An animal's behavior is both constrained by and an indication of the structure and function of the nervous system. Behavior, including both sensory input and motor output, is the major part of the phenotype through which natural selection acts on the nervous system. Comparative analysis of behavior coupled with comparative studies of nervous system organization will yield insights into the evolutionary process especially if the embryonic development of the nervous system is included. Gastropod molluscs are particularly useful for such studies because they exhibit species specific differences in behavior, their nervous systems are readily available for both anatomical and physiological analysis, and their development can be studied with relative ease.
diagram depicts an stylommatophoran land snail coming towards the viewer with
its sensory structures and central nervous system emphasized. These animals
have a pair of large posterior or ‘optic' tentacles containing an eye and a
chemosensory pad; a shorter pair of anterior tentacles with a chemosensory pad,
and a pair of labial pads or ‘lips' that also contain a chemosensory and perhaps
mechanosensory pad. Each of these sensory structures includes an accessory ganglion
each of which is connected to the cerebral ganglia of the CNS. Given this arrangement
of bilateral sensory structures, what sort of world do these snails live in?
Are they capable of integrating the input from all of these structures and constructing
a three dimensional world of odor objects? How do the functions of the various
sensory structures relate to the ecological niche and micro-habitat occupied
by different species of land snails? Finally how did this arrangement of structures
evolve from the marine ancestors of today's land pulmonates?
We have chosen to approach these questions by comparative analysis of the behavior of carnivorous (Haplotrema concavum, Euglandina rosea) herbivorous (Anguispira alternata, Mesodon thyroides, Cepaea nemoralis, Pallifera sp. ) and omnivorous (Rumina decollata) land snails in the laboratory and the field.
Occasionally we are asked to apply some of our work to practical problems concerning snails and slugs. Thus Merritt Gillilland's study of dispersal of an invasive land snail and JWA's test of the edge following hypothesis associated with a barrier to pest snails and slugs, the Flower Fortress. This latter is reported on another page of this web site.
MSU Zoology Department
Bishop's Museum Malacology page
Malacological Society of London
The Cephalopod Page
American Malacological Society
Molluscs as Art