Herbivorous insects

Barbehenn R (2001) Roles of peritrophic membranes in protecting herbivorous insects from ingested plant allelochemicals. Arch Insect Biochem Physiol 47 86-99 Barbehenn RV, Martin MM (1998) Formation of insoluble and colloidally dispersed tannic acid complexes in the midgut fluid ofManduca sexta (Lepidoptera Sphingidae) an explanation for the failure of tannic acid to cross the peritrophic envelopes of lepidopteran larvae. Arch Insect Biochem Physiol 39 109-117... 

A large number of phytophagous beetles is economically important as pests on crops, forests, and stored products, and they are vectors of fungi and viral plant diseases. On the other hand, many species have beneficial functions in the detritus cycle, and carnivorous species may feed on herbivorous insects. 

Feeny, P.P. Rosenberry, L. Carter, M. In "Herbivorous Insects Host Seeking Behavior and Mechanisms" Ahmad, S. Ed. Academic Press New York, 1983 pp. 27-76. 

Romeis, J., Stadler, E. and Wackers, E. L. 2005. Nectar- and pollen-feeding by adult herbivorous insects. In Plant-Provided Food for Carnivorous Insects A Protective Mutualism and Its Applications (Wackers, F. L., van Rijn, P. C. J. and Bruin, J., eds), pp. 178-220. Cambridge Cambridge University Press. 

Defensive agents occur widely in plants, except endemic species of isolated islands like Hawaii, reflecting the evolution of plants in the absence of herbivorous mammals. Why herbivorous insects did not raise defensive compounds in Hawaiian plants is not clear, however. Anyway, things have changed much in Hawaii introduced plants sum up to an astonishing record of 43.8% of all local flora (Gdbor 1997) and plenty of species of herbivorous mammals have been brought in. 

Prokopy, R.J. and Owens, E.D., Visual detection of plants by herbivorous insects. Annu. Rev. 

Lev-Yadun, S. et al.. Plant coloration undermines herbivorous insect camouflage, BioEssays 26, 1126, 2004. 

It has always amazed me that the importance of chemical compounds in ecological interactions between plant versus herbivore, insect versus insect, and plant versus plant has been universally accepted, but the importance of antimicrobials in microbial interactions has been ahnost universally denied. 

Such a strong impact on survivorship or fecundity, and on the fitness of individuals, means exerting strong natural selection on herbivorous insects. This should favor the rapid evolution of insect adaptations which overcome it. This is, of course, a common occurrence in the application of pesticides or the development of resistant crop plant cultivars (11). The supposition that plant defenses select for detoxication adaptations in insects is the foundation of the concept of coevolution (12). 

Schultz, J. C. "Impact of Variable Host Quality on Herbivorous Insects", R. F. Denno, M. S. McClure, eds.. Academic Press, NY, in press. 

In undisturbed ecosystems, plant and herbivorous Insect populations coexist In a steady state condition dictated by external biological and physical factors (parasites, predators, precipitation, temperature, soil quality, etc.). But this balance is also regulated by myriads of very fundamental Interactions, many or even most of which are yet unknown, between the plant allelochemi-cals and the biochemical, physiological, and behavioral functions of the Insect herbivores ( 1). 

The selection or avoidance of potential host plants by phytophagous Insects Is guided by a complex combination of physical and chemical stimuli. Color, shape and olfactory cues may play a role In the Initial orientation, whereas acceptance or rejection of a plant depends on texture as well as chemical stimulants or deterrents. Initiation of feeding Is stimulated or deterred by the presence or absence of specific chemicals or groups of chemicals, many of which have been Identified. The selection of a suitable plant for ovlposltlon Is also crucial for survival of the progeny of most herbivorous Insects, but the chemical factors Involved are known In relatively few cases. Ovlposltlon stimulants and deterrents often appear to be quite different from the chemicals that elicit or Inhibit feeding responses of larvae. 

Other benefits of large numbers of analogs to plants may include slower evolution of tolerance or lower rates of metabolism of mixtures compared with that of single compounds in herbivorous insects. Feng and Isman (1995) investigated the possibility of adaptation in herbivores by repeated selection of peach aphid colonies with either pure azadirachtin or neem seed extracts containing a large number of limonoids. The colonies treated with azadirachtin soon showed evidence of tolerance of this pure compound, whereas no evidence of tolerance was... 

Selective pressure exerted on herbivorous insects Delay for insects to evolve adaptations... 

Hougen-Eitzman, D. and Rausher, M.D. (1994). Interactions between herbivorous insects and plant-insect coevolution. American Naturalist 143 677-697. 

Broadway, R. M., Duffey, S. S., Pearce, G. and Ryan, C. A. (1986). Plant proteinase-inhibitors a defense against herbivorous insects. Entomologia Experimentalis etApplicata 41 33-38. 

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