Juvenile growth rate is an important life-history trait that affects the size at maturity, and may influence the development of sexual ornamentation. The sword of several species of the genus Xiphophorus (Teleostei: Poeciliidae) is an elaborate secondary sexual trait that confers an advantage in terms of sexual selection, counterbalanced by locomotive and predatory costs. This study assesses di...

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...

Dr. RAYMOND PEARL (1912) was the first worker to suggest that sexlinked factors were involved in the inheritance of fecundity. PEARL used as a measure of fecundity the eggs produced during the winter period. He proposed that two major dominant factors were responsible for high egg production, one of which resided in the sex chromosome. GOODALE (1919) and HURST (1921) each failed to confirm the ...

Sexual dimorphism is common across the animal kingdom, but the contribution of environmental factors shaping differences between the sexes remains controversial. In ectotherms, life-history traits are known to correlate with latitude, but sex-specific responses are not well understood. We analyzed life-history trait variation between the sexes of European perch (Perca fluviatilis L.), a common ...

the age of criminal responsibility of children in the islamic penalties act has been determined as religious bulugh (puberty) nasab. according to this, criminal authorities hold girls criminally liable and punishable at 9 complete lunar years and boys at 15 complete lunar years. unfortunately, our legislator has set criminal responsibility of children based on sexual maturity; therefore, thousa...

1. In environmental sex determination (ESD) gender is decided after conception, depending on the environment, rather than being genetically fixed. ESD in plants has been mainly studied in angiosperms, where the dominant form of ESD is sexual lability. Surprisingly, ESD has rarely been studied in homosporous ferns, the only plants in which ESD is the rule, rather than the exception. 2. Here, we ...

Question: Can intrasexual selection on male size and natural selection on female size in the shell-brooding cichlid Lamprologus callipterus explain the greatest male/female sexual size dimorphism (SSD) reported to date among animals? Mathematical methods: (1) Mortality model to predict male and female body sizes. (2) Gain rate maximization and (3) combined mortality/gain rate maximization model...

The present study depicts the first comprehensive description on population structure, growth pattern (length-weight relationships, LWRs and length-length LLRs), condition factor (allometric, KA; Fultonʹs, KF; relative, KR relative weight, WR), maturity (size at sexual maturity; Lm), form (a3.0) natural mortality (Mw) of Trichogaster fasciata (Bloch Schneider, 1801)in Ganges River, Northwestern...