Patricia Backwell

I received my formal education in South Africa. During my graduate years I worked on the breeding behaviour of several species of frogs. After my PhD I switched to studying fiddler crabs and completed three post-docs. I then did a year of lecturing in South Africa before moving to Panama to work for the Smithsonian for the next six years, still studying fiddlers. I took up my present post as lecturer at ANU at the start of 2002. All of this experience has forged me into the truly brilliant scientist that I am.

My current research is entirely field-based and I have spent many hours sitting on sunny beaches staring at amazing little crabs. Most of my fieldwork has been carried out in Mozambique, Japan, South Africa and Central America. I am now working on tropical Australian fiddlers. My main study site is in Darwin, NT.

Research interests

I work on the behavioural ecology of fiddler crabs. There are over 100 species of fiddlers world wide, and about 20 of them occur in Australia. They are often the most commonly seen inter-tidal animal on tropical mudflats, and are ecologically important as a major food source for shore birds. Although a lot is known about them as prey items, surprisingly little is known about their behaviour. They are ideal study animals because they occur in huge numbers and are exceptionally easy to catch, mark, observe and manipulate. They are sexually dimorphic, males having a single enlarged claw which is used both as a weapon and waved to attract mate-searching females. My work has covered a broad range of topics but I have concentrated on three main areas:


a. Male Uca lactea; b. Mangrove habitat; c. Male Uca elegans; d. Muddy habitat of Uca seismella.

The mate choice process

I am particularly interested in the process of mate selection. In most animal species, females have inherent mating preferences that can be demonstrated in simple laboratory studies involving two-choice tests. Under natural conditions, however, the actual process of mate choice is far more complex. There are many constraints that may prohibit females from expressing their preferences. They may face temporal or energetic constraints on free choice. Predation risk or variation in the quality of resources they encounter may affect their final choice. Similarly, variation in the social environment, such as male-male competition, levels of male phenotypic variation or operational sex ratios could influence their selection of mates. Much of my research focuses on the biotic and abiotic factors that determine the level at which females are able to express their underlying mating preferences.

Dishonest signalling


In animal communication it is generally true that the signals animals use convey accurate and honest information. Individuals of some species, however, produce deceptive signals that provide inaccurate information. This "cheating" may allow the signaller to attract mates or repel competitors when it would be incapable of doing so were it to signal honestly. Some fiddler crabs appear to signal deceptively. Fiddlers can autotomise their large claw and, through a series of moults, regenerate a new one. In most fiddler species, the regenerated claw is identical to the original. In some species, however, the regenerated claw is clearly different. It lacks teeth, has a smaller muscle mass and more delicate fingers. Males apparently quickly regenerate their claw to the same overall length as the original, but produce a cheaper version. This is less effective as a weapon but is lighter and therefore more easily waved. The regenerated claw appears to act as an effective visual bluff of fighting ability and may actually be preferred by mate searching females. I am presently investigating this apparent case of cheating.

Fighting neighbours and strangers

Male fiddlers use their enlarged claws in fights. First they threaten each other with aggressive waves, then they push each other with the front surface of the claw, and finally they interlock claws and grapple until one male, the loser, is flicked away. Territory owners fight approaching strangers that try to usurp their territories. They also fight neighbours to negotiate and demarcate territory boundaries. Strangers pose a greater threat than neighbours because losing a fight with a stranger means losing the entire territory whereas losing a fight with a neighbour only results in a slight reduction in territory size. In other animals, fights with both strangers and neighbours are thought to be tests of strength with the stronger male most likely to win. Oddly, in fiddler crabs, this does not appear to be the case. Fights between neighbours do not appear to be settled by brute force. Instead, it appears that residents use aggression as a sort of punishment against encroaching neighbours. The fight itself inflicts time and energy costs on the neighbour so, by consistently engaging the neighbour in a fight each time it encroaches, residents may decrease the likelihood of the neighbour returning to the disputed area. If this is true, then fights between neighbours and those between strangers are fundamentally different interactions. While strangers might fight to win, neighbours may not be trying to 'beat' the encroacher but rather to 'nag' it into respecting the border between them.


a. Male Uca capricornis; b. Male Uca elegans; c. Male Uca mjoebergi; d. Female Uca vomeris.

Research grants

  • 2012 -2014 ARC Discovery Grant ($340 000)
  • 2010 CMBE Research Grant ($ 20 000)
  • 2007-2009 ARC Discovery Grant ($263 000)
  • 2005 ARC LIEF Grant ($150 000)
  • 2004-2007 ARC Discovery Grant ($200 000)
  • 2003 Faculty Research Grant ($ 9 940)
    The Australian National University
  • 2001-2002 Travel Grant ($4 000)
    The Japan Society for the Promotion of Science
  • 2001 VC Endowment for Excellence ($30 000)
    The Australian National University
  • 2000 Invited Senior Researcher ($35 000)
    The Japan Society for the Promotion of Science
  • 2000 Johnson Research Award ($10 000)
    The Smithsonian Tropical Research Institute.

Editorial boards

  • 2013- Associate Editor, Methods in Ecology & Evolution; British Ecological Society / Wiley
  • 2013- Editor, Animal Behaviour; Elsevier
  • 2007-2012 Consulting Editor, Animal Behaviour; Elsevier
  • 2004-2007 Associate Editor, Behavioural Ecology & Sociobiology; Springer.

Potential students

PhD students are a valuable part of the fiddler crab research group. Both Australian and international students can get scholarships to undertake a PhD at ANU. Australian students can apply for an APA (Australian Postgraduate Award) that covers fees and living expenses. These are competitive scholarships and to be in the running, you need my strong support (this can usually be bought with chocolates) and a first class Honours mark. Applications are due at the end of October.

International students can apply for an IPRS (International Postgraduate Research Scholarship) which pays their fees, airfare and medical insurance. They also need to apply for an ANU PhD Scholarship that pays their living expenses. IPRS scholarships are extremely competitive. Applications are due at the end of August. See the ANU Scholarships page for more information.

PhD supervision


I have a very strong commitment to the success of my PhD students. For fiddler crab PhD's, the most sensible structure is for the thesis to be based on a set of 4-6 papers. In the first year, I work closely with the student, giving them the ideas and supporting them throughout the process of data collection. After the first field season, the student will continue to work closely with me in the writing of the papers. For the second field season, the student will play a greater role in the entire process. They will provide some of the ideas, will have greater responsibility in experimental design, analysis and writing. By the third field season, the student will be working more-or-less independently, but discussing their ideas and methods with me.
I expect students to write up their papers after each field season. This means that there is no stressful rush to write a thesis in the last six months of the PhD. I see a PhD as a slow and steady progression towards independent research. Please see the CrabLab website for information on the research station; fieldwork conditions; rules; schedules etc.

What past students say


Tanya Detto
Are you looking for a PhD, but not sure what to do? 
Do you live for field work in the tropics?
Want to work on a really charismatic animal but don't want the biggest milestones to be when you're lucky enough to actually find one of them?
Does the thought of waking up at 4am or working in the rain fill you with dread? Like the idea of a supervisor that's easy to talk to and supportive?
If you answered yes to any of these questions I suggest you have a chat with Pat about doing your PhD on fiddler crabs in Darwin.


Leeann Reaney
As an international PhD student, I found BoZo (now the Division of Evolution, Ecology and Genetics) a very fun and accommodating department to come into. Both the people and the research are vibrant and dynamic, making it a very stimulating working environment. I found it very easy to settle in. I also had immense fun doing a PhD under Pat Backwell. Working with the fiddler crabs in Darwin was incredibly enjoyable and provided me with so much canvas for field research. My enthusiasm and confidence for behavioural research has tripled during my time here!