Effects of cortisol administration on cooperative behavior in meerkat helpers

Experimental administration of stress hormones to meerkat helpers does not affect their contributions to cooperative activities. Previous work on cooperative breeders suggested that levels of stress hormones are related to helping behavior. We tested this experimentally by injecting meerkat helpers with cortisol, whilst matched controls received a saline injection. This did not lead to changes in cooperative behaviour, but induced females, and not males, to spend more time near pups and less time foragin

Playback of predator calls inhibits and delays dawn singing in a songbird community

Recent studies have demonstrated that experimental increases in perceived predation risk can substantially impair breeding behavior and reduce reproductive success. Perceived predation risk may also occur in the context of sexual signaling, with potential consequences for sexual selection. In songbirds, singing at dawn is an important sexual signal but may also attract predators. Here, we report on 2 experiments designed to test whether perceived predation risk affects the occurrence and timing of dawn singing in a songbird community. In a pilot experiment, we broadcast predator playbacks intermittently across half a forest plot and nonpredator playbacks across the other half throughout early spring. In the second experiment, we repeated the treatments in 16 independent but smaller plots (8 with predator calls and 8 with nonpredator calls). In the predator treatment, most species were less likely to sing at dawn (small, nonsignificant effects) and started later if they did sing (significant for 2 species). Meta-analyses combining the data from both experiments showed an overall significant effect of the treatment on both the likelihood and timing of singing. Species that were less likely to sing also sang later if they did sing, corroborating that an increase in perceived predation risk was the common cause of the effects on both measures

Effects of cortisol administration on cooperative behavior in meerkat helpers

Although the ultimate causes for variation in contributions to helping in cooperative breeders are increasingly well understood, the underlying physiological mechanisms remain largely unknown. Recent work has suggested that glucocorticoids (GC) may play an important role in the expression of cooperative behaviour. Here, we present the first experimental test of the effects of GCs on helper behaviour in a cooperative breeder. GC levels of adult female and male meerkat helpers were elevated with an intra-muscular injection of cortisol (hydrocortisone 21hemi-succinate sodiumsalt) dissolved in saline, whilst matched controls simultaneously received an injection of saline. There were no changes in pup feeding or sentinel behaviour, but females spent more time in close proximity to pups and less time foraging when GC levels were elevated. These results provide no evidence that GCs affect cooperative behaviour, but suggest that there may be an effect on affiliation with pups and foraging effort.The J. L. Dobberke Stichting, the Schure-Beijerink-Popping Fonds and the Prins Bernhard Cultuurfonds.http://beheco.oxfordjournals.orghb2016Zoology and Entomolog

Validation of a fecal glucocorticoid assay to assess adrenocortical activity in meerkats using physiological and biological stimuli

In mammals, glucocorticoid (i.e. GC) levels have been associated with specific life-history stages and transitions, reproductive strategies, and a plethora of behaviors. Assessment of adrenocortical activity via measurement of glucocorticoid metabolites in feces (FGCM) has greatly facilitated data collection from wild animals, due to its non-invasive nature, and thus has become an established tool in behavioral ecology and conservation biology. The aim of our study was to validate a fecal glucocorticoid assay for assessing adrenocortical activity in meerkats (Suricata suricatta), by comparing the suitability of three GC enzyme immunoassays (corticosterone, 11β-hydroxyetiocholanolone and 11oxo-etiocholanolone) in detecting FGCM increases in adult males and females following a pharmacological challenge with adrenocorticotropic hormone (ACTH) and biological stimuli. In addition, we investigated the time course characterizing FGCM excretion, the effect of age, sex and time of day on FGCM levels and assessed the potential effects of soil contamination (sand) on FGCM patterns. Our results show that the group specific 11β-hydroxyetiocholanolone assay was most sensitive to FGCM alterations, detecting significant and most distinctive elevations in FGCM levels around 25 h after ACTH administration. We found no age and sex differences in basal FGCM or on peak response levels to ACTH, but a marked diurnal pattern, with FGCM levels being substantially higher in the morning than later during the day. Soil contamination did not significantly affect FGCM patterns. Our results emphasize the importance of conducting assay validations to characterize species-specific endocrine excretion patterns, a crucial step to all animal endocrinology studies using a non-invasive approach.SUPPORTING INFORMATION : S1 FILE. Group FGCM response (median ± SE, μg/g) to a natural attack on a group member (ZIM005) that resulted in its permanent eviction. The victim showed the greatest FGCM response to the event. Group FGCM levels returned to baseline levels after the male was removed from the colony. “Within 48 h” represent FGCM levels measured within 2 days after the attack on M5 took place. = p < 0.01 (Fig A). Average (median ± SE) baseline FGCM levels (μg/g) in fecal samples deposited in the morning (AM), at midday (MD) and late afternoon (PM), as measured with the 11β-hydroxyetiocholanolone assay. N = 128 fecal samples from 13 individuals. = p < 0.05 (Fig B). Remove selectedThe Swiss National Science Foundation (grant no. 31003A_13676) to Marta B. Manser, the University of Zurich, and by an ERC grant (no. 294494, THCB2011) to Tim H. Clutton-Brock at the University of Cambridge.http://www.plosone.orgam2016Anatomy and Physiolog

Genetic Risk and Atrial Fibrillation in Patients with Heart Failure

Aims: To study the association between an atrial fibrillation (AF) genetic risk score with prevalent AF and all-cause mortality in patients with heart failure. Methods and results: An AF genetic risk score was calculated in 3759 European ancestry individuals (1783 with sinus rhythm, 1976 with AF) from the BIOlogy Study to TAilored Treatment in Chronic Heart Failure (BIOSTAT-CHF) by summing 97 single nucleotide polymorphism (SNP) alleles (ranging from 0–2) weighted by the natural logarithm of the relative SNP risk from the latest AF genome-wide association study. Further, we assessed AF risk variance explained by additive SNP variation, and performance of clinical or genetic risk factors, and the combination in classifying AF prevalence. AF was classified as AF or atrial flutter (AFL) at baseline electrocardiogram and/or a history of AF or AFL. The genetic risk score was associated with AF after multivariable adjustment. Odds ratio for AF prevalence per 1-unit increase genetic risk score was 2.12 (95% confidence interval 1.84–2.45, P = 2.15 × 10−24) in the total cohort, 2.08 (1.72–2.50, P = 1.30 × 10−14) in heart failure with reduced ejection fraction (HFrEF) and 2.02 (1.37–2.99, P = 4.37 × 10−4) in heart failure with preserved ejection fraction (HFpEF). AF-associated loci explained 22.9% of overall AF SNP heritability. Addition of the genetic risk score to clinical risk factors increased the C-index by 2.2% to 0.721. Conclusions: The AF genetic risk score was associated with increased AF prevalence in HFrEF and HFpEF. Genetic variation accounted for 22.9% of overall AF SNP heritability. Addition of genetic risk to clinical risk improved model performance in classifying AF prevalence

The influence of atrial fibrillation on the levels of NT-proBNP versus GDF-15 in patients with heart failure

In heart failure (HF), levels of NT-proBNP are influenced by the presence of concomitant atrial fibrillation (AF), making it difficult to distinguish between HF versus AF in patients with raised NT-proBNP. It is unknown whether levels of GDF-15 are also influenced by AF in patients with HF. In this study we compared the plasma levels of NT-proBNP versus GDF-15 in patients with HF in AF versus sinus rhythm (SR)

Comparing biomarker profiles of patients with heart failure:atrial fibrillation vs. sinus rhythm and reduced vs. preserved ejection fraction

Aims: The clinical correlates and consequences of atrial fibrillation (AF) might be different between heart failure with reduced vs. preserved ejection fraction (HFrEF vs. HFpEF). Biomarkers may provide insights into underlying pathophysiological mechanisms of AF in these different heart failure (HF) phenotypes. Methods and results: We performed a retrospective analysis of the BIOlogy Study to TAilored Treatment in Chronic Heart Failure (BIOSTAT-CHF), which was an observational cohort. We studied 2152 patients with HFrEF [ejection fraction (EF &lt; 40%)], of which 1419 were in sinus rhythm (SR) and 733 had AF. Another 524 patients with HFpEF (EF ≥50%) were studied, of which 286 in SR and 238 with AF. For the comparison of biomarker profiles, 92 cardiovascular risk markers were measured (Proseek® Olink Cardiovascular III panel). The circulating risk marker pattern observed in HFrEF was different than the pattern in HFpEF: in HFrEF, AF was associated with higher levels of 77 of 92 (84%) risk markers compared to SR; whereas in HFpEF, many more markers were higher in SR than in AF. Over a median follow-up of 21 months, AF was associated with increased mortality risk [multivariable hazard ratio (HR) of 1.27; 95% confidence interval (CI) 1.09–1.48, P = 0.002]; there was no significant interaction between heart rhythm and EF group on outcome. Conclusion: In patients with HFrEF, the presence of AF was associated with a homogeneously elevated cardiovascular risk marker profile. In contrast, in patients with HFpEF, the presence of AF was associated with a more scattered risk marker profile, suggesting differences in underlying pathophysiological mechanisms of AF in these HF phenotypes

Identifying optimal doses of heart failure medications in men compared with women: a prospective, observational cohort study

Background: Guideline-recommended doses of angiotensin-converting-enzyme (ACE) inhibitors or angiotensin-receptor blockers (ARBs), and β blockers are similar for men and women with heart failure with reduced ejection fraction (HFrEF), even though there are known sex differences in pharmacokinetics of these drugs. We hypothesised that there might be sex differences in the optimal dose of ACE inhibitors or ARBs and β blockers in patients with HFrEF. Methods: We did a post-hoc analysis of BIOSTAT-CHF, a prospective study in 11 European countries of patients with heart failure in whom initiation and up-titration of ACE inhibitors or ARBs and β blockers was encouraged by protocol. We included only patients with left ventricular ejection fraction less than 40%, and excluded those who died within the first 3 months. Primary outcome was a composite of time to all-cause mortality or hospitalisation for heart failure. Findings were validated in ASIAN-HF, an independent cohort of 3539 men and 961 women with HFrEF. Findings: Among 1308 men and 402 women with HFrEF from BIOSTAT-CHF, women were older (74 [12] years vs 70 [12] years, p&lt;0·0001) and had lower bodyweights (72 [16] kg vs 85 [18] kg, p&lt;0·0001) and heights (162 [7] cm vs 174 [8] cm, p&lt;0·0001) than did men, although body-mass index did not differ significantly. A similar number of men and women reached guideline-recommended target doses of ACE inhibitors or ARBs (99 [25%] vs 304 [23%], p=0·61) and β blockers (57 [14%] vs 168 [13%], p=0·54). In men, the lowest hazards of death or hospitalisation for heart failure occurred at 100% of the recommended dose of ACE inhibitors or ARBs and β blockers, but women showed approximately 30% lower risk at only 50% of the recommended doses, with no further decrease in risk at higher dose levels. These sex differences were still present after adjusting for clinical covariates, including age and body surface area. In the ASIAN-HF registry, similar patterns were observed for both ACE inhibitors or ARBs and β blockers, with women having approximately 30% lower risk at 50% of the recommended doses, with no further benefit at higher dose levels. Interpretation: This study suggests that women with HFrEF might need lower doses of ACE inhibitors or ARBs and β blockers than men, and brings into question what the true optimal medical therapy is for women versus men

Data from: Complete brood failure in an altricial bird is almost always associated with the sudden and permanent disappearance of a parent

1) A central goal in evolutionary ecology is to identify factors that explain variation in reproductive success, i.e. in the number of offspring produced. In altricial birds, a substantial part of this variation is determined by the number of nestlings that die before fledging, but the proximate cause of offspring mortality at a given nest is often unknown. 2) We used a uniquely comprehensive dataset of parental nestbox visits from seven breeding seasons to investigate the association between parental behaviour and nestling mortality in a population of blue tits (Cyanistes caeruleus). 3) In almost all nests that suffered complete brood mortality one of the parents had suddenly disappeared during the nestling stage. In contrast, parental disappearance in nests with partial brood mortality was rare and equally common as in nests with no brood loss. 4) With few exceptions, parents that disappeared during the nestling stage were never observed again and never returned to breed. In contrast, parents that remained after their partner disappeared were equally likely to be observed again or return to breed as parents of nests where both parents stayed. Visit rates at nests where a parent would disappear did not differ from those at nests where both parents stayed. 5) Taken together, our results show that - in contrast to partial brood failure - complete brood failure is almost always associated with the sudden and permanent disappearance of one of the parents, probably due to predation. Partial and complete brood mortality should therefore be treated as distinct processes that have different underlying causes

Data from: Complete brood failure in an altricial bird is almost always associated with the sudden and permanent disappearance of a parent

1) A central goal in evolutionary ecology is to identify factors that explain variation in reproductive success, i.e. in the number of offspring produced. In altricial birds, a substantial part of this variation is determined by the number of nestlings that die before fledging, but the proximate cause of offspring mortality at a given nest is often unknown. 2) We used a uniquely comprehensive dataset of parental nestbox visits from seven breeding seasons to investigate the association between parental behaviour and nestling mortality in a population of blue tits (Cyanistes caeruleus). 3) In almost all nests that suffered complete brood mortality one of the parents had suddenly disappeared during the nestling stage. In contrast, parental disappearance in nests with partial brood mortality was rare and equally common as in nests with no brood loss. 4) With few exceptions, parents that disappeared during the nestling stage were never observed again and never returned to breed. In contrast, parents that remained after their partner disappeared were equally likely to be observed again or return to breed as parents of nests where both parents stayed. Visit rates at nests where a parent would disappear did not differ from those at nests where both parents stayed. 5) Taken together, our results show that - in contrast to partial brood failure - complete brood failure is almost always associated with the sudden and permanent disappearance of one of the parents, probably due to predation. Partial and complete brood mortality should therefore be treated as distinct processes that have different underlying causes