Indirectly connected: simple social differences can explain the causes and apparent consequences of complex social network positions

This is the author accepted manuscript. The final version is available from Royal Society via the DOI in this record.Animal societies are often structurally complex. How individuals are positioned within the wider social network (i.e. their indirect social connections) has been shown to be repeatable, heritable and related to key life-history variables. Yet, there remains a general lack of understanding surrounding how complex network positions arise, whether they indicate active multifaceted social decisions by individuals, and how natural selection could act on this variation. We use simulations to assess how variation in simple social association rules between individuals can determine their positions within emerging social networks. Our results show that metrics of individuals' indirect connections can be more strongly related to underlying simple social differences than metrics of their dyadic connections. External influences causing network noise (typical of animal social networks) generally inflated these differences. The findings demonstrate that relationships between complex network positions and other behaviours or fitness components do not provide sufficient evidence for the presence, or importance, of complex social behaviours, even if direct network metrics provide less explanatory power than indirect ones. Interestingly however, a plausible and straightforward heritable basis for complex network positions can arise from simple social differences, which in turn creates potential for selection to act on indirect connections.The work was funded by a Research Fellowship from the EGI and a Junior Research Fellowship from Merton College, Oxford University to J.A.F., a BBSRC grant (BB/L006081/1) to B.C.S., and a Leverhulme Trust Early Career Fellowship to L.J.N.B

Poeta con mayúsculas

Publicat a El Periódico

Do female association preferences predict the likelihood of reproduction?

Sexual selection acting on male traits through female mate choice is commonly inferred from female association preferences in dichotomous mate choice experiments. However, there are surprisingly few empirical demonstrations that such association preferences predict the likelihood of females reproducing with a particular male. This information is essential to confirm association preferences as good predictors of mate choice. We used green swordtails (<i>Xiphophorus helleri</i>) to test whether association preferences predict the likelihood of a female reproducing with a male. Females were tested for a preference for long- or short-sworded males in a standard dichotomous choice experiment and then allowed free access to either their preferred or non-preferred male. If females subsequently failed to produce fry, they were provided a second unfamiliar male with similar sword length to the first male. Females were more likely to reproduce with preferred than non-preferred males, but for those that reproduced, neither the status (preferred/non-preferred) nor the sword length (long/short) of the male had an effect on brood size or relative investment in growth by the female. There was no overall preference based on sword length in this study, but male sword length did affect likelihood of reproduction, with females more likely to reproduce with long- than short-sworded males (independent of preference for such males in earlier choice tests). These results suggest that female association preferences are good indicators of female mate choice but that ornament characteristics of the male are also important

Postcopulatory sexual selection

The female reproductive tract is where competition between the sperm of different males takes place, aided and abetted by the female herself. Intense postcopulatory sexual selection fosters inter-sexual conflict and drives rapid evolutionary change to generate a startling diversity of morphological, behavioural and physiological adaptations. We identify three main issues that should be resolved to advance our understanding of postcopulatory sexual selection. We need to determine the genetic basis of different male fertility traits and female traits that mediate sperm selection; identify the genes or genomic regions that control these traits; and establish the coevolutionary trajectory of sexes

Emerging Infectious Disease leads to Rapid Population Decline of Common British Birds

Emerging infectious diseases are increasingly cited as threats to wildlife, livestock and humans alike. They can threaten geographically isolated or critically endangered wildlife populations; however, relatively few studies have clearly demonstrated the extent to which emerging diseases can impact populations of common wildlife species. Here, we report the impact of an emerging protozoal disease on British populations of greenfinch Carduelis chloris and chaffinch Fringilla coelebs, two of the most common birds in Britain. Morphological and molecular analyses showed this to be due to Trichomonas gallinae. Trichomonosis emerged as a novel fatal disease of finches in Britain in 2005 and rapidly became epidemic within greenfinch, and to a lesser extent chaffinch, populations in 2006. By 2007, breeding populations of greenfinches and chaffinches in the geographic region of highest disease incidence had decreased by 35% and 21% respectively, representing mortality in excess of half a million birds. In contrast, declines were less pronounced or absent in these species in regions where the disease was found in intermediate or low incidence. Also, populations of dunnock Prunella modularis, which similarly feeds in gardens, but in which T. gallinae was rarely recorded, did not decline. This is the first trichomonosis epidemic reported in the scientific literature to negatively impact populations of free-ranging non-columbiform species, and such levels of mortality and decline due to an emerging infectious disease are unprecedented in British wild bird populations. This disease emergence event demonstrates the potential for a protozoan parasite to jump avian host taxonomic groups with dramatic effect over a short time period

Building Babies - Chapter 16

In contrast to birds, male mammals rarely help to raise the offspring. Of all mammals, only among rodents, carnivores, and primates, males are sometimes intensively engaged in providing infant care (Kleiman and Malcolm 1981). Male caretaking of infants has long been recognized in nonhuman primates (Itani 1959). Given that infant care behavior can have a positive effect on the infant’s development, growth, well-being, or survival, why are male mammals not more frequently involved in “building babies”? We begin the chapter defining a few relevant terms and introducing the theory and hypotheses that have historically addressed the evolution of paternal care. We then review empirical findings on male care among primate taxa, before focusing, in the final section, on our own work on paternal care in South American owl monkeys (Aotus spp.). We conclude the chapter with some suggestions for future studies.Deutsche Forschungsgemeinschaft (HU 1746/2-1) Wenner-Gren Foundation, the L.S.B. Leakey Foundation, the National Geographic Society, the National Science Foundation (BCS-0621020), the University of Pennsylvania Research Foundation, the Zoological Society of San Dieg

A Comparison of DSM-IV and DSM-5 Panel Members' Financial Associations with Industry: A Pernicious Problem Persists

Lisa Cosgrove and Sheldon Krimsky examine the new competing interest disclosure policy of the American Psychiatric Association (APA) and report that DSM panel members still have considerable financial conflicts of interest

Renal Athersosclerotic reVascularization Evaluation (RAVE Study): Study protocol of a randomized trial [NCT00127738]

BACKGROUND: It is uncertain whether patients with renal vascular disease will have renal or mortality benefit from re-establishing renal blood flow with renal revascularization procedures. The RAVE study will compare renal revascularization to medical management for people with atherosclerotic renal vascular disease (ARVD) and the indication for revascularization. Patients will be assessed for the standard nephrology research outcomes of progression to doubling of creatinine, need for dialysis, and death, as well as other cardiovascular outcomes. We will also establish whether the use of a new inexpensive, simple and available ultrasound test, the renal resistance index (RRI), can identify patients with renal vascular disease who will not benefit from renal revascularization procedures[1]. METHODS/DESIGN: This single center randomized, parallel group, pilot study comparing renal revascularization with medical therapy alone will help establish an infrastructure and test the feasibility of answering this important question in clinical nephrology. The main outcome will be a composite of death, dialysis and doubling of creatinine. Knowledge from this study will be used to better understand the natural history of patients diagnosed with renal vascular disease in anticipation of a Canadian multicenter trial. Data collected from this study will also inform the Canadian Hypertension Education Program (CHEP) Clinical Practice Guidelines for the management of Renal and Renal Vascular Disease. The expectation is that this program for ARVD, will enable community based programs to implement a comprehensive guidelines based diagnostic and treatment program, help create an evidence based approach for the management of patients with this condition, and possibly reduce or halt the progression of kidney disease in these patients. DISCUSSION: Results from this study will determine the feasibility of a multicentered study for the management of renovascular disease

Maximum Host Survival at Intermediate Parasite Infection Intensities

BACKGROUND: Although parasitism has been acknowledged as an important selective force in the evolution of host life histories, studies of fitness effects of parasites in wild populations have yielded mixed results. One reason for this may be that most studies only test for a linear relationship between infection intensity and host fitness. If resistance to parasites is costly, however, fitness may be reduced both for hosts with low infection intensities (cost of resistance) and high infection intensities (cost of parasitism), such that individuals with intermediate infection intensities have highest fitness. Under this scenario one would expect a non-linear relationship between infection intensity and fitness. METHODOLOGY/PRINCIPAL FINDINGS: Using data from blue tits (Cyanistes caeruleus) in southern Sweden, we investigated the relationship between the intensity of infection of its blood parasite (Haemoproteus majoris) and host survival to the following winter. Presence and intensity of parasite infections were determined by microscopy and confirmed using PCR of a 480 bp section of the cytochrome-b-gene. While a linear model suggested no relationship between parasite intensity and survival (F = 0.01, p = 0.94), a non-linear model showed a significant negative quadratic effect (quadratic parasite intensity: F = 4.65, p = 0.032; linear parasite intensity F = 4.47, p = 0.035). Visualization using the cubic spline technique showed maximum survival at intermediate parasite intensities. CONCLUSIONS/SIGNIFICANCE: Our results indicate that failing to recognize the potential for a non-linear relationship between parasite infection intensity and host fitness may lead to the potentially erroneous conclusion that the parasite is harmless to its host. Here we show that high parasite intensities indeed reduced survival, but this effect was masked by reduced survival for birds heavily suppressing their parasite intensities. Reduced survival among hosts with low parasite intensities suggests costs of controlling parasite infections; however, the nature of such costs remains to be elucidated