Role of plant abundance in determining the abundance of herbivorous insects.

The proposal (Gaston and Lawton 1988a, b) that small species of insects are more abundant because they have lower per capita resource requirements than large species does not hold for aphids (Dixon 1990a). There are good theoretical grounds, supported by empirical data, for the suggestion that host specific aphids that live on uncommon plants incur great losses in finding their host plants and as a consequence have a lower realized r ( m ) and are rarer than aphids living on common plants. This is also likely to apply to other organisms that are host specific and 'time-limited' dispersers.