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E H Bryant

Publications and source records attributed to E H Bryant.

7 recordsLinked to original sources
PubMed1990

Loss of electrophoretic variation in serially bottlenecked populations.

Experimental bottleneck lines were generated from a single outbred population of the housefly using one, four, or 16 pairs of flies. These lines were followed through one, three, or five successive founder-flush cycles. After each flush 30 individuals from each line were assayed for electrophoretic variation at four initially polymorphic loci. Electrophoretic variation largely followed neutral expectation, the major exception being that the differentiation among 16-pair lines was greater than expected. All bottleneck sizes showed significant losses in genetic variation compared to the control, particularly for losses in numbers of alleles. These findings contrast theoretical predictions in that few lines and loci would be required to detect historical bottlenecks.

Alleles↗
PubMed1985

Fecundity and longevity of houseflies after space flight.

After 7 days of space flight house flies, Musca domestica, exhibited similar longevity, but a reduction in reproductive output as compared to earthbound controls. This reduction was not observed in later generations. These data suggest that space flight directly alters the rate of ovarian development, but that this effect is not genetically transmitted.

Animals↗
PubMed1980

A rare-male advantage in the housefly induced by wing clipping and some general considerations for Drosophila.

Multiple-choice crosses among five geographic strains of the housefly, Musca domestica L., were carried out in equal (10:10) and low-frequency (4:16) ratios. Initially, a low-frequency-male mating advantage was apparent, but further analyses related this minority advantage to a reduction of male mating success during marking by wing clipping. When there are fluctuating differences in the level of sexual vigor between competing male types over replicate trials of a cross, a mating advantage will accrue to the minority type. Even if males from the two competing strains are equally vigorous, such fluctuating differences will occur during sampling of flies. Harming the flies during marking will serve to enhance this effect and make significant departures toward greater mating success of rare males highly likely. This statistical bias in favor of minority males was substantiated in simulations of the KENCE-BRYANT model of mating success and compared with our results of a minority advantage in the housefly and with published results of a minority advantage in Drosophila. Our evidence, though circumstantial, that an advantage to minority males could have been induced by such an experimental bias suggests that a re-examination of existing data, as well as new experimentation, is necessary to discern whether or not a real rare-male advantage exists.

Animals↗
PubMed1979

Inbreeding and heterogamic mating: an alternative to Averhoff and Richardson.

An alternative explanation to the pheromonal control of mating through chemoreceptor saturation proposed by Averhoff and Richardson (1974) is offered for the apparent rise in heterogamic mating in their experiments, after several generations of full-sib mating. In a multiple-choice mating between two genotypic strains differing in their level of sexual vigor, there is a sequence from heterogamic to homogamic mating. It is proposed that, by reducing mating speed, inbreeding changes the rate of this sequence but not its pattern, so the apparent level of heterogamic mating will increase during inbreeding, for a fixed observation period. This hypothesis was tested using the Kence-Bryant model of mating success.

Animals↗