current Research

Potential short-term control measures for cane toads

I was very fortunate to have been able to come to Australia, where I undertook my PhD and then was employed as a postdoc in Professor Shine's lab at the University of Sydney. Most of my research focussed on the invasive cane toad, Chaunus (Bufo) marinus, which was introduced to Australia more than 70 years ago in a futile attempt to control pests on cane fields in Queensland. Since it's introduction the cane toad has spread, and continues to spread, across vast areas of Australia. Because it is toxic in all life-stages it is causing declines (and perhaps, local extinctions) of native predator populations. Although the cane toad thus is widely believed to be a major pest, very little is known about ecological processes at the toad invasion front. I studied the ecology of the cane toad, with emphasis on early life stages. My overall aim was to identify life-history traits that potentially could be exploited for control. For example, cane toads like many other water breeding amphibians rely upon waterbodies for reproduction. Waterbodies in many landscapes are a scarce resource. Hence, one of my initial studies was an investigation of spawning site selection by cane toads at an invasion front in tropical Australia. In March 2005 I surveyed waterbodies for signs of breeding in an area between Darwin and Kakadu. I recorded a range of variables from breeding- and non-breeding sites that may influence toads in their choice of spawning site. Collecting this data was exciting as crocodiles and water buffalos inhabited many of the waterbodies I examined. Another phenomenon that made this study an interesting experience was "Ingrid" - the hurricane - who was in the neighbourhood at the time of my visit. Anyway, when I compared variables from the two sets of sites (breeding vs non-breeding) I found that it was habitat variables that differed. Since some of these habitat variables could be manipulated there is potential for control. By manipulating waterbodies it would be possible to either discourage oviposition or to attract toads spatially and have concentrated communal breeding. The latter option would not only facilitate trapping and removal, but also exploit density-dependent mechanisms such as intraspecific competition and cannibalism for control of feral toad populations. Cannibalism is widespread among toad populations and may be an important viability reducing agent. Indeed, my research has shown that toads have evolved specific behaviours that facilitate cannibalism. By waving the middle toe of their rear feet up and down, medium-sized cane toads can attract smaller conspecifics within striking range. Click here for a video of a toe-waving toad.

I have also studied effects of toads on native mosquito species. This investigation yielded some very interesting and surprising results. Current research also involves behavioural responses by toad tadpoles to different stimuli and fitness costs of plastic traits (phenotypic plasticity). I believe that simple but effective control methods can be developed from a sound knowledge of basic toad ecology. It is my hope that in addition to conservation applications, my research will also yield new knowledge about the ecology of cane toads and contribute to the general science of biology.

Apart from studying the ecology of reptiles and amphibians I am also interested in photography, which I think combines very well with my research. I have taken numerous pictures during field work and travels. On this page I have included a few of them.

hager phyllomedusa


Scientific Papers

To request a reprint, please contact Mel:

Hagman, M.and Forsman, A. 2003. Correlated evolution of conspicuous colouration and body size in the poison frog family Dendrobatidae.Evolution 57(12):2904-2910.
Hagman, M., Pape, T. and Schulte, R. 2005. Flesh fly myiasis in Peruvian poison frogs (Anura: Dendrobatidae,Epipedobatesspp.).Phyllomedusa 4(1):69-73.
Hagman, M.2006.Dendrobates pumilio(Poison frog) poisoning.Herpetological Review (37)1:73-74.
Hagman, M.and Shine, R. 2006. Spawning-site selection by feral cane toads (Bufo marinus) at an invasion front in tropical Australia.Austral Ecology 31:551-558.
Forsman, A. andHagman, M.2006. Calling is an honest indicator of paternal genetic quality in male poison frogs.Evolution 60(10):2148-2157.
Hagman, M.and Schulte, R. 2007.Leptodeira annulata(common cat-eyed snake) prey.Herpetological Review 38:90.
Hagman, M.and Shine, R. 2007. Effects of invasive cane toads on Australian mosquitoes: does the dark cloud have a silver lining?Biological Invasions 9:445-452.
Hagman, M.and Shine, R. 2008. Understanding the toad code: behavioural responses of cane toad (Chaunus marinus) larvae and metamorphs to chemical cues.Austral Ecology 33:37-44.
Hagman, M.and Shine, R. 2008. Deceptive digits: the functional significance of toe waving by cannibalistic cane toads (Chaunus marinus).Animal Behaviour 75:123-131.
Hagman, M.and Shine, R. 2008. Australian tadpoles do not avoid chemical cues from invasive cane toads (Bufo marinus).Wildlife Research 35:59-64.
11. Hagman, M., B. L. Phillips, and R. Shine.  2008.  Tails of enticement: caudal luring by an ambush-foraging snake (Acanthophis praelongus, Elapidae). Functional Ecology:in press.
12. Hagman, M., R. Hayes, R. Capon, and R. Shine.  2008.  Alarm cues experienced by cane toad tadpoles affect post-metamorphic morphology and chemical defences. Functional Ecology:in press.


  1. Shine, R., Brown, G. P., Phillips, B. L., Webb, J. K. and Hagman, M. The biology, impact and control of cane toads: an overview of the University of Sydney research programAdobe pdf document. In: Proceedings of the Cane Toad Workshop, CRC for Invasive Animals, Brisbane June 2006.

Popular Articles

Hagman, M.1999. Pilgiftsgrodor. Terrariet 6(12): 4-18.
Hagman, M.2000. Costa Rica - den rika kusten. Terrariet 7(4): 3-12.
Hagman, M.2000. Odling av en stor pilgiftsgroda -Dendrobates tinctorius"Taffelberg". Terrariet 7(7): 4-8.
Hagman, M.2001. Att odla riktigt små kryp hemma. Terrariet 8(7): 9-12.
Hagman, M.2001. Terrarieteknik och växter. Terrariet 8(10): 3-12.

Conferences, Abstracts and Seminars

2000 Hagman, M.Oral presentation (invited seminar): Poison Dart Frogs - Natural history and captive propagation. The Scanian Herpetological Society, University of Lund, Sweden.
2001 Hagman, M.Oral presentation (invited seminar): Poison Dart Frogs - Natural history and captive propagation. The Tropical Society Amazonas, Malmo Museum, Sweden.
2002 Hagman, M.Oral presentation (invited seminars): Herpetology and the biology of Poison Dart Frogs. Vaxjo University, Sweden.
2003 Hagman, M.Oral presentation (invited seminars): Herpetology and the biology of Poison Dart Frogs. Vaxjo University, Sweden.
2003 Forsman, A. andHagman, M.Abstract: Correlated evolution of conspicuous coloration and body size in poison frogs (Dendrobatidae). The 9th Congress of the European Society for Evolutionary Biology. Leeds, United Kingdom, 18-24 August.
2004 Forsman, A. andHagman, M.Abstract: Calling performance of male poison dart frogs: a reliable predictor of offspring quality. 10th Jubilee Congress of the International Society for Behavioural Ecology.
2005 Hagman, M.Oral presentation (postgraduate seminar): Cane toad spawning-site selection: implications for control. Biological Sciences, University of Sydney.
2006 Hagman, M.Oral presentation: Cane toad spawning-site selection: implications for control. The annual conference of the Australian Society of Herpetologists (ASH). Healesville, Australia, 18-21 April.
2006 Hagman, M.Oral presentation: Communication systems of invasive toads: is there potential for control? The annual conference of the Australasian Society for the Study of Animal Behaviour (ASSAB). Sydney, Australia, 20-23 April.
2006 Hagman, M.Oral presentation: Chemical cues - repellents. Workshop: “The science of cane toad (Bufo marinus) invasion and control”. Co-hosted by the Invasive Animals Cooperative Research Program, Queensland Department of Natural Resources and Mines, and CSIRO. Brisbane, Australia, 5-6 June.
2006 Hagman, M.Oral presentation: Understanding the toad code: behavioural responses of cane toad (Bufo marinus) larvae to scent cues. Biological Sciences, University of Sydney, 15 August.
2006 Hagman, M.Poster: Spawning-site selection by feral cane toads (Bufo marinus) in Australia. Annual meeting of the British Ecological Society, Oxford, UK, 5-7 September.
2007 Hagman, M.Poster: Can the evolution of boldness facilitate rapid range expansions by invasive organisms? The 11th Congress of the European Society for Evolutionary Biology. Uppsala, Sweden, 20-25 August.

Grants and Awards

2004 Minor Field Study (MFS) funded by SIDA (Swedish International Development Cooperation Agency). Project Title: Dendrobatid Frog Myasis Investigation (Project took place in Cordillera Oriental, Peru)
2004 International Postgraduate Award (IPA), University of Sydney
2004 International Postgraduate Research Scholarship (IPRS), Australian Department of Education, Science, and Training
2006 Postgraduate Research Support Scheme (travel grant), University of Sydney
2006 Postgraduate Excellence Prize (finalist)
2007 Postgraduate Research Support Scheme (travel grant), University of Sydney
2007 University Student Grants Scheme. The Wildlife Preservation Society of Australia