Indirect selection on female extra-pair reproduction? Comparing the additive genetic value of maternal half-sib extra-pair and within-pair offspring

One specific hypothesis explaining the evolution of extra-pair reproduction (EPR) by socially monogamous females is that EPR is under indirect selection because extra-pair offspring (EPO) sired by extra-pair males have higher additive genetic value for fitness than the within-pair offspring (WPO) a female would have produced had she solely mated with her socially paired male. This hypothesis has not been explicitly tested by comparing additive genetic value between EPO and the WPO they replaced. We show that the difference in additive genetic breeding value (BV) between EPO and the WPO they replaced is proportional to the genetic covariance between offspring fitness and male net paternity gain through EPR, and estimate this covariance with respect to offspring recruitment in free-living song sparrows (Melospiza melodia). Recruitment and net paternity gain showed non-zero additive genetic variance and heritability, and negative genetic covariance. Opposite to prediction, EPO therefore had lower BV for recruitment than the WPO they replaced. We thereby demonstrate an explicit quantitative genetic approach to testing the hypothesis that EPR allows polyandrous females to increase offspring additive genetic value, and suggest that there may be weak indirect selection against female EPR through reduced additive genetic value for recruitment of EPO versus WPO in song sparrows

Water Stress Strengthens Mutualism Among Ants, Trees, and Scale Insects

Abiotic environmental variables strongly affect the outcomes of species interactions. For example, mutualistic interactions between species are often stronger when resources are limited. The effect might be indirect: water stress on plants can lead to carbon stress, which could alter carbon-mediated plant mutualisms. In mutualistic ant–plant symbioses, plants host ant colonies that defend them against herbivores. Here we show that the partners\u27 investments in a widespread ant–plant symbiosis increase with water stress across 26 sites along a Mesoamerican precipitation gradient. At lower precipitation levels, Cordia alliodora trees invest more carbon in Azteca ants via phloem-feeding scale insects that provide the ants with sugars, and the ants provide better defense of the carbon-producing leaves. Under water stress, the trees have smaller carbon pools. A model of the carbon trade-offs for the mutualistic partners shows that the observed strategies can arise from the carbon costs of rare but extreme events of herbivory in the rainy season. Thus, water limitation, together with the risk of herbivory, increases the strength of a carbon-based mutualism

Dalaman tarım işletmesinde yetiştirilen siyah-alacalarda buzağılama mevsiminin süt verimine etkisi

Data of 866 lactations collected from 251 cows raised at Dalaman State Farm in Mugla province between 1989 and 1996 were analyzed. Two calving seasons were determined on data set based on average monthly air temperature. These are the first calving season (November 1 - April 30 ) which is within the comfort zone for cows, and the second calving season (May 1 - October 31 ). Milk yield, calving year, lactation number and calving season were evaluated. The effect of lactation number (p<0.01), calving year (p<0.01) and, calving season (p<0.01) on 305-d milk yield were found statistically significant. The least-square means and standard errors of milk yield for the first and the second calving season were 7493.54±70.29 kg and 7180.63±81.08 kg, respectively.Mugla Ili Dalaman Tarım Isletmesinde 1989 1996 yılları arasında yetistirilen 251 hayvana iliskin toplam 866 laktasyon verileri toplanarak degerlendirilmistir.Aylık ortalama hava sıcaklıkları dikkate alınarak iki buzagılama mevsimi olusturulmustur. Bunlar, konfor sınırları içerisinde olan 1. buzagılama mevsimi (01 Kasım 30 Nisan) ve 2. buzagılama (01 Mayıs 31 Ekim) mevsimidir. Süt verimleri, buzagılama yılı, laktasyon sırası ve buzagılama mevsimi degerlendirilmistir. Yapılan degerlendirmede 305 günlük süt verimine laktasyon sırası (p<0.01), buzagılama yılı (p<0.01) ve buzagılama mevsiminin etkisi (p<0.01) önemli bulunmustur. Süt verimine iliskin 1. ve 2. buzagılama mevsiminin en küçük kareler ortalamaları ve standart hataları sırasıyla 7493.54±70.29 kg ve 7180.63±81.08 kg olarak belirlenmistir

Heritability of female extra-pair paternity rate in song sparrows (Melospiza melodia)

The forces driving the evolution of extra-pair reproduction in socially monogamous animals remain widely debated and unresolved. One key hypothesis is that female extra-pair reproduction evolves through indirect genetic benefits, reflecting increased additive genetic value of extra-pair offspring. Such evolution requires that a female's propensity to produce offspring that are sired by an extra-pair male is heritable. However, additive genetic variance and heritability in female extra-pair paternity (EPP) rate have not been quantified, precluding accurate estimation of the force of indirect selection. Sixteen years of comprehensive paternity and pedigree data from socially monogamous but genetically polygynandrous song sparrows (Melospiza melodia) showed significant additive genetic variance and heritability in the proportion of a female's offspring that was sired by an extra-pair male, constituting major components of the genetic architecture required for extra-pair reproduction to evolve through indirect additive genetic benefits. However, estimated heritabilities were moderately small (0.12 and 0.18 on the observed and underlying latent scales, respectively). The force of selection on extra-pair reproduction through indirect additive genetic benefits may consequently be relatively weak. However, the additive genetic variance and non-zero heritability observed in female EPP rate allow for multiple further genetic mechanisms to drive and constrain mating system evolution

State stigmatization in urban Turkey : Managing the 'insurgent' squatter dwellers in Dikmen Valley

This paper contributes to the accounts of territorial stigmatisation by examining the state role in it in the case of Turkey, a country that suffers from growing state power. The existing debates are mainly restricted to its function as an economic strategy paving the way for capital accumulation through devaluing working‐class people and places. Drawing on textual analysis of political speeches, local newsletters and mainstream national newspapers and fieldwork material that include interviews and observations in Dikmen Valley where some squatter communities mobilised against the state‐imposed urban transformation project, I demonstrate that state conceptualisation of “problem people” targets the “insurgent” rather than the “unprofitable” groups. Stigma in urban settings functions in inciting the desire to meet the patterns deemed appropriate by the state, rather than the market. Moving from that, I argue that stigma is used as a state‐led political strategy, which is integral to the growing authoritarianism in Turkey