Most Thysanoptera possess a haplo-diploid reproductive mode and reproduce via arrhenotoky. Females can mature eggs successively throughout almost their entire life, but in most terebrantian thrips spermiogenesis is complete by adult male eclosion, and testes contain only mature spermatids. In parasitoid wasps this phenomenon of preadult spermiogenesis is described as prospermatogeny. It is uncl...

To investigate reproductive behavior of individuals at increased risk of having a child with retinoblastoma (Rb), we conducted a cross-sectional questionnaire survey among 118 counselees visiting the Clinical Genetics Department of the National Rb Center in the Netherlands. The recurrence risk for counselees ranged from <1% to 50%. The response rate was 69%. Of 43 respondents considering having...

The genetic basis of division of labor in social insects is a central question in evolutionary and behavioral biology. The honey bee is a model for studying evolutionary behavioral genetics because of its well characterized age-correlated division of labor. After an initial period of within-nest tasks, 2-3 week-old worker bees begin foraging outside the nest. Individuals often specialize by bia...

In many regions of Asia and Africa, consanguineous marriages currently account for approximately 20 to 50% of all unions, and preliminary observations indicate that migrants from these areas continue to contract marriages with close relatives when resident in North America and Western Europe. Consanguinity is associated with increased gross fertility, due at least in part to younger maternal ag...

This study aims at investigating the effectiveness of nutritional supplements containing vitamins, minerals, and ammonia on the sexual and breeding behaviors in Ghezel sheep. To this end, 28 three and half-year old ewes (50±3 kilograms) with the record of giving birth to two lambs and 4 three-year old (90±3.5 kilograms) rams were used. The ewes were divided into two groups of A (i.e., treatment...

The Sumatran rhinoceros (Dicerorhinus sumatrensis) is on the verge of extinction in Malaysia. At the Sumatran rhinoceros Conservation Centre in Sungai Dusun, the reproductive behaviour of two female and two male rhinoceroses were studied for 8-10 months during attempts to breed them in captivity. Due to the paucity of scientific information on the reproductive biology of the Sumatran rhinoceros...

Objective: To assess perception and behavior after reproductive health counseling among adolescent patients in a tertiary care-based pediatric rheumatology clinic. Methods: Adolescent females seen at Stanford pediatric rheumatology clinic were prospectively enrolled during routine visits. At study start, standard clinic procedures for the following were reviewed with providers: 1) HEADSS (home,...

Social behaviors are key components of reproduction, because they are essential for successful fertilization. Social behaviors, such as courtship, mating, and aggression, are strongly associated with sex steroids, such as testosterone, estradiol, and progesterone. Secretion of sex steroids from the gonads is regulated by the hypothalamus-pituitary-gonadal (HPG) axis in vertebrates. Gonadotropin...

The reproductive behavior and the seasonal occurrence of Psecas viridipurpureus were studied at the Estação Ecológica do Noroeste Paulista, a small conservation area in the northwest region of São Paulo State, Brazil (49 degrees 22'50"W and 20 degrees 48'36"S). P. viridipurpureus occurred on "gravatá", a bromeliaceous plant (Bromelia balansae, Bromeliaceae) which does not accumulate rain water....

Timing of breeding to an optimal season is a requirement for a successful reproductive outcome in seasonally breeding species. Photoperiodic signals are capable of modifying the reproductive behaviour and reproductive systems in several vertebrate species. The cichlid fish Cichlasoma dimerus shows highly organized breeding activities and different social status. The aim of this study is to test...