Do male guppies distinguish virgin females from recently mated ones?

In some mating systems males should benefit from mating with virgin females because of their higher reproductive value. We determined experimentally whether and how males distinguish between virgin and recently mated females in the guppy, Poecilia reticulata, a promiscuous livebearer. In a free-swimming experiment, males showed flexible mating behaviour by adjusting their tactics according to the mating status of the female they encountered, virgin or mated. Males followed, nipped and copulated with virgins more than with mated females, but they performed more sneaky copulations with mated females, possibly because the latter were more reluctant to mate than virgin females. When, in another set of experiments, males received only the visual cues of both virgins and mated females they showed no preference for either, but when they were exposed only to the female olfactory cues, they associated considerably more with the smell of virgin females. These results suggest that male guppies assess female behavioural and olfactory cues to determine female virginity and then use different mating tactics depending on the female's status. It is possible that the changes in male mating behaviour increase male reproductive success.

Discourse of conscience in the assessment of voluntary assignments in equity

This article examines the continuing suitability of the existing Australian test for determining when a voluntary assignment of legal property has passed in equity. It suggests that the current test, which focuses upon the ‘completion’ by the donor of the all the necessary transfer formalities, and the underlying equitable maxims that support it, should be revised to better reflect the dual concerns of assignment and constructive trust. The article reviews the English authorities, in particular the English Court of Appeal in Pennington v Waine, which held that the equitable jurisdiction can validate a voluntary assignment of legal property where, in the circumstances, it would be unconscionable to allow the donor to resile. It is argued that this approach represents an appropriate progression because it provides greater scope for a particularised examination of the intention, circumstances and behaviour surrounding the purported assignment. A test which encourages greater contextual examination of the overall circumstances underlying the assignment process is consistent with the core expectations of equitable methodology. It supports the multi-layered process of determining whether a donor intended the assignment and further, whether that donor should be held liable as constructive trustee.

Rethinking ethics review as institutional discourse

In this article, the authors trace the emergence of an institutional discourse of ethical research and interrogate its effects in constituting what ethical research is taken to be and how ethical researchers are configured. They illuminate the dissonance between this regime of truth and research practice and the implications for the injunction to respect others, illustrating their case with instances from their interview study with anorexic teenage girls. The authors propose that conceptualising the regulation of research ethics as an institutional discourse opens up the possibility for asserting counterdiscourses that place relational ethics at the center of moral decision making in research.

Vocal mimicry in male bowerbirds : who learns from whom?

Vocal mimicry is one of the more striking aspects of avian vocalization and is widespread across songbirds. However, little is known about how mimics acquire heterospecific and environmental sounds. We investigated geographical and individual variation in the mimetic repertoires of males of a proficient mimic, the spotted bowerbird Ptilonorhynchus maculatus. Male bower owners shared more of their mimetic repertoires with neighbouring bower owners than with more distant males. However, interbower distance did not explain variation in the highly repeatable renditions given by bower owners of two commonly mimicked species. From the similarity between model and mimic vocalizations and the patterns of repertoire sharing among males, we suggest that the bowerbirds are learning their mimetic repertoire from heterospecifics and not from each other.

Mating effort and female receptivity : how do male guppies decide when to invest in sex?

Males vary in the degree to which they invest in mating. Several factors can explain this variation, including differences in males’ individual condition and the fact that males allocate their energy depending on the context they face in each mating attempt. Particularly, female quality affects male reproductive success. Here, we studied whether male guppies (Poecilia reticulata) strategically allocated more mating effort, in terms of mating behaviour and male–male competition, when they were matched with a receptive (R) female than a non-receptive one. In accordance with our prediction, we found that males increased their mating behaviour when they were with a receptive female. Even though male guppies can inseminate non-receptive females, we only found high levels of courtship between males that were with a receptive female rather than a non-receptive one. Although there was little affect of female receptivity on male–male competition, we found that males chased and interrupted courtships more with receptive females than with non-receptive females regardless of odour. Finally, we also studied whether the sexual pheromone produced by receptive female guppies is a cue that males use in order to increase their mating effort. We found that males were more attracted to a female when they perceived the sexual pheromone, but only increased their mating and aggressive behaviours when females showed receptive behaviour. This strategic increase in mating effort could result in higher male reproductive success because mating attempts towards receptive females are likely to be less costly and males could have a greater probability of fertilisation.

Male mate-searching strategies and female cues: how do male guppies find receptive females?

Locating potential mates is critical to mating. We studied males’ association with females and mate-searching patterns in the guppy, Poecilia reticulata, a promiscuous live-bearer. In the field, we examined whether male guppies respond differently to a shoal of conspecific fish based on the members of the shoal. We found that more males were attracted to shoals that contained receptive females than to shoals of nonreceptive females or males. We also conducted laboratory experiments to investigate how males use olfactory cues of nonreceptive and receptive females to search for and associate with females. We gave males the option to associate with nonreceptive females when olfactory cues of receptive or nonreceptive females were present and absent, and when olfactory cues were presented alone. Males associated with females most strongly when both cues were presented simultaneously, but when cues were presented separately males’ association with females differed with respect to the olfactory cues that were added. Males associated with females equally with visual and olfactory cues presented separately when the odour cues were from receptive females. However, when the odour cues were from nonreceptive females, males associated with females less with olfactory than visual cues. Searching activity increased when males had access only to olfactory cues. Taken together these results suggest that olfactory cues influence males’ association with females and searching behaviour, and these changes in behaviour are likely to maximize a male’s opportunity to encounter receptive females.

Religion, faith and the empowerment process : stories of Iranian people with diabetes

Empowerment concerning people with diabetes is well researched. However, few researchers specifically focus on the barriers to and facilitators of empowerment in Iranian people with diabetes. Understanding the factors could help health professionals facilitate self-empowerment more effectively. This study aims to determine the barriers to and facilitators of empowerment in Iranian people with diabetes. A qualitative exploratory study was conducted using in-depth interviews to collect the data from 11 women and men in 2007. Themes were identified using constant comparative analysis method. Common barriers to empowerment were similar to other chronic diseases: prolonged stress, negative view about diabetes, ineffective health-care systems, poverty and illiteracy. Diabetes education, fear of diabetes’ complications, self-efficacy and hope for a better future emerged as being crucial to empowerment. Facilitators specific to Iranians were: the power of religion and faith, the concept of the doctor as holy man, accepting diabetes as God’s will, caring for the body because it was God’s gift and support from families especially daughters. Empowerment was strongly influenced by cultural and religious beliefs in Iran and the power of faith emerged as an important facilitator of diabetes empowerment. The findings will help health professionals understand how Iranian people with diabetes view life and the factors that facilitate empowerment.

Frequency of Anti-HBc & HBV DNA detection in blood donors of Kerman province, Iran

Hepatitis B is a serious global infection disease and a major cause of mortality and morbidity worldwide. However, data on Occult Hepatitis B in Iran are scare. The current study assessed the frequency of Anti-HBc and HBV DNA in serum sample of healthy blood donors negative for HBsAg stratified by sex and age; and also investigated the relationship between detection of HBV-DNA and anti-HBc positivity. Since anti-HBc screening is not performed in Iranian Blood Bank, we assessed whether anti-HBc could be adopted as a screening assay for the donated blood. The study included a total of 1525 blood samples of blood donors negative for hepatitis B virus surface antigen ( 87% male with a mean age ± SD: of 31±8yr; and 13% female with a mean age ± SD of 30±6yr). Eight percent (121 out of 1525) of the blood samples with negative HBs-Ag were positive for Anti-HBc and were all from males. HBV-DNA was detected in 36 out of 121 anti-HBc+ specimens (29.7%). The study found a positive relation between anti-HBc positivity and detection of HBV-DNA in serum samples of HBs-Ag negative blood donors. Findings from this study suggest that, introducing anti HBc screening in Iran maybe very practical in order to limit the transmission risk of Occult Hepatitis B virus through blood transfusion.

Strategic male signalling effort in a desert-dwelling fish

Males often use elaborate courtship displays to attract females for mating. Much attention, in this regard, has been focused on trying to understand the causes and consequences of signal variation among males. Far less, by contrast, is known about within-individual variation in signal expression and, in particular, the extent to which males may be able to strategically adjust their signalling output to try to maximise their reproductive returns. Here, we experimentally investigated male courtship effort in a fish, the Australian desert goby, Chlamydogobius eremius. When offered a simultaneous choice between a large and a small female, male gobies spent significantly more time associating with, and courting, the former, probably because larger females are also more fecund. Male signalling patterns were also investigated under a sequential choice scenario, with females presented one at a time. When first offered a female, male courtship was not affected by female size. However, males adjusted their courtship effort towards a second female depending on the size of the female encountered previously. In particular, males that were first offered a large female significantly reduced their courtship effort when presented with a subsequent, smaller, female. Our findings suggest that males may be able to respond adaptively to differences in female quality, and strategically adjust their signalling effort accordingly.

The interval between sexual encounters affects male courtship tactics in a desert-dwelling fish

Courtship displays are often important in determining male mating success but can also be costly. Thus, instead of courting females indiscriminately, males might be expected to adjust their signalling effort strategically. Theory, however, predicts that such adjustments should depend on the rate with which males encounter females, a prediction that has been subject to very little empirical testing. Here, we investigate the effects of female encounter rate on male courtship intensity by manipulating the time interval between sequential presentations of large (high quality) and small (low quality) females in a fish, the Australian desert goby Chlamydogobius eremius. Males that were presented with a small female immediately after a large female reduced their courtship intensity significantly. However, males courted large and small females with equal intensity if the interval between the sequential presentations was longer. Our results suggest that mate encounter rate is an important factor shaping male reproductive decisions and, consequently, the evolutionary potential of sexual selection.

Bcp1, a gene required for male fertility in Arabidopsis

Male fertility in flowering plants is dependent on production of viable pollen grains within the anther. Genes expressed exclusively in the anther are likely to include those that control male fertility. On the basis of their tissue specificity, such genes have been isolated, yet in none of them has this function been demonstrated. Here we report that one such gene, Bcp1, is active in both diploid tapetum and haploid microspores and is required for pollen fertility. Perturbation of this gene in either tapetum or microspores prevents production of fertile pollen in transgenic Arabidopsis plants. When tapetum expression of this gene is perturbed, mature anthers contain dead shriveled pollen. On the other hand, when microspore expression is perturbed, anthers show 1:1 segregation of viable/aborted pollen. These findings identify a class of sporophytic/gametophytic genes controlling male fertility and, hence, reproduction in flowering plants.

Genetic control of male fertility in Arabidopsis thaliana : structural analysis of postmeiotic developmental mutants

Seven new male-sterile mutants (ms7–ms13) of Arabidopsis thaliana (L.) Heynh. (ecotype columbia) are described that show a postmeiotic defect of microspore development. In ms9 mutants, microspores recently released from the tetrad appear irregular in shape and are often without exines. The earliest evidence of abnormality in ms12 mutants is degeneration of microspores that lack normal exine sculpturing, suggesting that the MS12 product is important in the formation of pollen exine. Teratomes (abnormally enlarged microsporocytes) are also occasionally present and each has a poorly developed exine. In ms7 mutant plants, the tapetal cytoplasm disintegrates at the late vacuolate microspore stage, apparently causing the degeneration of microspores and pollen grains. With ms8 mutants, the exine of the microspores appears similar to that of the wild type. However, intine development appears impaired and pollen grains rupture prior to maturity. In ms11 mutants, the first detectable abnormality appears at the mid to late vacuolate stage. The absence of fluorescence in the microspores and tapetal cells after staining with 4′,6-diamidino-2-phenylindole (DAPI) and the occasional presence of teratomes indicate degradation of DNA. Viable pollen from ms10 mutant plants is dehisced from anthers but appears to have surface abnormalities affecting interaction with the stigma. Pollen only germinates in high-humidity conditions or during in-vitro germination experiments. Mutant plants also have bright-green stems, suggesting that ms10 belongs to the eceriferum (cer) class of mutants. However, ms10 and cer6 are non-allelic. The ms13 mutant has a similar phenotype to ms10, suggesting is also an eceriferum mutation. Each of these seven mutants had a greater number of flowers than congenic male-fertile plants. The non-allelic nature of these mutants and their different developmental end-points indicate that seven different genes important for the later stages of pollen development have been identified.