Alarm signals ecology

Mathis, A. and Smith, R.J.F., Intraspecific and cross-superorder responses to chemical alarm signals by brook stickleback, Ecology, 74, 2395, 1993. 

Chemically mediated interactions have important direct and indirect effects on communities from both ecological and evolutionary standpoints.22 341 Chemical defense or communication cannot be properly understood unless it is viewed through the lenses of population, community, and ecosystem processes, and this requires consideration of both the biotic and abiotic components of the natural environment.342 For example, chemically mediated foraging is affected by water flow because it relies on water-soluble cues that are carried away from prey.343 345 Similar constraints likewise modify the effectiveness of other waterborne cues, such as alarm signals, sexual pheromones, and settlement cues, in both mobile and sessile organisms.244 345 350... 

Taxonomic Comparisons. Obviously there are many variations on the basic injury released alarm pheromone theme in fishes and other organisms. A more comprehensive examination of the distribution and variations of this phenomenon might reveal patterns. For example, are there alarm substances that are predator attractants and others that are predator repellants Are some ecological niches more amenable to chemical alarm signaling than others Electrical ostariophysans, for example, seem to lack the alarm pheromone system (Pfeiffer 1977) but may use their electrical signals in some comparable manner. 

The term recruitment , like the term alarm has become diffuse as the diversity and complexity of social insect behavior has emerged. In this review we will take recruitment to mean the inducement of workers to move from one area to another, either to retrieve food or to move to new territory or a new nest site. The chemical signals involved are usually, but not always, deposited on the substratum, and may therefore also constitute an orientation signal. The two possible functions of trail pheromones , recruitment of nest mates and orientation to food or nest, need to be carefully separated to estimate the importance of these chemical signals in the ecology of each species. 

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