Sensory information, particularly chemical signals and flow detection, play a critical role in the lives of many marine animals. A number of projects can be done readily to expand our knowledge of the stimuli animals encounter in their natural environment and of the sampling methods animals have evolved to utilize these stimuli for adaptive behavior. Such behavioral regulation helps to shape population and species interactions.
Lobsters use a series of different "pheromones" to regulate their social behavior from dominance fights to courtship; after one brief fight they recognize individuals by chemical signals in the urine. Using different bioassays we can begin to characterize the chemical identity of the signals. Simple chemical methods can precede more sophisticated chemical analysis to identify the signal compounds.
The organization of lobster social behavior is based in part on remembering the outcome of previous fights. This leads to dominance order. We know little about other crustaceans in this respect.
Characterizing the responses of lobsters and/or other crustaceans to a broad spectrum of compounds: in the past, crustaceans have been presented primarily with amino acids as the chemical stimuli. What else can they detect? This could be approached behaviorally and/or physiologically.
Chemotaxis and trail-following behavior in crawling gastropods: both field studies and Y-maze choice experiments have shown that mud snails use distance chemoreception for prey location and it is also thought to use chemosensory cues for trail-following. Further experiments could show what compounds mud snails are sensitive to, what orientation technique they use, and whether crawling gastropods have similar chemically-mediated behaviors similar to crustaceans.
Orientation of starfish to odor sources: starfish have a decentralized nervous system with no brain. Even so, they can locate food and show a variety of complex behaviors. Chemosensory signals seem to be a key part of their decision-making and coordinating processes, but it still is not clear precisely how. Manipulation of odor delivery and using local desensitization may answer some questions about starfish behavior. Brittle stars, horseshoe crabs, and other benthic invertebrates are interesting subjects of similar study.
The very early embryonic development of fish larvae shows sensory organs such as eyes, ears, and noses with brain connections a few days after fertilization. New research in needed to see how these early systems function, including learning while still in the egg..
