314
P. 9. MEADOWS AND J. I. UAMPBELTA
of Lottia to other areas, prove conclusively that the algal mat actually
develops more fully within the species’ territory than on adjacent
areas, because individuals actively push off not only intruders of their
own species, but also those of other species.
Behaviour leading to spaced out patterns of distribution is therefore
well documented for the adults of a number of marine and freshwater
invertebrates as well as for the settling larvae of several marine species.
The complexity of this behaviour has been emphasized by the studies
of Hazlett (1966) on the importance of the past and present environment, of Snyder and Snyder (1971) on the significance of intra-specific
repellent chemicals, and of Stimson (1970) on the function of territorial
behaviour in maintaining food supplies. For the future, an experimental dehition of the relationship between gregariousness and spacing
out is likely to be rewarding, and to lead to a better understanding of
the role these factors play in determining localized patterns of
distribution.
D. Associations with plants
Seaweeds cover many rock surfaces on the shore and in the sea, and
their species are zoned vertically. Certain sedentary and mobile
invertebrates are found exclusively on one or a few of these species,
which has led many research workers to suggest that their localized
distribution is the result of habitat selection. Almost all of the
experimental work published to date has been concerned with the
settlement of the larvae of sedentary invertebrates whose adults are
normally found attached to a particular seaweed. Little attention has
been paid to the possible preferences of mobile animals that live on
seaweeds except for some researches on the food preferences of molluscs
which will be considered below (Food Selection).
As with gregarious behaviour, settlement on seaweeds has been
approached either from an ecological point of view, in which larvae are
offered a range of seaweed species for settlement, or from a biochemical
point of view, when inert surfaces are treated with seaweed extracts and
these then offered to larvae.
In the 6rst category, much attention has been paid to the preferences
of Spirorbis spp. (Polychaeta). Spirorbis borealis, the most commonly
studied species, usually occurs on Fucus serratus L., but sometimes on
other fucoids. I n laboratory experiments its larvae settle on Fucus
species in preference to other seaweeds and related Spirorbis spp.
behave similarly (Garbarini, 1936; Gross and Knight-Jones, 1967; Gee
and Knight-Jones, 1962; de Silva, 1962; Gee, 1965). Hydroids and
P. 9. MEADOWS AND J. I. UAMPBELTA
of Lottia to other areas, prove conclusively that the algal mat actually
develops more fully within the species’ territory than on adjacent
areas, because individuals actively push off not only intruders of their
own species, but also those of other species.
Behaviour leading to spaced out patterns of distribution is therefore
well documented for the adults of a number of marine and freshwater
invertebrates as well as for the settling larvae of several marine species.
The complexity of this behaviour has been emphasized by the studies
of Hazlett (1966) on the importance of the past and present environment, of Snyder and Snyder (1971) on the significance of intra-specific
repellent chemicals, and of Stimson (1970) on the function of territorial
behaviour in maintaining food supplies. For the future, an experimental dehition of the relationship between gregariousness and spacing
out is likely to be rewarding, and to lead to a better understanding of
the role these factors play in determining localized patterns of
distribution.
D. Associations with plants
Seaweeds cover many rock surfaces on the shore and in the sea, and
their species are zoned vertically. Certain sedentary and mobile
invertebrates are found exclusively on one or a few of these species,
which has led many research workers to suggest that their localized
distribution is the result of habitat selection. Almost all of the
experimental work published to date has been concerned with the
settlement of the larvae of sedentary invertebrates whose adults are
normally found attached to a particular seaweed. Little attention has
been paid to the possible preferences of mobile animals that live on
seaweeds except for some researches on the food preferences of molluscs
which will be considered below (Food Selection).
As with gregarious behaviour, settlement on seaweeds has been
approached either from an ecological point of view, in which larvae are
offered a range of seaweed species for settlement, or from a biochemical
point of view, when inert surfaces are treated with seaweed extracts and
these then offered to larvae.
In the 6rst category, much attention has been paid to the preferences
of Spirorbis spp. (Polychaeta). Spirorbis borealis, the most commonly
studied species, usually occurs on Fucus serratus L., but sometimes on
other fucoids. I n laboratory experiments its larvae settle on Fucus
species in preference to other seaweeds and related Spirorbis spp.
behave similarly (Garbarini, 1936; Gross and Knight-Jones, 1967; Gee
and Knight-Jones, 1962; de Silva, 1962; Gee, 1965). Hydroids and