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At least 415 records · Page 23Linked to original sources
PubMed1993

Postcopulatory sexual selection in an arctiid moth (Utetheisa ornatrix).

The offspring of twice-mated female Utetheisa ornatrix show low incidence of mixed paternity. Most progeny are sired exclusively by one male, the larger one, irrespective of parental age, male pyrrolizidine alkaloid content, mating order, between-mating interval, or duration of copulation. Data are presented suggesting that the female herself may exert control over the process by which one set of sperm is utilized at the expense of the other. Evidence for such postcopulatory female choice of sperm had not previously been obtained for an insect. Promiscuity provides the female with a means for accruing nuptial gifts (nutrients, defensive alkaloids). Sperm selection provides her with the option of utilizing sperm from larger, potentially more fit, males.

Animals↗
PubMed1999

Heritability of body mass, a sexually selected trait, in an arctiid moth (Utetheisa ornatrix).

In the moth Utetheisa ornatrix (Lepidoptera: Arctiidae), females mate preferentially with larger males. Large body mass is advantageous to both sexes: large males sire more young than small males, and large females have higher fecundity than small females. Here we report that body mass is heritable in both sexes, indicating that by choosing larger males females obtain genetic benefits for their offspring. Choosy females also receive extra nutrient and defensive alkaloid by way of their partner's spermatophores, but these gifts do not affect the heritability of body mass. These results indicate that by exercising mate choice female Utetheisa receive both direct phenotypic and indirect genetic benefits.

Animals↗
PubMed2005

Concentrating on beauty: sexual selection and sociospatial memory.

In three experiments, location memory for faces was examined using a computer version of the matching game Concentration. Findings suggested that physical attractiveness led to more efficient matching for female faces but not for male faces. Study 3 revealed this interaction despite allowing participants to initially see, attend to, and match the attractive male faces in the first few turns. Analysis of matching errors suggested that, compared to other targets, attractive women were less confusable with one another. Results are discussed in terms of the different functions that attractiveness serves for men and women.

Analysis of Variance↗
PubMed2001

Unpredictable offspring survivorship in the damselfly, Megaloprepus coerulatus, shapes parental behavior, constrains sexual selection, and challenges traditional fitness estimates.

Evolutionary biologists typically assume that the number of eggs fertilized or developing embryos produced is correlated with an individual's fitness. Using microsatellite markers, we document for the first time estimates of realized fitness quantified as the number of offspring surviving to adulthood in an insect under field conditions. In a territorial damselfly whose males defend tree hole oviposition sites, patterns of offspring survivorship could not be anticipated by adults. Fewer than half of the parents contributing eggs to a larval habitat realized any reproductive success from their investment. The best fitness correlate was the span over which eggs in a clutch hatched. Among parents, female fecundity and male fertilization success were poor predictors of realized fitness. Although body size was correlated with female clutch size and male mating success, larger parents did not realize greater fitness than smaller ones. The uncoupling of traditional fitness surrogates from realized fitness provides strong empirical evidence that selection at the larval stage constrains selection on mated adults.

Animals↗
PubMed1992

Update on pregnancy, condom use, and prevalence of selected sexually transmitted diseases in adolescents.

Adolescent pregnancy and its consequences continue as major sources of morbidity in the United States. A teenager who becomes a parent is at a significant disadvantage in becoming a contributing adult, both psychosocially and economically. The physician who cares for adolescents has the responsibility of helping parenting teens to find needed support so that they will be able to overcome this significant hurdle. Attention from public agencies has focused on increasing condom use as one approach to adolescent pregnancy prevention. The major advantage of using condoms is that they also prevent transmission of sexually transmitted diseases. Of note is that level of knowledge about condoms is not related to their use, and engaging in high-risk behaviors is related to a decreased likelihood of condom use. With rates of condom use estimated at less than 50%, rates of sexually transmitted disease remain high, as reported in recent surveys.

Adolescent↗
PubMedDate not supplied

Evaluation and management of selected sexually transmitted diseases.

Sexually transmitted diseases (STDs) represent some of the oldest and most prevalent infectious diseases of humans. Currently and with changes in lifestyles, the short list of STDs has grown to currently comprise 21 different infections and infestations. In this review, we concentrate on those infections that are common and which require special approach and handling. Gonorrhea and nongonococcal urethritis comprise more than half of STDs. The approach and management of these patients is briefly outlined. The important role contact tracing and education play in improving preventive practices of these infections is emphasized. Syphilis is presented in a simplified approach touching on presentation, diagnosis and treatment.

Anti-Bacterial Agents↗