A key prediction of theories of differential allocation and sexual conflict is that male phenotype will affect resource allocation by females. Females may adaptively increase investment in offspring when mated to high quality males to enhance the quality of their offspring, or males may vary in their ability to manipulate female investment post-mating. Males are known to be able to influence fe...

Objective: In this study we investigated the effects of spearmint (Mentha spicata Labiatae) on the reproductive system, fertility and number of offspring in adult male rats. Materials and Methods: Adult Wistar male rats in one control (C) and three experimental groups (I, II and III) received 0, 10, 20 and 40 mg/kg spearmint extract orally for 45 days, respectively.  Following this treatment, t...

Telomeres, repetitive DNA sequences found at the ends of linear chromosomes, play a role in regulating cellular proliferation, and shorten with increasing age in proliferating human tissues. The rate of age-related shortening of telomeres is highest early in life and decreases with age. Shortened telomeres are thought to limit the proliferation of cells and are associated with increased morbidi...

In many taxa there is considerable intraspecific variation in life history strategies from within a single population, reflecting alternative routes through which organisms can achieve successful reproduction. Atlantic salmon Salmo salar (Linnaeus) show some of the greatest within-population variability in life history strategies amongst vertebrates, with multiple discrete male and female life ...

Introduction: There are several evidences that show various environmental stresses during pregnancy, affect physiological behavior of the offspring. In this study the effects of REM (Rapid Eye Movement) sleep deprivation of pregnant rats on spatial learning of adult male offspring by Morris water maze were investigated. Methods: Water tank technique was used for inducing REM sleep deprivatio...

Varroa destructor is a worldwide ectoparasite of serious economic importance for beekeeping. Severe colony mortality is routine in parasitized European honey bees (EHB) colonies in Europe, Asia and North America. This study was carried out in Heredia, Costa Rica. The reproductive ability of varroa mites was determined approximately 240 h after cell sealing in worker brood from four Africanized ...

Semelparous organisms have a simple life cycle characterized by immediate death after reproduction. We assume that semelparous life histories can be separated into a juvenile non-reproductive period followed by an adult period during which reproduction is possible. We derive formulae for the optimal age and size at reproduction and for the optimal size of the offspring (e.g., seeds). Our main c...

BACKGROUND Few studies have reported on long-term harms caused by ADHD drugs but they are known to impair growth. OBJECTIVE To assess whether ADHD drugs impair reproduction in mammals. METHODS Systematic review of reproduction in studies of animals treated with ADHD drugs. DATA SOURCES PubMed, Biosis and EMBASE. RESULTS We included 17 studies. The studies were generally of poor quality ...

If a honeybee (Apis mellifera) colony loses its queen, worker bees develop their ovaries and produce male offspring [1]. Kin selection theory predicts that the degree of altruism in queenless colonies should be reduced because the relatedness of workers to a hivemate's offspring is less in queenless colonies than it is to the daughters of the queen in queenright colonies [2-4]. To explore this ...