Sperm competition intensity affects sperm precedence patterns in a polyandrous gift-giving spider

Abstract Sperm competition drives traits that enhance fertilization success. The amount of sperm transferred relative to competitors is key for attaining paternity. Female reproductive morphology and male mating order may also influence fertilization, however the outcome for sperm precedence under intense sperm competition remains poorly understood. In the polyandrous spider Pisaura mirabilis, males offer nuptial gifts which prolong copulation and increase sperm transfer, factors proposed to alter sperm precedence patterns under strong sperm competition. First, we assessed the degree of female polyandry by genotyping wild broods. A conservative analysis identified up to four sires, with a mean of two sires per brood, consistent with an optimal mating female rate. Then we asked whether intense sperm competition shifts sperm precedence patterns from first male priority, as expected from female morphology, to last male advantage. We varied sexual selection intensity experimentally and determined competitive fertilization outcome by genotyping broods. In double matings, one male monopolised paternity regardless of mating order. A mating order effect with first male priority was revealed when females were mated to four males, however this effect disappeared when females were mated to six males, probably due to increased sperm mixing. The proportion of males that successfully sired offspring drastically decreased with the number of competitors. Longer copulations translated into higher paternity shares independently of mating order, reinforcing the advantage of traits that prolong copulation duration under intense competition, such as the nuptial gift. Sperm competition intensity enhances the impact of competitive sexual traits and imposes multiple effects on paternity

Calibration of cognitive tests to address the reliability paradox for decision-conflict tasks

Standard, well-established cognitive tasks that produce reliable effects in group comparisons also lead to unreliable measurement when assessing individual differences. This reliability paradox has been demonstrated in decision-conflict tasks such as the Simon, Flanker, and Stroop tasks, which measure various aspects of cognitive control. We aim to address this paradox by implementing carefully calibrated versions of the standard tests with an additional manipulation to encourage processing of conflicting information, as well as combinations of standard tasks. Over five experiments, we show that a Flanker task and a combined Simon and Stroop task with the additional manipulation produced reliable estimates of individual differences in under 100 trials per task, which improves on the reliability seen in benchmark Flanker, Simon, and Stroop data. We make these tasks freely available and discuss both theoretical and applied implications regarding how the cognitive testing of individual differences is carried out.</p

JASP: Graphical Statistical Software for Common Statistical Designs

This paper introduces JASP, a free graphical software package for basic statistical procedures such as t tests, ANOVAs, linear regression models, and analyses of contingency tables. JASP is open-source and differentiates itself from existing open-source solutions in two ways. First, JASP provides several innovations in user interface design; specifically, results are provided immediately as the user makes changes to options, output is attractive, minimalist, and designed around the principle of progressive disclosure, and analyses can be peer reviewed without requiring a "syntax". Second, JASP provides some of the recent developments in Bayesian hypothesis testing and Bayesian parameter estimation. The ease with which these relatively complex Bayesian techniques are available in JASP encourages their broader adoption and furthers a more inclusive statistical reporting practice. The JASP analyses are implemented in R and a series of R packages

AGO6 Functions in RNA-Mediated Transcriptional Gene Silencing in Shoot and Root Meristems in Arabidopsis thaliana

RNA-directed DNA methylation (RdDM) is a small interfering RNA (siRNA)-mediated epigenetic modification that contributes to transposon silencing in plants. RdDM requires a complex transcriptional machinery that includes specialized RNA polymerases, named Pol IV and Pol V, as well as chromatin remodelling proteins, transcription factors, RNA binding proteins, and other plant-specific proteins whose functions are not yet clarified. In Arabidopsis thaliana, DICER-LIKE3 and members of the ARGONAUTE4 group of ARGONAUTE (AGO) proteins are involved, respectively, in generating and using 24-nt siRNAs that trigger methylation and transcriptional gene silencing of homologous promoter sequences. AGO4 is the main AGO protein implicated in the RdDM pathway. Here we report the identification of the related AGO6 in a forward genetic screen for mutants defective in RdDM and transcriptional gene silencing in shoot and root apical meristems in Arabidopsis thaliana. The identification of AGO6, and not AGO4, in our screen is consistent with the primary expression of AGO6 in shoot and root growing points

Crime fiction, South Africa : a critical introduction

Crime fiction is an emergent category in South African literary studies. This introduction positions South African crime fiction and its scholarship in a global lineage of crime and detective fiction. The survey addresses the question of its literary status as ‘highbrow’ or ‘lowbrow’. It also identifies and describes two distinct sub-genres of South African crime fiction: the crime thriller novel; and the literary detective novel. The argument is that South African crime fiction exhibits a unique capacity for social analysis: a capacity which is being optimised by authors and interrogated by scholar

The brain as 'immunoprecipitator' of serum autoantibodies against N-Methyl-D-Aspartate receptor subunit NR1

Autoantibodies (AB) against N-methyl-D-aspartate receptor subunit NR1 (NMDAR1) are highly seroprevalent in health and disease. Symptomatic relevance may arise upon compromised blood-brain barrier (BBB). However, it remained unknown whether circulating NMDAR1 AB appear in the cerebrospinal fluid (CSF). Of n5271 subjects with CSF-serum pairs, 26 were NMDAR1 AB seropositive, but only 1 was CSF positive. Contrariwise, tetanus AB (non-brain-binding) were present in serum and CSF of all subjects, with CSF levels higher upon BBB dysfunction. Translational mouse experiments proved the hypothesis that the brain acts as an 'immunoprecipitator'; simultaneous injection of NMDAR1 AB and the non-brain-binding green fluorescent protein AB resulted in high detectability of the former in brain and the latter in CSF