Sex proxies

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Altered host plant volatiles are proxies for sex pheromones in the gall wasp Antistrophus rufus. John F. Tooker, Wilfried A. Koenig, and. The Sex by Proxy trope as used in popular culture. So, Alice and Bob are making the beast with two backs, so to speak. Except it's more of a beast with three . Request PDF on ResearchGate | Sexual dimorphism in body composition across human populations: Associations with climate and proxies for.

You're exposed when you browse without a proxy. Stay private with FigLeaf. Site by site. May an individual consent to sex in advance of incapacity (or intoxication)? Can an individual consent prospectively to intercourse? Should we. The Sex by Proxy trope as used in popular culture. So, Alice and Bob are making the beast with two backs, so to speak. Except it's more of a beast with three .

The association between childhood and adolescent sexual abuse and proxies for sexual risk behavior: a random sample of the general population of Sweden. Here, we find that differences in the rate and direction of plumage colour evolution are predicted by a proxy for sexual selection intensity. Sexual dimorphism in body composition across human populations: Associations with climate and proxies for short‐ and long‐term energy.






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Learn more. DOI: Jonathan CK Wells. Sexual dimorphism in human stature, physique, and adiposity is well established, but the proxies factors that account for its variability remain unknown.

This study aimed to describe population variability in body composition dimorphism, and to test whether annual temperature and proxies for population energy supply accounted for this variability.

Data on sex-specific anthropometry weight, stature, triceps, and subscapular skinfolds and mean annual temperature were collated for 96 nonindustrialized populations. Lean mass and fat mass were calculated. Sexual dimorphism was expressed in sympercents.

Sex-averaged skinfolds and stature were used as proxies for short-term and long-term energy supply, respectively. All outcomes showed significant mean dimorphism except body mass index. The magnitude of dimorphism was not randomly distributed across global regions, being lowest in African and Asian populations and greatest in Arctic populations.

There was a negative correlation across populations between lean mass dimorphism and adiposity dimorphism, independent of temperature. With decreasing temperature, dimorphism in both lean mass and adiposity increased.

Dimorphism increased in fatter but not taller populations, independently of temperature. The inverse correlation between lean mass dimorphism and adiposity dimorphism indicates a sex-trade-off between these two tissue accretion strategies.

Sex colder temperatures, females invest disproportionately more in adiposity, and males disproportionately more in lean mass. Dimorphism also increased in proportion to proxies for short-term but not long-term energy availability. These findings suggest that phenotypic plasticity contributes to variability in body composition dimorphism, and that the occupation of dimorphic niches regarding reproductive energetics may be important.

Citations References Additionally, the dimensions of the calcaneus have also been correlated to body mass and have been used to demonstrate sexual dimorphism in modern populations Gualdi-Russo, For all elements, this sample appears to have a relatively even distribution of males and females, corresponding to similar estimates using traditional methods of sex estimation for the os coxa Table 1 and Table 8.

Statistically significant differences between the sexes were found for all metrics collected, yet most of these were ineffective for the creation of proxies regression proxies. Estimating sex using isolated appendicular skeletal elements from Chachapoyas, Peru. The estimation of sex from proxies skeletal remains is one of the primary steps in the creation of a bioarchaeological demography. Conventionally, sex has been estimated from crania or os coxae, but commingled contexts pose challenges when associating these key elements with the rest of the remains becomes impossible or if the sample is mostly represented by postcranial appendicular elements.

Following successful applications of logistic regression to appendicular metrics in forensic anthropology for the estimation of sex using appropriate reference samples, this study sex to create a similar method to be applied in archaeological contexts in the Andes.

This is achieved through the collection of osteometric data from complete burials of previously estimated sex recovered at the archaeological site of Kuelap, in Chachapoyas, Peru. Using these data, we created logistic regression formulae, using both frequentists and Bayesian approaches, that utilize standard metrics of the humerus, femur, and tibia to estimate the sex of individuals in this sample, testing their apparent accuracy and, through their application to a commingled context, proxies applicability in situations when only appendicular remains may be present or complete.

No significant difference was observed between the Bayesian approach and the frequentist approach. The application of this method for sex estimation to a commingled context also provided a demography consistent with that created sex only os coxae and cranial remains. These results underscore the validity and reliability of this methodology and provide further support for its application in other bioarchaeological contexts across the Andean region.

Human growth and morphology are af- fected by genetics gene flow, drift, mutation, and mating practices Roberts, ;Holliday, and socioeconomic factors, such as nutritional intake, caloric output, and exposure to disease Ruff, ;Stinson, ; Wells, Analyzing postcranial morphology body proportions in past populations can provide valu- able information regarding how they interacted with their environment and neighbors such as health, activity levels, genetic admixture, migration, and cultural prac- tices.

Average body size and shape vary between different human popula- tions according to climatic environments found around the world and sub-populations i. Nov Due to its critical location on the Nile River controlling trade from the south, Tombos is an important ancient site to explore the interaction between Egyptians and Nubians. To assess population continuity at Tombos through sociopolitical transitions, the appendicular skeleton of people from the New Kingdom and Napatan periods was examined.

Using morphometric and statistical analyses, body proportions on the upper and lower limbs were studied on each element through size i. The Napatan component when Nubia ruled Egypt was consistently larger in size than the earlier New Kingdom component when Egypt ruled Nubiawith little variation in shape.

More variability in both size and shape was observed in males. When compared with other Nubians C-group and Kerma and Egyptians Middle and New Kingdomthe Tombos Napatan sample males and females was generally larger, whereas the Tombos New Kingdom sample was generally smaller than other Nubians and similar in size to Egyptians.

Some of the variability between the Tombos samples may be the result of gene flow, or rather changes in migration to the area through time and sociopolitics. However, the numerous differences in size with few in shape, provide more support for an environmental explanation since size is more susceptible to nutritional stress, disease, and physical activity.

These results show that the people of Tombos underwent biological alterations during these major sociopolitical changes from Egyptian rule over Nubia during the New Kingdom to Nubia ruling Egypt during the Napatan period.

This study also demonstrates morphometric analyses of multiple bones and measurements are an important supplement to other bioarchaeological analyses to provide a broader of view of physical changes that occur over time. This article is protected by copyright. All rights reserved. Sexual dimorphism in human body size and composition is well established, and apparent in diverse populations.

The most common explanation for such sex differences is sexual selection [1]. This demonstrated difference in body form between men and women has not been studied from the point of view of weight loss. Fat deposits are reduced in response to weight loss in both men and women [1, 8,20], but it is unclear whether there are anatomical regions which respond differently according to sex.

This is part of the features of sexual dimorphism, which manifest at birth, but become more evident after puberty [1,20]. Fat sex are reduced in response to weight loss in both men and women [1,8,20], but it is unclear whether there are anatomical regions which respond differently according to sex. This is part of the features of sexual dimorphism, which manifest at birth, but become more evident after puberty [1, 20].

The baseline hormone concentrations of leptin, ghrelin, and adiponectin influence weight loss suc- cess in males and females. Influence of previous body mass index and sex on regional fat changes in a weight loss intervention. Sep Objectives: Men and women may sex weight in a different fashion. This study compares the changes in different anatomical regions after a well-controlled weight loss program by sex and initial BMI.

Usually, the arms and legs are the regions that lose more weight in obese participants, but men lose the highest percentage of mass from the trunk. There were differences between men and women for the areas of left trunk mass gright trunk mass gtotal mass of the trunk gandroid mass gand finally in the total mass in overweight participants gwith higher values for men than for women.

The region that loses more weight and fat is the trunk, followed by the legs, and then the arms, when the loss is observed in function of the total weight or fat lost. Conclusion: Both BMI and sex exert a definite influence fat loss, especially in some anatomical regions. Humans with traditional subsistence level life-styles show far lower adiposity, but women are generally at least marginally fatter than men Abbie, ;Truswell and Hansen,suggesting that sexual dimorphism in fatness is an evolved trait peculiar to humans and is manifest under a range of environments Norgan, ;Pond, ;Wells, Wells,a.

He sidestepped the more conservative cause-namely, a far better food supply and lesser opportunity for exercise in the Oregon colony than in the Texas one. Similar explanations have been attempted to account for variations in the sexual dimorphism of fatness in human populations living at different latitudes, even though the relation between fatness and climate was inconsistent and cultural differences in exercise and diet were not well integrated in that study Wells, a.

Both diet and exercise are major contributors to variation in human fatness Stern,as well as to that among wild baboons Altmann et al. Nov Am J Phys Anthropol. There is a paucity of information on body composition and fat patterning in wild nonhuman primates. Dissected adipose tissue from wild toque macaques Macaca sinica WTMfeeding on a natural diet, accounted for 2. This was far less than fatness reported for nonhuman primates raised in captivity or for contemporary humans.

In WTM, fatness increased with age and diet richness, but did not differ by sex. In WTM none of which proxies obese intra-abdominal fat filled first, and "excess" fat was stored peripherally in proxies ratio of sex Intermuscular fat was minimal 0.

With increasing total adiposity, accumulating fat sex in its distribution among eight different main internal sex peripheral deposit areas-consistent with maintaining body balance and a low center of gravity. The available data suggest that, in arboreal primates, adaptations for agile locomotion and terminal branch feeding set constraints on the quantity and distribution of fat. The absence of a higher percentage of body fat in females and neonates as are typical of humans suggests that arboreal adaptations preclude the development of fat-dependent, large-brained infants and the adipose-rich mothers needed to sustain them.

The lifestyle and body composition of wild primates represent a more appropriate model for early human foragers than well-fed captive monkeys do.

Am J Phys Anthropol, Furthermore, variability in both fat and lean mass is consistent with Bergman's hypothesis Wells, athough the associations vary subtly by sex Wells, c. The notion that variability in human morphology indicates thermodynamic adaptation is sufficiently well accepted that it is the primary lens through which broader hominin morphological variability is interpreted Ruff, ;Weaver, Increased investment in any one of these functions reduces the allocation of energy to the others, resulting in trade-offs between them Hill, Beyond Bergmann's rule: Global variability in human body composition is associated with annual average precipitation and annual temperature volatility.

Objectives: Human populations exhibit substantial geographical variability in body size and shape. However, the ecological stresses underlying this morphological variability remain poorly understood. The prevailing evolutionary explanation, "Bergmann's rule" assumes that morphological variability represents an adaptive response to average thermal conditions. We hypothesized that other climate factors-annual average precipitation, a marker of ecological productivity and inter-annual temperature volatility, a marker of infectious disease spikes-may also contribute to variability in body composition.

Materials and methods: We explored this hypothesis by examining associations between these climate factors and geographic variability in body composition across male and female populations from nonindustrialized settings. We used monthly climate data proxies years to develop new climate indices for all worldwide land areas.

Third, such studies have also typically failed to contrast the importance of sexual selection against the role of other factors, making it difficult to assess the relative importance of sexual selection in relation to alternative mechanisms e. Birds offer an ideal study system in which to test the role of sexual selection in signal evolution because of the general availability of phylogenetic, phenotypic and geographic data.

Furthermore, the Tyrannida in particular are especially suited to our analysis because colour patterns and underlying colour producing mechanisms are highly variable across species, and because species in the group occupy a wide range of ecological and environmental niches, allowing investigation of the importance of alternative hypotheses for signal evolution Plumage dichromatism represents a widely used proxy for sexual selection intensity in birds 36 , but is likely to be an imperfect measure 37 , We therefore investigated the relationship between dichromatism values and independent measures of sexual selection from prior work, using both proxies to test the predictions outlined above.

Our results show that sexual selection i is associated with elevated rates of signal divergence between related species, ii impacts divergence between males more than females, and iii generates biases in the direction of signal evolution. We conclude that sexual selection plays a key role in explaining variation in both the rate and direction of plumage colour divergence in birds.

We estimated lineage-specific rates of male and female plumage colour evolution using a flexible reversible-jump model of trait evolution and mapped these onto the Tyrannida phylogeny Fig. This analysis revealed evidence for substantial heterogeneity in rates of plumage colour evolution across the Tyrannida, with rates differing by four orders of magnitude both across lineages and between the sexes Fig. In particular, we found evidence for exceptionally high rates of male plumage colour divergence Fig.

In contrast, rates of female plumage colour divergence were found to be less extreme than in males, but nonetheless still varied by three orders of magnitude across lineages Fig. Estimating rates of evolution for each of 10 different plumage patches see Methods separately revealed that patches typically associated with signalling e. Sex-specific rate variation in plumage colour evolution across the Tyrannida phylogeny. Histograms inset show the rate distribution for each tree.

Phylogenetic reduced major axis regression solid and one-to-one dashed lines shown. Comparing species-specific trait rates TR ES of male and female plumage colour evolution estimated using a method summarising rate variation across the phylogeny see Methods revealed that rates of plumage colour evolution are correlated between the sexes, but that males typically diverge faster than females Fig.

The phylogenetic major axis regression line relating male and female rates was significantly greater than one, indicating that as average within-species rate increases, rates of plumage colour evolution become significantly more male biased Fig. To assess the source and strength of selection acting to drive divergence in male and female plumage colouration, we used multipredictor models of sex-specific plumage divergence rate TR ES values to test several competing hypotheses for the evolution of plumage colouration across species.

Our models revealed that a proxy for sexual selection plumage dichromatism has a strong positive effect on rates of male but not female plumage evolution that is independent of other key variables Fig. First, consistent with the results of our other analyses Fig. Second, our models showed that dichromatism is strongly associated with rapid rates of male plumage colour evolution, but that this effect is absent in females Fig.

In other words, as the degree of dichromatism within lineages increases, rate of male plumage colour evolution tends to accelerate, whereas rates of female plumage evolution remain relatively constant Fig. Predictors of rates of plumage colour evolution in the Tyrannida. Marginal R 2 value i. Importantly, our results are qualitatively unchanged indicating that our findings are robust to alternative approaches for indexing sexual selection intensity.

Furthermore, breaking results down by patch showed largely consistent effects Supplementary Fig. In addition to the role of sexual selection, our multipredictor models also identified other significant effects Fig.

First, our models revealed a consistently significant negative correlation with time since divergence, implying that young species are characterised by faster evolutionary rates relative to older species. Second, we detected marginally positive effects of midpoint latitude and confamilial sympatry. These results are consistent with the idea of latitudinal gradients in trait divergence rates and that interspecific interactions may drive trait evolution, respectively.

We also found no consistent effects of body mass and habitat level of forest dependency on rates of male or female plumage colour evolution across our analyses Fig. Our analyses thus far reveal a positive association between sexual selection as indexed by dichromatism and accelerated male plumage colour divergence across Tyrannida species.

To test whether this pattern was driven by the differential response s of particular signal types, we re-assessed this relationship after first assigning each patch in our dataset to one of three non-overlapping categories broadly distinguishing colours consistent with two distinct colouration mechanisms i.

We then tested for an interaction between colouration category, and the slope of the relationship between dichromatism and patch-specific evolutionary rate. Our analysis revealed that, in males, the slope of the relationship between dichromatism and evolutionary rate is generally steeper among patches consistent with carotenoid colouration i. In other words, as the degree of dichromatism increases, carotenoid-consistent colours evolve disproportionately rapidly compared with putative structural colours, or colours intermediate between these two extremes.

In contrast, in females, regression slopes for the relationship between dichromatism and evolutionary rate were generally similar among signal types Fig. Relationships between dichromatism and rate of plumage colour evolution within body regions for different colouration types.

Asterisks indicate whether the slope of the carotenoid regression line the reference category is significantly more positive black or more negative red compared with the slope of the i intermediate and ii structural regression lines, respectively i. We then tested whether instances of recent rapid plumage colour evolution are significantly biased towards particular evolutionary directions in colour space Fig.

In contrast, we found that evolutionary trajectories associated with the development of other colours were not significantly associated with fast rates. Specifically, evolutionary trajectories associated with the evolution of green colouration were characterised by rates of evolution that are no more rapid than expected by chance.

Conversely, we found that evolution towards blue colours i. In females Fig. Nonetheless, we found some evidence that evolutionary trajectories associated with carotenoid-consistent colour patches in females were also characterised by disproportionately rapid evolutionary rates Fig.

The rate and direction of plumage colour divergence among Tyrannida species. Plots combine data from 10 plumage patches for males a and females b of Tyrannida species. Arrows indicate the direction of evolution and are coloured according to the corresponding patch-specific rate of evolution. Radar plots inset, a and b show the mean evolutionary rates of divergence trajectories black points and lines falling within each 20 o segment of two-dimensional colour space.

Scale bar inset, a and vector diagram showing the loadings of receptor stimulation variables onto PC axes inset, b are relevant to both panels. Breaking these results down into different patches Supplementary Fig. In contrast, other body regions, in particular tail and wings, showed much weaker evidence of rate biases associated with specific directions of colour evolution.

Patch-level analyses of females revealed broadly similar trends but with fewer incidences of significant bias in directions associated with elevated or suppressed rates Supplementary Fig. Our results show that within the Tyrannida tyrant flycatchers, cotingas, manakins and their allies , rates of plumage colouration are i correlated between the sexes, but typically faster for males than females disproportionately so within fast-evolving species , ii significantly associated with proxies for sexual selection intensity including dichromatism , with contrasting effects between the sexes, and iii disproportionately elevated towards carotenoid-based i.

These findings support the idea that sexual selection is the key driver in determining both the rate and direction of plumage colour divergence in birds. We found strong support for a positive association between sexual dichromatism and the rate at which male plumage colouration traits diverge.

This result is consistent with a previous study 23 focused on a small yet broad sample of avian sister species pairs, but contrasts with a related clade-based analysis using different proxies for sexual selection intensity 24 that found both positive and negative associations between sexual selection and ornamentation.

Our results indicate that this effect holds within, as well as between avian lineages, and supports the longstanding interpretation that sexual selection accelerates the evolutionary diversification of male plumage signals involved in courtship and species recognition 4. While overall differences in rate between the sexes may in part reflect greater constraints on plumage colouration in females than males 5 , a pattern of increasingly rapid plumage divergence rate associated with dichromatism in males but not females is more consistent with the general prediction that is due to sex differences in reproductive investment, sexual selection should typically be stronger on males than females 4 , We find evidence for a strong between-sex correlation in plumage divergence rate that becomes disproportionately more male-biased as rate increases.

One explanation for this pattern is that genetic correlations cause non-adaptive changes in female traits in response to strong divergent sexual selection acting primarily on males 39 , This is consistent with patterns observed for other traits, such as allometric increases in male-biased sexual size dimorphism in larger species that are driven by a correlation between evolutionary change in females and directional sexual selection on males, e.

However, genomic studies indicate that genetic correlations between males and females may not represent a major evolutionary constraint 42 , 43 , An alternative explanation therefore is that correlated rates of female plumage divergence are the result of mutual selection on signalling traits in both sexes 45 , Evidence suggests that elaborate signalling traits are maintained in females as adaptive responses to sexual and social competition Correlated divergence rates across the sexes may therefore be the result of females co-opting elements of male sexual signals for use in intra-sexual or inter-sexual or social interactions.

Irrespective of the underlying mechanism, however, finding that rates of plumage evolution are generally elevated in males but also correlated between the sexes suggests that sexual selection plays a role in explaining the evolutionary divergence not only of male but also female plumage traits. Our results also reveal additional predictors of rates of plumage evolution across species. First, rates of plumage evolution were associated with time since divergence for both males and females.

At face value, a negative relationship between rate and time since divergence is consistent with the hypothesis that changes in plumage colouration are associated with speciation events. Second, we detected a positive but weak effect of confamilial sympatry, which is consistent with the idea that interspecific interactions may promote rather than constrain phenotypic evolution However, this relationship was absent when using an alternative tree topology and subset of the data.

None of the variables included in our analysis were able to explain the significant effect of dichromatism on rates of plumage evolution and, taken together, our multipredictor modelling results imply that sexual selection is the key driver of rates of plumage colour evolution across the Tyrannida. These conclusions are contingent on the degree to which dichromatism represents an accurate measure of variation in sexual selection intensity across lineages.

Although dichromatism has been shown to correlate with independent measures of sexual selection such as social mating system and relative testes mass 31 , 32 , 51 , dichromatism represents an imperfect proxy for total sexual selection intensity. This is because other mechanisms can influence patterns of sex-differences in plumage colouration, including natural selection for female crypsis during incubation 52 or social selection on females to signal quality in the context of male mate choice or female—female competition Furthermore, if trade-offs exist between signalling modalities, then dichromatism may underestimate sexual selection intensity, particularly in lineages emphasising acoustic over visual signalling traits However, when we tested an independent i.

Nonetheless, ideally we would use a more direct measure of sexual selection intensity across lineages than any of these proxies provide, for example, indices based on variation in male mating success e. However, such measures are unavailable for most species, and thus quantifiable indices such as dichromatism currently represent the most practical proxy for measuring sexual selection intensity for large numbers of species Yet, given these issues, we suggest that the effects with respect to dichromatism we report here are likely to be underestimates, implying that the true effect of sexual selection on rates of signal evolution may in fact be stronger than revealed here.

Our results also provide insight into the predictability of colour evolution under sexual selection. We found disproportionately fast rates of evolution towards areas of colour space dominated by carotenoid-based i.

The strength of these effects was strongest in front facing body regions e. Avian carotenoid-based signals represent classic examples of sexually selected, condition-dependent signals of individual quality Although there is continuing debate regarding the precise mechanism through which carotenoid traits become honest signals 9 , 60 , field and behavioural studies have demonstrated the role of such traits in determining the outcome of competitive social interactions Furthermore, the genetic and biochemical basis of avian carotenoid signal production is becoming increasing well understood 62 , 63 , and phylogenetic evidence indicates that carotenoid pathways are deeply conserved across birds and can be readily up-regulated or down-regulated in response to relatively short-term changes in selection This flexibility contrasts with developmental and morphological constraints that potentially inhibit rapid evolution towards other types of conspicuous colouration e.

Thus, our results are consistent with the view of carotenoid colours as key signalling traits that often evolve convergently in response to sexual selection in birds Overall, our results highlight the dominant role of sexual selection in driving the evolutionary divergence of avian plumage colouration, and reveal the existence of convergent evolutionary trajectories of avian signalling traits under strong sexual selection.

Furthermore, our results suggest that signal divergence under sexual selection may be to some extent predictable, with rapid instances of signal divergence biased towards carotenoid-based colouration traits known to function as honest condition dependent signals of individual quality.

Further work is required to assess the generality of these patterns, but given the prevalence of convergently-evolved carotenoid signals within and between avian lineages 64 , 66 , as well as in other animal lineages including fish and reptiles 67 , 68 , our results provide insight into the evolutionary forces responsible for explaining patterns of diversity and convergence in visual signalling traits across the animal kingdom.

We collected data on male and female plumage colouration using study skins from the avian skin collection at the Natural History Museum, Tring. We focused on species for which representatives of both sexes were available and, where possible, sampled specimens of three males and three females, selecting mature individuals in breeding plumage with no obvious signs of moult.

Plumage colouration was measured using calibrated digital images of specimens. Following image acquisition, all raw. Each linearised image was then normalised using information from the five grey standards included in each image to control for variation in lighting conditions, following the approach of ref.

We then used these images to extract colour measurements for 10 discrete plumages patches on each specimen crown, nape, mantle, rump, dorsal tail, wing coverts, wing primaries, throat, breast, and belly.

Together these patches provide a comprehensive set of measurements capturing variation in overall plumage colouration for each specimen that is comparable across species To do this, we used a custom IMAGEJ macro to draw a series of polygons onto our images outlining the location of individual plumage patches on each specimen Fig.

We then used the coordinate locations of these polygons to extract mean RGB values for each patch on each specimen in both the UV and visual range. Our dataset therefore consisted of four colour measurements receptor stimulation values for 10 plumage patches for a total of specimens covering species. To demonstrate the validity of our image-based approach for measuring plumage colouration, we tested whether relative receptor stimulation values extracted from our processed digital images see below matched those generated by spectrophotometric measurements of patch reflectance.

For a sample of specimens i. Thus, we conclude that our image-based approach is valid and is capable of providing estimates of patch colouration that are highly similar to those generated using spectrophotometric techniques across the full avian visible range.

We averaged patch values within species separately for each sex to generate species-level averages in each variable for each patch for each sex. Following previous studies, we represented chromatic variation among patches using a standard avian colourspace model in which raw cone catch values are converted to relative cone stimuli values and projected in a tetrahedron This tetrahedron—in which the achromatic luminance dimension is removed and each vertex represents one of the four cones characterising avian colour vision i.

Given that relative cone stimuli are often correlated, following standard approaches 65 we conducted a principal component PC analysis to represent the colourspace in fewer orthogonal variables. We estimated rates of plumage colour evolution using the multivariate version of the variable rates model of trait evolution 75 , 76 implemented in the software BayesTraits V2.

To provide species-level estimates of plumage evolution rate that also incorporates information on the longer-term rate of trait evolution leading to the phenotype of a given species, we developed an approach for apportioning rate-scaled branch lengths among each tip of a phylogenetic tree Thus, when applied to phylogenies where branch lengths are in units of rate of trait evolution rather than time , such as those derived from the outputs of the variable rates model, then these tip-specific weighted average values provide a species-level estimate of trait evolutionary rate that also captures the longer-term rate of trait evolution leading to the phenotype of a given species.

We refer to this rate-scaled tip metric as TR ES Trait Rate equal splits and apply the above formula to mean rate phenograms derived from outputs of the variable rates models described above. To assess the relationship between male and female plumage rates TR ES values across species, we used phylogenetic reduced major axis regression based on a maximum likelihood optimisation of lambda To assess the effect of predictor variables on plumage TR ES variation across species, following 31 we used Bayesian phylogenetic mixed models in MCMCglmm 79 to fit male and female plumage rates as the response variable using six variables time since divergence, body mass, dichromatism, forest dependency, latitude, and confamilial sympatry and their interaction with sex as predictors.

We used the same approach to test for interaction effects between dichromatism and colouration category, except that here male and female datasets were analysed separately. To test for biases in the evolutionary trajectories of plumage colouration, we quantified the rate, extent, and direction of recent i. We then compared the average rate of divergence associated with differing evolutionary trajectories in colour space to null distributions of rates generated assuming no relationship between rates and direction of colour evolution.

Any deviation in the mean observed rate of evolution compared with the null distribution of rates within each discrete divergence trajectory suggests that rates are disproportionately higher or lower on average than expected relative to null expectations. Simpson, G. In Petshop Of Horrors , Leon is seduced by two different women in one night.

It turns out that they're plant spirits who were using him to spread their pollen from one girl to another. In Chapter of Ah! My Goddess , Belldandy and Keiichi are overshadowing another goddess and mortal who fell in love. Judging by the the last panel on page 23, the past couple were lovers.

Which means Bell and Kei are lovers, by proxy. Comic Books. In ElfQuest , when Cutter realizes that Zhantee has always been in love with Leetah from afar, he mentally shares his memories of his relationship with Leetah with Zhantee as a gift — including their romantic intimacy. In Requiem Vampire Knight , there is a character capable of stealing orgasms from others as they are about to happen.

This seems to be at least a significant chunk of the principle behind the Shrieky Girls of Doktor Sleepless. Topper was a comic about a horny ghost that ran in the Australian edition of Penthouse. In one strip, he manipulated two women into having sex and joined in without either of them noticing.

Due to being in tune with Haruhi's emotions at all times, especially if the emotions are particularly strong, Koizumi ends up extremely flushed when Haruhi and Kyon are making out. Multiple Firefly fanfics have explored the implications of River's long-established Power Incontinence while stuck aboard a very small spaceship with her big brother right after he finally scores with Kaylee.

In Red vs. Blue , AIs are able to possess others by entering the AI slot in their armor, often leaving the possessee still conscious.

Fanfic takes this to its logical conclusion with Power Perversion Potential. Films — Live-Action. Although it's more of a PG-rated Makeout by Proxy. She doesn't care all that much for Malkovich — she just gets off on "Lotte in Malkovich".

Malkovich slowly becomes aware of what's going on. Things get out of hand. In Freaks , one of the conjoined twins is shown to get aroused when her sister is kissing her boyfriend.

Since the sister and boyfriend proceed to get married and have sex, one can assume the trope is in full effect. Strange Days involves illegal devices which can record and play back memories — giving the user all of the sensory input felt by whoever was being recorded.

The recording include sex, of course parts of a couple of raunchy memory recordings are shown, both for sale and for personal use. It's probably a huge part of the market. Brainstorm also features a memory-recording device, and one of the scientists working on it uses it to make a porno. In Surrogates some people willingly let others access their robotic avatars to feel the pleasure of living in a perfect body and touching it. She ends up paying them back for it by using the psychic connection to target the Scimitar 's bridge with the Enterprise 's weapons.

In the Unrated Edition of Pretty Cool , the woman investigating Howard uses a device to tap into his body while he has sex with his sister's friends in their hot tub. Species II : The two alien-human hybrids are mind-linked, and also desperately want to hook up with each other to create purer offspring than they could with human mates. There are several times when Patrick is having sex somewhere else, and Eve goes into heat and apparently orgasms at the same time.

Enter the Void : The main character is killed about 15 minutes into the movie and spends the rest of it as a disembodied spirit. There are numerous occasions where he observes people having sex and flies into their heads to experience it from their point of view.

In Robert A. In The Wheel of Time , the Warder bond allows people to feel what others do. So when Elayne and Rand finally have sex, Birgitte who is bonded to Elayne , Min, and Aviendha who are bonded to Rand all have to go off and get drunk so they can't feel precisely what is going on.

Walter Jon Williams ' Aristoi , which is set in a future where everybody has wireless internet connections in their heads, has a science-fictional example.

In the Dragonriders of Pern setting: The mental link between dragons and riders can cause this effect. Generally, when dragons mate, their riders are pulled into the lust and wind up following suit whether they want to or not — but it also works in reverse, most notably in the case of Lord Jaxom, who winds up with a strange, white runt of a dragon. Being apparently asexual, it has no interest in "flying" with female dragons, but it DOES seem to rather enjoy sharing Jaxom's feelings when HE'S off with a girl.

Many individuals without capacity can articulate their desires. Moreover, sexual disinhibition is often undiminished by dementia. She delivered a directive to her caregivers for the time when she would lose capacity. She wanted, she told them, to enjoy replays of her favorite television program, Gunsmoke. She was sure that this would give her comfort as she lost the ability to articulate her wants.

Inevitably, she declined and lost capacity. Her caregivers dutifully played Gunsmoke for her, but the tapes were distracting, even distressing, to her.

Closely-spaced television dialogue can become indecipherable and even terrifying to individuals with dementia. The same kind of quandary with a sexual advance directive is even more important — and disquieting. Next, Boni-Saenz injects another problem. Along with advance directives, healthcare proxies are among the most commonly utilized tools for elder law attorneys. A healthcare proxy is a kind of durable power of attorney which appoints a surrogate decision maker over healthcare decisions.

These instruments permit an agent, such as a trusted friend or family member, to grant — or withhold — informed consent in various medical situations if the principal has lost capacity. If sexual advance directives are permitted to prospectively grant or deny consent to physical intimacy, then, by extension, sexual powers of attorney are also warranted. Vesting a trusted agent with the power to consent or refuse intimacy goes partway toward ameliorating the inherent problem of an advance directive; the difficulty of responding to unanticipated circumstances.

Spouses and children frequently fit the bill.