How Animals Perceive Secondary Plant Compounds

Club‐Shaped Organs as Additional Osmophores within theSauromatumInflorescence: Odour Analysis, Ultrastructural Changes and Pollination Aspects4

“…Nearly all major constituents of the volatile blend have already been identified as potent attractants to various insects ( Table 1): among these we find oligosulphides, ethanol, isobutanol, 1-octen-3-ol, 3-hydroxy-2-butanone, 3-octanone, butyric acid, isovaleric acid, ethyl acetate, methyl butyrate, toluene, 2-phenylethanol and various monoterpenes. Undoubtedly, these compounds can participate in a wide range of volatile blends required to attract all the insects hitherto reported (Städler, 1992 [97] ; Frazier, 1992 [25] ; Dobson, 1994 [17] ).…”

Stimulation of Feeding: Insect Control Agents

“…The cucurbitacins, which arrest and cause compulsive feeding in diabroticite beetles, are the most powerful feeding stimulants known. We have not been as fortunate with feeding stimulants for other insect species (for reference consult the literature on feeding behavior and sensory discrimination in insects: Blom, 1978;Dethier, 1973;Dethier and Kuch, 1971;Frazier, 1992;Hsiao, 1969;Ma, 1972;Mitchell, 1974;van Drongelen, 1979). Interestingly, the number of individual chemicals that stimulate feeding is not very large; sucrose is the main feeding stimulant for many insect species.…”

Chemosensory basis of feeding and oviposition behaviour in herbivorous insects: a glance at the periphery

“…Evidently, it is the combined input from all eight taste neurons in the maxillary styloconica sensilla and thus the across-fibre pattern of firing generated by them that determines the considerable subtlety in host-plant preference of caterpillars. Several recent studies have shown that broad spectrum deterrent neurons in caterpillars can act as so-called labelled lines (for explanations of across-fibre patterning and labelled-line coding concepts, see Dethier, 1982;Schoonhoven, 1987;Frazier, 1992). This appears from the observation that the degree to which certain deterrent compounds coated on acceptable food cause a preference for control food can be correlated with firing rates of deterrent receptors in several caterpillar species (Blaney et al, 1987;Luo et al, 1995;Simmonds et al, 1995;Messchendorp et al, 1996).…”

“…During the host selection process, two main phases can be distinguished: (1) selection at a distance, in which the insect relies on vision and olfaction, and (2) selection during contact, in which the insect gathers mechanosensory information on plant texture and, in most cases of decisive importance, on plant chemicals present either on the plant surface or in the plant interior by means of its gustatory receptors. Acceptance has been interpreted as a sign of recognition: the complex chemical profile or 'Gestalt' of the plant is encoded by gustatory receptors, the neural message that contains this code matches a hypothetical template in the brain and acceptance of the plant ensues (Dethier, 1982;Schoonhoven, 1987;Simmonds & Blaney, 1991;Frazier, 1992). Here I will focus on the mechanisms of chemosensory recognition.…”

“…Revealing sensory codes i.e. the profile of sensory input which signals acceptability or rejection as deduced from behavioural output (input-output approach), has been a major objective in basic, mechanistic studies of insect-plant relationships (Dethier, 1982;Schoonhoven, 1987;Frazier, 1992). Insight into those sensory mechanisms known to largely determine host-plant selection behaviour will contribute to knowledge of factors determining host-plant range.…”