Host plant finding by insects - undersowing crop plants with clover reveals the missing link
نویسندگان
چکیده
Characteristic volatile chemicals are credited with the major role of guiding herbivorous insects to their host plants. Studies comparing how insects find host plants growing in backgrounds of clover and bare soil indicated that it is not chemical, but visual stimuli that govern where the insects land. A mechanism of hostplant finding is proposed in which chemical cues start and end the process of host-plant selection and in which the missing (central) link, based on "appropriate/inappropriate" landings, is governed by visual stimuli. This missing link operates via the insects landing indiscriminately on green surfaces but avoiding brown surfaces, such as soil. Hence, host plants growing in bare soil are colonized by more insects than similar plants growing amongst green non-host plants. Five earlier mechanisms of host-plant finding, plus the "Resource concentration hypothesis" and the "Enemies hypothesis" are discounted. The new theory answers also why wild host-plants growing under natural conditions are not decimated by pest-insects, a question that has puzzled entomologists for decades.
منابع مشابه
Host Plant Selection by Insects
Host plant selection by insects is often divided into „host plant finding‟ and „host plant acceptance.‟ While the two are easy to separate conceptually, in practice, they are really part of a continuum of three, rather than two, inextricably bonded links. However, the central link of host plant finding, thought previously to be governed by volatile chemicals, has, until now, proved intractable ...
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