Animal population regulation

A major problem facing population ecologists is that of detecting factors promoting population regulation. Some attempts to survey the literature on population studies for different patterns of density dependence have produced misleading results. I have shown that problems include the short duration of many data sets and the inclusion of data from both spatial and temporal studies. I have also compared the effectiveness of various methods for detecting density dependence in data sets derived from a food limited model population with realistic levels of variability in the food supply.

• Latto (1989). The analysis of density dependence in insect populations. Unpublished Ph.D. thesis, Imperial College, London, UK.
• Latto, J. & Hassell, M.P. (1987).  Do pupal predators regulate the winter moth? Oecologia, 74, 153-155.
• Latto, J. & Bernstein, C. (1990). Regulation in natural insect populations: reality or illusion? Acta Oecologia, 11, 121-130 and Reply 135-136.
• Hassell, M.P., Latto, J. & May, R.M. (1989). Seeing the wood for the trees: detecting density dependence from existing life table studies. Journal of Animal Ecology, 58, 883-892.

Generalist predators

It is well established that natural enemies (predators and parasitoids) can cause a variety of patterns of mortality amongst spatially  distributed prey or host individuals within a given generation. The potential importance of these patterns of mortality has been considered mainly within the context of models for coupled interactions involving specific and synchronized natural enemies, as appropriate for many insect parasitoid systems. The comparable picture where prey mortality is caused by generalist (or polyphagous) natural enemies that are partially or completely uncoupled from a particular prey species have been relatively neglected.

• Latto, J. & Hassell, M.P. (1988). Generalist predators and the importance of spatial density dependence. Oecologia, 77, 375-377.

Size distributions and self-thinning in animal populations

Animal populations seem to possess more normally distributed weight distributions compared to plant populations. Simple models which predict skewed weight distributions in animal populations fail because they omit important features of real populations such as emigration and size dependent mortality.

An animal equivalent of the '-3/2 power rule' for self-thinning in plants has been proposed: the '-4/3 power rule'. It is based  upon the relationship between animal body weights and their metabolic rate (Kleiber's law). I am interested in the problems and possibilities with
using this relationship and have suggested a more general form for an animal self thinning law. Some experimental support for such a broader approach has been provided.

• Latto, J. (1992). The differentiation of animal body weights. Functional Ecology, 6, 386-395.
• Latto, J. (1994). Evidence for a self-thinning curve in animals. Oikos, 69,531-534.

The effects of multiple parasitoid species on the gall-forming midge, Rhopalomyia californica.
 
 

This work has been carried out in collaboration with Cheryl Briggs who has details (and further pictures) at her web site: http://socrates.berkeley.edu/~cbriggs/

 

Latto, J. & Briggs, C.J. (1995). Factors affecting distribution of the gall forming midge Rhopalomyia californica. (Diptera: Cecidomyiidae). Environmental Entomology, 24, 679-686. Briggs, C.J & Latto, J. (1996). The window of vulnerability of the gall forming midge Rhopalomyia californica Felt Diptera: Cecidomyiidae) to attack by four parasitoid species. Ecological Entomology, 21, 128-140. Briggs, C. J. and J. Latto (2000). The effects of dispersal on the population dynamics of a gall-forming midge and its parasitoids. Journal of Animal Ecology, 69, 96-105.  Briggs, C.J. and Latto, J. (2001) Interactions between the egg and larval parasitoids of a gall forming midge and their impact on the host. Ecological Entomology, 26, 109-116.

 

Other projects
 

From my undergraduate research project;

• Latto, J. & Fitter, A.H. (1989). Plant succession in Middle Wood, Askham Bog. The Naturalist, 114, 115-127.

• Latto, J. & Wright, H. (1995). Allelopathy in seeds. Journal of Biological Education, 29, 123-128.

• Latto, J., Coleman, G. & Tait, R. (1996). The measurement of height differences in ecological studies. Journal of Biological Education, 30, 270-274.

• Lloyd-Smith J.O., P.C. Cross, C.J. Briggs, M. Daugherty, W.M. Getz, J. Latto, M.S. Sanchez, A. B. Smith, and A. Swei. (2005). Should we expect population thresholds for wildlife disease? Trends in Ecology and Evolution, 20(9): 511-519.