210
WILLIAM C. YOUNG
IV. Fishes
Detailed and careful descriptions of behavior believed to be hormone
dependent have been given for many fishes and need not be repeated
here. A few articles and reviews which would lead a reader into the
literature in this field are cited (57, 60, 67, 91, 101-107). The behavior
described is courtship, mating in the viviparous species, spawning, nest
building, territorial fighting, and parental behavior including fanning the
eggs, guarding the eggs, and feeding activities. The suggestion has been
made that hypothalamic, hypophyseal, thyroid, and gonadal hormones
participate in different ways in the regulation of migratory behavior,
but it is evident from reviews by investigators active in the field (37, 58,
108) that we are far from an understanding of the internal mechanisms
and external stimuli by which this latter behavior is regulated.
Methods of measuring these types of behavior have been described:
fighting, nest building, courtship, spawning, and parental behavior in
the three-spined stickleback, Gasterosteus aculeatus (58,107,109);
courtship and mating behavior by the swordtail, Xiphophorus hellen (105,
110); courtship and mating behavior of Phtypoecilus sp. (124, 105);
fighting and nesting behavior of the Siamese fighting fish, Betta splendens (111, 112); nest building, spawning, and "incubation" behavior of
the African mouthbreeder, Tilapia macrocephala (101, 113); courtship
and mating behavior of the guppy, Lebistes reticuhtus (60, 91); spawning behavior of the whitefish, Coregonus lavaretus (62); spawning
behavior of the gobiid Bothygobius soporator (114); fanning behavior
of the river bullhead, Coitus gobio (115); swimming activity of the goldfish Carassius auratus (116); swimming speed, territorial defense, and
schooling behavior of the Pacific salmon, Oncorhynchus sp. (117, 118);
swimming movements of the three-spined stickleback (37, 119).
In fishes, although quantitative differences exist (101, 111), many
of the elements enumerated above are displayed by both sexes (57, 62,
101, 104, 106, 112, 120-122).
In at least one species, Tihpia macrocephcda, none of the patterns of reproductive behavior thus far investigated is entirely characteristic of either sex. These observations can only
mean that fish of one sex commonly possess the nervous mechanism capable of mediating the reproductive behavior of the opposite sex (57,
120.) In the other vertebrate phyla a greater dimorphism of behavior
is shown (101). Although it is not complete (2, 9, 65), the difference is
sufficient to suggest that a change in the direction of greater dimorphism
of behavior has occurred as the higher vertebrates have evolved.
The relationship of gonadal hormones to the behavior of fishes has
been the subject of many investigations (123), and in general the valid-
WILLIAM C. YOUNG
IV. Fishes
Detailed and careful descriptions of behavior believed to be hormone
dependent have been given for many fishes and need not be repeated
here. A few articles and reviews which would lead a reader into the
literature in this field are cited (57, 60, 67, 91, 101-107). The behavior
described is courtship, mating in the viviparous species, spawning, nest
building, territorial fighting, and parental behavior including fanning the
eggs, guarding the eggs, and feeding activities. The suggestion has been
made that hypothalamic, hypophyseal, thyroid, and gonadal hormones
participate in different ways in the regulation of migratory behavior,
but it is evident from reviews by investigators active in the field (37, 58,
108) that we are far from an understanding of the internal mechanisms
and external stimuli by which this latter behavior is regulated.
Methods of measuring these types of behavior have been described:
fighting, nest building, courtship, spawning, and parental behavior in
the three-spined stickleback, Gasterosteus aculeatus (58,107,109);
courtship and mating behavior by the swordtail, Xiphophorus hellen (105,
110); courtship and mating behavior of Phtypoecilus sp. (124, 105);
fighting and nesting behavior of the Siamese fighting fish, Betta splendens (111, 112); nest building, spawning, and "incubation" behavior of
the African mouthbreeder, Tilapia macrocephala (101, 113); courtship
and mating behavior of the guppy, Lebistes reticuhtus (60, 91); spawning behavior of the whitefish, Coregonus lavaretus (62); spawning
behavior of the gobiid Bothygobius soporator (114); fanning behavior
of the river bullhead, Coitus gobio (115); swimming activity of the goldfish Carassius auratus (116); swimming speed, territorial defense, and
schooling behavior of the Pacific salmon, Oncorhynchus sp. (117, 118);
swimming movements of the three-spined stickleback (37, 119).
In fishes, although quantitative differences exist (101, 111), many
of the elements enumerated above are displayed by both sexes (57, 62,
101, 104, 106, 112, 120-122).
In at least one species, Tihpia macrocephcda, none of the patterns of reproductive behavior thus far investigated is entirely characteristic of either sex. These observations can only
mean that fish of one sex commonly possess the nervous mechanism capable of mediating the reproductive behavior of the opposite sex (57,
120.) In the other vertebrate phyla a greater dimorphism of behavior
is shown (101). Although it is not complete (2, 9, 65), the difference is
sufficient to suggest that a change in the direction of greater dimorphism
of behavior has occurred as the higher vertebrates have evolved.
The relationship of gonadal hormones to the behavior of fishes has
been the subject of many investigations (123), and in general the valid-