According to Bernarys and Singer (2002), polyphagy
may occur at the species, population or individual levels.
Hackman (1966) noted that flightlessness and ballooning were associated with polyphagy
and with hosts that grow in dense groves.
Castilleja using mixed hosts may have obtained less harmful quantities of toxins from the hosts, analogous to arguments made for polyphagy
in mammalian herbivores (Freeland and Janzen 1974).
Similar arguments have been advanced to explain an apparent association between tree feeding and polyphagy
(Futuyma 1976; Fiedler 1995a), but these hypotheses has never been tested using phylogenetic methods.
gracile meets the criteria for polyphagy
(multiple plants from multiple families; Bernays & Chapman 1994), but because weight gain was often minimal in the growth experiments, the degree of polyphagy
is somewhat uncertain.
In this paper, we make the case that there is, in addition, a distinction between polyphagy
at the population level and polyphagy
by the individual organism.
Apart from the Jatropha genetic group, which occurs in a separate ecological niche, most of the putative species exhibit high levels of polyphagy
(Burban et al.
16 seems to be a truly general food-web model, for it describes all types of trophic relationships including autotrophy and heterotrophy, monophagy, polyphagy
, omnivory, cannibalism and mutual predation, intra- and inter-specific competition, and single- to multiple-species population interactions.
by egg parasitoids can favorably impact their suitability as control agents because alternate hosts may assist their permanence and population growth in the field (Correa-Ferreira 2002).
Given the high degree of polyphagy
that typifies T.
Johansen & Mojica (1997) point out the high polyphagy
In view of its polyphagy
, the introduction and establishment of P.