150
V. G. DETHIER
carnivores, rely principally upon the olfactory sense, to which their
vision and hearing are subordinate. Most insects are olfactory animals
par excellence. All the macrosmatic animals orient themselves almost
exclusively by odors in air or water but rely for avoidance chiefly on
vision or touch. Their orientation is concerned with locating food, a
mate, or a site for laying eggs. In each case the finding is but the first
step in a chain of events constituting a complicated and specific behavior
pattern. As releasing stimuli, that is, stimuli which release innate behavior patterns (Tinbergen, 1951), odors and tastes enable animals to
recognize their mates, nest-mates, nest, food, and hosts. They are usually
sign or token stimuli, so designated because they are compounds which
have no intrinsic value for the organism.
In the past ethologists have tended to avoid those facts of behavior
regulated by taste and smell, partly because man is microsmatic, and
partly because of the dearth of information relative to the chemical
senses. An ignorance of sensory physiology in general has led more than
a few into the misadventure of bestowing magical and mysterious powers
upon animals in order to make their behavior meaningful. During the
first quarter of the present century and ten years preceding it studies
of the senses of taste and smell were themselves generally exploratory
in nature. They were devoted to localization of sensory areas, histological descriptions, a sketchy appraisal of the role played by these senses
in some aspects of behavior, and attempts at classifying tastes and odors.
During this period eight major reviews were written (Nägel, 1894; Cohn,
1914; Henning, 1924; Parker, 1922; Zwaardemaker, 1895; von Frisch,
1926; Skramlik, 1926; Crozier, 1934). Following this era of productivity
there came a mild drought punctuated by a plethora of theories of mode
of action. The third quarter of our century has witnessed a renewal of
experimental work. Already it has generated the appearance of eight
more major reviews (Moncrieff, 1944; Geldard, 1950, 1953; Jahn and
Wulff, 1950; Pfaffmann, 1951a, b; LeMagnen, 1953; Wenzel, 1954)
which, while tending to show how meager has been the progress, do,
nevertheless, possess a certain stimulating value. With reference to insects alone there have been seven reviews since 1914 (Mclndoo, 1914;
von Frisch, 1921, 1934; Minnich, 1929; Dethier and Chadwick, 1948;
Dethier, 1953a, 1954b).
As a new experimental era now unfolds some of the outstanding
progress in the field of chemoreception is seen to be its application to
problems of behavior, especially that of insects. This reassessment of
problems long investigated but little understood comes at a time when
there is revived interest in the entire field of behavior. The interest
is signaled by new approaches to the problem of commensalism (Daven-
V. G. DETHIER
carnivores, rely principally upon the olfactory sense, to which their
vision and hearing are subordinate. Most insects are olfactory animals
par excellence. All the macrosmatic animals orient themselves almost
exclusively by odors in air or water but rely for avoidance chiefly on
vision or touch. Their orientation is concerned with locating food, a
mate, or a site for laying eggs. In each case the finding is but the first
step in a chain of events constituting a complicated and specific behavior
pattern. As releasing stimuli, that is, stimuli which release innate behavior patterns (Tinbergen, 1951), odors and tastes enable animals to
recognize their mates, nest-mates, nest, food, and hosts. They are usually
sign or token stimuli, so designated because they are compounds which
have no intrinsic value for the organism.
In the past ethologists have tended to avoid those facts of behavior
regulated by taste and smell, partly because man is microsmatic, and
partly because of the dearth of information relative to the chemical
senses. An ignorance of sensory physiology in general has led more than
a few into the misadventure of bestowing magical and mysterious powers
upon animals in order to make their behavior meaningful. During the
first quarter of the present century and ten years preceding it studies
of the senses of taste and smell were themselves generally exploratory
in nature. They were devoted to localization of sensory areas, histological descriptions, a sketchy appraisal of the role played by these senses
in some aspects of behavior, and attempts at classifying tastes and odors.
During this period eight major reviews were written (Nägel, 1894; Cohn,
1914; Henning, 1924; Parker, 1922; Zwaardemaker, 1895; von Frisch,
1926; Skramlik, 1926; Crozier, 1934). Following this era of productivity
there came a mild drought punctuated by a plethora of theories of mode
of action. The third quarter of our century has witnessed a renewal of
experimental work. Already it has generated the appearance of eight
more major reviews (Moncrieff, 1944; Geldard, 1950, 1953; Jahn and
Wulff, 1950; Pfaffmann, 1951a, b; LeMagnen, 1953; Wenzel, 1954)
which, while tending to show how meager has been the progress, do,
nevertheless, possess a certain stimulating value. With reference to insects alone there have been seven reviews since 1914 (Mclndoo, 1914;
von Frisch, 1921, 1934; Minnich, 1929; Dethier and Chadwick, 1948;
Dethier, 1953a, 1954b).
As a new experimental era now unfolds some of the outstanding
progress in the field of chemoreception is seen to be its application to
problems of behavior, especially that of insects. This reassessment of
problems long investigated but little understood comes at a time when
there is revived interest in the entire field of behavior. The interest
is signaled by new approaches to the problem of commensalism (Daven-