My research interests relate to the population dynamics of plant feeding insects, especially leaf beetles. I try to understand what factors determine the abundance and fluctuations of leaf beetles in the field. Such knowledge may, for example, be applied to the development of environmentally sound control methods of insect pests in forest plantations and crop fields, or to the utilization of plant feeding insects in biological control of exotic weeds.

          My PhD project considered leaf beetles that were pests on willow (Salix) plantations in Sweden. Currently, I am studying the biological control of weeds (Tamarix) in North America using a leaf beetle specialized to feed on Tamarix. Although the two projects can be viewed as having opposite aims, i.e. to seek knowledge to either reduce or promote insect damage, the scientific questions that we ask are based on the same ecological principles. I study the effects of host plant quality factors, natural enemies and abiotic factors (such as climate and day lengths) on leaf beetles. I am also interested in how diversity influences population dynamics of plant feeding insects.

          Additional projects have considered colonization patterns of native insects onto exotic plant species, and plant responses to insect damage.

Publications

Dalin, P. Formation and the role of leaf trichomes in plant resistance. In: A. Schaller (ed.) Induced Plant Resistance to Herbivory. Springer, Netherlands. In progress.

Dalin, P. & Björkman, C. (2006) Native insects colonizing introduced tree species – patterns and potential risks. In: T.D. Paine (Ed.) Invasive Forest Insects, Introduced Forest Trees, and Altered Ecosystems. Springer, Netherlands.

JOURNALS

Dalin, P. (2006) Habitat difference in willow leaf beetle abundance: plant quality or natural enemies? Bulletin of Entomological Research. In press.

Dalin, P., Kindvall, O. & Björkman, C. (2006) Predator foraging strategy influences prey population dynamics: arthropods predating a gregarious leaf beetle. Link

Dalin, P., Björkman, C. & Eklund, K. (2004) Leaf beetle grazing does not induce willow trichome defence in the coppicing willow Salix viminalis. Agricultural and Forest Entomology, 6, 105-109.

Björkman, C., Dalin, P. & Eklund, K. (2004) Stink-bugs as predators on insect pests in willow plantations. Entomologisk Tidskrift, 125, 13-19.

Dalin, P. & Björkman, C. (2003) Adult beetle grazing induces willow trichome defence against subsequent larval feeding. Oecologia, 134, 112-118.

Björkman, C., Dalin, P. & Eklund, K. (2003) Generalist natural enemies of a willow leaf beetle (Phratora vulgatsissima): abundance and feeding habits. Journal of Insect Behaviour, 16, 747-764.

PROCEEDINGS/ THESES

Dudley, T.L., Dalin, P. & Bean, D.W. (2006) Status of biological control of Tamarix spp. in California. In: M.S. Hoddle & M.W. Johnson (Eds.) Proceedings of the Fifth California Conference on Biological Control. Riverside, CA. pp.137-140.

Dalin, P. (2006) Population dynamics of willow leaf beetles in managed and natural willow stands. In: N. Kamata, A.M. Liebhold, D.T. Quiring & K.M. Clancy (Eds.) Proceedings IUFRO Kanazawa 2003 International Symposium “Forest Insect Population Dynamics and Host Influences”. p. 140.

Dalin, P. (2004) Food web interactions and population variability of leaf beetles in managed and natural willow stands. PhD-thesis. Swedish University of Agricultural Sciences, Uppsala. Silvestria 303. http://diss-epsilon.slu.se/archive/00000559/

Dalin, P. (1999) Predation on eggs of the willow leaf beetle Phratora vulgatissima in short rotation willow plantations. MSc-thesis. Department of Entomology, Swedish University of Agricultural Sciences. 1999:1.

MANUSCRIPTS SUBMITTED/ IN PROGRESS

Björkman, C., Dalin, P. & Ahrne, K. Costs of a plant defence induced by herbivore feeding. Submitted to Oecologia.

Dalin, P., Björkman, C. & Kindvall, O. Temporal stability of leaf beetle populations in managed and natural willow stands: an empirical example on the variation in the role of bottom-up and top-down forces. In progress.