The relative concentrations of catecholamine in the nervous system of the entomophilic nematode Romanomermis culicivorax were measured under different experimental conditions by a glyoxylic acid-induced fluorescence procedure. A greater concentration of catecholamine was recorded in the nervous system of adult males and females than in postparasitic juveniles. A higher concentration of catechol...

In natural populations, courting males of Araneus diadematus are often consumed by females before they have successfully copulated. Despite the possible nutritional benefits of sexual cannibalism for females, the male can derive no benefit by being consumed before copulation. In this study, females that consumed a single male significantly increased their body mass, regardless of the quality of...

In a wide variety of animal species, females produce vocalizations just before, during or immediately after copulation. These calls are thought to be sexually selected traits that function to incite males to compete for access to the calling females in such a way that, by calling, females maximize the quality and/or the number of their mating partners. The signalling of individual identity with...

The objective of this study was to determine size of testes, sexual behaviour, semen quality and testosterone concentration on 40 Ossimi rams in relation to scrotal circumference and age. Rams were divided into two groups similar in age and body weight. Group A with age of 1-1.5 years old and group B with 2-2.5 years old. Each group was divided into subgroups according to the scrotal circumfere...

Abstract Introduction Male genitalia are thought to ensure transfer of sperm through direct physical contact with female during copulation. However, little attention has been given their pre-copulatory role respect sexual selection and conflict. Males the fruitfly Drosophila pachea have a pair asymmetric external genital lobes, which primary structures stabilize copulatory complex male genitali...

Abstract The effects of mating experience on male behavior are mediated by four factors: cost, such as resource depletion, perception opportunities, self-perception attractiveness, and female quality. For example, encountering females might increase expectations prospective while copulation increases attractiveness in males. To determine the relative importance these factors, effect two compone...

The medial preoptic area (MPOA) is a critical regulatory site for the control of male sexual behavior. We first measured glutamate in 2 min microdialysate samples from the MPOA before, during, and after copulation by male rats. There was a slight [approximately 140% of baseline (BL)] rise in extracellular glutamate when the female was presented, a significant increase (approximately 170% of BL)...