Chemical signals multiple functions

There are numerous other examples of plants, insects, large herbivores, and other organisms playing synergistic roles in nature s balance. Multiple functions are typical of plant compounds and do not contradict in any way their main role as chemical-defense and signal-induction compounds. A trait that serves multiple functions in a given plant or animal is more likely to survive the rigors of natural selection. 

Multiple approaches have been taken to understand the nature of pheromones in rodents. Bottom-up approaches start with assessing the effect of candidate molecules on physiological function. Top-down approaches start with a behavior and search for the chemical signals that trigger it. 

The smell of death comes in multiple forms, each of which can directly and indirectly affect crustacean behavior, ecology, and the role of crustaceans in community organization and ecosystem function. The smell of conspecific death is a powerful determinant of individual behavior that can cascade up to have larger scale consequences. Additionally, microbes can use chemical signals to gain preferential access to nutritionally rich, food-fall resources and make these less available to crustacean scavengers. Each of these situations is discussed briefly below. 

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