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Jumping insects - Honours project

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I have recently published some work on insect jumping here But what i really wanted to look at was the association between either insect jumping speed / acceleration with limb length. But also insect jumping ability with adhesive pads, as i suspect that long legs in insects are less for allowing them to jump faster, but rather for allowing them to jump from smooth surfaces without slipping. Although, they do look hilarious when they slip. I want to do this by comparing take off velocity and acceleration in a whole pile of crickets that we find around campus.

insect clinging - honours project

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Insects are very good at clinging to surfaces using their claws. However, this might start becoming a problem as they get bigger. That's because to stick to things with claws they need very fine, sharp claws. But we know from our scaling lectures that as things get bigger the diameter of things is also expected to increase. So how do they do it? Does claw morphology change with size, or do larger bugs simply stick less well? To answer this we will need a combination of SEM images of insect claws, and some performance estimates of insect sticking ability, probably using something like an insect centrifuge. We currently have a whole stack of rhino beetle grubs which would be great for this project, and are due to hatch out this summer. Keen to try your luck at making one? Blue print below ;)

Are water dragons really water dragons? - Honours project

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I have been wondering about this for some time. Often i will come across water dragons in places where there is no water (e.g. Alexander headland) and other times i come across a nice body of water, but never see any water dragons. (think about all the small lakes on campus). I want to use GIS style mapping in R or other wise to overlay the distribution of water dragons with surface features. The comparison i want to make, is a water dragons preferring habitats on the edge of water bodies, or are water dragons just preferring areas of a steep slope (which just happen to be associated with water bodies, or both?

Lizard hurdles - Honours project

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So i have been working on lizards running on two or four legs for some time now, Check this out. I think it tends to be related to the ability of lizards to raise their body centre of mass to get over obstacles. Are bipedal lizards better able to do this? I have collected a stack of data on this, but it needs to be analysed, and maybe to collect more data where parts are missing. The eventual goal is to combine this with data from robots running on two and four legs over obstacles. These robots are currently being constructed by the engineering honours students here at USC. So get on board if lizards are your thing.

Cat biomechanics - honours project

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Cats are really good at jumping, and maneuvering mid air. Just check out these videos i captured of my house cat What i am interested in is how does rotation along the spine in mid-air work? How long does it take, and how might this be affected by body size. Lots of 3D biomechanics questions here. This will also fit into a much larger project we are planning on house cat movement using accelerometers. Anyway, have some more cat videos nice! 

Jumping sea slaters - honours project

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I was walking along the rocks of the spit in Mooloolaba on the Sunshine Coast a few weeks (maybe months?) ago, and i saw these little critters sitting just above the water line, jumping from rock to rock. I returned a few days later with a bucket and a net, and set about the task of trying to catch a few of them, so i could bring them back to the lab to understand how they jump. You see the thing is that most Slaters will have ten or more legs, so the thought occurred to me that it must be super hard to co-ordinate all ten legs at once to power the jump. I had just published a paper on jumping froghoppers and leaf hoppers in the Royal society interface  and they used only their back two legs. After what i would describe as a disproportionally long period of time i did succeed in catching a few and brought them back to my lab to film them on the fastec camera. I got a few jumps at 250 fps, and it looks like only the back two pairs of legs are involved with the jump Though

Jumping without slipping

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The image here is of a leafhopper. These leafhopper and their close relatives the froghoppers are capable of amazing jumping feats. Philaenus frog-hoppers have relatively short hind legs (66% of the body length), are able to accelerate in less than 1 ms to take-off velocities of up to 4.7 m s−1, when jumping from high-density foam. In comparison, Aphrodes leafhoppers (pictured here) have longer hind legs (84% of the body length), take longer (4.4 ms) to accelerate and achieve take-off velocities of up to 2.9 m s−1 on high-density foam. On a rough substrate such as foam, spines or claws on the hind legs may be able to grip, but they may not be able to engage with smooth surfaces, like glass. This is because insects also cannot rely on classic friction alone, Their take-off angle α = tan−1(Fnormal/Fshear) = tan−1(1/μ) is limited by the friction coefficient μ (Amontons' law of friction: Fshear = μ Fnormal, where Fshear is the force parallel to the surface and Fnormal the loa

Dinosaur biomechanics

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Thought I would post a couple of link to some videos of quails running which were part of our study into the way theropod dinosaurs may have moved. Links to the study is here  We compared measurements of step width against the speed of the animal, measured directly for the modern species, or by using stride length as a proxy for the extinct theropods. In all three groups, step width decreased with increasing speed. In other words, as the animal moved faster, the left and right feet were placed closer towards the body midline, and at the fastest speeds of locomotion, the feet could even cross over the midline. So this told us that the extinct theropods that made the footprints were at least following the same general principle seen in modern bipeds. Interestingly, however, the way in which step width decreased with increasing speed was different between the three groups. This pattern of similarity and contrast suggests that the extinct theropods were moving more like m