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Dennis Hasselquist

Professor | PhD

I am a professor in animal ecology with a broad interest in evolutionary and behavioural ecology. Much of my research centers around aspects related to “eco-immunology” – a newly emergent, interdisciplinary research field that examines interactions among host physiology and disease ecology in a range of environmentally relevant contexts. My research encompasses theoretical, methodological and empirical studies related to various eco-immunological issues such as the identification and quantification of immune costs (both in terms of physiology and Darwinian fitness), direct and long-term (hidden) costs of infection (telomeres and senescence), sexual selection and honest signaling, and immunity effects of maternal programming (antibody and hormone transfer to offspring).

A backbone of my research is the ongoing long-term project on the great reed warblers at Lake Kvismaren, Sweden. Over the last 35 years, I have coordinated a multitude of ecological studies on this unique study system (e.g. studies on the social and genetic mating systems, bird song, inbreeding, malaria parasites and geolocator studies). The data generated in this project includes a large multi-generational pedigree, based on >2500 DNA-sampled individuals, of which we for >700 have detailed information on lifetime reproductive success, lifespan, behaviour and morphological traits. These data provide the base for very good estimates of Darwinian fitness, as well as for QTL mapping, selection and microevolution studies of behavioural (e.g. spring arrival) and morphological traits. Other research themes are molecular and genomic ecology, e.g. immune gene evolution, telomere ecology and sex chromosome evolution in birds.

Most recent research highlights

Asghar, M., Palinauskas, V., Zaghdoudi-Allan, N., Valkiunas, G., Muhkin, A., Platonova, E., Färnert, A., Bensch, S. & Hasselquist, D. 2016. Parallel telomere shortening in multiple body tissues owing to malaria infection. Proceedings of the Royal Society B 283:20161184.

The impact of infections on telomere attrition in different body tissues within an individual is unknown. In this study, we experimentally infected siskins (Spinus spinus) with the avian malaria parasite Plasmodium ashfordi, and used real time quantitative PCR to measure telomere length. Over 105 days post infection, malarial infection resulted in parallel telomere shortening in blood and tissue from of all six major organs investigated (liver, lungs, spleen, heart, kidney and brain), suggesting that the infection had induced systemic stress. Our results have far-reaching implications for understanding how short-term effects of an infection can translate into long-term costs, such as organ dysfunction, degenerative diseases and aging.

Asghar M, Hasselquist1,† D, Hansson B, Zehtindjiev P, Westerdahl H  & Bensch†, S. 2015. Hidden costs of infection: chronic malaria accelerates telomere degradation and senescence. Science 347:436-8 (1Corresponding author. These two authors contributed equally to this study.)

This paper in Science (23 Jan 2015) has been recommended at Faculty1000Prime, and has already rendered huge interest with >17000 views of the abstract and 2500 downloads of pdf/full text during the first month. Read the fulltext or download a reprint (pdf; 420 Kb). We show that a seemingly harmless infection (chronic avian malaria) with no visible direct effects on behaviours (singing and nestling feeding), annual reproduction or survival to next year, over the long-term shortens lifespan (with 33%) and reduces lifetime offspring numbers (with >50%) in wild songbirds. These ‘hidden’ long-term costs inducing senescence could be mediated by accelerated telomere degradation, as malaria-infected birds showed faster telomere shortening, both in wild and experimentally infected great reed warblers. (Telomeres protect the chromosome ends and their shortening may be a link to ageing and senescence).


Retrieved from Lund University's publications database

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Dennis Hasselquist
E-mail: dennis.hasselquist [at]



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