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Sammanfattning

In nature, insects live in an olfactory landscape of diverse semiochemicals. When odor molecules are released from "attractive" and "inhibitory" sources, they can mix together, and travel in the form of complex plumes similar to those seen in the form of smoke plumes. To locate and select hosts or conspecifics and to avoid non-hosts or danger, insects must discriminate between these "positive" and "negative" signals present in the odor plumes. Various factors affect this discrimination of "positive" and "negative" signals, of which odor plume structure and odor source interactions are of importance. Odor dispersion takes place by molecular diffusion and wind turbulence. With molecular diffusion, random movement of molecules gradually causes them to move away from each other with time, and creates clines of concentration on very small scales (mm-cm). However, odor dispersal strongly depends on wind and turbulence, which are the most frequent odor dispersal features that an insect has to deal with in order to find its odor source over distance. In an odor plume, odors travel in package or filament laden air interspersed by clean air. These filaments maintain their highest concentrations near the odor source and, as they travel downwind, become elongated and torn apart by eddies and wind turbulence. Consequently, the odor concentration within plumes decreases as they move downwind, but as odor filaments are interspersed with pockets of clean air and due to their filamentous nature, compound ratios stay very similar. Insects infrequently or never utilize time-averaged concentrations and instead use near-instantaneous concentrations. With distance from the odor source, the plume width and height increase, while filament intensity and intermittency decrease and distance between filaments increase. This implies that the interval between filaments and the concentration within filaments may both provide important information for insects trying to locate odor sources. Behavioral studies suggest that odor-induced and wind-guided (anemotaxis) behaviors are the key components for insects to locate the odor sources. The insect olfactory system identifies odors of interest in complex plumes for successful selection of mate or host. Many electro-physiological (extracellular as well as intracellular) studies also suggest that precise temporal or spatio-temporal patterns of olfactory neurons underlie the spatio-temporal neural codes for odors. Among these, several studies suggest that co-localization of disparate olfactory receptor neurons in the same sensillum, specificity of olfactory receptor proteins, and neuronal interactions in the primary olfactory centre (antennal lobe) and higher brain centre (mushroom body and calyx) all play roles in the coding of complex mixture of odors in a plume. Thus, odor plume structure and interaction between plumes may play a key role in host or mate selection in phytophagous insects. Plume structure can be analyzed with advanced technologies and analytical tools such as photo ionization detectors and electroantennography as well as by those that are simple and less expensive, like soap bubbles generators. However, there is very little, if any, understanding of interactions of odor plumes and their implications on insect's behaviors and sensory physiologies; these areas should be a focus of future research. © 2013 by Nova Science Publishers, Inc. All rights reserved.

Publicerad i

Titel: Lepidoptera : classification, behavior and ecology
Utgivare: Nova Science Publishers, Inc.

SLU författare

UKÄ forskningsämne

Zoologi

Publikationens identifierare

  • ISBN: 9781624172489

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/132198