In contrast, the functional response consists of a change in conversion efficiency (a) or capture rate (c).
The relationship between available energy and reproductive efforts can be explained with the life history theory in the trade-off between fecundity and growth/survival.
[7][8] One way this can occur is through exploitation competition: the differential efficiency in use of available resources, for example, an increase in spiders' web size (functional response).
The other possibility is interference competition where site owners actively prevent other foragers from coming in vicinity.
The concept of numerical response becomes practically important when trying to create a strategy for pest control.
The study of spiders as a biological mechanism for pest control has driven much of the research on aggregational response.
According to the authors of the alternative view, the data show that true interactions in nature are so far from the Lotka-Volterra extreme on the interference spectrum that the model can simply be discounted as wrong.