1. The adaptive significance of the observed variations in sex ratios in non-marine ostracods is unclear. This study quantified the fecundity of females taken from a presumed fully sexual Eucypris virens population that were experimentally combined with different proportions of males (male : female sex ratios: 1 : 1, 1 : 2, 1 : 4, 1 : 8 and 0 : 1). 2. The results yielded no indications that female fecundity is altered by short-term variations in the proportion of males, at least not within the range of sex ratios that are common in natural ostracod populations. Complete removal of males, however, did strongly reduce hatching success of dried eggs. This suggests the need for multiple mating events during the reproductive lifetime of the female. It also emphasizes the need for a minimum number of males, although this minimum number evidently may be rather low, as we found a high number of spermatozoa in the seminal receptacles after a single mating event. 3. The sex ratio in the source population was strongly female biased (1 : 3.4; n = 514), whereas in the hatchling assemblages reared in the laboratory, males and females were found in equal proportions (1 : 1.0; n = 1516), irrespective of the prevailing sex ratio. This clear discrepancy is intriguing, and points to the importance of epigenetic factors for the determination of field sex ratios.

Experimental assessment of the fecundity of Eucypris virens (Ostracoda, Crustacea) under natural sex ratios / J., Vandekerkhove; R., MATZKE KARASZ; F., Mezquita; Rossetti, Giampaolo. - In: FRESHWATER BIOLOGY. - ISSN 0046-5070. - 52:6(2007), pp. 1058-1064. [10.1111/j.1365-2427.2007.01753.x]

Experimental assessment of the fecundity of Eucypris virens (Ostracoda, Crustacea) under natural sex ratios

ROSSETTI, Giampaolo
2007-01-01

Abstract

1. The adaptive significance of the observed variations in sex ratios in non-marine ostracods is unclear. This study quantified the fecundity of females taken from a presumed fully sexual Eucypris virens population that were experimentally combined with different proportions of males (male : female sex ratios: 1 : 1, 1 : 2, 1 : 4, 1 : 8 and 0 : 1). 2. The results yielded no indications that female fecundity is altered by short-term variations in the proportion of males, at least not within the range of sex ratios that are common in natural ostracod populations. Complete removal of males, however, did strongly reduce hatching success of dried eggs. This suggests the need for multiple mating events during the reproductive lifetime of the female. It also emphasizes the need for a minimum number of males, although this minimum number evidently may be rather low, as we found a high number of spermatozoa in the seminal receptacles after a single mating event. 3. The sex ratio in the source population was strongly female biased (1 : 3.4; n = 514), whereas in the hatchling assemblages reared in the laboratory, males and females were found in equal proportions (1 : 1.0; n = 1516), irrespective of the prevailing sex ratio. This clear discrepancy is intriguing, and points to the importance of epigenetic factors for the determination of field sex ratios.
2007
Experimental assessment of the fecundity of Eucypris virens (Ostracoda, Crustacea) under natural sex ratios / J., Vandekerkhove; R., MATZKE KARASZ; F., Mezquita; Rossetti, Giampaolo. - In: FRESHWATER BIOLOGY. - ISSN 0046-5070. - 52:6(2007), pp. 1058-1064. [10.1111/j.1365-2427.2007.01753.x]
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11381/1628232
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 18
  • ???jsp.display-item.citation.isi??? 16
social impact