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Biomedical subjects

J P Kruijt

Publications and source records attributed to J P Kruijt.

4 recordsLinked to original sources
PubMed1983

The influence of siblings on the development of sexual preferences of male zebra finches.

Broods of young zebra finches were either raised by their own species or cross-fostered by Bengalese finches. Both were isolated visually from other birds at the age of 2 months. Sexual preferences of males were examined at maturity, in a choice between 1 zebra finch female and 1 Bengalese finch female, by measuring the number of song strophes directed at each. Males raised by their own species sang exclusively for the zebra finch female. Cross-fostered males raised without siblings or with only 1 sibling sand exclusively for the Bengalese finch female. A large number of cross-fostered males raised with 2-4 siblings showed at least 5% singing for the zebra finch female, and a small number did so predominantly. It is concluded that under the conditions of these experiments, the development of sexual preferences of zebra finch males is affected by both parental and sibling influences. It is possible that the earlier evidence for a predisposition to response to conspecifics put forward by Immelmann could be explained by hitherto uncontrolled differences in experience.

Animals↗
PubMed1980

Genotypic differences in mating success and the maintenance of the alcohol dehydrogenase polymorphism in Drosophila melanogaster: No evidence for overdominance or rare genotype mating advantage.

Strains of Drosophila melanogaster having different alcohol dehydrogenase (Adh) genotypes (FF, FS, or SS) were assembled in a mating chamber in varying ratios, and the mating successes were recorded. In experiments with a 25:25 ratio, the FF males succeeded in mating more than did FS and SS males, while the FS males surpassed the SS males. As for the females, FF also surpassed SS. In experiments with a 5:45 or 45:5 ratio, some differences from the 25:25 ratio occurred, but in these cases the rare genotypes were at a disadvantage. In one case, female genotypes (FF vs. SS) displayed a difference in mating latency time, but male genotypes did not. The findings did not suggest that rare genotype mating advantage and overdominance in mating success play a role in the maintenance of the Adh polymorphism.

Alcohol Oxidoreductases↗
PubMed1975

"Supernormality" in a learning situation.

Four pigeons were trained to peck at a 37-spot stimulus for food. While this training continued, two of the pigeons received extinction training to a 21-spot stimulus and the other two received extinction training to a plain white stimulus. In a subsequent generalization test of stimuli which varied in number of spots, pigeons extinguished on the 21-spot stimulus responded most to the 52- and 69-spot stimuli. This "peak shift" in responding is functionally similar to "supernormality" seen in the egg-retrieval responses of gulls. Possible causes of these two phenomena are discussed and compared.

Animals↗