342
P. 9. MEADOWS AND J. I. UAMPBELL
and successful behavioural sequence. It follows that young crabs are
likely to be at a selective disadvantage compared t o older ones and
so it is interesting to find that the young of the spiny lobster Jasus
Zalandei may experience a similar disadvantage (Fielder, 1965). Invertebrates living in fresh water are likely to show similar abilities
although there is very little evidence. Further investigations should be
concentrated on the relationship between learning in laboratory experiments and habitat selection in the field. It would be interesting to know
for example what ranges of shape, size, colour and so on a species can
learn to recognize, and whether these do in fact occur in the species’
natural environment. Even at the present time it might be possible
to make ecologically s i g d c a n t deductions about the distribution of
octopi from the detailed work already published on their learning
abilities (Wells, 1962).
We should now turn to consider how an animals’ previous
experience or previous environmental history affects its behaviour
(Brown, 1939; Popham, 1941; above, pp. 290-291). The light reactions
of several species of aquatic invertebrate are largely dependent on the
conditions of illumination to which the animals have been previously
exposed. The freshwater isopod AseZZzts communiis (Banta, 1910) and
the intertidal gastropod Littorim littorea (L.) (Newell, 1958) are both
photopositive when dark adapted but photonegative in the light;
Newell, however, encountered a lot of variation amongst his animals
and his paper should be consulted for further details. The physiological basis of the response has been investigated on the intertidal
amphipod Cammarus annulatus S. I. Smith (Smith, 1905). Smith
transferred dark adapted animals into the light and measured their
responses to light and the migration of their eye pigment. During the
&st 10 minutes they were indifferent to light, slightly photonegative, or
slightly photopositive, and then subsequently became strongly photopositive; this latter change was associated with the time at which their
eye pigment migrated from its dark adapted to its light adapted
position. In a similar way an animal’s previous environmental history
can influence its temperature preferences, its food preferences, and
its aggressiveness. The temperature preferences of the freshwater
gastropods Planorbis cornew rubra L. and Lirnnea stagnalis L. are related to their previous temperature rbgime (%bczyliski, 1966), Pacific
starfish of the genus Pisaster show an increased preference for snails if
they are fed on these for three months previously (Landenberger, 1968),
and the aggressive tendencies of the hermit crab Calcinus tibicen are
dependent on its previous experience (Hazlett, 1966) (see section on
spacing out). Where past experience or past environmental history
P. 9. MEADOWS AND J. I. UAMPBELL
and successful behavioural sequence. It follows that young crabs are
likely to be at a selective disadvantage compared t o older ones and
so it is interesting to find that the young of the spiny lobster Jasus
Zalandei may experience a similar disadvantage (Fielder, 1965). Invertebrates living in fresh water are likely to show similar abilities
although there is very little evidence. Further investigations should be
concentrated on the relationship between learning in laboratory experiments and habitat selection in the field. It would be interesting to know
for example what ranges of shape, size, colour and so on a species can
learn to recognize, and whether these do in fact occur in the species’
natural environment. Even at the present time it might be possible
to make ecologically s i g d c a n t deductions about the distribution of
octopi from the detailed work already published on their learning
abilities (Wells, 1962).
We should now turn to consider how an animals’ previous
experience or previous environmental history affects its behaviour
(Brown, 1939; Popham, 1941; above, pp. 290-291). The light reactions
of several species of aquatic invertebrate are largely dependent on the
conditions of illumination to which the animals have been previously
exposed. The freshwater isopod AseZZzts communiis (Banta, 1910) and
the intertidal gastropod Littorim littorea (L.) (Newell, 1958) are both
photopositive when dark adapted but photonegative in the light;
Newell, however, encountered a lot of variation amongst his animals
and his paper should be consulted for further details. The physiological basis of the response has been investigated on the intertidal
amphipod Cammarus annulatus S. I. Smith (Smith, 1905). Smith
transferred dark adapted animals into the light and measured their
responses to light and the migration of their eye pigment. During the
&st 10 minutes they were indifferent to light, slightly photonegative, or
slightly photopositive, and then subsequently became strongly photopositive; this latter change was associated with the time at which their
eye pigment migrated from its dark adapted to its light adapted
position. In a similar way an animal’s previous environmental history
can influence its temperature preferences, its food preferences, and
its aggressiveness. The temperature preferences of the freshwater
gastropods Planorbis cornew rubra L. and Lirnnea stagnalis L. are related to their previous temperature rbgime (%bczyliski, 1966), Pacific
starfish of the genus Pisaster show an increased preference for snails if
they are fed on these for three months previously (Landenberger, 1968),
and the aggressive tendencies of the hermit crab Calcinus tibicen are
dependent on its previous experience (Hazlett, 1966) (see section on
spacing out). Where past experience or past environmental history