The Sleep Ecophysiology Group studies sleep behaviour and neurophysiology in diverse animals, including mammals, avian and non-avian reptiles, fishes, and invertebrates, often in naturalistic or wild environments.  Using this strong comparative approach that integrates behavioural ecology with neuroscience, we aim to provide insight into:

(I) The evolution of sleep and sleep state components
(II) The causes and consequences of inter- and intra-specific variation in sleep duration
(III) Animals that forgo sleep when competing demands favour extended wakefulness
(IV) The role of ecological factors, such as predation risk, in determining where, when and how long animals sleep
(V) Local aspects of sleep
(VI) Sleep-dependent cognition in birds
(VII) The effects of pollution (light and sound) on sleep in birds

The research interests of each group member can be found below.

Lab Head

A/Prof John Lesku

Lesku2I’m interested in most things related to sleep.  Using behavioural observations, accelerometry for remote monitoring and neurophysiological recording techniques, I seek to provide insight into how sleep and sleep functions have evolved in different types of animals, from flatworms to birds and mammals.  I also study how ecological factors (e.g., predation risk, reproduction) influence the amount, composition, depth and timing of sleep.  Most recently, these interests have expanded to include how anthropogenic pollution influences sleeping brain activity in mammals and birds.

I completed my B.Sc. in zoology at the University of Guelph (Canada) in 2002.  I then did a MSc with Drs Charles Amlaner and Steven Lima at Indiana State University (USA) (2003-2006).  This work consisted mostly of phylogenetic comparative analyses of sleep quotas as a means for testing interspecific support for various non-exclusive hypotheses for the functions of sleep.  These, and other, studies provided evidence that the risk of predation can reduce the amount of rapid eye movement (REM) sleep over both evolutionary and ecological timescales, in prey.  From there I joined the Avian Sleep Group of Dr Niels Rattenborg at the Max Planck Institute for Ornithology – Seewiesen (Germany).  My PhD focused on the evolution and regulation of sleep states in birds (2007-2011).  I stayed in Seewiesen for the remainder of 2011 as a postdoc.  Working with Drs Rattenborg and Mihai Valcu, and Prof Dr Bart Kempenaers, we studied breeding pectoral sandpipers on the tundra in Barrow, Alaska; work that provided the first direct evidence that sleep loss can be evolutionarily adaptive.  For my contributions to this group effort, I was given the Young Investigator Award by the Sleep Research Society (USA).  After 5 wonderful years in Germany, I took up a University Postdoctoral Research Fellowship at The University of Western Australia (2012).  Soon thereafter I was offered a continuing position at La Trobe University, which I commenced in 2013.  From 2014-2017, I was an Australian Research Council (ARC) Discovery Early Career Researcher Award (DECRA) Research Fellow. Throughout 2020, I was the Acting (interim) Head of Department of Ecology, Environment and Evolution. I was promoted to Associate Professor effective January 2021.

Postgraduate Students

Shauni OmondCharacteristics and mechanisms of sleep in the free-living platyhelminth flatworm

Omond2Sleep is a much-studied behaviour across animals, with humans spending roughly one-third of their lives in this vulnerable state.  But where did it all start?  My research looks at the evolutionary origins of sleep.  My main research animal is platyhelminth flatworms – a phylum that appeared 800 million years ago, to determine if the processes that maintain and regulate sleep in humans is shared across distantly-related animals.  To do this, I use a combination of behavioural, pharmacological, biochemical, and electrophysiological techniques.  As well as looking at flatworms, I examine the phylogenetic breadth of sleep, through the study of animal phyla previously unstudied with respect to sleep.  Collectively, these studies will provide insight into when, why, and how sleep first appeared.  I am co-supervised by Assoc Prof Bruno van Swinderen at The University of Queensland and Dr Matthew Hale at La Trobe University.

Erika Zaid – Reproductive sleeplessness in dasyurid marsupials

ZaidSleep is a prominent part of animal life, but our understanding of the adaptive value of sleep remains incomplete.  Even though it is generally thought that reduced performance is an inevitable outcome of sleep loss, some animals may perform well on little sleep when ecological demands favour extended periods of wakefulness.  One of the best mammal candidates for such sleeplessness is antechinus, as these marsupials die synchronously after just one intense mating season.  My project, based in the Otways, examines the activity patterns of dusky antechinus in a real-world environment in and outside the breeding season, and quantifies the concentration of various hormones that may predict activity levels.  Furthermore, to provide insight into sleep evolution and function, my research seeks to determine relatedness among animals to see whether the most active males sire more offspring.  I am co-mentored by Dr Kylie Robert also at La Trobe University and Dr Peter Meerlo at the University of Groningen in The Netherlands.

Fledged PhD Students

Dr Robin JohnssonCognition and sleep in Australian magpies (2022)

Advanced cognition is a key trait enhancing the fitness of many wild animals. Maintaining the neural mechanisms for advanced cognition, including specialized memory, is energetically expensive, and is critically dependent on sleep. Robin’s dissertation provided insight into (1) the regulation of sleep in Australian magpies, (2) evidence for tool-use, and (3) means-end understanding, and (4) that cognition depends upon the duration of prior sleep. Robin is now a postdoc in the USA working with Dr Timothy Roth at Franklin & Marshall College.

Dr Michael Kelly – An investigation into sleep in sharks: behavioural and electrophysiological approaches (2020)

Sleep is widespread across the animal kingdom. Some animals, including mammals and birds, have two types of sleep. Recent studies have identified two kinds of sleep some reptiles and zebrafish. Surprisingly, data on the simple presence of sleep in sharks, the earliest group of jawed vertebrates, has been wholly lacking. Mike’s dissertation offered integrative investigations into the diversity of activity patterns in sharks, as well as behavioural and physiological evidence for sleep in elasmobranchs, using measures of muscle tone, metabolic rate, and brain activity.

Dr Farley Connelly – Impacts of anthropogenic pollution on cognition and sleep in an urban bird (2020)

Urban areas worldwide are expanding at unprecedented rates, often with devastating consequences to wildlife. Humans generate various forms of urban pollution that impact wildlife, including anthropogenic noise and artificial light at night. The effect such pollutants have on wildlife physiology and behaviour has been extensively studied, but their impact on cognitive performance and sleep remained poorly understood. Utilizing wild and captive Australian magpie populations, Farley explored the effect anthropogenic noise on cognitive performance, as well as the impact noise and artificial light night have on sleep.

Dr Anne Aulsebrook – Impacts of streetlights on sleep in urban birds (2019)

Increasing artificial light at night (ALAN) is one of the most rapid and pervasive changes to our natural environment. Nevertheless, the consequences of ALAN for wildlife are only beginning to be understood. A likely impact of ALAN is the disruption of endogenous daily rhythms, or circadian rhythms, including the sleep-wake cycle. Anne’s PhD research investigated the impacts of ALAN on sleep and melatonin profiles of two urban bird species, the black swan (Cygnus atratus) and the pigeon (Columba livia). She is now a Marie Curie Fellow at the Max Planck Institute for Ornithology, Seewiesen, Germany.

Masters and Honours Students

Sophia Lee, Honours Student – Dose-dependent sleep homeostasis in a cartilaginous fish

LeeSophia will conduct research into the significance of rest in fiddler rays. Based at the Queenscliff Marine Research Station, she will conduct behavioral assays on captive rays to determine when they are asleep. Notably, there is presently no evidence for a homeostatically regulated sleep state in cartilaginous fishes. Sophia will discover when these elasmobranchs sleep and how that sleep is regulated.

Vincent Knowles, M.Sc. Student – Does behavioural synchrony predict reproductive success in black swans?

Former Honours Students

Brayden J. Redwood – Increased activity of dusky antechinus (Antechinus swainsonii) males during the breeding season

Chris Vapp – Effects of decapitation and regeneration on the activity patterns in planaria flatworms (Girardia tigrina)

Linh Ly – Activity patterns in jellyfish

Alicia Dimovski – Artificial light pollution: shifting spectral wavelengths to mitigate ecological and health consequences in a nocturnal mammal

Shauni Omond – Searching for sleep in an evolutionarily simple bilaterian

Danielle Eastick – The thermoregulatory role of the southern cassowary’s (Casuarius casuarius) casque

Michael Kelly – Unilateral eye closure as an anti-predator behavior in juvenile saltwater crocodiles (Crocodylus porous)

Laura Tieri – Absence of local sleep homeostasis-like patterns under isoflurane anaesthesia in the pigeon (Columba livia)