Short photoperiods affect male hamster sociosexual behaviors in the presence and absence of testosterone

Influence of gonadal hormones on odours emitted by male meadow voles (Microtus pennsylvanicus)

“…The hormonal and neural changes that underlie this phenomenon are unknown and may involve interactions among components of the hypothalamicpineal-pituitary axis. Similar results and interpretations have been suggested to account for the inability of gonadal hormones to affect odour preferences of female meadow voles (Ferkin & Zucker, 1991), and scent marking, social and copulatory behaviour in male golden hamsters (Mesocricetus auratus), in short photoperiods (Morin & Zucker, 1978;Miernicki et al, 1990).…”

“…When considered together, these studies suggest that seasonal differences in olfactory stimuli emitted by males and females are mediated by photoperiod changes in gonadal hormone secretion. In other rodent species, gonadectomy also reduces the attractiveness of odours to the opposite sex, the amounts of olfactory investigation, and scent marking; replacement with gonadal hormones reinstated these behaviours (Scott & Pfaff, 1970;Brown, 1978;Albers & Rowland, 1989;Johnston, 1990;Miernicki et al, 1990). …”

“…Odour-producing glands increase in size and secretory activity at puberty and during the breeding season when androgen concentrations are high (Quay, 1968;Christiansen et al, 1978;Jannett, 1978;Adams et al, 1980). Castration results in a decrease in the development and reduced secretory activity by specialized glands and tissues in the integu¬ ment; these changes are reversed by androgen replacement (Jannett, 1978;Powers et al, 1985;Rowsemitt et al, 1988;Johnston, 1990;Miernicki et al, 1990). Pituitary hormones may also affect odour production (Thody & Shuster, 1975;Keverne, 1981), independently of or synergistically with androgens (Ebling et al, 1975;Thody et al, 1976).…”

Reactions of female bank voles Clethrionomys glareolus to male chemosignals

“…Similarly, in the meadow vole the female-attractant cue in male odours is reduced after gonadectomy but is reinstated by testosterone treatment (Ferkin et al 1992). Gonadectomy in other rodent species also reduces the attractiveness of odours to the opposite sex and the extent of olfactory investigation, while replacement with gonadal hormones restores such behaviour (Scott and Pfaff 1970, Johnston 1990, Miernicki et al 1990.…”

Effect of different photoperiods and melatonin treatment on rabbit reproductive performance

“…Moreover, supplemental lighting programs produced positive effects on female reproductive precocity, kindling rate, and litter size at birth in rabbits under tropical conditions in Nigeria and Guadeloupe (Berepubo et al 1993;Depres et al 1996). Moreover, in seasonally breeding Syrian hamsters, day length influenced the copulatory behavior as males ceased to display ejaculatory behavior after several weeks of exposure to short day lengths (Powers et al 1989;Miernicki et al 1990). Studies approaching photoperiod manipulation in rabbit farming have generally shown a significant improvement in receptivity and fertility of does when the daylight length was artificially increased (Harris et al 1982;Boyd 1986).…”