Feeding sites

Fenoll, C., Aristizabal, F.A., Sanz-Alferez, S. and del Campo, F.F. (1997a) Regulation of gene expression in feeding sites. In Fenoll, C., Grundler, F.M.W. and Ohl, S.A. (eds) Cellular and Molecular Aspects of Plant—Nematode Interactions. Kluwer Academic Publishers, Dordrecht, The Netherlands, pp. 133-149. 

EN can be administered through four routes, which have different indications, tube placement options, advantages, and disadvantages (Table 58-1). The choice depends on the anticipated duration of use and the feeding site (i.e., stomach versus small bowel). 

The significance of such spatial arrays lies in the behavioral responses of insects foraging in these trees. If certain leaf types are unavailable while others are preferred, then such spatial arrays force insects to move about in search of good feeding sites (29). For insects which spend much time (or all of their lives) feeding in one place (sessile species, such as aphids), this search is performed once after a suitcible site is located, these insects are restricted to one portion of their... 

Shorter-term temporal variation in leaf quality should act to complicate the spatial arrays described above. Thus, not only may a foraging insect have difficulty locating suitable feeding sites in space, but their locations may shift from time to time or continuously, as seasonal changes, induction effects, or even plant pathogen attack (44) alter tissue quality. A suitable tissue at one time may not be suitable later in the day, or later in the insect s life. 

Second, the increased movement necessary for locating widely dispersed feeding sites should increase contact rates with enemies. Movement makes insects more conspicuous to parasitoids or predators sensitive to it (50,51). Random encounters with arthropod predators or parasites should increase with searching activity, as would risk of dislodgement and fallout. 

But why would a caterpillar not feed for up to 12 hours If suitable food is widely scattered and risks of movement eunong feeding sites are high (above), many insects may be forced to feed only at night (29,54). In north temperate forests, such an insect will "starve" for from 8 to 14 hours. One consequence of this tactic may be that the first meal of the evening may be very risky. 

Fig. 4.6. Stink bug damage to soybean pods. Pod discoloration due to fungi and bacteria introduced at the feeding site. Pod in the center is undamaged. (Photo courtesy of R. Lut-trell)...

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