My main research interest revolves around what can be referred to as Evolutionary Ecophysiology, in which function and mechanism are linked to better understand behaviour from an evolutionary perspective. In this context we are interested in the physiological and behavioural mechanisms mediating the trade-offs that constitute the selection pressures that shaped behaviour over evolutionary time. We focus on the two main life-history trade-offs: (1) between number and quality of offspring, and (2) between current and future reproduction (also known as ‘costs of reproduction’). The latter trade-off is of particular interest since the costs of reproduction are conceptually identical with senescence acceleration, which is also a core interest.

 

• Current project themes are:

• Telomeres are regions of non-coding DNA at the end of linear chromosomes, consisting of tandem repeated highly conserved DNA sequence (5'-TTAGGG-3')_n . There are indications that telomere length predicts remaining life span, possibly because telomere-shortening rate is accelerated by oxidative stress. We study telomeres and their relation to age, survival and reproduction using pulsed field gel electrophoresis applied under supervision of Ellis Mulder . In addition to our 'own' study species (Jackdaw - Jelle Boonekamp, Zebra Finch -Michael Briga. Great Tit - Els Atema) we study telomere shortening in Oystercatchers in collaboration with Kees Oosterbeek ( SOVON ), in Common Terns in collaboration with Christina Bauch (PhD-student supervised by Prof. Peter Becker , Vogelwarte Helogoland, Wilhelmshafen), and in Purple-Crowned Fairy Wrens with Anne Peters.
• Meta-analysis is a useful tool to develop a quantitative synthesis of research results. Among other things, we meta-analysed papers on the association between telomere length and mortality in humans (PhD-project of Jelle Boonekamp ), and the associations between carotenoids on the one hand, and oxidative stress plus immune function on the other hand (PhD-Project of Mirre Simons).
• Human height and its evolution through natural and sexual selection was the subject of the recently completed PhD-Project of Gert Stulp , that I co-supervised with Bram Buunk .

 

Selected recent publications:

(see ResearchGate for a complete list and PDF's of most papers, and Google Scholar for citations)

• JJ Boonekamp, MJP Simons, L Hemerik & S Verhulst 2013. Telomeres behave as measure of somatic redundancy rather than biological age. Aging Cell, online
• MJP Simons, W Koch & S Verhulst 2013. Dietary restriction of rodents decreases aging rates without affecting initial mortality rate - a meta-analysis. Aging Cell, online .
• C Bauch, P Becker & S Verhulst 2013. Telomere length reflects phenotypic quality and costs of reproduction in a long-lived sea bird, the common tern. Proc R Soc. 280: 20122540.
• K Riebel, M Spierings, MJ Holveck & S Verhulst 2012. Phenotypic plasticity of avian learning strategies. Animal Behaviour 84: 1533-1539.
• MJP Simons, A Cohen & S Verhulst 2012. What does carotenoid-dependent coloration tell? Plasma carotenoid level signals immunocompetence and oxidative stress in birds - a meta-analysis. PLoS One 7: e43088.
• G Stulp, B Kuijper, TV Pollet, AP Buunk & S Verhulst 2012. Intralocus sexual conflict over human height. Biology Letters 8: 976Ð978.
• S Bouwhuis, R. Choquet, BC Sheldon & S Verhulst 2012. The forms and fitness cost of senescence: age-specific recapture, survival, reproduction and reproductive value in a wild bird population. The American Naturalist 179, E15-E27.
• PJ van der Most, B de Jong, HK Parmentier & S Verhulst 2011. Trade-off between growth and immunocompetence: a meta-analysis of selection experiments. Functional Ecology 25, 74-80.
• HM Salomons, GA Mulder, M Linskens, M Haussmann, L. van de Zande & S Verhulst 2009. Telomere shortening patterns and survival in free-living corvids. Proc R Soc 276: 3157-3165.
• S Verhulst & J-A Nilsson 2008. The Timing of Birds' Breeding Seasons; A review of experiments that manipulated timing of breeding. Phil Trans Roy Soc Ser B 363: 399-410.