Semiochemicals interactive

Social hymenoptera must contend with other organisms chemically mimicking a semiochemical to gain advantage. Chemical mimicry may result from the organism biosynthesizing the compounds themselves or simply acquiring the chemical odor of the host colony once inside. The many interactions are well reviewed [4,6,128] and include mimicry by hymenoptera of the same or different species, other arthropods, and even orchids. 

Pohnert G (2004) Chemical defense strategies of marine organisms. In Schulz S (ed) Chemistry of pheromones and other semiochemicals, vol 1. Springer, Berlin, pp 179-219 Pohnert G (2005) Diatom/copepod interactions in plankton the indirect chemical defense of unicellular algae. ChemBioChem 6 946-959... 

Graphs in Chapter 11 have shown that, at skeletal level, the diversity of natural products is highest for the Indo-Pacific area. Although a similar semiquantitative analysis for the actual metabolites is difficult to make, the trend is expected to be the same because of the highly interacting forms of life, semiochemicals in coral reefe should prove an even more common system of communication than in... 

Chapters in this volume consider how plants use chemicals to defend themselves from insect herbivores the complexity of floral odors that mediate insect pollination tritrophic interactions of plants, herbivores, and parasitoids, and the chemical cues that parasitoids use to find their herbivore hosts the semiochemically mediated behaviors of mites pheromone communication in spiders and cockroaches the ecological dependence of tiger moths on the chemistry of their host plants and the selective forces that shape the pheromone communication channel of moths. 

Each review is written by an internationally recognized expert and presents descriptions of the chemicals involved, the effects of semiochemically mediated interactions on reproductive success, and the evolutionary pathways that have shaped the chemical ecology of arthropods. 

Figure 15.8 Schematic representation of the proposed mechanisms for mode of action of OBPs in the perireceptor events. Pheromone (or other semiochemicals) enters the sensillar lymph through cuticular openings (pore tubules), is solubilized by an odorant-binding protein, transported to the olfactory receptors, and protected from degrading enzymes. Interaction with negatively charged sites at the surface of the dendrites triggers a conformational change that leads to the formation of a C-terminal a-helix. The insertion of this helix into the binding cavity ejects the pheromone to the olfactory receptors.

The behavioral responses of males of H. virescens and H. subflexa to semiochemicals have been of considerable interest to us for reasons already mentioned. Two assay systems were employed to analyze both precourtship and close-range courtship behaviors (18). The first, used in the analysis of male activation, orientation, and initial analysis of courtship interactions, consisted of a 1.5 x 0.5 x 0.5-m plexiglass wind tunnel through which air was pulled at a constant rate. In our initial... 

Although many aspects of both the male and female reproductive behaviors of H. subflexa are similar to those of H. virescens, small differences do exist (11,18). Flight tunnel studies of the semiochemically induced behavioral interactions between H. subflexa and H. virescens indicated that males of the two species respond quite differently to the naturally released sex pheromone of the other species. 

Semiochemicals can be placed into two distinct classes Pheromones control intraspecific interactions. These semiochemicals provide information regarding a range of behaviours including mate selection, aggregation, dispersal (alarm pheromones), oviposition and food sources (trail pheromones). Allelochemicals control interspecific interactions such as host and non-host identification by primary colonizers (plant or animal) and whether a food source is already exploited through tritrophic interactions (signals indicating the presence of primary colonizers). 

As the variety of chemical interactions between organisms became better understood during the 1960s and 1970s, many authors attempted to classify the interactions and the chemical agents involved. If pheromones describe intraspecific signals, what terms should be used for interspecific chemical interactions In the recent aquatic chemosensory literature, authors seem to be almost equally divided between using semiochemicals and infochemicals. ... 

Semiochemicals (from the Greek semeion mark or signal) are the chemicals, acquired or produced by the sender, involved in the chemical interactions between organisms (Nordlund and Lewis 1976) (Table 2.1). In their original definition, Law and Regnier (1971) used the phrase chemical signals for transmitting information between individuals [my italics], which is fine for pheromones but causes a... 

B. Semiochemical A chemical involved in the chemical interaction between organisms (Nordlund and Lewis 1976)... 

Infochemical was proposed by Dicke and Sabelis (1988) as a term to replace semiochemical at the head of the classification. They argued that the cost-benefit of the interaction should be the only criterion, not the origin of the chemicals concerned. This was prompted perhaps by their work on tritrophic interactions, which have volatiles produced by the herbivores themselves and also induced in their host plants. However, indirectly produced or induced volatiles were already... 

In this chapter, we review the ways whereby lobsters chemically communicate with each other and the contexts in which they do it. We make a distinction between different types of chemicals. Based on the terminology of Wyatt (Chap. 2), we use semiochemicals as chemicals involved in animal interactions and pheromones as a subset of semiochemicals used in intraspecific contexts. We also use cues as chemicals that benefit the receiver and not necessarily the sender, with a prime example being alarm cues released in the blood of injured conspecifics. 

The individuals in animal societies interact via a complex web of semiochemical signals. Eusocial species of social insects and social mammals are characterized by reproductive division of labour. In some species, group members fight to establish which animals will reproduce. Other species use pheromones that act as signals rather than as coercion. The mechanisms used in social insects and in mammals have many similarities. 

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