Reproductive traits of tropical tree species vary predictably in relation to successional stage, but this variation may be due to the species' phylogenetic histories rather than selective pressures imposed by regeneration requirements. Reproductive phenology, tree size at the onset of reproduction, and fecundity of 11 sympatric, closely related Macaranga species were studied to investigate with...

Despite a large body of knowledge about the evolution of life histories, we know little about how variable food availability during an individual's development affects its life history. We measured the effects of manipulating food levels during early and late larval development of the mosquito Aedes aegypti on its growth rate, life history and reproductive success. Switching from low to high fo...

Perihypothalamic thyroid hormone signaling features prominently in the seasonal control of reproductive physiology. Triiodothyronine (T(3)) signaling stimulates gonadal development, and decrements in T(3) signaling are associated with gonadal regression. Type 3 iodothyronine deiodinase (DIO3) converts the prohormone thyroxine (T(4)) into biologically inactive 3,3',5'-triiodothyronine, and in lo...

Physiological mechanisms mediating carryover effects, wherein events or activities occurring in one season, habitat, or life-history stage affect important processes in subsequent life-history stages, are largely unknown. The mechanism most commonly invoked to explain carryover effects from migration centres on the acquisition and utilization of resources (e.g. body mass, or individual 'conditi...

A trade-off between sex and somatic maintenance is fundamental to life-history theory. Tests of this trade-off usually emphasize deleterious consequences of increased reproduction on life span. Here we show the reverse effect, that reductions in the expected life span elevate sexual activity. Experimentally parasitized male Drosophila nigrospiracula lived shorter lives, but before dying, they c...

Breast cancer is the most common cancer among Malaysian women. This study aimed to determine the reproductive for premenopausal breast cancer risk in Kuala Lumpur, Malaysia. A case-control study was conducted in 216 histopathologically confirmed cases of premenopausal breast cancer and 216 community-based controls that were matched by age within a 5-year period and ethnicity. The results of thi...

A history of previous birth of a low birthweight infant, previous cesarean sections, multiple previous spontaneous abortions, prior stillbirth, or uterine anomaly identifies women at increased risk for recurrent abortion, preterm birth, or stillbirth. We review the evidence for the potential benefit of reproductive history in identifying strategies for evaluation and treatment to prevent recurr...

In a previous communication (Smith and Record, 1955) it was observed that there appeared to be an association between mongolism and primogeniture which invites investigation of the fertility of mothers of mongols. Such a study is by no means new. It has been attempted by many previous workers, prompted perhaps by the observations that the risk of producing a mongol increases sharply with advanc...

Human mating and reproductive behaviour can vary depending on various mechanisms, including the local sex ratio. Previous research shows that as sex ratios become female-biased, women from economically deprived areas are less likely to delay reproductive opportunities to wait for a high-investing mate but instead begin their reproductive careers sooner. Here, we show that the local sex ratio al...

A postal questionnaire was used in a nationwide case control study of women with scleroderma to investigate whether there was an increased rate of spontaneous abortion before the onset of the disease. The results from 155 case control pairs studied showed that the women with scleroderma had twice the rate of spontaneous abortion and three times the rate of fertility problems (no successful preg...