What Determines Gecko Fighting Performance | An Honours Project by Rebecca Wheatley

This is Rebecca. She just submitted her Honours thesis, and is probably chilling with a vodka lemonade on a beach somewhere. Or else she's wishing she was.

A couple months ago, I asked Bec to describe her thesis - and to show me the experiments she had running. Here's what she said:

My research is using Asian house geckos as a model to answer questions about how morphology, performance, metabolic rate and personality interact to affect fighting ability in animals.

Rebecca's work is exciting because few studies have evaluated how morphology (or body size | shape), physiology, and personality work together to determine animal performance.

And can animals really have personalities? Of course, but not like you and I do. In the non-human world, personality can refer to repeatable differences in behaviour among individuals. For example, some individuals consistently tend to be shy, and others tend to be bold. Boldness | shyness is important for animals, as it can determine the likelihood of obtaining food or mates, or getting captured by predators.

When I caught up with Rebecca, she was measuring geckos' metabolism in purpose-designed jars, which were hooked up to specialised equipment that measures oxygen consumption. Oxygen consumption is one way that scientists assess metabolic rate in animals in the lab.

Collecting data on gecko metabolism

Rebecca was also video recording interactions between randomised pairs of geckos. Asian house geckos are aggressive little lizards, and will sort out dominance via displays of their open mouths, biting, and | or chasing. In her thesis, Rebecca looked at which animals were likely to be dominant, and whether that depended on their metabolism, morphology, and | or personality. 

collecting data on gecko fighting

And what did she find? The oversimplified version is that bite force, body mass, and running speed were most important in determining gecko dominance. Big, fast, hard-biting geckos were likely to be winners. The surprising thing was that metabolism and boldness didn't seem related to fighting performance.

There's a lot more to Rebecca's research: she used all the information she collected on morphology | physiology | behaviour to test important ecological theories about how individuals should interact (known as game theories). But we'll talk more about that another time - we don't want to give away everything just yet.

Thank you Rebecca, for taking the time to share your honours work with us, and for being such a wonderful labmate!

written and photographed by Amanda Niehaus, PhD

Fieldwork, Groote Eylandt, NT

Leaving Darwin, the propellers outside hummed loudly (reassuringly). We pressed our noses to the windows, looked out on the wild top coast of Australia. The fires lit by thousands of years of tradition. And then, we were there. Over the mines, into the red dirt.

the GEMCO manganese mine

On the deck with Jennifer and her niece; with Chopper; with MacBook Pro

We drove east to Umbakumba then headed into the bush on sandy tracks. We set up tents on top of a berm, feeling {relatively} safe from water-borne crocs and collected firewood from the beach. We watched a heavy moon pull itself up into the sky.

Picnic Beach, Groote Eylandt | Jaime and Eddie set out, bait, and mark quoll traps

Under Jaime's guidance, we set out traps for quolls, hoping to catch at least a few to obtain measurements and hair samples.

We caught 4. Plus a few bandicoots. It was good enough for Jaime to get her samples, and good enough for me - these were the first wild quolls I'd seen.

It was only a week ago we got back from Groote Eylandt. What a special place. Wild, and raw, and special. An island of contrasts, between a traditional culture and a modern mining industry. An island with a lot of crocodiles.

It was my first trip up, and Nelle came along. We met the Rangers and friends and family and Gavin and Kerry and the rest of the team and Alex-from-Stanford. We drank tea on the deck at the Ranger station, and packed up everything {but petrol} for a quoll-catching venture to the east side of the island. {Former labmate} Billy was appointed Ranger Coordinator. We learned our first Anindilyakwan words. We entertained Nelle, and learned the value of ABC for Kids downloads {and PhD students}.

A quoll curled up in its very own, custom-made pillowcase | fishing for dinner

We were almost as successful catching fish ... the ocean here teems with them {apparently} but we didn't have much luck. Three fish only made it into our bellies.

That's ok. We had plenty of patience ... and potatoes. 

- written byAmanda Niehaus

Trade-offs in Gecko Design

Sounds glam, right? Gecko design?

At the 2012 SICB in Charleston, Skye presented research that shows how traits that improve bite force in geckos have negative impacts on the gecko's sprint speed. Meaning that males who are better fighters might also be less adept at escaping predators ...

Costly design indeed.

Let's learn more by having a look at Skye's abstract, with {comments in brackets from me}.

Trade-offs and compensatory traits: bite force and sprint speed pose conflicting demands on the design of male geckos (Hemidactylus frenatus)

by Skye Cameron, Melissa Wynn and Robbie Wilson

The evolution of exaggerated ornaments and armaments is driven by the benefits accrued to reproductive success and by the costs imposed on viability. {This means that} when traits are required to perform multiple functions that are important to both reproduction and viability, trade-offs can result in a compromised phenotype.

{Imagine, for example, a species of bird in which females are more likely to mate with males that have larger tails; but males with larger tails are more likely to be captured by predators. Both reproductive potential and survival are important to the male - so evolutionarily, the bird may end up compromising on tail length to make sure he both reproduces and survives.}

image

{Intuitively, we expect that exaggerated male traits (like super-long tails) would decrease locomotor capacity, resulting in lower survival rates due to predation.} Despite only mixed empirical support for such locomotor costs, recent studies suggest these costs may be masked as a result of the evolution of compensatory mechanisms that offset any detrimental effects.

{What are compensatory mechanisms? Imagine if that bird with the long tail-feathers developed longer wings, that enhanced its flying abilities. It might offset some of the survival costs of the long tail.}

In this study, {Skye} provides a comprehensive assessment of the importance of potential locomotor costs that are associated with improved male-male competitive ability by simultaneously testing for locomotor trade-offs and compensatory mechanisms. For males of the Asian house gecko (Hemidactylus frenatus), both fighting capacity and escape performance are likely to place conflicting demands on an individual’s phenotype.

image

Males that are highly territorial and aggressive are more likely to require greater investment in jaw size/strength in order to compete with rival males; {Skye} found that males with larger heads had stronger bites and showed greater prey-capture and fighting capacity. This performance trade-off was amplified for male geckoes with larger heads when {they were} sprinting up inclines.

image

{So, what does this mean? Geckoes with large heads are better at fighting and better at capturing prey, but may be worse at evading predators themselves. A compensatory mechanism would be something - like longer legs - that would enhance their ability to avoid predation.} {However, Skye} found little evidence for compensatory mechanisms that off-set the functional trade-off between bite force and sprint speed.

Ongoing work in this area includes testing the survival of male geckoes with different sized heads in controlled-but-natural conditions.

Bigger *is* Better: Phallus size and male physical performance across temperatures

The second presentation we'll discuss is Robbie's. Robbie's talk - though sadly fraught with technological difficulties - conveyed to the audience the answer to that age-old question:

does a bigger phallus actually mean the male is better?

I won't give away the ending just yet, (or maybe I will ... ) - in mosquitofish, anyway - the answer seems to be yes.

Bigger is Better in all environments: temperature-induced variation in phallus size is a reliable indicator of male physical performance and gamete quality

Males of many organisms possess elaborated structures that are used to engage in fights with other males and/or to attract females during courtship. The size and elaboration of these secondary sexual traits can be affected by the environment via its influence on the condition of an individual male. This link between male condition and the elaboration of male sexual signals is one of the most important mechanisms maintaining the reliability of these traits as signals of male quality.

male elk use extravagant antlers to battle for females

The role temperature plays in mediating the condition of individual males and the size and elaboration of their sexually selected traits is currently unknown. Males of the eastern mosquitofish (Gambusia holbrooki) possess a modified anal-fin phallus (gonopodium) that is used as both a signal of dominance and a stabbing weapon during male-male competitive bouts {as well as to fertilise females}.

image

{Robbie} examined the effect of temperature on the size of this putative sexual signal (phallus size) by chronically exposing males to either 20° or 30°C for four weeks. {He} also tested the influence of these thermal environments on various measures of male quality; including male territorial performance, swim speed and gamete function.

Males chronically exposed to 30°C possessed longer phalluses, greater ejaculate sizes, larger testes and faster sperm swimming speeds than those exposed to 20°C. This is the first study to show that environmental variation in phallus size can be a reliable indicator of male physical performance and gamete quality.

{And what does this mean, and why does it matter? Well, it means that mosquitofish may have higher reproductive outputs in warmer environments, and might do even better than they currently do when climates warm further. In Australia, mosquitofish are invasive and by out-competing and eating eggs and young of natives, they are aiding the decline of native fish populations.}

Not good. Who knew that global warming would increase phallus sizes ...

Death After Sex in the Australian Bush

Charleston wasn't just about pizza and beer, though with any scientific conference that's always a part of it ...

First up, we'll hear about Jaime's poster. Jaime did a 1st class honours degree in the lab, studying the way Rhinella marinus (cane toad) tadpoles respond to the presence of predators in their environment. But that's not what she was presenting here ... Jaime also recently was accepted into the PhD program at UQ to study quolls on Groote Eylandt, and she was keen to get the word out there about her new study system.

Now.

More about quolls and sex and the bush, as conveyed by Jaime and her co-authors on the poster, Robbie and Billy {with clarifications from me along the way}

image by Candice Bywater

Death after Sex in the Australian Bush: determinants of survival and reproduction in males of the world’s largest semelparous* mammal {*meaning they die after breeding!}

The northern quoll (Dasyurus hallucatus) is a medium-sized (approx. 1 kg) predatory marsupial previously common across the entire top-end of Australia. This species is the largest known semelparous mammal in the world, which means mating is highly synchronous, males live for only one year, and males undergo total die-offs soon after the mating season.

Such population-wide male die-offs are presumably due to the physiological stress of procuring copulations and the intense fighting among males. A small proportion of females will survive to produce a second litter, but there are no documented cases of survival to a third breeding season. The young are born after a short gestation period and then carried in a rudimentary pouch for approximately 60-70 days.

Females will then leave young in dens while they forage, returning to suckle until young are independent at 4 – 5 months. Both sexes are solitary throughout the year with a home range averaging 35 ha for females and approximately 100 ha for males during the breeding season but varies greatly between individuals.

During {Jaime's} study, {she} will be investigating the morphological and performance determinants of both survival to reproductive-age and fecundity among males of this species on Groote Eylandt, an Indigenous-managed island off the coast of the Northern Territory. Northern quolls are still highly abundant on this island and this population offers a unique opportunity to understand the evolution of this extreme mating system and the role physical performance plays in the reproductive success of males.

We can't wait to hear more!

A Little Bit About Our Research on Performance

The basis of our lab's research is performance - performance of animals, including humans, in the context of their biotic or abiotic environments. We're interested in trade-offs between traits such as speed and endurance; the ways that changes in temperature or oxygen levels or life stages affect performance; and - in the case of sport - we're interested in optimising performance levels.

Currently, we're looking at projects such as:



1. Skill, balance, and athleticism in soccer performance (humans)

See the following posts for more detail:
Research and Innovation in Soccer (on our soccer website)
Measuring Individual Performance in a Team Context (on our soccer website)
The Importance of Effective Receiving and Passing (on our soccer website)
Assessment of Receiving and Passing Skills (on our soccer website)

 

 2. Weapon strength in signalling animals (crustaceans, lizards)

See the following publications for more details:

Wilson RS, James RS, Bywater C, Seebacher F. 2009. Costs and benefits of increased weapon size differ between sexes of the slender crayfish, Cherax dispar. Journal of Experimental Biology 212:853-858. View abstract here.

Seebacher F & Wilson RS. 2007. Individual recognition in crayfish (Cherax dispar): the roles of strength and experience in deciding aggressive encounters. Biology Letters 3:471-474. View abstract here. 

Seebacher F & Wilson RS. 2006. Fighting fit: Thermal plasticity of metabolic function and fighting success in the crayfish Cherax destructor. Functional Ecology 20: 1045-1053. View abstract here. 

crustaceans fighting to establish dominance

3. Tradeoffs in locomotor performance (fish, crustaceans, amphibians, insects, humans)

See the following publications for more details:

Angilletta MJ, Wilson RS, Niehaus AC & Ribiero P. 2008. The fast and the fractalous: tradeoffs between running speed and manoeuvrability in leaf-cutter ants. Functional Ecology 22:78-83. View abstract here.

James RS & Wilson RS. 2008. Explosive jumping: Morphological and physiological specialisations for extreme jumping in Australian rocket frogs. Physiological and Biochemical Zoology 81:176-185. View abstract here.

Wilson RS & James RS. 2004. Constraints on muscular performance: trade-offs between power output and fatigue-resistance in skeletal muscle. Proceedings of the Royal Society of London B 271: S222-S225.

Van Damme R, Wilson RS, Van Hooydonck B, & Aerts P. 2002. Performance constraints in decathletes. Nature 415:755-756. View abstract here.

  

do a male threadfin rainbowfish's streamers affect his swimming?

4. The myriad ways that the abiotic environment (i.e. temperature, pH, UV radiation, oxygen levels, etc) or the biotic environment (i.e. competitors, predators, etc) influences performance (frogs, fish, crustaceans, lizards)
See the following posts for more detail:
Run Gecko Run
Measuring Toad Jumps
Studying Mosquitofish in the South of France

And the following selected publications:
Wilson RS, Lefrancois C, Domenici P & Johnston IA. 2010. Environmental influences on unsteady swimming behaviour: consequences for predator-prey and mating encounters in teleosts In Fish Locomotion: An eco-ethological perspective (Eds Domenici, P & Kapoor, BG). Science Publishers, NH, USA. 

Barth B & Wilson RS. 2010. Life in Acid: interactive effects of pH and natural organic acids on growth, development and locomotor performance of larval striped marsh frogs (Limnodynastes peronii). Journal of Experimental Biology 213: 1293-1300. View full text here.

Condon CHL & Wilson RS. 2006. Effect of thermal acclimation on female resistance to forced matings in the eastern mosquito fish. Animal Behaviour 72: 585-593. View abstract here.

Wilson RS. 2005. Temperature influences swimming and sneaky-mating performance of male mosquitofish Gambusia holbrooki. Animal Behaviour 70:1387-1394. 

Billy measures jumping performance in a toad metamorph

Tackling the Problem of Diving in Football

Some consider it an art form, others cheating. Whatever your thoughts, diving by soccer players is one of the most controversial and despised actions in sport. Diving represents a deliberate attempt to deceive the referee, with players falling – even rolling around - to suggest they’ve been illegally fouled. Diving has long been a source of embarrassment for the world’s most popular sport, yet even football’s governing body (FIFA) has had little success at stamping out this behaviour.

University of Queensland PhD student Gwendolyn David, along with her supervisor Dr Robbie Wilson and other UQ colleagues have taken a fresh look at diving behaviour in an attempt to identify the mechanisms that can be used to control it.

image

In a study published this week in the prestigious open-access journal, PLOS One [http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0026017] these researchers explored the behaviour of soccer players and referees in the context of animal signalling theory.
“Theory predicts that deceptive behaviour should occur only when the prospective benefits outweigh the costs and when the risk of detection is low,” says Ms David. “So we expected that deception would be driven by the potential payoffs and would be limited by punishment.”

David undertook a play-by-play examination of 60 matches across six high-profile professional leagues to see when and where players faked fouls, and when they were likely to get away with it (or not). She found that – as predicted - diving occurred most often when the potential payoff was greater: namely, in the offensive side of the field and when the two teams had tied scores.

But the most exciting result came from looking between the leagues. “We found that players dived more often in leagues where referees were more likely to reward dives with a free-kick or penalty,” says Dr Wilson.

This means that when referees don’t detect or punish diving then dives are more common. “The most effective means of controlling deception, whether it’s a footballer or an animal, is via punishment. But, of the more than 2800 falls we observed and the 169 dives, we never once saw a diving player punished,” says David.

“Our results clearly show that reducing deception in sports like soccer is largely up to the referee and governing bodies. Players will try to deceive referees when the benefits are high, but better detection and administration of punishment may help reduce its prevalence” says Dr Wilson.

“Some progressive professional leagues, such as the Australian A-League and American MLS, have already started handing down punishments for players found guilty of diving. This is the best way to decrease the incentive for diving,” said Dr Robbie Wilson.

For more information on the study or for interviews, please contact Dr Robbie Wilson (Senior Researcher) at +61 458204962 or r.wilson@uq.edu.au. For other information on this research group’s work see the lab soccer website: www.soccerscience.net.

Honest Signalling in Koalas

Dr Bill Ellis is a postdoctoral researcher in the lab, who spends much of his time in the field tracking and studying koalas (and other cool animals).

In a recent project, Bill and colleagues (from Australia and the University of Vienna) learned that male koalas - which make loud, grunting bellows - have a particular vocal anatomy that means their call can give others a non-visual indication of the caller's body size.

This is the first time that a permanently-descended larynx has been found in a marsupial.

Pretty cool.

Though Robbie and the rest of us in the lab weren't part of this research, we're proud of Bill's awesome work, and thought you might like to read about it! You can find out more about the project here, on the Koala Ecology Group website or more about animal signalling here.

Animal Signalling

We're giving signals whether we know it or not. All the time - and without saying a word - we show others that we're bored or interested or infatuated or annoyed ... And this ability certainly isn't unique to humans.

Signalling is pretty much everywhere in the animal kingdom.

We know that some organisms use displays or calls or body structures to attract mates ... or ward off intruders ... or show how wonderfully strong and appealing they are. (Hmmm ... can you think of any examples?)

But what scientists are starting to figure out is that not all these signals are - shall we say - honest. Sometimes appearances aren't the same as reality. And there are times when it pays to show what you might be, rather than what you actually are. We're studying dishonesty in signalling in a number of different research systems, including crabs (who signal strength via their claws) and soccer players (who signal fouls via dives).

photo by Skye Cameron

You can read more about our signalling work here:
Cheating pays off for females but not males
How humans differ from crabs

Or here:
Walter G, Van Uietregt V, & Wilson RS. 2011. Social control of unreliable signals of strength in males but not females of the crayfish Cherax destructor. Journal of Experimental Biology. 214: 3294-3299.

Wilson RS & Angilletta MJ. In press. Dishonest signals of strength. In Ed. D. J. Irschick, M. Briffa, and J. Podos. Animal Signalling: a Functional Perspective. Ralph Wiley Press.

Wilson RS, Condon CH, David G, FitzGibbon SI, Niehaus AC & Pratt K. 2010. Females prefer athletes, males fear the disadvantaged: different signals used in female choice and male competition have varied consequences. Proceedings of the Royal Society of London Series B 277: 1923-1928. 
 
Wilson RS, James RS, Bywater C & Seebacher F. 2009. Costs and benefits of increased weapon size differ between sexes of the slender crayfish, Cherax dispar. Journal of Experimental Biology 212:853-858.

Bywater C, Angilletta MJ and Wilson RS. 2008. Weapon size is a reliable predictor of weapon strength and social dominance in females of the slender crayfish. Functional Ecology. 22:311-316.

Seebacher F & Wilson RS. 2007. Individual recognition in crayfish (Cherax dispar): the roles of strength and experience in deciding aggressive encounters. Biology Letters 3:471-474. 
 
Wilson RS, Angilletta MJ, James RS, Navas C & Seebacher F. 2007. Dishonest signals of strength in male slender crayfish (Cherax dispar) during agonistic interactions. The American Naturalist. 170:284-291

Cheating Pays Off for Females But Not Males

In the social circles of crustaceans, the claw means everything. Larger claws can be used to signal dominance, staving off unnecessary battles between poorly-matched opponents. However, if two similarly-sized individuals fight it out - it's usually the one with the stronger claw that wins.

Fighting fiddler crabs - photo by Skye Cameron

Unlike humans, where opponents can assess strength visually (e.g. bicep size), crustacean muscle is contained within a hard exoskeleton. This means that crustaceans can't determine each others' strength without testing it in combat, and it opens the possibility for cheating. Cheating could benefit individuals by gaining them dominance without having to fight; meaning access to better quality food, enhanced mating opportunities, and safer shelters - all without risk of bodily harm in combat or the high metabolic costs associated with maintaining strong claw muscles.

And cheating may be as easy as growing a large, wimpy claw.

By and large, animals are thought to signal their value (i.e. strength, power, dominance) honestly. But Dr. Robbie Wilson of the University of Queensland has found that many crustacean species actually cheat - producing large but weak claws that fool potential competitors.

These are exciting findings, because they show that cheating is likely to evolve under particular circumstances.

As part of his honours research in Dr. Wilson's lab, Gregory Walter found that female crayfish, Cherax destructor, are more likely to benefit from cheating compared with males. In his experiments, he measured claw sizes, body sizes, and claw force for each crayfish, and then observed which crayfish won in competitive, same-sex bouts - and, importantly, whether dominance was gained by signalling or battling.

Cherax destructor - photo by Gregory Walter

"We found that having large, wimpy claws was prevalent among both males and females," explains Dr. Wilson. "But only females gained dominance by cheating."

It turns out that male C. destructor tended to fight more often than females, so dominance among males was acquired via claw strength - an unfakeable trait. On the other hand, dominance among female C. destructor was most often determined via signalling alone, leaving claw strength untested and rewarding females with large, but weak, claws.

"In fact, females were pretty bad at judging each others' potential strength [based on claw size]," Dr. Wilson continues. "Giving sub-standard females the chance to be dominant."

This work has just been published as:
Walter G, Van Uietregt V, & Wilson RS. 2011. Social control of unreliable signals of strength in males but not females of the crayfish Cherax destructor. Journal of Experimental Biology. 214: 3294-3299.

You can read more about Dr. Wilson's research on honest signalling here. 
Written by Dr. Amanda Niehaus

Studying Mosquitofish from the South of France is Not as Glamorous as It Sounds, Part 3

The fish have been collected, the experimental plans organised, and now ... it's time to watch and swim and measure fish.

 

Robbie and Frank split up the work associated with their experiment - Robbie observed the females' behaviour and Frank measured metabolic rates.  

Here's the behavioural set-up:

And the metabolic set-up:

 

Frank swam fish in a little glass jar to ramp up their metabolic rates, so he and Robbie could calculate the metabolic scope.

That's all we can say for now, as the data haven't been analysed and the paper has yet to be written. But we wanted to give you some insight into what an eco-physiological experiment entails. It may not be as glamorous as it sounds, but the excitement of discovery and exploring new ideas is what keeps scientists going. The development of an experiment like this one was a lot of fun!

Studying Mosquitofish from the South of France is Not as Glamourous As It Sounds, Part 2

We now return to our story of mosquitofish from murky waters in southern France ... gallantly collected and brought back to the lab, where they were used to address a very important question:

How expensive is pregnancy?

Now, having been pregnant once before, I was willing to share my own experiences with expense in pregnancy: the financial costs associated with becoming addicted to eBay; the social costs of inexplicable moodiness; the energetic costs of lumbering to and from the bathroom; the mental costs manifested in an inability to concentrate/find keys/remember things.

But, apparently fish are different.

Mosquitofish, in fact, are live-bearers that can produce 20 to 70 young in a pregnancy - young that altogether can weigh up to 30-40% of the female's own body weight.

This extra mass and the energy required to produce all these baby fish can substantially increase a female's metabolism - even when she's resting. A higher resting (or basal) metabolism would be expected to limit a female's metabolic scope.

What's metabolic scope? It's the difference between resting and maximum metabolic rates - or the amount by which the body can increase metabolism to deal with high levels of physical activity or stresses. Because maximum metabolic rates are limited by the body's capacity to uptake oxygen and eliminate cell waste, they don't change much. So we expect the metabolic scope of a pregnant mosquitofish to diminish as her resting metabolic rate increases.

But.

That's not all.

Temperature also increases the resting metabolic rate of fish: higher temperatures mean higher resting metabolic rates.

So that's what Robbie and Frank and their French collaborators were keen to look at - how temperature affects the metabolic scope of pregnant mosquitofish.

(to be continued ...)

Studying Mosquitofish from the South of France is Not as Glamourous As It Sounds, Part 1

Recently, Robbie was invited to collaborate with scientists at France's prolific CNRS (Centre National de la Resherche Scientifique). These researchers included Head of the CNRS's Ariege unit, Prof Jean Clobert; and Marie Curie Fellow, Dr Camille Bonneaud. Robbie joined his long-time Australian collaborator and friend - A/Prof Frank Seebacher - in the idyllic location of Moulis* to study the behaviour, physiology, and performance of the invasive mosquitofish (Gambusia holbrooki) relative to their state of pregnancy.

*Let me assure you, that for all the un-glamourousness of the fish- and data-collection, the research station was spectacularly situated.

Imagine working in a well-funded research program in a quaint French village, in a building that adjoins a rushing brook amidst the green-capped mountains of the Pyrenees.
Mag. nif. ique.

But, alas, mosquitofish don't like pristine, bubbling streams. They prefer dank, stagnant places. So when Robbie and Frank took a drive toward the Mediterranean coast, it was looking for swamps. And though there are no pictures to document the collection of the fish, it allegedly involved:

1) wading through reeking swamp mud
2) numerous biting insects
3) a decomposing, floating, probable-mammal the size of a beaver
4) a swift change of clothes before returning to the hire car

And a pink net.

Some hearty beef stew and a few beers upon returning home didn't hurt, either.

Then it was off to the lab to set up the experiments ... (to be continued) ...

Biodiversity Research with Anindilyakwa Rangers

Our team has headed back up to Groote Eylandt (and I'm still here ... sigh ... ), so I thought I might take this opportunity to talk more about our collaboration with the Anindilyakwa people of the island. We have much to learn from each other - but more than that, collaboration between scientists and Indigenous peoples can be a rewarding and effective means of conserving the environment.

Aboriginal Australians have a powerful cultural connection to their environment. It sustains them, physically and spiritually. Conservation of biodiversity is innate, and information about the environment - the organisms that inhabit it, the seasonality of events - have been passed down via narratives and stories for thousands of years. Though this knowledge is more qualitative than quantitative, it represents a long-term picture of the environment that few, if any, scientific studies would provide.

Besides, the ability of Aboriginal trackers and rangers to navigate the bush is incomparable - which facilitates conservation-based studies of wildlife, including the northern quoll. On our trips to Groote Eylandt, our team trains the Indigenous Rangers in scientific methods of capturing, tagging, and 'processing' animals. We talk through research ideas, hypotheses, protocols, and analyses with them. And we absorb their beautiful culture.

We'll be sharing more about our current trip shortly, including photos of some very non-quoll-related fish, and a story about why Billy is currently sitting poolside at the resort, rather than working. (Ahem)

How to Catch and Process a Quoll*

*and no ... we're not making sausages out of them ...

So how do you catch a feisty little marsupial, that's nocturnal and ground-dwelling and generally doesn't like to be caught?
Ecologists typically use baited traps, but of a sort that aren't likely to harm the captured animal - like this Elliott Trap, which has a door that springs shut when the animal steps inside.

Just before dark, our intrepid quoll-catchers set out the traps (with goodies inside) and then return to camp to give the quolls a chance to find - and take - the bait.

When a quoll's been captured, we take it back to the lab to 'process' it. Which sounds really suss but actually just means that we measure them and add tracking and identification devices to them. This is so we can obtain information about the health and size of the quolls, and keep track of particular individuals over time.

After we've taken all the important measurements, it's time to 'mark' the animals. In this study, we mark with ear tags, pit tags (like microchips), and collars - which may seem like overkill, but actually allows us to collect different kinds of data.

Ear tags are like earrings that have a specific number on them, unique to the animal. This means that if we catch this quoll again, we can easily and quickly determine its identity. Ear tags, toe tags, and leg or flipper bands (depending on the animal of focus) are commonly-used by ecologists for this purpose.

Pit tags are the second line of identification ... they're inserted under the skin, and hold all the relevant information about the animal - just like the microchip that you can get for your dog or cat. The coolest thing about pit tags? You read them with a scanner.

(as in, "clean up on aisle 3 ... ")

And collars - they're for the purpose of tracking the animal, using either radio frequencies or GPS (depending on the type of collar). By tracking individuals, ecologists can learn more about how the animals interact with each other, how large their range is, and how much they move around. If you want to know more, we talked about tracking koalas here and here.

After all this, the quoll is released back into the wild ... where it is no longer the anonymous little carnivore it once was.

So now you know how to catch and process a quoll. (Or, for that matter, any animal of ecological interest). Please use your wisdom for good, not evil.

Thanks Gavin, Sean, Robbie, Billy and Bill for the great photos!

Run Gecko Run (Don't Ever Look Back)

How do scientists study running performance? Well, with humans we'd take subjects out onto a track and measure how fast they could sprint between two points.

With geckoes?

It's pretty much the same. Except we have
to design a track that encourages the gecko to move as quickly as it can in a straight line. (Because geckoes aren't as good at taking verbal directions as humans are ... )

Skye's current experiment is based around this running track. She puts a gecko into the near end (as shown in the top photo) and then chases it down the track with a foam paddle. Don't worry, the gecko's fine - the paddle is just to prevent it from stopping or turning around or anything that might disrupt measurements.

As the gecko runs down the track (away from us, in this picture), it passes the 4 light sensors that help Skye to accurately record the gecko's speed. Skye repeats the run 3 times more, so that she can get the gecko's fastest performance (best of 12 time splits - 3 trials x 4 sensors).

After measuring running performance, Skye takes the weight of the gecko to account for its body size in her calculations. This is because larger geckoes will be able to run faster independently of temperature.

Then, the gecko returns to its home in the lab.

Each gecko completes 8 running trials at temperatures between 15 and 38 degrees Celcius. Some populations won't ever have seen some of these temperature extremes in the wild (and others will have). 

Skye is predicting that where a gecko comes from will affect how it performs at these different temperatures. For example, at low temperatures geckoes from tropical North Queensland should perform more poorly than geckoes from Brisbane - because, in nature, Brisbane geckoes experience low temperatures every year (and tropical geckoes don't). 

Skye's still working hard measuring gecko running speeds ... so we can't tell you any results yet. But watch this space!

Why Temperature Matters to Geckoes

At the moment, Skye's doing a really cool experiment looking at how Asian house geckoes from different environments handle changes in temperature.

Why is this important? Well,
climates are changing. And scientists want to know how species will handle climate change - will they go extinct? will they do even better?

To answer these questions, we have to know more about how species perform across their natural range. Because animals that are already living close to their thermal limits might be at greater risk if things heat up, or even cool down. And because some animals have a greater capacity to rapidly adjust to temperature change (or acclimate) than others. And because most of the animals on the planet are what we call ectotherms, which (unlike humans) can't warm themselves up internally: their digestion, brainpower, muscle activity - everything - is dependent on the temperature in their environment.

So what's Skye doing? She's collected Asian house geckoes from across their latitudinal range in Australia - from Brisbane all the way up to Cape York. (ahem - more traveling??). Geckoes from all these different populations have grown up in quite different environments - but in general, temperatures get hotter and less variable as you head north from Brisbane.

Which leads us to some fundamental questions in thermal ecology: do animals in these different environments become 'experts' at performing under just those conditions? Or can they perform over a wide range of temperatures - just not very well? Is the pattern changeable (suggesting acclimation) or unchangeable (suggesting adaptation)?

Skye is testing these questions by looking at the running performance of geckoes from different populations  - across a range of temperatures. If you've ever watched a gecko on your window at night, you'll see why running is so important to them - it's how they catch prey, but also how they escape from predators and is a key factor in determining dominance of individuals.

So looking at running performance is a great way to assess how temperature affects the geckoes' ability to survive and make babies.

This is just a teaser, really. Letting you know why *some* people spend hours tending to and running geckoes in all sorts of temperatures. In the next post, I'll talk a bit more about the specifics of Skye's study - including her amazing experimental set-up!