Reproductive modes and strategies in vertebrate evolution

Angelini, F.; Ghiara, Gianfranco

doi:10.1080/11250008409439459

Cited by 56 publications

(36 citation statements)

References 174 publications

(63 reference statements)

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“…In this regard, the large number of previtellogenic and vitellogenic follicles present inside the mature female gonads may be consistent to guarantee the reproductive success of this species, because numerous follicles undergo to atresia during all different stages of oocyte growth (Chieffi, 1961;Mellinger, 1974). The persistence of germ cells that are not organized into follicles found in one mature Torpedo female is more difficult to explain, and, even though it is very attractive, it could suggest that in this aplacental viviparous species a typical K reproductive strategy (see Angelini and Ghiara, 1984) has not been completely established, as staminal germ cells may persist in the adult too. Such an idea should be discarded as no oogonia and/or early meiotic germ cells were found in all other subadult and adult females whose gonads were totally sectioned.…”

Section: Discussionmentioning

confidence: 99%

An ultrastructural study of germ cells during ovarian differentiation in Torpedo marmorata

2001

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An ultrastructural investigation, performed on embryos, neonates, subadult and adult females, demonstrated that in Torpedo marmorata oogenesis occurs very early in life and continues, in its proliferative phase, also after birth. Clusters of early meiotic cells were already evident in the ovarian cortex of 6-cm-long embryos, as well as in the ovary of newborns and three-month-old young. Conversely, in the ovaries of subadult and adult females, all the germ cells present were organized into follicles, and no clusters of oogonia and early meiotic cells were generally found in the cortex, except for one adult female where clusters of germ cells not organized in follicles were found in the cortex. These data demonstrated that, in Torpedo marmorata, oogenesis is immediate, and, as oogonia persist after birth, more similar to that of mouse, monkey, rabbit, and ferret (Mauleon Arch Anat Microsc, 1967; 56:125-150;Byskov and Hoyer 1994) than to that of human, rat, pig, and guinea pig (Byskov and Hoyer 1994). Such a pattern is in agreement with the reproductive strategy of Torpedo, a scantly prolific species with low uterine fecundity. The presence of meiotic cells that are not organized in follicles in one adult female might be consistent with the large individual variability characterizing cartilaginous fishes. The possibility that such a character is typical of mature females should be rejected as oogonia and early meiotic cells were not found inside the totally sectioned gonads of subadult and adult females.

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Section: Discussionmentioning

confidence: 99%

An ultrastructural study of germ cells during ovarian differentiation in Torpedo marmorata

2001

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“…This has led some Authors to attribute most of them to adaptation by individual specimens to such proximal factors as water temperature and food supply (Angelini & Ghiara, 1984;Minami & Tanaka, 1992). At higher latitudes, for example, the limitation of productivity to short periods of the year cannot support a long season of repeated spawning.…”

Section: Discussionmentioning

confidence: 99%

Reproductive biology of turbot(Psetta maxima)and brill(Scophthalmus rhombus)(Teleostei, Pleuronectiformes) in the Adriatic Sea

Caputo

Candi

Colella³

et al. 2001

Italian Journal of Zoology

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The reproductive biology of two commercially important flatfish, turbot (Psetta maxima) and brill (Scophthalmus rhombus), in the Adriatic Sea was investigated by histology and macroscopic analysis of gonads. Different patterns of vitellogenesis and spawning were observed in the two species. In turbot, gonad development culminates annually from March to May and the seasonal egg batch develops synchronously, the eggs becoming ready at about the same time. In brill, the ovary contains several oocyte batches in different stages of maturity, indicating intermittent release of ripe eggs in the course of a long spawning season (January-July). These data are discussed and compared with observations on reproduction of turbot and brill for other areas of their distribution ranges.

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“…All these observations together suggest that, in the females of this species, a partial recrudescence of ovarian activity occurs in early winter. This phenomenon, described also for the male gonad (Angelini et al 1986), can be explained by assuming that P. sicula originally had two seasonal ovulatory waves, one in the summer and another in the fall, similar to the lizards normally living in warm habitats (Angelini & Ghiara 1984). According to Arnold (1989), P. sicula was originally a warm-adapted species living in North Africa or the Middle East, and only later did it migrate to southern Europe.…”

Section: Discussionmentioning

confidence: 99%

Seasonal-dependent effect of temperature on the response of adenylate cyclase to FSH stimulation in the oviparous lizard, Podarcis sicula

Borrelli

Stasio²,

Motta³

et al. 2000

Journal of Endocrinology

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The study of environmental factors affecting vertebrate reproduction has long interested both developmental and evolutionary biologists. Although photoperiod has been considered to be an important environmental parameter for vertebrates such as birds, temperature is probably a primary external factor responsible for reproductive cyclicity in reptiles. In spite of the progress made in the understanding of reptilian reproductive strategies and adaptations, much remains to be learned about the interplay between endocrine physiological factors, such as hormones, and environmental parameters.In this report, we have examined the effects of in vivo administered FSH on oocyte recruitment during the most significant periods of the reproductive cycle of the lizard, Podarcis sicula. The results show that when FSH is administered in proximity to the reproductive period, it stimulates oocyte growth and ovulation; when the hormone is administered at the beginning of the winter stasis it affects ovarian activity without inducing ovulation. Ovarian adenylate cyclase activity is moderately sensitive to in vitro FSH stimulation during the pre-and post-reproductive periods. The sensitivity to hormone stimulation increases significantly during the reproductive period and winter stasis.We have also tested the hypothesis that environmental temperature affects the responsiveness of ovarian adenylate cyclase to FSH stimulation. For such a purpose, we exposed animals to 28 C or 4 C in different periods of the ovarian cycle. The results show that, whenever the temperature applied mimics the thermal regime of the coming season, adenylate cyclase sensitivity to FSH shifts towards levels that anticipate the natural responsiveness.

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Reproductive modes and strategies in vertebrate evolution

Cited by 56 publications

References 174 publications

An ultrastructural study of germ cells during ovarian differentiation in Torpedo marmorata

An ultrastructural study of germ cells during ovarian differentiation in Torpedo marmorata

Reproductive biology of turbot(Psetta maxima)and brill(Scophthalmus rhombus)(Teleostei, Pleuronectiformes) in the Adriatic Sea

Seasonal-dependent effect of temperature on the response of adenylate cyclase to FSH stimulation in the oviparous lizard, Podarcis sicula

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