Individual Variation in Physiology & Behaviour

Within a given species, it is recognised that all animals are not the same. Some are more athletic, some require more food, some are more aggressive, some are more shy, and so on. A common goal through much of our research is to understand how this variation is important for the ecology of animals and how it may affect how different animals respond to challenges in their environment, including food shortages, temperature changes, and hypoxia.

Our work in this theme has been performed across numerous species from different regions and lifestyles, and across life-stages, ranging from larvae to mature adults. Of particular interest to our team is how physiological traits can effect behaviour or, conversely, how behavioral tendencies can shape individual physiological traits associated with bioenergetics and performance.

We often observe that, in the presence of environmental stressors, relationships between physiological (e.g. metabolism) and behavioural (e.g. risk-taking) traits can be altered, depending on the nature of the stressor. Much of our current work examines the generality of this effect and the implications for ecology and selective processes.

Example Papers:

Cortese, D, Crespel, A, Mills, S, Norin, T, Killen, SS, Beldade, R. In Press. Adaptive effects of parental and developmental environments on offspring survival, growth and phenotype. Functional Ecology. 00:00-00.

Pilakouta, N, O’Donnell, P, Crespel, A, Levet, M, Claireaux, M, Kristjánsson, BK, Skúlason, S, Lindström, J, Metcalfe, N, Killen, SS, Parsons, K. 2022. Warmer environments can reduce sociability in an ectotherm. Global Change Biology. PDF

Chrétien, E., Boisclair, D., Cooke, S.J. and S.S. Killen. 2021. Social group size and shelter availability influence individual metabolic traits in a social fish. Integrative Organismal Biology. 3: obab032 PDF

Crespel, A., Miller, T., Rácz, A., Lindström, J., Parsons, K.J., Killen, S.S. 2021. Density influences the heritability and genetic correlations of fish behavioural traits under trawling-associated selection. Evolutionary Applications. 14:2527–2540.

Cortese, D., Norin, T., Beldade, R., Crespel, A., Killen, S.S., Mills, S.. 2021. Physiological and behavioural effects of anemone bleaching on symbiont anemonefish in the wild. Functional Ecology. 00:1–11 PDF

Pineda, M., Aragao, I., McKenzie, D.J., Killen, S.S. 2020. Social dynamics obscure the effect of temperature on air breathing in Corydoras catfish. Journal of Experimental Biology. 223: jeb222133 doi: 10.1242/jeb.222133 PDF

Zavorka, L., Koeck, B., Armstrong, T.A., Soganci, M., Crespel, A., Killen, S.S. 2020. Reduced exploration capacity despite brain volume increase in warm acclimated common minnow. Journal of Experimental Biology. 223: jeb223453 PDF

Cooper, B., Adriaenssens, B., Killen, S.S. 2018. Individual variation in the compromise between social group membership and exposure to preferred temperatures. Proceedings of the Royal Society B. 285: 20180884. 10.1098/rspb.2018.0884. PDF

McLean, S., Persson, A., Norin, T., Killen, S.S. 2018. Metabolic costs of feeding predicatively alter the spatial distribution of individuals in fish schools. Current Biology. 28: 1144-1149 PDF

Fu, S.J., Peng, J., Killen, S.S. 2018. Digestive and locomotor capacity show opposing responses to changing food availability in an ambush predatory fish. Journal of Experimental Biology. jeb.173187 doi: 10.1242/jeb.173187 PDF

Killen, S.S., Esbaugh, A.J., Martins, N.D., Rantin, F.T., McKenzie, D.J. 2018. Aggression supersedes individual oxygen demand to drive group air-breathing in a social catfish. Journal of Animal Ecology. 87: 223-234. PDF

McKenzie, D.J, Blasco, F.R., Belao, TC, Martins, N.D., Killen, S.S., Taylor, E.W., Rantin, F.T. 2017. Physiological determinants of individual variation in sensitivity to an organophosphate pesticide in Nile tilapia Oreochromis niloticus. Aquatic Toxicology. 189: 108-114. PDF

Polverino, G., Bierbach, D., Killen, S.S., Uusi-Heikkilä, S., Arlinghaus, R. 2016. Body length rather than routine metabolic rate and body condition correlates with risk-taking behaviour in juvenile zebrafish (Danio rerio). Journal of Fish Biology. 89:2251-2267 PDF

Palacios, M., Killen, S.S., Nadler, L., White, J.R., McCormick, M.I. 2016. Top-predators negate the effect of mesopredators on prey physiology. Journal of Animal Ecology. 85: 1078–1086 DOI: 10.1111/1365-2656.12523 PDF

Nadler, L.E., Killen, S.S., McClure, E.C., Munday, P.L., McCormick, M.I. 2016. Shoaling reduces metabolic rate in a gregarious coral reef fish species. Journal of Experimental Biology. 219: 2802-2805 doi: 10.1242/jeb.139493 PDF

Killen, S.S., Fu, C., Wu, Q., Wang, Y.-W., and Fu, S-J. 2016. The relationship between metabolic rate and sociability is altered by food-deprivation. Functional Ecology. DOI: 10.1111/1365-2435.12634 PDF

Metcalfe, N.B., Van Leeuwen, T.E., Killen, S.S. 2016. Does individual variation in the metabolic phenotype predict behaviour and performance in fish? Journal of Fish Biology. DOI: 10.1111/jfb.12699. Invited Article. PDF

McKenzie, D.J., De Campos Belao, T., Killen, S.S., Rantin, T. 2015. To boldly gulp: standard metabolic rate and boldness have context-
dependent influences on risk-taking to breathe air in a catfish. Journal of Experimental Biology. 218, 3762-3770 PDF

Killen, S.S., Croft, D.P., Salin, K., Darden, S.K. 2015. Male sexually coercive behaviour drives increased swimming efficiency in female guppies. Functional Ecology. doi: 10.1111/1365-2435.12527 PDF

Killen, S.S., Reid, D., Marras, S., Domenici, P. 2015. The interplay between aerobic metabolism and antipredator performance: preparedness to escape is related to recovery rate after exercise. Frontiers in Physiology. 6: 111. doi:10.3389/fphys.2015.00111. PDF

Marras, S.*, Killen, S.S.*, Lindstrom, J., McKenzie, D.J, Steffensen, J.F., Domenici, P. 2015. Fish swimming in schools save energy regardless of their spatial position. Behavioural Ecology and Sociobiology. 69:219–226. DOI: 10.1007/s00265-014-1834-4. *these authors contributed equally. PDF

Killen, S.S. 2014. Growth trajectory influences temperature preference in fish through an effect on metabolic rate. Journal of Animal Ecology. 83: 1513–1522. PDF

Killen, S.S., Mitchell, M.D., Rummer, J.L., Chivers, D.P., Ferrari, M.C.O., Meekan, M., McCormick, M.I. 2014. Aerobic scope predicts dominance during early life in a tropical damselfish. Functional Ecology. 28: 1367–1376. PDF

Killen S.S., Marras, S., McKenzie, D.J. 2014. Fast growers sprint slower: effects of food deprivation and re-feeding on sprint swimming performance in individual juvenile European sea bass. Journal of Experimental Biology. 217: 859-865. PDF

Killen S.S., Marras, S., Metcalfe, N.B., McKenzie, D.J., Domenici, P. 2013. Environmental stressors alter relationships between physiology and behaviour. Trends in Ecology and Evolution. 28:651-658. PDF

Marras S., Killen S.S., Domenici, D., Claireaux, G., McKenzie, D.J. 2013. Relationships among traits of aerobic and anaerobic swimming performance in individual European sea bass Dicentrarchus labrax. PLoS ONE 8(9): e72815. doi:10.1371/journal.pone.0072815. PDF

Killen, S.S., Marras, S., Steffensen, J.F., McKenzie, D.J. 2012. Aerobic capacity influences the spatial position of individuals within fish schools. Proceedings of the Royal Society B. 279: 357-364. Featured as a Research Highlight in Nature. PDF

Killen, S.S., Marras, S., Ryan, M.R., Domenici, P, McKenzie, D.J. 2012. A relationship between metabolic rate and risk-taking behaviour is revealed during hypoxia in juvenile European sea bass. Functional Ecology. 26: 134-143. PDF

Burton, T., Killen, S.S., Armstrong, J.D., Metcalfe, N.B. 2011. What causes intra-specific variation in resting metabolic rate and what are its ecological consequences? Proceedings of the Royal Society B. 278: 3465-3473. PDF

Killen, S.S., Marras, S., McKenzie, D.J. 2011. Fuel, fasting, fear: routine metabolic rate and food deprivation exert synergistic effects on risk-taking in individual juvenile European sea bass. Journal of Animal Ecology. 80: 1024–1033. PDF

Marras, S., Killen, S.S., Claireaux, G., Domenici, P., McKenzie, D.J. 2011. Behavioural and kinematic components of the fast-start escape response in fish: individual variation and temporal repeatability. Journal of Experimental Biology. 214: 3102-3110.

Killen, S.S., Brown, J.A., Gamperl, A.K. 2007. The effect of prey density on foraging mode selection in juvenile lumpfish: balancing food-intake with the metabolic cost of foraging. Journal of Animal Ecology. 76: 814-825. PDF