Abstract
Summary
Low- and high-frequency vowels in the stressed syllable of French first names may respectively project impressions of largeness/masculinity and smallness/femininity.
Abstract
Given ...that first names can have a lifelong impact on the bearer, parents should choose a name based on the impressions they want their offspring to evoke in other people. This name-to-mental-image association can be mediated through sound symbolism: a natural link between the sounds and meaning of a word. From an evolutionary perspective, parents should pick names which sounds convey traits advantageous in human sexual selection: largeness and masculinity for males through lower-frequency sounds as opposed to smallness and femininity for females through higher-frequency sounds. Using a database of French first names from 1900 to 2009, we observed a sex-biased sound symbolism pattern in the last syllable, which is the perceptually prominent one in French. Male names were more likely to include lower-frequency vowels (e.g. /o/, /ã/) and female names higher-frequency vowels (e.g. /i/, /e/). Unexpected patterns in consonants were observed in masculine names with higher-frequency sounds (e.g. /s/, /ʃ/) in the last syllable and lower-frequency sounds (e.g. /b/, /g/) in the first syllable. However, little variance was explained and the modest size effect suggests that cultural traits influence these sex differences. Lastly, exploratory analyses revealed a phonetic masculinization in women's first names that has increased since the 1960s.
How adaptation appears and is later refined by natural selection has been the object of intense theoretical work. However, the testing of these theories is limited by our ability to estimate the ...strength of natural selection in nature. Using a long-term cline series, we estimate the selection coefficients acting on different alleles at the same locus to analyze the allele replacement observed in the insecticide resistance gene Ester in the mosquito Culex pipiens in the Montpellier area, southern France. Our method allows us to accurately account for the resistance allele replacement observed in this area since 1986. A first resistance allele appeared early, which was replaced by a second resistance allele providing the same advantage but at a lower cost, itself being replaced by a third resistance allele with both higher advantage and cost. It shows that amelioration of the adaptation (here resistance to insecticide) through allele replacement was successively achieved by selection of first a generalist allele (i.e., with a low fitness variance across environments) and later a specialist allele (i.e., with a large fitness variance across environments). More generally, we discuss how precise estimates of the strength of selection obtained from field data help us understand the process of amelioration of adaptation.
Although there are quite important geographical variations in the frequency of left-handers around the world, nothing is known about its temporal evolution. During the upper Palaeolithic (ca. 35 ...000-10 000 YBP), humans painted 'negative hands' by blowing pigments with a tube onto one hand applied on the rock in caves in Western Europe, by blowing pigments on their own hand through a tube held in the other hand. The frequency of left-handers prevailing during this period could thus be assessed. For comparison, the handedness of French university students has been observed for the same task. No difference was detected between the two proportions of left-handers, separated by more than 10 000 years. Implications for the evolution of the polymorphism of handedness are discussed.
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Sexual ornaments are often assumed to be indicators of mate quality. Yet it remains poorly known how certain ornaments are chosen before any coevolutionary race makes them indicative. Perceptual ...biases have been proposed to play this role, but known biases are mostly restricted to a specific taxon, which precludes evaluating their general importance in sexual selection. Here we identify a potentially universal perceptual bias in mate choice. We used an algorithm that models the sparseness of the activity of simple cells in the primary visual cortex (or V1) of humans when coding images of female faces. Sparseness was found positively correlated with attractiveness as rated by men and explained up to 17% of variance in attractiveness. Because V1 is adapted to process signals from natural scenes, in general, not faces specifically, our results indicate that attractiveness for female faces is influenced by a visual bias. Sparseness and more generally efficient neural coding are ubiquitous, occurring in various animals and sensory modalities, suggesting that the influence of efficient coding on mate choice can be widespread in animals.
Immune cells such as glioblastoma‐associated macrophages play a crucial role in the progression and invasiveness of glioblastoma multiforme. In article number 1806590, Marcel Alexander Heinrich, Jai ...Prakash, and co‐workers describe a novel 3D bioprinted model of glioblastoma multiforme in the form of mini‐brains that allow the study of the specific interaction between these macrophages and tumor cells, as well as the testing of the chemo‐ and immunotherapy in a biologically relevant fashion.
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The sexual swellings of female primates have generated a great deal of interest in evolutionary biology. Two hypotheses recently proposed to elucidate their functional significance argue that maximal ...swelling size advertises either female fertility within a cycle or female quality across cycles. Published evidence favours the first hypothesis, and further indicates that larger swellings advertise higher fertility between cycles. If so, a male preference for large swellings might evolve, driving females to use swellings as quality indicators, as proposed by the second hypothesis. In this paper, we explore this possibility using a combination of empirical field data and mathematical modelling. We first test and find support for three key predictions of the female-quality hypothesis in wild chacma baboons (Papio ursinus): (i) inter-individual differences in swelling size are maintained across consecutive cycles, (ii) females in better condition have larger swellings and higher reproductive success, and (iii) males preferentially choose females with large swellings. We then develop an individual-based simulation model that indicates that females producing larger swellings can achieve higher mating success even when female-female competition is low and within-female variance in the trait is high. Taken together, our findings show that once sexual swellings have evolved as fertility signals, they might, in certain socio-sexual systems, be further selected to act as quality signals. These results, by reconciling two hypotheses, help to clarify the processes underlying sexual swelling evolution. More generally, our findings suggest that mate choice for direct benefits (fertility) can lead to indirect benefits (good genes).
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It has recently been reported that the synaptic acetylcholinesterase (AChE) in mosquitoes is encoded by the ace-1 gene, distinct and divergent from the ace-2 gene, which performs this function in ...Drosophila. This is an unprecedented situation within the Diptera order because both ace genes derive from an old duplication and are present in most insects and arthropods. Nevertheless, Drosophila possesses only the ace-2 gene. Thus, a secondary loss occurred during the evolution of Diptera, implying a vital function switch from one gene (ace-1) to the other (ace-2). We sampled 78 species, representing 50 families (27% of the Dipteran families) spread over all major subdivisions of the Diptera, and looked for ace-1 and ace-2 by systematic PCR screening to determine which taxonomic groups within the Diptera have this gene change. We show that this loss probably extends to all true flies (or Cyclorrhapha), a large monophyletic group of the Diptera. We also show that ace-2 plays a non-detectable role in the synaptic AChE in a lower Diptera species, suggesting that it has non-synaptic functions. A relative molecular evolution rate test showed that the intensity of purifying selection on ace-2 sequences is constant across the Diptera, irrespective of the presence or absence of ace-1, confirming the evolutionary importance of non-synaptic functions for this gene. We discuss the evolutionary scenarios for the takeover of ace-2 and the loss of ace-1, taking into account our limited knowledge of non-synaptic functions of ace genes and some specific adaptations of true flies.
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Acetylcholinesterase (AChE) is the target of two major insecticide families, organophosphates (OPs) and carbamates. AChE insensitivity is a frequent resistance mechanism in insects and responsible ...mutations in the ace gene were identified in two Diptera, Drosophila melanogaster and Musca domestica. However, for other insects, the ace gene cloned by homology with Drosophila does not code for the insensitive AChE in resistant individuals, indicating the existence of a second ace locus. We identified two AChE loci in the genome of Anopheles gambiae, one (ace-1) being a new locus and the other (ace-2) being homologous to the gene previously described in Drosophila. The gene ace-1 has no obvious homologue in the Drosophila genome and was found in 15 mosquito species investigated. In An. gambiae, ace-1 and ace-2 display 53% similarity at the amino acid level and an overall phylogeny indicates that they probably diverged before the differentiation of insects. Thus, both genes are likely to be present in the majority of insects and the absence of ace-1 in Drosophila is probably due to a secondary loss. In one mosquito (Culex pipiens), ace-1 was found to be tightly linked with insecticide resistance and probably encodes the AChE OP target. These results have important implications for the design of new insecticides, as the target AChE is thus encoded by distinct genes in different insect groups, even within the Diptera: ace-2 in at least the Drosophilidae and Muscidae and ace-1 in at least the Culicidae. Evolutionary scenarios leading to such a peculiar situation are discussed.
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