Sex ratio and the evolution of aggression in fruit flies.

Aggressive behaviours are among the most striking displayed by animals, and aggression strongly impacts fitness in many species. Aggression varies plastically in response to the social environment, but we lack direct tests of how aggression evolves in response to intra-sexual competition. We investigated how aggression in both sexes evolves in response to the competitive environment, using populations of Drosophila melanogaster that we experimentally evolved under female-biased, equal, and male-biased sex ratios. We found that after evolution in a female-biased environment-with less male competition for mates-males fought less often on food patches, although the total frequency and duration of aggressive behaviour did not change. In females, evolution in a female-biased environment-where female competition for resources is higher-resulted in more frequent aggressive interactions among mated females, along with a greater increase in post-mating aggression. These changes in female aggression could not be attributed solely to evolution either in females or in male stimulation of female aggression, suggesting that coevolved interactions between the sexes determine female post-mating aggression. We found evidence consistent with a positive genetic correlation for aggression between males and females, suggesting a shared genetic basis. This study demonstrates the experimental evolution of a behaviour strongly linked to fitness, and the potential for the social environment to shape the evolution of contest behaviours.

Male reproductive aging arises via multifaceted mating-dependent sperm and seminal proteome declines, but is postponable in Drosophila.

Declining ejaculate performance with male age is taxonomically widespread and has broad fitness consequences. Ejaculate success requires fully functional germline (sperm) and soma (seminal fluid) components. However, some aging theories predict that resources should be preferentially diverted to the germline at the expense of the soma, suggesting differential impacts of aging on sperm and seminal fluid and trade-offs between them or, more broadly, between reproduction and lifespan. While harmful effects of male age on sperm are well known, we do not know how much seminal fluid deteriorates in comparison. Moreover, given the predicted trade-offs, it remains unclear whether systemic lifespan-extending interventions could ameliorate the declining performance of the ejaculate as a whole. Here, we address these problems using Drosophila melanogaster. We demonstrate that seminal fluid deterioration contributes to male reproductive decline via mating-dependent mechanisms that include posttranslational modifications to seminal proteins and altered seminal proteome composition and transfer. Additionally, we find that sperm production declines chronologically with age, invariant to mating activity such that older multiply mated males become infertile principally via reduced sperm transfer and viability. Our data, therefore, support the idea that both germline and soma components of the ejaculate contribute to male reproductive aging but reveal a mismatch in their aging patterns. Our data do not generally support the idea that the germline is prioritized over soma, at least, within the ejaculate. Moreover, we find that lifespan-extending systemic down-regulation of insulin signaling results in improved late-life ejaculate performance, indicating simultaneous amelioration of both somatic and reproductive aging.

An exploration into the motivation for gluten avoidance in the absence of coeliac disease.

AIM: To explore the motivation for gluten avoidance in the absence of coeliac disease (CD) and ascertain what symptoms are triggered by gluten and what beliefs/reasons influence this decision. BACKGROUND: Links between physical/psychological symptoms and gluten in CD are well known but less is known about those who self-select a gluten-free diet (GFD) in the absence of CD. METHODS: An empirical study using responses to an anonymous on-line questionnaire. Closed questions were used as a screening tool to exclude participants who had CD, wheat allergy or were following a low FODMAP diet. Data from participants using a GFD in the absence of a medical diagnosis was then analysed using thematic analysis. RESULTS: 120 initial responses, 87 were completed in full. 23 respondents fulfilled the inclusion criteria for thematic analysis. 7 different themes emerged, including one for signs/symptoms. Other themes identified included difficulties of a GFD, health beliefs, feelings and influence on decision to follow a GFD. Responses indicate that the reasons for gluten avoidance are in the most part reasoned and logical and were based around participants' self-management of symptoms. CONCLUSION: Symptoms included those typical of irritable bowel syndrome (IBS), but also infertility, low mood/energy, immune function and weight management and visual and auditory hallucinations. It appears the majority of responses analysed thematically could fit into the spectrum of non-coeliac gluten sensitivity (NCGS). Findings also suggest more support at all levels of medical care may help patients establish if it is gluten, rather than wheat or FODMAPs particularly fructans that are contributing to signs/symptoms.

Long-term responses to treatment in UK veterans with military-related PTSD: an observational study.

OBJECTIVES: Military-related trauma can be difficult to treat. Evaluating longer term responses to treatment and identifying which individuals may need additional support could inform clinical practice. We assessed 1-year outcomes in UK veterans treated for post-traumatic stress disorder (PTSD). DESIGN: Within-participant design. SETTING: The intervention was offered by Combat Stress, a mental health charity for veterans in the UK. PARTICIPANTS: The sample included 401 veterans who completed a standardised 6-week residential treatment. Of these, 268 (67%) were successfully followed up a year after the end of treatment. METHODS: A range of health outcomes were collected pretreatment and repeated at standard intervals post-treatment. The primary outcome was severity of PTSD symptoms, and secondary outcomes included measures of other mental health difficulties (depression, anxiety and anger), problems with alcohol, and social and occupational functioning. RESULTS: Significant reductions in PTSD severity were observed a year after treatment (PSS-I: -11.9, 95% CI -13.1 to -10.7). Reductions in the secondary outcomes were also reported. Higher levels of post-treatment functional impairment (0.24, 95% CI 0.08 to 0.41) and alcohol problems (0.18, 95% CI 0.03 to 0.32) were associated with poorer PTSD treatment response at 12 months. CONCLUSIONS: This uncontrolled study suggests the longer term benefits of a structured programme to treat UK veterans with PTSD. Our findings point to the importance of continued support targeted for particular individuals post-treatment to improve longer term outcomes.

Mental health and functional impairment outcomes following a 6-week intensive treatment programme for UK military veterans with post-traumatic stress disorder (PTSD): a naturalistic study to explore dropout and health outcomes at follow-up.

OBJECTIVE: Combat Stress, a UK national charity for veterans with mental health problems, has been funded by the National Health Service (NHS) to provide a national specialist service to deliver treatment for post-traumatic stress disorder (PTSD). This paper reports the efficacy of a PTSD treatment programme for UK veterans at 6 months follow-up. DESIGN: A within subject design. SETTING: UK veterans with a diagnosis of PTSD who accessed Combat Stress. PARTICIPANTS: 246 veterans who received treatment between late 2012 and early 2014. INTERVENTION: An intensive 6-week residential treatment programme, consisting of a mixture of individual and group sessions. Participants were offered a minimum of 15 individual trauma-focused cognitive behavioural therapy sessions. In addition, participants were offered 55 group sessions focusing on psychoeducational material and emotional regulation. MAIN OUTCOME MEASURES: Clinicians completed measures of PTSD and functional impairment and participants completed measures of PTSD, depression, anger and functional impairment. RESULTS: We observed significant reductions in PTSD scores following treatment on both clinician completed measures (PSS-I: -13.0, 95% CI -14.5 to -11.5) and self-reported measures (Revised Impact of Events Scale (IES-R): -16.5, 95% CI -19.0 to -14.0). Significant improvements in functional impairment were also observed (eg, Health of the Nation Outcome Scales (HONOS): -6.85, 95% CI -7.98 to -5.72). There were no differences in baseline outcomes between those who completed and those who did not complete the programme, or post-treatment outcomes between those we were able to follow-up at 6 months and those lost to follow-up. CONCLUSIONS: In a naturalistic study we observed a significant reduction in PTSD scores and functional impairment following treatment. These improvements were maintained at 6 month follow-up. Our findings suggest it may be helpful to take a closer look at combining individual trauma-focused cognitive behaviour therapy and group sessions when treating veterans with PTSD. This is the first UK study of its kind, but requires further evaluation.

RT-PCR for the pseudogene-free amplification of the glyceraldehyde-3-phosphate dehydrogenase gene (gapd).

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is an enzyme which catalyses the conversion of glyceraldehyde-3-phosphate to 1,3 diphosphoglycerate. It is considered to be constitutively expressed in all cells, and as such the gene for GAPDH (gapd) is commonly used as a benchmark reference in expression studies. However, previous investigations have demonstrated that gapd may show altered gene expression in a number of disease states and under certain experimental conditions, suggesting that results of experiments using gapd as a control should be interpreted with caution. Furthermore, consideration must be given to the potential co-amplification of pseudogenes of gapd during RT-PCR. Here, we describe a method to avoid the amplification of contaminating pseudogenes through the design of primers that bind only to genuine gapd mRNA transcript.