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Female Behaviour (female + behaviour)
Selected AbstractsA Quantified Ethogram for Oviposition in Triturus Newts: Description and Comparison of T. helveticus and T. vulgarisETHOLOGY, Issue 4 2005Karen M. Norris Female newts of the genus Triturus deposit and wrap their eggs individually in the submerged leaves of aquatic macrophytes. Although this behaviour has previously been described, the different elements of the oviposition process have not been fully characterized nor any attempt made to quantify the behavioural elements. The study examined the oviposition behaviour of the two similarly sized species, Triturus helveticus and T. vulgaris on a standardized substrate macrophyte, Rorippa nasturtium,aquaticum. Continuous focal sampling was used to develop a baseline of discrete behavioural elements enabling quantification and comparison of oviposition behaviour between the two species. The results showed that the same pattern of elements was followed for each egg laid and the same key elements of the process were present in each newt species. Although these are broadly similar in size, there were striking differences in certain aspects of the oviposition sequence between the two species. Key findings were that leaf sniffing and leaf flexing and a measure of the duration of ovipositing were all significantly greater in females of T. helveticus and females of T. vulgaris laid significantly more eggs than those of T. helveticus in a standard observation period. The work presented here defines a baseline ethogram and shows how it can be used to reveal quantifiable differences in closely related species. This demonstrates its value in furthering our understanding of oviposition , a key aspect of female behaviour currently understudied in Triturus behavioural ecology, despite its intrinsic interest and value in understanding recruitment and maintenance of populations. [source] Female Choice, Female Reluctance to Mate and Sexual Selection on Body Size in the Dung Fly Sepsis cynipseaETHOLOGY, Issue 7 2000Wolf U. Blanckenhorn We investigated the mechanisms of sexual selection in the common dung fly Sepsis cynipsea and how these affect selection on body size at the population level. Because of the presumed costs associated with mating, we predicted that there would be a decrease in the general reluctance of females to mate with any particular male at higher male densities at the mating site, a fresh cow pat, resulting in indirect female choice and a decrease in the strength of sexual selection. In contrast, classical direct female choice and male-male competition should result in increased selection intensities because more opportunities for choice and competition exist at higher densities. Female reluctance to mate and female assessment of males are expressed in prominent female behaviour to repel mates in several insect species, including S. cynipsea. Laboratory pair-wise choice experiments showed that large males were more likely to obtain copulations, which also ensued more promptly, suggesting female assessment of male quality (direct female choice). There was a basic influence of male activity but little further effect of male scramble competition on the outcome of mating. Another laboratory experiment showed a decrease in female shaking duration per male, associated with an asymptote in the shaking duration per female, as male density and harassment increased, but did not show the increase in mating frequency predicted by the female reluctance hypothesis. A study estimating sexual selection differentials in the field showed that directional selection for larger males was present overall and was negatively related to seasonally mediated variation in male density. Our study suggests that direct female choice in combination with indirect female choice (due to an interaction of female reluctance to mate and male persistence) is most consistent with the behavioural and selection patterns observed in S. cynipsea, but male effects cannot be definitively excluded. [source] Testosterone response to GnRH in a female songbird varies with stage of reproduction: implications for adult behaviour and maternal effectsFUNCTIONAL ECOLOGY, Issue 4 2007JODIE M. JAWOR Summary 1Despite considerable recent interest in plasma and yolk testosterone (T) in female birds, relatively little is known about environmental regulation of female T, individual variation in female T or the relationship between plasma and yolk T. 2In breeding females of a wild population of dark-eyed junco (Junco hyemalis), we assessed variation in the responsiveness of the hypothalamo-pituitary-gonadal (HPG) axis to a challenge with gonadotropin-releasing hormone (GnRH) by measuring circulating T before and 30 min after a standardized injection of GnRH. We asked whether response to challenge varied seasonally or with stage of reproduction and whether it was repeatable within individuals or related to T deposited in eggs. 3Initial and post-challenge levels of T were measured using enzyme immunoassay. In a subset of these females, luteinising hormone (LH) was measured using radioimmunoassay (RIA). In addition, eggs were collected from nests of 15 females that had received a GnRH challenge, and yolk T was measured using RIA. 4During most of the breeding season, plasma T did not increase in response to GnRH. GnRH consistently caused increases in plasma T only during the 7 days before oviposition, when females were rapidly depositing yolk in eggs but had not yet begun to lay them. Among a small subset of females we found a positive correlation between the magnitude of this increase in plasma T in response to GnRH during egg development and the amount of T deposited in the yolk of eggs collected at a later time. 5These results suggest that ovarian response to GnRH-induced increases in LH is greatest when females are actively depositing yolk into eggs. Factors that stimulate the release of GnRH during egg formation may result in higher levels of plasma T which could influence adult female behaviour. Further, because plasma T was correlated with later yolk T, factors that stimulate GnRH release may also lead to higher levels of yolk T potentially influencing offspring development or behaviour. [source] Active brood care in Cancer setosus (Crustacea: Decapoda): the relationship between female behaviour, embryo oxygen consumption and the cost of broodingFUNCTIONAL ECOLOGY, Issue 2 2002J. A. Baeza Summary 1,Previous studies have shown that oxygen is limiting in embryo masses of marine invertebrates. It has been suggested that several behaviours found in brooding females of brachyuran crabs are used to ventilate and provide oxygen to the embryo masses. 2,The relationship between female brooding behaviour, oxygen consumption of embryos and oxygen provision to the brood mass for embryos at different developmental stages was studied, using the marine crab Cancer setosus. The changes in oxygen consumption of brooding females associated with changes in oxygen provision to the brood were also estimated. 3Brooding females of C. setosus behaved differently from non-brooding females. Abdominal flapping was associated with an increase in oxygen availability in the centre of the brood mass; the frequency of abdominal flapping increased with embryonic development, as oxygen demand of crab embryos increased. Oxygen consumption of brooding females also increased throughout embryonic development. The difference in oxygen consumption between brooding and non-brooding females was used as an indicator of the cost of oxygen provision (brooding). 4,These results provide the first evidence , among crabs and other marine invertebrates , of a direct link between active brood care and oxygen provision. It is possible that parental care in marine invertebrates is strongly linked to oxygen provision, since oxygen limitation has been reported for several brooding taxa. The simple physiological constraint of oxygen provision in marine invertebrates may have important ecological and evolutionary consequences. [source] Work and Employment in Small Businesses: Perpetuating and Challenging Gender TraditionsGENDER, WORK & ORGANISATION, Issue 1 2000Susan Baines More and more women and men are becoming dependent on some form of small business activity for all or part of their livelihoods but there is little research offering insight into gender and working practices in small businesses. In this article we assess some theoretical approaches and discuss these against an empirical investigation of micro-firms run by women, men and mixed sex partnerships. In the ,entrepreneurship' literature, with its emphasis on the individual business owner, we find little guidance. We argue that in the ,modern' micro-business, family and work are brought into proximity as in the ,in between' organizational form described by Weber. The celebrated ,flexibility' of small firms often involves the reproduction within modernity of seemingly pre-modern practices in household organization and gender divisions of labour. This is true in the Britain of the 1990s in a growing business sector normally associated neither with tradition nor with the family. Tradition, however, is never automatic or uncontested in a ,post-traditional society'. A minority of women and men in micro-enterprises actively resist traditional solutions and even traditional imagery of male and female behaviour. For this small group alone new economic conditions seem to bring new freedom. [source] Temperature and life history: experimental heating leads female tree swallows to modulate egg temperature and incubation behaviourJOURNAL OF ANIMAL ECOLOGY, Issue 1 2009Daniel R. Ardia Summary 1Life-history decisions are strongly affected by environmental conditions. In birds, incubation is energetically expensive and affected significantly by ambient temperature. We reduced energetic constraints for female tree swallows (Tachycineta bicolor) by experimentally heating nests during incubation by an average of 6·9 °C to test for changes in incubation behaviour. 2Females in heated boxes (hereafter ,heated females') increased time spent incubating and maintained higher on-bout and off-bout egg temperatures. This indicates that female energetic constraints, not maximizing developmental conditions of offspring, determine incubation investment. Furthermore, this result suggests that embryonic developmental conditions in unmanipulated nests are suboptimal. 3We found individual variation in how females responded to experimental heating. Early-laying (i.e. higher phenotypic quality) females with heated nests increased egg temperatures and maintained incubation constancy, while later-laying (lower quality) heated females increased incubation constancy. Changes in egg temperature were due to changes in female behaviour and not due directly to increases in internal nest-box temperatures. 4Behaviour during the incubation period affected hatching asynchrony. Decreased variation in egg temperature led to lower levels of hatching asynchrony, which was also generally lower in heated nests. 5Our study finds strong support for the prediction that intermittent incubators set their incubation investment at levels dictated by energetic constraints. Furthermore, females incubating in heated boxes allocated conserved energy primarily to increased egg temperature and increased incubation attentiveness. These results indicate that studies investigating the role of energetics in driving reproductive investment in intermittent incubators should consider egg temperature and individual variation more explicitly. [source] Are parental care trade-offs in shorebirds driven by parental investment or sexual selection?JOURNAL OF EVOLUTIONARY BIOLOGY, Issue 4 2009V. A. OLSON Abstract Sexual selection, mating systems and parental behaviour are closely linked, although the exact nature of their relationship is controversial. The parental investment hypothesis (PIH) states that parental care disparity drives sexual selection intensity, because the sex providing less care competes for the sex that provides more. In contrast, the sexual selection hypothesis (SSH) asserts that more intense sexual selection on males leads to reduced male parental investment. We tested these hypotheses using directional phylogenetic comparative methods in shorebirds, which have an unusually diverse array of breeding systems. Changes in parental care and sexual selection intensity were tightly correlated, and we carried out three sets of analyses focusing on changes in male behaviour, female behaviour and in either sex. The results from the analyses were consistent with both PIH and SSH, although the patterns in male transition were sensitive to model values. We propose two explanations for these results. First, phylogenetic transitions may be idiosyncratic so that they depend on the ecological circumstances of individual species. Second, transitions in social traits, such as breeding systems, may be rapid and take place in ecological time, so directional phylogenetic methods that work through longer time scales may not infer accurately the timing and direction of all changes. [source] Hofmannsthal, Elektra and the Representation of Women'sBehaviour Through MythGERMAN LIFE AND LETTERS, Issue 1 2000Philip Marshall Ward In Elektra Hofmannsthal created a drama more of its time than he cared to admit, but he concealed this specificity in the ,eternal' materials of myth. The play came into being in response to the promptings of a director (Max Reinhardt) and an actress (Gertrud Eysoldt). Contemporaries received the play as a revision, either for good or bad, of accepted ideas of the Greeks. In a climate which identified a parallel between the ,cathartic' effect of Greek tragedy and the ,cathartic' treat-ment of hysteria in the new psychoanalysis, Elektra was readily understandable as an ,hysteric'. Hofmannsthal does not present her specifically as such but participates in a fin de siécle trend to use hysteria as a synecdoche for female behaviours which challenged the status quo. Hofmannsthal's own attitudes to women imply an anxiety about counter-cultural behaviour which, in Elektra, he mediates through two literary precedents: Sophocles's Electra and Goethe's Iphigenie auf Tauris. The article concludes by illustrating how Hofmannsthal constructs Elektra's behaviour as ,improper'. [source] | |||||||||||||