Seed dispersal by wind is a critical yet poorly understood process in tropical forest trees. How tree size and fecundity affect this process at the population level remains largely unknown because of insufficient replication across adults. We measured seed dispersal by the endangered neotropical timber species big-leaf mahogany (Swietenia macrophylla King, Meliaceae) in the Brazilian Amazon at ...

There is a long-standing debate on the role of genetic factors influencing homosexuality because the presence of these factors contradicts the Darwinian prediction according to which natural selection should progressively eliminate the factors that reduce individual fecundity and fitness. Recently, however, Camperio Ciani, Corna, and Capiluppi (Proceedings of the Royal Society of London, Series...

Although the primary function of mating is gamete transfer, male ejaculates contain numerous other substances that are produced by accessory glands and transferred to females during mating. Studies with several model organisms have shown that these substances can exert diverse behavioural and physiological effects on females, including altered longevity and reproductive output, yet a comprehens...

This study is based on a representative sample of 709 Danish women aged between 25 and 45 who were interviewed in 1979. The purpose was to estimate the proportion of women with reduced fecundity who seek medical care and to identify sociodemographic variables associated with presentation to the medical care system. The study showed that the majority of women with reduced fecundity did not seek ...

We studied the time of initial sexual maturity and the fecundity of the goldfish Carassius auratus under semi-controlled conditions. During the study the water temperature fluctuated from 21 to 30 degrees C, the pH between 7 and 8, and the dissolved oxygen between 5.5 and 7 ppm. Sixty days old juvenile fish received prophylactic treatments of brackish water (15 per thousand) and methylene blue ...

A population with two alleles at one locus is considered. It is assumed that there is random mating of adults and that matings in which a particular pair of genotypes is involved may have a different mean number of offspring, or fecundity, than other types of matings. There is assumed to be no other selection. It is shown that the genotypic frequencies that maximize the mean fecundity of the po...

The demographic variance of an age-structured population is defined. This parameter is further split into components generated by demographic stochasticity in each vital rate. The applicability of these parameters are investigated by checking how an age-structured population process can be approximated by a diffusion with only three parameters. These are the deterministic growth rate computed f...

In beginning of 21 century, various industries have been set up for boosting the production of various substances of commercial importance. A distillery factory has been established in industrial development area of Gorakhpur (GIDA). It releases its effluent in the adjoining field/aquatic bodies that directly or indirectly pose a threat to aquatic biota in general and fishes in particular. Pres...

Sardinella sindensis is one of the dominant small pelagic fish of Karachi coast of Pakistan. Investigation on fecundity of sind sardinella was studied from January 2001 to April 2002. A total of 37 ovaries were examined of stages IV-VI (when not running). Mean fecundity ranged from 47521 to 110876 eggs. Log-log relationship between fecundity with total body-length, fish-weight & ovary weight we...

Many mutations that dramatically extend life span in model organisms come with substantial fitness costs. Although these genetic manipulations provide valuable insight into molecular modulators of life span, it is currently unclear whether life-span extension is unavoidably linked to fitness costs. To examine this relationship, we evolved a genetically heterogeneous population of Caenorhabditis...