Search results for "reproductive and urinary physiology"
showing 10 items of 365 documents
Body size and mating strategies in the simultaneous hermaphrodite Oxynoe olivacea (Mollusca, Opisthobranchia, Sacoglossa).
2004
Summary 1To better understand the role and importance of body size in hermaphroditic mating system theory, the mating behaviour of the shelled sacoglossan Oxynoe olivacea was studied. This simultaneous hermaphrodite exhibits bilateral and unilateral sperm transfer and thus it is particularly suitable for studies on hermaphrodite sexual conflict. 2In this study three hypotheses on body size were tested: that O. olivacea partner size has an effect on (i) mating mode choice, (ii) duration of mating modes, and (iii) choice of sexual role. Furthermore, we tested Charnov's hypothesis that in O. olivacea, like many simultaneous hermaphrodites, a sexual conflict exists and the male role is preferre…
Food availability and the male's role in parental care in double-brooded TreecreepersCerthia familiaris
1996
The aim of this work was to examine differences in paternal and maternal care in a double-brooded, monogamous species, the Treecreeper Certhia familiaris, in relation to food availability. As a measure of parental care, we recorded the hourly feeding activity of parents when the nestlings from their first and second breeding attempts were 7 and 12 days old. Feeding frequency of the first brood increased with the age of the nestlings and also with the brood size when 12 days old. While the feeding activities of the females were similar with respect to the first and second broods, the males were less active and failed to provide any food to their nestlings in 15 cases out of 28 second broods.…
Ability of the ISAS3Fun Method to Detect Sperm Acrosome Integrity and Its Potential to Discriminate between High and Low Field Fertility Bulls
2021
The objective of the present study was to investigate whether fertility differences in bulls are reflected in variations of sperm quality when analysing only one ejaculate per male. Two experiments were performed. In the first experiment, frozen semen samples from 20 adult bulls were tested
4-Bromophenyl 2,4-dibromophenyl ether
2002
The title compound, C12H7Br3O, belongs to a group of flame retardants known as polybrominated diphenyl ethers (PBDE). Salient features of the packing of the title compound are infinite intermolecular Br⋯Br contact chains along the b direction.
2,3,4,5,6-Pentabromophenyl phenyl ether
2002
The title compound, C12H5Br5O, belongs to a group of flame retardants known as polybrominated diphenyl ethers (PBDE). Salient features of the packing are stabilization due to intermolecular Br⋯Br contacts in the ab plane and aromatic intermolecular contacts along the c direction.
4-Bromophenyl 2,3,4,5,6-pentabromophenyl ether
2002
The title compound, C12H4Br6O, belongs to a group of flame retardants known as polybrominated diphenyl ethers (PBDE). Intermolecular Br⋯Br contacts in the bc plane give a sheet-like character to the structure of the title compound.
Operational sex ratio and resource defence as predictors of the mating system in European bitterling
2003
Operational sex ratio (OSR), the ratio of sexually active males to fertilizable females in a population, plays a central role in the theory of mating systems by predicting that the intensity of male–male competition and the degree of sexual selection increases as the OSR becomes increasingly male biased. At high values of OSR, however, resource defence theory predicts the breakdown of territoriality and a shift towards scramble competition with a decrease in sexual selection. The direction that correlations between OSR and resource competition and variance in mating success will take depends on the biology of the species of interest. We investigated the effects of male population density an…
Running against time: conservation of the remaining hawksbill turtle (Eretmochelys imbricata) nesting population in the Dominican Republic
2012
Saona Island hosts the last hawksbill turtle (Eretmochelys imbricata) nesting population in the Dominican Republic, which has experienced a severe decline in the last decades, mostly due to illegal egg take. Here we present the results of an artificial incubation programme started in 2007 to protect the clutches from human predation. A preliminary survey in 2006 showed that about 60% of clutches laid were taken by humans. Over the study period (2007–2010) we recorded 400 clutches, of which 38.2% were predated by humans, 40.7% were artificially incubated and 21% were incubated in situ. Overall, the artificial incubation programme allowed the release of 12,340 hatchlings. No differences were …
Seasonal shifts in the diet of lake zooplankton revealed by phospholipid fatty acid analysis
2009
SUMMARY 1. We analysed the phospholipid fatty acid (PLFA) profiles of seston and of the dominant zooplankter, Daphnia longispina, through the open water period in a small, dystrophic lake to investigate seasonal variation in the diet of Daphnia. Phytoplankton, heterotrophic bacteria, green sulphur bacteria and methane-oxidizing bacteria (MOB) were all present in the water column of the lake, and previous studies have indicated that vertically migrating Daphnia can exploit all these potential food sources. 2. For adult Daphnia, although there was some correspondence between the PLFA profile of Daphnia and the concurrent seston PLFA profile, strongest correlations were between the Daphnia PLF…
Food saltiness optimization using in-mouth sensors
2011
Food saltiness optimization using in-mouth sensors. International symposium olfaction & electronic noses (ISOEN 2011)