PROCEEDINGS OF ' THE SECTION ON ANIMAL BEHAVIOUR ANDSOCIOBIOLOGY OF THE ECOLOGICAL SOCIETY OF AMERICA

An afternoon programme of invited papers on Sexual Behaviour was held in conjunction withthe one hundred twenty-fourth meeting of the American Association for the Advancement of Sciencein Indianapolis, Indiana, on 29th December, 1957 . J. T. Emlen, University of Wisconsin, was in thechair. Abstracts of the papers are presented below .

THE DEVELOPMENT OF SEXUAL BEHAVIOUR

BY EVELYN SHAWAmerican Museum of Natural Science

Sexual behaviour in the adult is defined as anorganised sequential pattern of events . Littleis known of the development, order of appear-ance and frequency of these events in fishes,amphibia, reptiles and birds . However, it isknown that 'some mammals execute sexual-likeresponses long before maturity .Two factors which are influential in the

development of sexual behaviour are hormonesand external environmental conditions. Pre-cocious sexual maturity may be induced byhormone injection . Hormone deprivation re-

ENDOCRINE CONTROL OF SEXUAL BEHAVIOUR

BY ADAM ANTHONYPennsylvania State University

This paper reviewed current ideas regardingdirect and indirect hormonal regulation of sexbehaviour in mammals . Available evidenceindicates that the basic neural components ofsex behaviour have a genetic basis which iscommon to both sexes. Gonadal hormones andexperience facilitate, in some unknown fashion,the translation of this pre-determined behav-ioural repertoire into expression . Gaps in ourunderstanding of endocrine-sex behaviour inter-actions include : (1) the role of foetal-hormonesin neural maturation ; (2) influence of adrenalsor thyroids on the responsiveness of tissuesmediating sex behaviour ; and (3) the dependence

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suits in lowered sexual activity . Restricted earlyenvironments, in which preceptual opportunitiesand contact with species mates are reduced,results in lowered sexual activity in manyadults .Our present knowledge leaves us with no

concrete conclusions. We need objective studiesof the motor development of the organism,further correlation between physiological andbehavioural changes and a standardised analyt-ical methodology so that work of individualinvestigators can be compared .

of endocrine action on genetic constitution,perceptual stimuli and CNS regulatory factorsschematically summarised in Figure 1 (notreproduced here.)

Comparative studies of endocrine-sex be-haviour interactions in other species, particu-larly seasonal breeders, should provide a morecomprehensive picture of the dependence ofmating on sex hormones and experience. This isapparent when one realises that much of ourpresent knowledge is based on work withlaboratory rodents which represent less thantwo per cent. of the available native species .