Research

Arthropod Ecophysiology Group

Climate change, arthropod overwintering and pest outbreaks

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Group Leader: Prof. Jeff Bale

Picture of Prof. J.S. Bale

The main research interests of the arthropod ecophysiology group concern the Effects of abiotic factors on insects, Insect-host plant relationships, and Invertebrates and water quality.

Effects of abiotic factors on insects

Much of the early work in this area concerned aphids, particularly the role of temperature in determining the annual abundance and outbreaks of pest species with anholocyclic clones through the lethal and sub-lethal effects of cold. Studies have been conducted in the Arctic on the impacts of climate warming on soil-inhabiting and above ground species, and in the Antarctic on the comparative cold tolerance of herbivorous and predatory beetles. Recent and ongoing research has developed a protocol based around cold tolerance and winter survival by which to assess the establishment potential of non-native glasshouse biocontrol agents in the UK. Currently we are investigating rapid cold hardening abilities in aphids and Antarctic arthropods, and the freeze tolerant responses of hoverfly predators of aphids.

Hayward S.A.L., Worland M.R., Convey, P. and Bale, J.S. (2003) Temperature preferences of the mite, Alaskozetes antarcticus, and the collembolan, Cryptopygus antarcticus from the maritime Antarctic. Physiological Entomology 28, 114-121

Hart, A.J., Bale, J.S., Tullett, A.G., Worland, M.R. and Walters, K.F.A. (2002) Effects of temperature on the establishment potential of the predatory mite Amblyseius californicus McGregor (Acari: Phytoseiidae) in the UK. Journal of Insect Physiology 48, 593-600.

Bale, J.S. (2002) Insects and low temperatures: from molecular biology to distributions and abundance. Philosophical Transactions of the Royal Society B 357, 849-862.

Bale, J. S. et al., (2002) Herbivory in global climate change research: direct effects of rising temperatures on insect herbivores. Global Change Biology 8, 1-16.

Insect-host plant relationships

The nutritional quality of host plants has a major influence on the development and reproduction of herbivorous insects, such as the interaction between the concentration of amino acids in phloem and the performance of aphids. Initial studies in this area used different nitrogen application regimes to produce plants of different 'quality' and assesses the response of aphids by diet analysis (stylectomy), feeding behaviour (electrical penetration graphs), amino acid metabolism (honeydew clocks) in relation to measured of rates of aphid increase. In collaboration with Jeremy Pritchard and John Newbury we now have a range of knockout mutants of Arabidopsis with well defined and differing amino acid profiles that will allow these aphid-host plant interactions to be studied using transcriptomic and metabolomic techniques.

Hale, B.K., Bale, J.S., Pritchard, J., Masters, G.J. and Brown, V.K. (2003) Effects of host plant drought stress on the performance of the bird cherry-oat aphid, Rhopalosiphum padi (L.): a mechanistic analysis. Ecological Entomology 28, 666-677.

Doering-Saad, C., Newbury, H.J., Bale, J.S. and Pritchard, J. (2002) Use of stylectomy and RT-PCR for the detection of transporter mRNAs in sieve elements. Journal of Experimental Botany 53, 631-637.

Ponder, K.L., Pritchard, J., Harrington, R. and Bale, J.S. (2001) Feeding behaviour of the aphid Rhopalosiphum padi on nitrogen and water stressed barley (Hordeum vulgare) seedlings. Bulletin of Entomological Research 91, 123-130.

Invertebrates and water quality

There is a wide range of organisms that can infest various stages in the water treatment processes by which potable (drinking quality) water is produced. Control options in such environments are limited compared with agricultural systems. A recent project has investigated the biology and population dynamics of chironomid (midge) infestations in granular activated carbon (GAC) beds. A management system has been devised that combines a knowledge of the sensitivity of different life cycle stages to anaerobic conditions, and duration of exposure at different water temperatures to maximise population decline. Similar approaches are now being applied to other invertebrate species.

Olsen, A., Bale, J.S., Leadbeater, B.S.C., Callow, M.E. and Holden, J.B. (2003) Developmental thresholds and day-degree requirements of Paratanytarsus grimmii and Corynoneura scutellata (Diptera: Chironomidae), two midges associated with potable water treatment. Physiological Entomology 28, 315-322.

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