Rutgers screw over Trivers
I never intended this blog to be for rants, but when I heard about what has happened to one of the world's best evolutionary biologist I had to write something. It appears that Robert Trivers (a couple of his seminal papers linked below) has been suspended by Rutgers University because he admitted to students that he was teaching a class that he knew nothing about. The University made him teach a course on 'Human Aggression' by the head of the Anthropology department, and admitted to students that he didn't know anything about the subject but would be learning along with them. I have pasted the link to the Yahoo news site below. For a University to treat any member of staff like this is appalling, it is just highlighted by the fact that he is such a pivotal figure in modern evolutionary biology. I am personally upset because my PhD was about parent-offspring conflict, an idea that he formulated. Rutgers need to be held accountable for treating a member of staff in such a bad way.
A couple of his papers:
Trivers (1974) Parent-offspring conflict. Amer. Zool., 14:249-264
When parent-offspring relations in sexually reproducing species are viewed from the standpoint of the offspring as well as the parent, conflict is seen to be an expected feature of such relations. In particular, parent and offspring are expected to disagree over how long the period of parental investment should last, over the amount of parental investment that should be given, and over the altruistic and egoistic tendencies of the offspring as these tendencies affect other relatives. In addition, under certain conditions parents and offspring are expected to disagree over the preferred sex of the potential offspring. In general, parent-offspring conflict is expected to increase during the period of parental care, and offspring are expected to employ psychological weapons in order to compete with their parents. Detailed data on mother-offspring relations in mammals are consistent with the arguments presented. Conflict in some species, including the human species, is expected to extend to the adult reproductive role of the offspring: under certain conditions parents are expected to attempt to mold an offspring, against its better interests, into a permanent nonreproductive.
Trivers & Hare (1976) Haplodiploidy and the evolution of the social insect. Science, 191:249-263
Halminton (1) was apparently the first to appreciate that the synthesis of Mendelian genetics with Darwin's theory of natural selection had profound implications for social theory. In particular, insofar as almost all social behavior is either selfish or altruistic (or has such effects), genetical reasoning suggests that an individual's social behavior should be adjusted to his or her degree of relatedness, r, to all individuals affected by the behavior. We call this theory kinship theory. The social insects provide a critical test of Hamilton's kinship theory. When such theory is combined with the sex ratio theory of Fisher (9), a body of consistent predictions emerges regarding the haplodiploid Hymenoptera. The evolution of female workers helping their mother reproduce is more likely in the Hymenoptera than in diploid groups, provided that such workers lay some of the male-producing eggs or bias the ratio of investment toward reproductive females. Once eusocial colonies appear, certain biases by sex in these colonies are expected to evolve. In general, but especially in eusocial ants, the ratio of investment should be biased in favor of females, and in it is expected to equilibrate at 1 : 3 (male to female). We present evidence from 20 species that the ratio of investment in monogynous ants is, indeed, about 1 : 3, and we subject this discovery to a series of tests. As expected, the slave-making ants produce a ratio of investment of 1 : 1, polygynoys ants produce many more males than expected on the basis of relative dry weight alone, solitary bees and wasps produce a ratio of investment near 1 : 1 (and no greater than 1 : 2), and the social bumblebees produce ratios of investment between 1 : 1 and 1 : 3. In addition, sex ratios in monogynous ants and in trapnested wasps are, as predicted by Fisher, inversely related to the relative cost in these species of producing a male instead of a female. Taken together, these data provide quantitative evidence in support of kinship theory, sex ratio theory, the assumption that the offspring is capable of acting counter to its parents' best interests, and the supposition that haplodiploidy has played a unique role in the evolution of the social insects. Finally, we outline a theory for the evolution of worker-queen conflict, a theory which explains the queen's advantage in competition over male-producing workers and the workers' advantage regarding the ratio of investment. The theory uses the asymmetries of haplodiploidy to explain how the evolved outcome of parent-offspring conflict in the social Hymenoptera is expected to be a function of certain social and life history parameters.
Just in case anyone is interested, I now have a flickr account (http://www.flickr.com/photos/alexmthompson/). I'll be updating it with mainly nature photos, with some from my PhD research. I have a friend who has a great flickr page, Dom Cram (http://www.flickr.com/photos/canvas-wisdom) so check him out too.
Here is an image from my new flickr account:
I know that I usually only blog about biology, conservation and cool new science but #NekNominations are in the press a lot at the moment and I thought that it was worth blogging about. I saw a video on youtube of a South African guy who gave a homeless guy a sandwich, a chocolate bar and a bottle of coke at a traffic light for his #NekNomination, instead of downing some horrid drink. So when I got nominated I thought I would do the same. I bought a homeless girl a pizza (it was a wet, cold day in England), some orange juice, and some dog food and treats for her dog. I think that this is a good use of a #NekNomination, so I implore people: if you get nominated then do something good! Buy a homeless person a meal, donate something to charity, volunteer at an animal sanctuary, just put some good back into the world. (I've tried to upload the video but am not sure if it has worked).
So #NekNominate away but #improvesomeonesday
Singing in the moonlight
A cool new paper has just been published in Biology Letters by York et al about the influences of the phases of the moon on the singing behaviour of the white-browed sparrow-weaver.
Singing in male birds has traditionally been seen as a signal of quality and is used in many species as a method of mate attraction. This behaviour has recently started to receive a lot of attention due to the effects of anthropogenic lighting, such as street lights, on the calling behaviour of birds that live in urban areas. However, the study by York et al took place in the Kalahari, a natural habitat with limited anthropogenic lighting, and they investigated the effects of the moons light on singing. The study found that :
"Males started singing earlier when the moon was full compared with when it was new, as long as the moon was above the horizon at dawn. During these exposed full moon dawns, males sang over a longer performance period and produced more song during that period compared with exposed new moon dawns."
The authors highlight the links of their study with research on anthropogenic light effects, which can produce reproductive benefits as males sing earlier. They point out that their research suggests that the sensitivities that allow birds to adapt to lighting in cities may have evolved to take advantage of the natural variation in light provided by the moon.
This is a really interesting study that takes a novel approach to look at a well studied area of avian behaviour, and it poses questions about what researchers should be thinking about when they study singing in the wild....they need to keep track of the moon!
York, Young & Radford (2014) Singing in the moonlight: dawn song performance of a diurnal bird varies with lunar phase. Biology Letters, 10:20130970
It is well established that the lunar cycle can affect the behaviour of nocturnal animals, but its potential to have a similar influence on diurnal species has received less research attention. Here, we demonstrate that the dawn song of a cooperative songbird, the white-browed sparrow weaver (Plocepasser mahali), varies with moon phase. When the moon was above the horizon at dawn, males began singing on average 10 min earlier, if there was a full moon compared with a new moon, resulting in a 67% mean increase in performance period and greater total song output. The lack of a difference between full and new moon dawns when the moon was below the horizon suggests that the observed effects were driven by light intensity, rather than driven by other factors associated with moon phase. Effects of the lunar cycle on twilight signalling behaviour have implications for both pure and applied animal communication research.
For more information on this cool study system click on this link: Sparrow-Weaver Project
This is the first time that I have spotted a paper after I had seen it presented at a conference. This work was presented at ISBE in Lund 2012, and was probably the most highly attended talk that I went to (people were sitting on the floor). The paper seeks to ask the question, in humans, of whether a males ability is correlated with his attractiveness. It is trying to get at mate selection in humans and whether females may choose males that have better 'fitness'.
The results of the study show that women rated the faces of male cyclists who performed better in the Tour de France as more attractive as those that performed worse. The author suggests that as endurance may be beneficial to humans that the work hints that endurance capacity may have been subject to sexual selection. The work is interesting because it brings much of what is known from work on animals, such as that by Peterson & Husak (2006), that show that females prefer males who perform better in whole organism performance traits. Interestingly, females rating of attractiveness depended on which stage of their reproductive cycle they were in and whether they were on the pill. With women on the pill and men having a weaker preference for better performing male faces. The author also investigated masculinity and likeability, finding that there was no association between masculinity and performance, which may be surprising considering the proposed benefits of testosterone on strength. However, there was a strong association between likeability and performance.
It's an interesting paper that brings together work on animals that is fairly well known and understood in different animal taxa with sexual selection in humans, providing a new perspective on male facial attract
Postma (2014) A relationship between attractiveness and performance in professional cyclists. Biology Letters, 10:20130966
Females often prefer to mate with high quality males, and one aspect of quality is physical performance. Although a preference for physically fitter males is therefore predicted, the relationship between attractiveness and performance has rarely been quantified. Here, I test for such a relationship in humans and ask whether variation in (endurance) performance is associated with variation in facial attractiveness within elite professional cyclists that finished the 2012 Tour de France. I show that riders that performed better were more attractive, and that this preference was strongest in women not using a hormonal contraceptive. Thereby, I show that, within this preselected but relatively homogeneous sample of the male population, facial attractiveness signals endurance performance. Provided that there is a relationship between performance-mediated attractiveness and reproductive success, this suggests that human endurance capacity has been subject to sexual selection in our evolutionary past.20130966
It's a pretty sexy topic and so has received press on the BBC new website and probably many others too.
Today I have been doing a literature review on sperm competition and the adaptations that males have evolved to 'win' this evolutionary battle. The papers have been about seminal proteins that reduce female receptivity, the transfer of pheromones to make females less attractive, evolution of mating plugs, and the evolution of longer, faster sperm that are produced in larger quantities from larger testis. But I have come across a paper that I had read a long time ago, related to human morphology and sperm competition, and I just wanted to share it. It's a great paper and deals with an area that is fairly taboo in science, sperm competition and sex in humans.
Abstract and title:
Gallup Jr., Burch, Zappieri, Parvez, Stockwell & Davis (2003) The human penis as a semen displacement device. Evolution and Human Behaviour, 24:277-289
Inanimate models were used to assess the possibility that certain features of the human penis evolved to displace semen left by other males in the female reproductive tract. Displacement of artificial semen in simulated vaginas varied as a function of glans/coronal ridge morphology, semen viscosity, and depth of thrusting. Results obtained by modifying an artificial penis suggest that the coronal ridge is an important morphological feature mediating semen displacement. Consistent with the view of the human penis as a semen displacement device, two surveys of college students showed that sexual intercourse often involved deeper and more vigorous penile thrusting following periods of separation or in response to allegations of female infidelity.
An interesting new paper has just come out in PNAS. One of the findings of the paper is that a return migration happened 3000 years ago, taking back western Eurasian genes down Eastern Africa all the way to the Southern tip of the continent. This means that Khoi San peoples have genetic ties to the peoples of Southern Europe. An interestingly, as Neanderthals are thought to have interbreed with modern humans in Europe, that there may be a weak Neanderthal genetic signal in the Khoi San.
Pickrell et al (2014) Ancient west Eurasian ancestry in southern and eastern Africa. PNAS, DOI: 10.1073/pnas.1313787111
The history of southern Africa involved interactions between indigenous hunter–gatherers and a range of populations that moved into the region. Here we use genome-wide genetic data to show that there are at least two admixture events in the history of Khoisan populations (southern African hunter–gatherers and pastoralists who speak non-Bantu languages with click consonants). One involved populations related to Niger–Congo-speaking African populations, and the other introduced ancestry most closely related to west Eurasian (European or Middle Eastern) populations. We date this latter admixture event to ∼900–1,800 y ago and show that it had the largest demographic impact in Khoisan populations that speak Khoe–Kwadi languages. A similar signal of west Eurasian ancestry is present throughout eastern Africa. In particular, we also find evidence for two admixture events in the history of Kenyan, Tanzanian, and Ethiopian populations, the earlier of which involved populations related to west Eurasians and which we date to ∼2,700–3,300 y ago. We reconstruct the allele frequencies of the putative west Eurasian population in eastern Africa and show that this population is a good proxy for the west Eurasian ancestry in southern Africa. The most parsimonious explanation for these findings is that west Eurasian ancestry entered southern Africa indirectly through eastern Africa.
A good write up of the paper by New Scientist:
I am a behavioural ecologist, my main interests revolve around familial conflicts and their resolutions. However, my scientific interests are fairly broad.