| the development of photorefractoriness in termination of the breeding season in the tropical brahminy myna: role of photoperiod. | gonads of brahminy myna (sturnus pagodarum) spontaneously regress in july/august when the daylength is still stimulatory. experiments were conducted to investigate if photoperiod was involved in the timing of gonadal regression and if photorefractoriness terminated the breeding season in this species. the observations obtained in the present study clearly show that: i) increasing photoperiods of spring/summer programmed for eventual gonadal regression in the late summer; ii) the birds developed ... | 2007 | 2043258 |
| steroidal feedback on photoperiodic induction of testicular growth and development in two bird species. | present study was performed to demonstrate the effect of exogenous administration of testosterone propionate on photoperiodic induction of testicular growth and development in brahminy myna (sturnus pagodarum) and baya weaver (ploceus philippinus). two groups of brahminy myna and baya weaver (n=5 each) were exposed to 15l:9d (group-i) and 9l:15d (group-ii), and received 30 microg of tp bird(-1) for 15 days. then, the photoperiod was reversed; the one receiving 15l was exposed to 9l and vice vers ... | 2012 | 23033649 |
| photosensitivity in body mass and testicular activity of brahminy myna, sturnus pagodarum. | this study analyzed photoperiodic sensitivity of brahminy myna (sturnus pagodarum), which is a seasonally breeding bird species. during regression phase of the reproductive cycle (in early september), groups of myna were exposed to artificial photoperiods that were either close to or longer than those brahminy myna experiences at this time in wild at 29 degrees n. following a 14-week exposure to such photoperiods (hours of light: hours of darkness; 13l:11d, 12l:12d, 11.5l:12.5d and 11l:13d), the ... | 2006 | 15535468 |
| photoperiodic control of annual reproductive cycle in subtropical brahminy myna, sturnus pagodarum. | the aims of this investigation were to: (i) study the effect of the length of photoperiod on the timing of onset of gonadal recrudescence and postreproductive decline in photoresponsivity, and (ii) identify the mechanism(s) involved in the initiation of gonadal recrudescence in the subtropical brahminy myna (sturnus pagodarum). two series of experiments were performed using adult birds: (1) groups of birds were subjected to 12l:12d, 14l:10d, and 16l:8d in january and to 12l:12d and 14l:10d in ma ... | 1993 | 8428647 |
| termination of photorefractoriness in the brahminy myna, sturnus pagodarum: role of photoperiods and gonadal hormones. | in brahminy myna a photosensitive species, long days caused full gonadal development followed by rapid regression, whereas short days inhibited these responses. experiments were performed to investigate the effects of duration of photoperiod and gonadal hormones on the recovery of photosensitivity to long photoperiods in male birds. groups of photorefractory birds were subjected to 8-, 9- or 11-hr daily photoperiods for 45 (6.5 weeks) or 63 (9 weeks) days and then transferred to 15 h daily photo ... | 1992 | 1506016 |
| seasonal reproduction in subtropical brahminy myna, sturnus pagodarum: role of photoperiod. | experiments were performed to study the extent of the involvement of photoperiod in the timing of seasonal reproduction in brahminy myna (sturnus pagodarum). the reproductive cycle corresponds to annual variations in day length and there is a marked seasonal variation in the photogonadal response of birds, which is evident when birds are shifted from normal day length to long photoperiods (15l:9d) every month. this is supported by the results from constant long (15l:9d) and short (9l:15d) photop ... | 1991 | 1936916 |
| effect of photoperiod length on body mass and testicular growth in the house sparrow (passer domesticus) and brahminy myna (sturnus pagodarum). | two experiments studied the relative effects on body mass and testicular growth of stimulatory photoperiods applied simultaneously to two photosensitive species, the house sparrow (passer domesticus) and brahminy myna (sturnus pagodarum). experiment 1 on the house sparrow consisted of two parts. in experiment 1a, beginning on 24 march 2002, short day pretreated sparrows were exposed for 12 weeks to 13l: 11d (13 h light: 11 h darkness), 20l: 4d and ndl (control). experiment 1b was similar to 1a e ... | 2006 | 16438917 |