There are three sex ratio strategies (SRS) in nature-male-biased sex ratio, female-biased sex ratio and, equal sex ratio. It was R. A. Fisher who first explained why most species in nature display a sex ratio of ½. Consequent SRS theories such as Hamilton's local mate competition (LMC) and Clark's local resource competition (LRC) separately explained the observed deviations from the seemingly u...

the biological parameters of sympiesis striatipes ashmead, one of the most abundant hymenopterous ectoparasitoid of phyllocnistis citrella stainton in ehime province of japan, were studied under laboratory and field conditions. the mean immature developmental time and adult longevity at different temperatures (22 to 31â°c), 50-70% rh and 12l: 12d photoperiod decreased as the temperature increas...

the biology of chrysocharis pentheus (walker) (hymenoptera: eulophidae), the most abundant endoparasitoid of phyllocnistis citrella stainton (lepidoptera: gracillariidae) in ehime prefecture, japan, was studied under laboratory and field conditions. the mean immature developmental time and adult longevity at different temperatures (22 to 31°c) under 50-70% rh decreased as the temperature increa...

this study presents data on age structure, sex ratio, growth, length-weight relationships and condition factor of four populations (n=312) of  two alburnoides species, collected in 2005 and 2006 from the tajan river (caspian sea basin), the ghara-chai and jajrud rivers (namak lake basin), and cheshmeh-ali spring (kavir basin) of iran. sex ratio of the fish, in the studied localities, except in ...

the size composition, growth pattern, sex ratio and feeding habits of the blue swimming crab, portunus segnis from persian gulf in south of iran, was studied. sampling was performed by trawl net during a one- year period (july 2011 to may 2012) as processed 864 crabs was collection. the crabs carapace width ranged were from 7.5-17.5 cm for males and 7.0-16.5 cm for females. the crab carapace le...

it is not clear whether sibling's gender ratio is associated with attention deficit hyperactivity disorder (adhd). this study examines whether inattentiveness severity and hyperactivity/impulsivity severity are associated with birth order of children with adhd.participants are a clinical sample of 173 children and adolescents with adhd and 43 ones without adhd. diagnoses were made using diagnos...