Insects behavioral response

The sex pheromone communication system basically involves the release of specific chemicals from a pheromone producer (emitter), the transmission of these chemicals in the environment to a receiver, and the processing of these signals to mediate appropriate behavioral responses in the receiver. The chemicals transmitted downwind have been the most obvious targets for characterization. The code was first broken with the publication in 1959 (3) of the sex pheromone for the domesticated silkworm Bombyx mori after extraction of a half million female silkworm pheromone glands and 30 years of classical chemical analyses. The pheromone was found to be (E10, Z12)-hexadecadien-l-ol, which was called bombykol. This work showed that there was nothing magical about the communication system, and chemists around the world were "attracted" to this area of research on insect pheromones. 

Fluorinated pheromones have been synthesized in order to determine the impact of fluorination on detection by insects. Possible effects on the behavior response would be of interest in order to discover compounds able to lower the reproductive potential of destructive insects. 

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... 

The Importance of developing crop plants that are resistant to major Insect pests has created a need for detailed examination of the mechanisms Involved In resistance. The widely recognized classification proposed by Painter W appears to provide an acceptable break-down of the possible bases of resistance for most purposes. However, some modification of the terminology may be desirable before beginning to analyze the Individual mechanisms Involved. The term "nonpreference" refers to a behavioral response of the Insect to a plant, whereas "antibiosis" and "tolerance" refer to plant characteristics. This anomaly has been addressed by Kogan and Ortman ( ), who suggested the term "antlxenosls" to describe the plant properties responsible for nonpreference. 

Innate responses of the parasitoids Cotesia glomerata and C. rubecula (Hymenoptera Braconidae) to volatiles from different plant-herbivore complexes. Journal of Insect Behavior 9 525-538. 

Margolies, D. C., Sabelis, M. W. and Boyer, J. E. (1997). Response of a phytoseiid predator to herbivore-induced plant volatiles selection on attraction and effect on prey exploitation. Journal of Insect Behavior 10 695-709. 

At a finer level of resolution, compounds with similar hydrocarbon skeletons may vary in functional group, degree of unsaturation, or oxidative state. For example, the volatile methyl esters of benzoic, salicylic and anthranilic acids (1 Fig. 5.1) differ only in -position functionality, but they are olfactorily distinct to humans and at least to some phytophagous insects (Raguso et al, 1996 Maekawa et al., 1999). Furthermore, many scent compounds have positional isomers and enantiomers that elicit different behavioral responses from flower visitors (Williams and Whitten, 1983 Hick et al, 1999). The refinement of capillary gas chromatography-mass... 

Rust, M. K. and Bell, W. J. (1976). Chemo-anemotaxis a behavioral response to sex pheromone in nonflying insects. Proceedings of the National Academy of Sciences, USA 73 2524-2526. 

Grant, A. J., O Connell, R. J. and Eisner, T. (1989). Pheromone-mediated sexual selection in the moth Utetheisa ornatrix olfactory receptor neurons responsive to a male-produced pheromone. Journal of Insect Behavior 2 371-385. 

As in most Lepidoptera, spruce budworm males locate conspecific females by flying upwind along a pheromone plume. The blends and release rates of these pheromone components form an important part of a specific communication system for the species. Once the communication system of an insect is understood, especially the pheromone chemistry as it relates to male behavior, it can be used in a variety of ways. For example, pheromones can be used to detect the presence of an insect in an area, to remove males from a population by trapping or poisoning and in air-permeation techniques in which the controlled and continuous release of pheromone components in the forest can disrupt mating. The latter use of pheromones appears to alter the normal male behavioral responses to the natural pheromone (16). 

As is the case for all sensory pathways, the capacity to perceive and respond to olfactory cues (odorants) is the combined result of events that take place in both peripheral and central processing centers. These steps, which will be discussed in detail below, begin with the molecular transduction of chemical signals in the form of odorants into electrical activity by olfactory receptor neurons (ORNs) in the periphery whose axonal projections form characteristic synaptic connections with elements of the central nervous system (CNS). Within the CNS, complex patterns of olfactory signals are integrated and otherwise processed to afford recognition and ultimately, the behavioral responses to the insect s chemical environment. Within the context of pheromone recognition these responses would likely be centered on various elements of the insect s reproductive cycle. 

The sense of smell in animals and their behavioral response to the presence of certain types of molecule has been exploited by plants in the evolution of their own reproductive processes. Many plants produce smells that mimic either the pheromones of insects or olfactory... 

Recent research has shown that the pheromone mediated behavior of lepidopterous insects is very complex. The chemical components of the pheromones are usually simple molecules, but complex mixtures involving permutations of geometry, functionality, and chain length are often required to elicit the complicated behavioral repertoire that eventually culminates in mating. To elucidate the chemical and behavioral aspects of this communications system, we have used a combination of methods including collection of the volatiles emitted by the female, analysis by high resolution capillary gas chromatography (GC), and the sequential and temporal analysis of the male s behavioral response to the pheromone blend and components thereof. New liquid phases and state of the art techniques have been developed for capillary GC to separate all the components of a pheromone blend. With these methods the chemical communication systems of Heliothis virescens (F.) and H. subflexa (Gn.) have been analyzed and certain aspects have been elucidated. 

First identified in Asian elephants during a headspace analysis of volatiles collected from secretions of the musth temporal gland of adult males,156 frontalin (52) is a bicyclic ketal, which is structurally reminiscent of the male mouse priming pheromone component 3,4-dehydro-ara-brevicomin (37). Frontalin (52), Z-7-dodecen-l-yl acetate (51), was already known because of its chemosensory role in the insect world it is an aggregation pheromone in bark beetles.157 Interestingly, the ratio of the two enantiomers of frontalin (52) changes with age and stage of musth and elicits different behavioral responses.158... 

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