Should females prefer to mate with low-quality males?

We analyse a model of mate choice when males differ in reproductive quality and provide care for their offspring. Females choose males on the basis of the success they will obtain from breeding with them and a male chooses his care time on the basis of his quality so as to maximise his long-term rate of reproductive success. We use this model to establish whether high-quality males should devote a longer period of care to their broods than low-quality males and whether females obtain greater reproductive success from mating with higher quality males. We give sufficient conditions for optimal care times to decrease with increasing male quality. When care times decrease, this does not necessarily mean that high-quality males are less valuable to the female because quality may more than compensate for the lack of care. We give a necessary and sufficient condition for high-quality males to be less valuable mates, and hence for females to prefer low-quality males. Females can prefer low-quality males if offspring produced and cared for by high-quality males do well even if care is short, and do not significantly benefit from additional care, while offspring produced and cared for by low-quality males do well only if they receive a long period of care.     

Ought we to sentence people to psychiatric treatment?

In principle, there seem to be three main ways in which society can react when people commit crimes under influence of mental illness. (1) The standard model. We excuse them. If they are dangerous they are detained in the interest of safety of the rest of the citizens. (2) The Swedish model. We hold them responsible for their criminal offence, we convict them, but we do not sentence them to jail. Instead, we sentence them to psychiatric treatment. (3) My model. We sentence them to jail, but offer them (voluntary) psychiatric treatment. The advantages of my model are obvious. We get a clear delineation of roles. We allow the psychiatrist to be just a doctor, not a warden. We liberate psychiatry of the objective of deciding whether people who were mentally ill when they committed criminal offences 'could have acted otherwise' -- a hopeless task. We allow that psychiatrists live up to their professional ethical code (The Hawaii Declaration). We treat psychically ill persons as 'normal', we allow them to repent their crimes, which renders easier their recovery. However, two objections to my model come to mind. First of all, is it not unfair to sentence people to jail who could not help doing what they did? And, secondly, the question of fairness set to one side, is it not inhumane to sentence mentally ill persons to jail? Is it not inhumane to the mentally ill persons themselves, and does it not mean that they will be a burden to other prisoners? In my paper I show that, if our system of criminal punishment takes a civilised form, neither of these objections carries any weight.     

Can we predict ectotherm responses to climate change using thermal performance curves and body temperatures?

Thermal performance curves (TPCs), which quantify how an ectotherm's body temperature (T_b) affects its performance or fitness, are often used in an attempt to predict organismal responses to climate change. Here, we examine the key – but often biologically unreasonable – assumptions underlying this approach; for example, that physiology and thermal regimes are invariant over ontogeny, space and time, and also that TPCs are independent of previously experienced T_b. We show how a critical consideration of these assumptions can lead to biologically useful hypotheses and experimental designs. For example, rather than assuming that TPCs are fixed during ontogeny, one can measure TPCs for each major life stage and incorporate these into stage‐specific ecological models to reveal the life stage most likely to be vulnerable to climate change. Our overall goal is to explicitly examine the assumptions underlying the integration of TPCs with T_b, to develop a framework within which empiricists can place their work within these limitations, and to facilitate the application of thermal physiology to understanding the biological implications of climate change.     

Can evolution of sexual dimorphism be triggered by developmental temperatures?

Genetic prerequisites for the evolution of sexual dimorphism, sex-specific heritabilities and low or negative genetic correlations between homologous traits in males and females are rarely found. However, sexual dimorphism is evolving rapidly following environmental change, suggesting that sexual dimorphism and its genetic background could be environmentally sensitive. Yet few studies have explored the sensitivity of the genetic background of sexual dimorphism on environmental variation. In this study, on Drosophila melanogaster, we used a large nested full-sib-half-sib breeding design where families were split into four different developmental temperatures: two constant temperature treatments of 25 and 30 °C and two cycling temperatures with means of 25 and 30 °C, respectively. After emergence, we tested heat shock tolerance of adult flies. We found that sexual dimorphism was strongly affected by temperature during development. Moreover, we found that female heritability was significantly lower in flies developing at hot temperature and more so under hot and cycling temperatures. Interestingly, most of the genetic variation for heat shock tolerance was orthogonal (i.e. noncorrelated) between sexes, allowing independent evolution of heat shock tolerance in males and females. These findings give support to the hypothesis that the evolution of sexual dimorphism can be influenced by the environments experienced during development.     

Montane forest birds in winter: do they regularly move to lower altitudes? Observations from the Eastern Cape,South Africa

Seasonal altitudinal migration to lower altitudes including the coast has been ascribed to a number of forest birds, of which 14 species occur at Fort Fordyce Reserve in the Eastern Cape, South Africa. Based on our observations and ringing at this site (2007–2017), as well as concurrent data from the South African Bird Atlas Project (SABAP2), we suggest that in this region only three species, the African Dusky Flycatcher Muscicapa adusta, White-starred Robin Pogonocichla stellata and Barratt's Warbler Bradypterus barratti, are regular altitudinal migrants. For two other species, the Grey Cuckooshrike Coracina caesia and Yellow-throated Woodland Warbler Phylloscopus ruficapilla, local movements apparently occur, but these may take place within the coastal zone rather than between the coast and inland forests.     

Can the cause of aggregation be inferred from species distributions?

Species distributions often show an aggregated pattern, which can be due to a number of endo- and exogenous factors. While autologistic models have been used for modelling such data with statistical rigour, little emphasis has been put on disentangling potential causes of aggregation. In this paper we ask whether it is possible to infer sources of aggregation in species distributions from a single set of occurrence data by comparing the performance of various autologistic models. We create simulated data sets, which show similar occupancy patterns, but differ in the process that causes the aggregation. We model the distribution of these data with various autologistic models, and show how the relative performance of the models is sensitive to the factor causing aggregation in the data. This information can be used when modelling real species data, where causes of aggregation are typically unknown. To illustrate, we use our approach to assess the potential causes of aggregation in data of seven bird species with contrasting statistical patterns. Our findings have important implications for conservation, as understanding the mechanisms that drive population fluctuations in space and time is critical for the development of effective management actions for long-term conservation.     

Can metabolic plasticity be a cause for cancer? Warburg-Waddington legacy revisited

Fermentation of glucose to lactate in the presence of sufficient oxygen, known as aerobic glycolysis or Warburg effect, is a universal phenotype of cancer cells. Understanding its origin and role in cellular immortalization and transformation has attracted considerable attention in the recent past. Intriguingly, while we now know that Warburg effect is essential for tumor growth and development, it is thought to arise because of genetic and/or epigenetic changes. In contrast to the above, we propose that Warburg effect can also arise due to normal biochemical fluctuations, independent of genetic and epigenetic changes. Cells that have acquired Warburg effect proliferate rapidly to give rise to a population of heterogeneous progenitors of cancer cells. Such cells also generate more lactate and alter the fitness landscape. This dynamic fitness landscape facilitates evolution of cancer cells from its progenitors, in a fashion analogous to Darwinian evolution. Thus, sporadic cancer can also occur first by the acquisition of Warburg effect, then followed by mutation and selection. The idea proposed here circumvents the inherent difficulties associated with the current understanding of tumorigenesis, and is also consistent with many experimental and epidemiological observations. We discuss this model in the context of epigenetics as originally enunciated by Waddington. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s13148-011-0030-x) contains supplementary material, which is available to authorized users.     

Can hyperparasitoids cause large‐scale outbreaks of insect herbivores?

Synchronous population fluctuations occur in many species and have large economic impacts, but remain poorly understood. Dispersal, climate and natural enemies have been hypothesized to cause synchronous population fluctuations across large areas. For example, insect herbivores cause extensive forest defoliation and have many natural enemies, such as parasitoids, that may cause landscape‐scale changes in density. Between outbreaks, parasitoid‐caused mortality of hosts/herbivores is high, but it drops substantially during outbreak episodes. Because of their essential role in regulating herbivore populations, we need to include parasitoids in spatial modelling approaches to more effectively manage insect defoliation. However, classic host‐parasitoid population models predict parasitoid density, and parasitoid density is difficult to relate to host‐level observations of parasitoid‐caused mortality. We constructed a novel model to study how parasitoids affect insect outbreaks at the landscape scale. The model represents metacommunity dynamics, in which herbivore regulation, colonisation and extinction are driven by interactions with the forest, primary parasitoids and hyperparasitoids. The model suggests that parasitoid spatial dynamics can produce landscape‐scale outbreaks. Our results propose the testable prediction that hyperparasitoid prevalence should increase just before the onset of an outbreak because of hyperparasitoid overexploitation. If verified empirically, hyperparasitoid distribution could provide a biotic indicator that an outbreak will occur.     

Can respect be key to gender justice?

Equality and respect are, together with dignity, considered foundational values in international human rights discourse. While equality in particular has been established as a widely accepted goal in the women's rights movement, respect is, however, less commonly invoked. Based on long‐term ethnographic fieldwork conducted among the Arsi Oromo of Ethiopia, this article examines the notion of wayyuu, a tacit moral model of respect and sacredness that is central to institutions and norms that have secured women certain rights and power. These norms and institutions represent a challenge to the liberal feminist conceptualization of gender equality that dominates international women's rights discourse. Drawing on theories of respect and on feminist and anthropological discussions of equality, I argue that even though there are certain limitations inherent in wayyuu, the sacredness it entails and the implications this has had for women's status and power among the Arsi Oromo call for an exploration of respect not as an alternative to equality, but as a complementary notion which to a greater extent could be included in global discussions of gender justice.     

Can biosensors help to protect drinking water?

A large proportion of drinking water is abstracted for treatment from lowland rivers—about 30% in the UK—and this water is at particular risk from sudden and poisonous industrial or agricultural pollution. To cover the range of potential pollutants it may be possible to use biosensors as broadband monitors for toxins. The underlying assumption is that some biological processes, when challenged with a toxin, will be affected in a way analogous to that of man, and that therefore on-line scrutiny of such processes will provide early warning of substances liable to be detrimental to human health. Suitable processes for study might involve multi-cellular organisms, whole cells or enzymes. To date, most practical work has concentrated on fish, but enzymes and single cells hold out the promise of quicker response and, possibly, easier maintenance.     

Can Wolbachia be used to control malaria?

Malaria is a mosquito-borne infectious disease caused by Plasmodium parasites transmitted by the infectious bite of Anopheles mosquitoes. Vector control of malaria has predominantly focused on targeting the adult mosquito through insecticides and bed nets. However, current vector control methods are often not sustainable for long periods so alternative methods are needed. A novel biocontrol approach for mosquito-borne diseases has recently been proposed, it uses maternally inherited endosymbiotic Wolbachia bacteria transinfected into mosquitoes in order to interfere with pathogen transmission. Transinfected Wolbachia strains in Aedes aegypti mosquitoes, the primary vector of dengue fever, directly inhibit pathogen replication, including Plasmodium gallinaceum, and also affect mosquito reproduction to allow Wolbachia to spread through mosquito populations. In addition, transient Wolbachia infections in Anopheles gambiae significantly reduce Plasmodium levels. Here we review the prospects of using a Wolbachia-based approach to reduce human malaria transmission through transinfection of Anopheles mosquitoes.