PhDStudies on Deroceras reticulatum (Müller), the
grey field slug, indicate that this animal is responsive to
food odours and can therefore. select its food. Olfactory
responses to food odours are monitored by distance
chemoreceptors while contact chemoreception is responsible
for the gustatory stimuli associated with taste. Both types
of sensory perception are important in the feeding cycle.
The former has been investigated with the aid of a timelapse
camera and the behaviour of slugs monitored in the
presence of various food materials and their components.
Gustatory responses have been assessed by a feeding assay
which permits the quantitive analysis of food ingested.
These two aspects of feeding behaviour have been combined
to provide a framework for the improved formulation of
slug baits for use in agriculture. The two molluscicides
metaldehyde and methiocarb have been compared in laboratory
and field tests for their efficiency in poisoning slugs
and their effects on soil fauna. The field results, which
included comparisons between laboratory and commercial
metaldehyde formulations, indicate the importance of
monitoring the residual population of slugs which remains
after baiting. It appears that the true level of bait
efficiency may be obscured if tests are concerned only with
recording the number of poisoned animals trapped. The
addition of a mammal repellent to slug baits does not appear
to adversely affect their attraction to slugs but individual
formulations may vary considerably in both their palatability
and their effectiveness. The laboratory feeding tests have
suggested that Derbceras reticulatum habituates to certain
diets and that the feeding response may decline over a few
days - this can be restored by presenting a novel food to
the animals. The meal size of this species can be
manipulated in the laboratory by altering the diet'and by
the addition of attractive components. Some attempt has
been made to define these compounds with a view to improving
the consumption of baits by slugs in the field
