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L Ehrman

Publications and source records attributed to L Ehrman.

At least 19 recordsLinked to original sources
PubMed1992

Developmental isolation and subsequent adult behavior of Drosophila paulistorum. I. Survey of the six semispecies.

We present results deriving from the inception of an investigation (involving 4,000 scored matings) into the development of discriminatory behavior in Drosophila paulistorum. We examined two complementary situations for their effects on mating behavior: physical isolation (seclusion) beginning at each of six developmental stages and exposure to heterosemispecifics during all preadult stages (mixed culturing). Preadult seclusion at certain stages decreased sexual isolation between three of four semispecific pairs. Seclusion effect, or lack thereof, varied with semispecies and with the stage at which seclusion was imposed: the earlier the stage at which seclusion was initiated, the more drastic the effect. In contrast, mixed culturing increased sexual isolation between the one pair of semispecies that was tested.

Animals↗
PubMed1990

Developmental isolation and subsequent adult behavior of Drosophila pseudoobscura.

When isolated from all contact with other flies until the opportunity to exercise mating choices, Drosophila pseudoobscura displays genetically-mediated compensatory behavior: heterokaryotypic females are more vulnerable than homokaryotes to wholly restricted contact with conspecifics. They are less able to demonstrate normal frequency-dependent sexual selection after isolation than their own homokaryotypes. However, the later the isolation in this holometabolous insect--eggs, first instars, second instars, third instars, pupae, imagoes--the fewer the behavioral effects of this isolation.

Animals↗
PubMed1984

Sequences homologous to P elements occur in Drosophila paulistorum.

P elements, a class of mobile genetic elements that cause hybrid dysgenesis in Drosophila melanogaster, have thus far been shown to occur only in this species. Using whole genome blot analysis, we present evidence which indicates that sequences homologous to D. melanogaster P elements also occur in Drosophila paulistorum, a distant relative. D. paulistorum is considered a species complex, consisting of six known incipient species or semispecies. All six semispecies possess P element homologous sequences. We further show that there is conservation of restriction enzyme recognition sites between the D. melanogaster and D. paulistorum P element sequences. The presence of P elements in these two species may clarify the roles of recent invasion and rapid loss in the temporal distribution of P elements in Drosophila.

Animals↗
PubMed1977

Interorder transfer of mycoplasmalike microorganisms between Drosophila paulistorum and Ephestia kühniella. II. Numbers of MLO and sterility.

A successful attempt was made to culture the mycoplasmalike microorganism causing semispecific hybrid male sterility in Drosophila paulistorum utilizing Ephestia kühniella as the intermediate host. Data gleaned from this passage indicates that the induction of sterility depends upon the quality not the quantity of infectious intracellular symbionts.

Animals↗
PubMed1977

A test for rare male mating advantage at an "enzyme locus" in Drosophila.

Matings between Drosophila pseudoobscura strains differing at the amylase (Amy) locus were observed in Elens-Wattiaux chambers. Males homozygous for either Amy1.00 or Amy0.84 alleles in the CH gene arrangement enjoyed a mating advantage when moderately rare, but none when quite rare. The minority male advantage for strains differing at the Amy locus, and other loci linked to it, was comparable in size to that observed between strains carrying the ST or CH gene arrangements, and either alike or different at the Amy locus. Although some features of our results are puzzling, there is evidence that the Amy locus and others for which it serves as a marker have effects on mating behavior which include some degree of rare male mating advantage.

Alleles↗
PubMed1976

Ethological isolation and mating experience in Drosophila paulistorum.

With few exceptions, previously published experiments documenting ethological isolation between Drosophila populations have used young virgin females. We have observed directly females of Drosophila paulistorum semispecies in choice experiments with both homogamic and heterogamic males. Aged females' sexual selection did not differ from that of young females. Previous heterogamic copulatory experience did not change the degree of sexual isolation; however, females with homogamic copulatory experience showed a significantly higher preference for homogamic males.

Aging↗
PubMed1975

Pole cells of Drosophila paulistorum: embryologic differentiation with symbionts.

The pole cells of young D. paulistorum embryos are destined to form the germinal cells of both male and female imagoes. In addition, specialized portions of the midgut may be derived from pole cell progenitors. In this initial study of their embryogenesis by means of electron microscopy, various stages of pole cell development are shown in both non-hybrid (potentially fertile) and intersemispecific hybrid (potentially sterile as males) materials. Originally, approximately 5 or 6 cells emerge to form the early polar cap and subsequently divide asynchronously until the 35-50 cells of the late polar cap are derived. Unlike other Drosophila species, however, mycoplasma-like symbionts, apparently an hereditary infection, have been traced to locations within the cytoplasm of these pole cells. They are depicted as arriving there after transmission via the egg cytoplasm, implicating this as their probable route of entry into the future germinal tissues of adult flies. It is postulated that these microorganisms function as an infectious reproductive isolating mechanism fostering hybrid male sterility between D. paulistorum semispecies.

Animals↗