Nicholas J. Mills
    Associate Professor and Associate Entomolgist
    212 Wellman Hall
    Phone #: (510) 642-1711
    FAX #: (510) 642-7428
    nmills@nature.berkeley.edu



    Research Interests

    The focus of my research group is the biological control of insect pests and the ecology of insect parasitoids. Classical biological control has an outstanding history of success in the sustained regional control of invading pests and provides exciting opportunities for both lab and field-based ecological research. However, not all biological control introductions result in spectacular reductions of pest damage and so a major emphasis in our work is to address arguably one of the most challenging questions in biological control research: what are the determinants of success in classical biological control? In addition to classical biological control, the augmentation of naturally-occurring parasitoid populations is an aspect of biological control that is rapidly gaining attention. The use of parasitoids as biological pesticides raises some very interesting questions that we have recently begun to explore on performance characteristics of parasitoids, strategies for parasitoid release and the optimization of parasitoid impact.

    It is also important to realize that parasitoids, as macroparasites of phytophagous insect hosts, represent a very significant component of the terrestrial fauna, known not only for their importance in biological control and population ecology, but also because of their fascinating and diverse lifestyles and their value in the analysis of biodiversity and community ecology. As a result, our research interests span the general biology of parasitoids, the population ecology of parasitoids and structure and function in parasitoid communities as well as biological control. One of the most satisfying aspects of our work is the knowledge that we are pursuing an environmentally-sound program which has the potential to reduce pesticide pollution and to restore the natural balance of ecological systems.



    Current Projects

    One of the major research programs in our laboratory is directed toward the biological control of the codling moth, Cydia pomonella, a notorious fruit-borer that is the key pest of apple, pear and walnut production in California and worldwide. As an exotic pest, codling moth has no specialized parasitoids in the US and we are conducting foreign exploration for parasitoids in Central Asia, evaluating the potential performance of individual parasitoid species, and selecting the best combination for field release. However, as the codling moth is a fruit-boring pest, classical parasitoid introductions alone are unlikely to achieve the degree of control required for commercial fruit production and so we are also investigating the potential to augment populations of Trichogramma platneri, a naturally-occurring egg parasitoid. We have recently been able to demonstrate a significant impact of Trichogramma augmentation on codling moth in all three commodities and are currently examining this tritrophic (tree-moth-parasitoid) system in detail to identify the limiting characteristics of the parasitoid and the influence of release strategy on parasitoid impact. The population dynamics and community ecology of parasitoids is another underlying theme of our research. We have recently used a prospective population model to question whether heteronomous hyperparasitism is compatible with biological control of whiteflies and are currently developing a model to select the best combination of parasitoids for introduction against the codling moth. We have also developed the concept of parasitoid guilds, a functional classification of parasitoid lifestyles, that facilitates the analysis of structure, diversity and function in parasitoid communities. We are currently using this approach to analyze the parasitoid communities associated with oak gall wasps in California and other phytophagous insect taxa.



    Selected Publications

    Riddick, E.W. and Mills, J.N. 1994. Potential of adult carabids (Coleoptera: Carabidae) as predators of fifth-instar codling moth (Lepidoptera: Tortricidae) in apple orchards in California. Environ. Entomol. 23:1338-1345.

    Kenis, M., Hulme, M.A., and Mills, N.J. 1996. Comparative developmental biology of populations of three European and one North American Eubazus spp. (Hymenoptera: Braconidae), parasitoids of Pissodes spp. weeviles (Coleoptera: Curculionidae). Bulletin of Entomol. Res. 86:143-153.

    Getz, W.M. and Mills, N.J. 1996. Host-parasitoid coexistence and egg-limited encounter rates. American Naturalist 148:301-315.

    Hawkins, B.A. and Mills, N.J. 1996. Variability in parasitoid community structure. J. Animal Ecol. 65:501-516.

    Mills, N.J. and Gutierrez, A.P. 1966. Prospective modelling in biological control: an analysis of the dynamics of heteronomous hyperparasitism in a cotton-whitefly-parasitoid system. J. Applied Ecol. In Press


    Current Graduate students:
    • Greg Fanslow
    • Jan Hirabayashi
    • Sarah Mansfield
    • Diane Stark
    • Tania Zaviezo


    Names of Post-docs/Researchers/Specialists/SRAs, etc.:
    • Ulrich Kuhlman, Postdoctoral Fellow
    • Lou Dixon, Staff Research Associate