A marine biological invasion is a natural process accelerated by human activities, and the crab Charybdis hellerii is an example of a globally widespread invasive species. This study evaluated color variation in C. hellerii and its relationship to the sex, size and sexual maturity of these crabs, and compared the efficiency of a freeware digital image-editing program with a commercially availab...

Social conditions experienced prior to sexual maturity influence reproduction later in life in many animals. In simultaneous hermaphrodites variation in mating group size influences reproductive investment. As the mating group size increases, reproductive resources devoted to the female function decrease in favor of the male function. Prior to sexual maturity many hermaphrodites have a protandr...

CONTEXT The time of life in which peak bone mass in the axial skeleton is attained has been the subject of considerable controversy, with estimates ranging from the time of sexual and skeletal maturity to the fifth decade of life. OBJECTIVE The objective was to examine whether dual energy x-ray absorptiometry (DXA) and computed tomography (CT) values for bone mass and bone density (BD) in the...

An experiment was carried out with SHAVER Starbro broiler parent stock from one day old to the point of peak production to investigate the growth, early laying performance and their adaptability during brooding, growing and early laying periods. The experimental period was divided into five phases, phase I (0 – 2 week), phase II (3 – 8 week), phase III (9 – 22 week), phase IV (23 – sexual matur...

In human populations, variation in mate availability has been linked to various biological and social outcomes, but the possible effect of mate availability on health or survival has not been studied. Unbalanced sex ratios are a concern in many parts of the world, and their implications for the health and survival of the constituent individuals warrant careful investigation. We indexed mate ava...

Observations of the external morphology of wild-caught and captive male brown long-eared bats (Plecotus auritus) revealed a marked seasonal pattern of spermatogenesis, similar to that established by histological examination of other temperate-zone vespertilionids, with a peak in testes size in August and a lag between testicular growth and epididymal distension. This was followed by complete ce...

OBJECTIVE This research tests the influences of age, biological, and psychosocial factors on sexual expression in later life. METHOD The American Association of Retired Persons Modern Maturity Sexuality Survey collected data on diagnosed illnesses, treated illnesses, sexual desire, sexual attitudes, partner circumstances, and sexual behavior from 1,384 persons ages 45 and older. Ordered logis...

M A T U R A T I O N and maintenance of ovarian function are under the control of the pituitary gonadotrophins. The capacity of the ovary to respond to FSH stimulation develops gradually with age, and is most pronounced when the animal approaches sexual maturity. In very young animals reactivity to gonadotrophins is found to be lacking, and up to a certain age, which is characteristic for each s...