Females can solve the problem of low signal reliability by assessing multiple male traits.

Male signals that provide information to females about mating benefits are often of low reliability. It is thus not clear why females often express strong signal preferences. We tested the hypothesis that females can distinguish between males with preferred signals that provide lower and higher quality direct benefits. In the field cricket, Gryllus lineaticeps, females usually prefer higher male chirp rates, but chirp rate is positively correlated with the fecundity benefits females will receive from males only for males that have experienced low quality diets. We paired females with muted males that were maintained on low or high nutrition diets, during the interactions we broadcast a replacement high chirp rate, and we observed whether females mated with the assigned male. Females were more likely to mate when paired with low nutrition males. These results suggest that females have evolved assessment mechanisms that allow them distinguish between males with preferred signals that provide high quality benefits (low nutrition males with high chirp rates) and males with preferred signals that provide low quality benefits (high nutrition males with high chirp rates).

Spontaneous male death and monogyny in the dark fishing spider.

Monogyny (male monogamy) is found in a diverse assemblage of taxa, and recent theoretical work reveals that a male-biased sex ratio can favour the evolution of this relatively rare mating system. We integrate this theoretical framework with field observations and laboratory experiments involving the sexually size dimorphic fishing spider, Dolomedes tenebrosus, to test the prediction that this species exhibits monogyny. Field surveys revealed a male-biased sex ratio, likely resulting from different life-history strategies (early male maturation). Results from mating trials supported our prediction of monogyny as we discovered that males mate with a single female. Unexpectedly, however, we observed that mating results in obligate male death and genital mutilation. Additional field observations of released individuals suggest that males are not limited by their ability to encounter additional females. Controlled laboratory assays demonstrated that males discriminate among virgin and non-virgin female silk cues, consistent with predictions of first-male sperm precedence. In summary, we report a novel case of male self-sacrifice in a species that exhibits female-biased sexual size dimorphism, male-biased sex ratio, genital mutilation and a suggestion of first-male sperm precedence; all of which are consistent with theoretical predictions of the evolution of monogyny.

Pregnancy outcomes in women with Ebstein's anomaly: data from the Registry of Pregnancy And Cardiac disease (ROPAC).

OBJECTIVE: Ebstein's anomaly is a rare congenital cardiac condition and data regarding pregnancy outcomes in this patient group are scarce. We evaluated the maternal and perinatal risks of pregnancy in 81 women with Ebstein's anomaly. METHODS: The Registry of Pregnancy and Cardiac disease is a prospective global registry of pregnancies in women with structural cardiac disease. Pregnancy outcomes in women with Ebstein's anomaly were examined. The primary outcome was the occurrence of a major adverse cardiac event (MACE) defined as maternal mortality, heart failure, arrhythmia, thromboembolic event or endocarditis. Secondary endpoints were obstetric and perinatal outcomes and the influence of pregnancy on tricuspid valve regurgitation as well as right atrial and ventricular dimensions. RESULTS: In the 81 women with Ebstein's anomaly (mean age 29.7±6.1 years, 46.9% nulliparous), MACE occurred in 8 (9.9%) pregnancies, mostly heart failure (n=6). There were no maternal deaths. Prepregnancy signs of heart failure were predictive for MACE. Almost half of the women were delivered by caesarean section (45.7%) and preterm delivery occurred in 24.7%. Neonatal mortality was 2.5% and 4.9% of the infants had congenital heart disease. In the subgroup in which prepregnancy and postpregnancy data were available, there was no difference in tricuspid valve regurgitation grade or right atrial and ventricular dimensions before and after pregnancy. CONCLUSIONS: Most women with Ebstein's anomaly tolerate pregnancy well, but women with prepregnancy signs of heart failure are at higher risk for MACE during pregnancy and should be counselled accordingly.

Tradeoffs limit the evolution of male traits that are attractive to females.

Tradeoffs occur between a variety of traits in a diversity of organisms, and these tradeoffs can have major effects on ecological and evolutionary processes. Far less is known, however, about tradeoffs between male traits that affect mate attraction than about tradeoffs between other types of traits. Previous results indicate that females of the variable field cricket, Gryllus lineaticeps, prefer male songs with higher chirp rates and longer chirp durations. In the current study, we tested the hypothesis that a tradeoff between these traits affects the evolution of male song. The two traits were negatively correlated among full-sibling families, consistent with a genetically based tradeoff, and the tradeoff was stronger when nutrients were limiting. In addition, for males from 12 populations reared in a common environment, the traits were negatively correlated within populations, the strength of the tradeoff was largely invariant across populations, and the within-population tradeoff predicted how the traits have evolved among populations. A widespread tradeoff thus affects male trait evolution. Finally, for males from four populations assayed in the field, the traits were negatively correlated within and among populations. The tradeoff is thus robust to the presence of environmental factors that might mask its effects. Together, our results indicate there is a fundamental tradeoff between male traits that: (i) limits the ability of males to produce multiple attractive traits; (ii) limits how male traits evolve; and (iii) might favour plasticity in female mating preferences.

Influencing Exercise and Hydration Self-Care Practices of Baccalaureate Nursing Students.

PURPOSE: Health promotion is often neglected by students during their nursing education, yet research indicates that self-care practices can significantly reduce compassion fatigue and burnout. An intervention study investigated strategies to increase exercise and hydration in baccalaureate nursing students. METHOD: Using a convenience sample ( n = 73), data were collected through pre- and postsurveys of nursing students participating in an 8-week period that focused on strategies to increase walking and drinking water. FINDINGS: Several significant trends emerged from the study participants ( n = 21). Younger (18-25 years) students perceived their health status as excellent to good, while older (26-50+ years) students viewed their health status as fair to poor. Although no significant difference in exercise occurred between pre- and postsurvey, a trend of an increase in frequency was noted. A dramatic increase of nearly 16 ounces in water consumption was reported on both clinical ( p = .032) and nonclinical ( p = .028) days. The findings are supported by Pender's health promotion model concept of self-efficacy. CONCLUSION: The frequency of exercise and amount of hydration increased during the 8-week intervention period. Despite a small sample size and short intervention period, results merit further research on the positive influences of self-care practices in nursing students.

The relative importance of different direct benefits in the mate choices of a field cricket.

Discussions about the evolution of female mating preferences have often suggested that females should express multiple strong preferences when different male traits are correlated with different mating benefits, yet few studies have directly tested this hypothesis by comparing the strength of female preferences for male traits known to be correlated with different benefits. In the variable field cricket, Gryllus lineaticeps, females receive fecundity and fertility benefits from mating with males with higher chirp rates and life-span benefits from mating with males with longer chirp durations. Although females prefer higher chirp rates and longer chirp durations when the other trait is held constant, it is possible that they give priority to one of these song traits when both vary. In this study, we examined the relative importance of chirp rate and chirp duration in female mate choice using single-stimulus presentations of songs that varied in both chirp rate and chirp duration. Females expressed both directional and stabilizing preferences based on chirp rate, responding most strongly to a chirp rate approximately one standard deviation above the population mean. Females did not express preferences based on chirp duration, and did not express correlational preferences. These results suggest that females may give priority to the reproductive benefits provided by males that produce higher chirp rates.

Males Can Benefit from Sexual Cannibalism Facilitated by Self-Sacrifice.

In a number of species, males are cannibalized by females after mating (reviewed in [1, 2]), and some males actually appear to facilitate their own cannibalism (reviewed in [3]). Such self-sacrifice can evolve if being eaten sufficiently enhances either fertilization success (mating effort) or offspring number or fitness (paternal effort). While there is some support for the mating-effort hypothesis, few studies have found support for paternal effort. We used two experiments to test the paternal-effort hypothesis in the dark fishing spider, Dolomedes tenebrosus. Males of this species provide themselves as a material contribution: they spontaneously die during copulation and are subsequently eaten by females. In support of the paternal-effort predictions, when females were allowed to consume their mating partner, we found large and significant increases in (1) the number, (2) the size, and (3) the survivorship of the offspring. Similar benefits were not seen when females were allowed to consume a cricket in lieu of a male, suggesting that it is the consumption of the male's body per se that is responsible for these fitness benefits. Together, our results suggest that D. tenebrosus males can benefit from self-sacrifice behavior through paternal effort. Such behavior may be particularly likely to evolve when high rates of postcopulatory cannibalism trap males into investing in their first mate instead of investing in acquiring additional matings and/or if strong first-male sperm precedence reduces the benefits of both investing in additional matings and paternity protection.

Along came a spider who sat down beside her: Perceived predation risk, but not female age, affects female mate choosiness.

Organisms often exhibit behavioral plasticity in response to changes in factors, such as predation risk, mate density, and age. Particularly, female mate choosiness (the strength of female's attraction to male traits as they deviate from preferred trait values) has repeatedly been shown to be plastic. This is due to the costs associated with searching for preferred males fluctuating with changes in such factors. Because these factors can interact naturally, it is important to understand how female mate choosiness responds to these interactions. We studied the interaction between perceived predation risk and female age on the variable field cricket, Gryllus lineaticeps. Females were either exposed or not exposed to predation cues from a sympatric, cursorial, wolf spider predator, Hogna sp. We then tested the females at one of three adult ages and measured their choosiness by recording their responsiveness to a low quality male song. We found female choosiness plasticity was affected by neither age nor the interaction between age and perceived predation risk. Perceived predation risk was the only factor to significantly affect the plasticity of female mate choosiness: females were less choosy when they perceived predation risk and were more choosy when they did not. Predation may be such a strong source of selection that, regardless of differences in other factors, most individuals respond similarly.

Female life span and fertility are increased by the ejaculates of preferred males.

In animals with internal fertilization, sperm competition among males can favor the evolution of male ejaculate traits that are detrimental to females. Female mating preferences, in contrast, often favor traits in males that are beneficial to females, yet little is known about the effect of these preferences on the evolution of male ejaculates. A necessary condition for female preferences to affect the evolution of male ejaculate characteristics is that females select mates based on a trait correlated with ejaculate quality. Previous work has shown that females of the variable field cricket, Gryllus lineaticeps, prefer males that produce calling songs containing faster and longer chirps. In this study, we tested the hypothesis that females receive more beneficial ejaculates from preferred males. Females were placed on either a high- or a reduced-nutrition diet then mated twice to a male of known song phenotype. Females received only sperm and seminal fluid from males during these matings. There was no effect of male song phenotype on any fitness component for females on the high-nutrition diet. Reduced-nutrition females mated to males that produced preferred song types, however, lived longer, produced more eggs, produced more fertile eggs, and had a higher proportion of their eggs fertilized than those mated to other males. The life-span benefit was positively associated with male chirp duration, and the reproductive benefits were positively associated with male chirp rate. We explored two possible mechanisms for the life span and reproductive benefits. First, a path analysis suggested that part of the effect of male chirp duration on female life span may have been indirect; females mated to males that produced longer chirps showed delayed oviposition, and females that delayed oviposition lived longer. Males that produce longer chirps may thus transfer fewer or less potent oviposition stimulants to females in their seminal fluid. Second, there was a positive correlation between male chirp rate and the number of sperm transferred to females. The fertility benefit may thus have resulted from females receiving more sperm from males that produce faster chirps. Finally, there was a negative phenotypic correlation between male chirp rate and chirp duration, suggesting that females may have to trade off the life span and reproduction benefits when selecting a mate.

Parasitoid infestation changes female mating preferences.

Females often adjust their mating preference to environmental and social conditions. This plasticity of preference can be adaptive for females and can have important consequences for the evolution of male traits. While predation and parasitism are widespread, their effects on female preferences have rarely been investigated. Females of the cricket Gryllus lineaticeps are parasitized by the parasitoid fly Ormia ochracea. Infestation with fly larvae substantially reduces female life span and thus reproductive opportunities of the cricket. Both female G. lineaticeps and flies orient to male song and both prefer male songs with faster chirp rates to songs with slower chirp rates. We tested the effect of parasitic infestation on female responsiveness to male song and female chirp rate preferences. The proportion of individuals responding to male songs did not differ between infested and control females. Control females preferred intermediate chirp rates to slow chirp rates and did not discriminate between fast and intermediate chirp rates. In contrast, infested females showed no preferences in the choice trials, indicating reduced chirp rate selectivity. This plasticity in female preferences may be adaptive; parasitized females may have a higher probability of reproducing before they are killed by the parasitoids if they are less selective (i.e. there will be a larger pool of males considered acceptable). The change in preferences suggests relaxed selection on male chirp rate during times of parasitism.

Eavesdropping parasitoids do not cause the evolution of less conspicuous signalling behaviour in a field cricket.

Males of many species produce conspicuous mating signals to attract females, but these signals can also attract eavesdropping predators and parasites. Males are thus expected to evolve signalling behaviours that balance the sexual selection benefits and the natural selection costs. In the variable field cricket, Gryllus lineaticeps, males sing to attract females, but these songs also attract the lethal parasitoid fly Ormia ochracea. The flies use male crickets as hosts for their larvae, primarily search for hosts during a 2 h period following sunset and prefer the same song types as female crickets. We tested whether males from high-risk populations reduce the risk of parasitism by singing less frequently or by shifting their singing activity to a time of the night when the risk of parasitism is low. We compared male singing activity and its temporal pattern between six high-risk and six low-risk populations that were reared in a common environment. There was no effect of parasitism risk on either total male singing activity or the temporal pattern of male singing activity. Males from high-risk populations thus sang as frequently as males from low-risk populations. These results suggest that sexual selection on male singing behaviour may be substantially stronger in high-risk populations than in low-risk populations. It is possible that other traits may have evolved to reduce parasitism risk without compromising mate attraction.

Costly signals in a field cricket can indicate high- or low-quality direct benefits depending upon the environment.

The handicap hypothesis proposes that male signals provide reliable information to females because only males of high condition provide high-quality mating benefits and can afford the costs of producing attractive signals. In the context of direct benefits, the handicap hypothesis predicts that benefit quality and signal attractiveness will positively covary among genotypes, positively covary among environments, or be affected by congruent genotype-environment interactions. The latter should occur if the relative condition of a genotype is environment-dependent. We tested these predictions in the variable field cricket, Gryllus lineaticeps. An interaction between male family and nutritional environment affected the expression of a costly signal preferred by females, while only male family affected direct benefit quality. These noncongruent effects of family and nutritional environment are inconsistent with the handicap hypothesis, and appear to have resulted from variation among nutritional environments in the relationship between signal attractiveness and benefit quality. Surprisingly, signal attractiveness was positively correlated with benefit quality when males experienced a low nutrition environment but negatively correlated with benefit quality when males experienced a high nutrition environment. As a result, female choice for direct benefits may be difficult, particularly in heterogeneous environments, unless females can assess the environmental histories of males.

Female field crickets incur increased parasitism risk when near preferred song.

Female animals often prefer males with conspicuous traits because these males provide direct or indirect benefits. Conspicuous male traits, however, can attract predators. This not only increases the risk of predation for conspicuous males but also for the females that prefer them. In the variable field cricket, Gryllus lineaticeps, males that produce preferred song types provide females with greater material benefits, but they are also more likely to attract lethal parasitoid flies. First, we conducted a field experiment that tested the hypothesis that females have a greater risk of fly parasitism when in association with preferred high chirp rate males. Females were nearly twice as likely to be parasitized when caged with high chirp rate song than when caged with low chirp rate song. Females may thus be forced to trade off the quality of the benefits they receive from mating with preferred males and the risk of being killed by a predator when near these males. Second, we assessed female parasitism rates in a natural population. Up to 6% of the females were parasitized in field samples. Because the females we collected could have become parasitized had they not been collected, this provides a minimum estimate of the female parasitism rate in the field. In a laboratory study, we found no difference in the proportion of time parasitized and unparasitized females spent hiding under shelters; thus, differences in activity patterns do not appear to have biased our estimate of female parasitism rates. Overall, our results suggest that female association costs have the potential to shape the evolution of female mating preferences.

False promises: females spurn cheating males in a field cricket.

Females commonly prefer to mate with males that provide greater material benefits, which they often select using correlated male signals. When females select higher-benefit males based on correlated signals, however, males can potentially deceive females by producing exaggerated signals of benefit quality. The handicap mechanism can prevent lower-quality males from producing exaggerated signals, but cannot prevent cheating by higher-quality males that choose to withhold the benefit, and this poses a major problem for the evolution of female choice based on direct benefits. In a field cricket, Gryllus lineaticeps, females receive seminal fluid products from males with preferred songs that increase their fecundity and lifespan. We tested the hypothesis that female behaviour penalizes males that provide lower-quality benefits. When females were paired with males that varied in benefit quality but had experimentally imposed average songs, they were less likely to re-mate with males that provided lower-quality benefits in the initial mating. This type of conditional female re-mating may be a widespread mechanism that penalizes males that cheat on direct benefits.

Genetic variation in maternal investment patterns in platyfish Xiphophorus maculatus.

Maternal investment in offspring is constrained by a variety of trade-offs, and the investment pattern expressed by an individual can have important fitness consequences. The authors investigate two maternal investment tradeoffs in the southern platyfish, Xiphophorus maculatus: investment in offspring size versus number, and investment in sons versus daughters. Variation in maternal age and size often confound measurements of investment patterns. Because allelic variation at a single locus in platyfish has a major effect on age and size at sexual maturation, investment patterns within a single age and size genotype could be examined, minimizing the influence of these factors on investment patterns. In addition, the platyfish sex determination system allows experimental investigation of relative investment in sons and daughters because different mating types produce different brood sex ratios. Total investment in broods did not differ among sibships, but the investment pattern did; some produced larger but fewer offspring, whereas others produced smaller but more offspring. In addition, there was no evidence of differential investment in sons and daughters; broods with all sons did not differ in size or weight from broods with an equal proportion of the sexes. This result provides direct support for the assumption of equal investment in sons and daughters that is common in discussions of sex-ratio evolution and sex allocation.