Incest avoidance, extrapair paternity, and territory quality drive divorce in a year-round territorial bird

Divorce can be an important behavioral strategy to improve fitness. This is particularly relevant for species that are territorial year-round with continuous partnerships, where individuals face constraints on partner choice due to limited vacancies and dispersal opportunities. We tested several hypotheses for divorce in such a species, the cooperatively breeding bird Malurus coronatus. Based on 9 years of detailed information on dispersal and survival of 317 breeding pairs, we tested whether divorce is driven by inbreeding avoidance, by a better partner or territory, or by social variables (number of subordinates and fidelity of partners). We found that divorce is important to escape incest: incestuous pairs were substantially more likely to divorce (64%) than non-incestuous pairs (14%). However, incestuous pair bonds lasted up to a year, highlighting constraints on breeder dispersal. Non-incestuous pairs also divorced, but here the only predictor for divorce was the presence of extrapair offspring in a previous brood. Although reproductive failure did not trigger divorce, and reproductive success did not improve in the year following divorce, females that dispersed after divorce obtained higher quality territories, unlike females that dispersed after their partner died. Thus, divorce may be a strategy to improve long-term benefits associated with better territories. Some divorces appeared to be forced evictions by older females, although direct evidence for this is limited. Taken together, our findings demonstrate the complexity of factors that affect the occurrence of divorce when partner choice is constrained

No evidence for constitutive innate immune senescence in a longitudinal study of a wild bird

Aging is associated with declines in physiological performance; declining immune defenses particularly could have consequences for age-related fitness and survival. In aging vertebrates, adaptive (memory-based) immune responses typically become impaired, innate (nonspecific) responses undergo lesser declines, and inflammation increases. Longitudinal studies of immune functions in wild animals are rare, yet they are needed to understand immunosenescence under evolutionarily relevant conditions. Using longitudinal data from a tropical passerine (Malurus coronatus) population, we investigate how population trends emerge from within-individual changes and between-individual heterogeneity (e.g., selective disappearance) in immune status. We quantified constitutive immune indexes (haptoglobin [inflammation associated], natural antibodies, complement [lytic] activity, and heterophil-lymphocyte ratio; n p 505–631) in individuals sampled one to seven times over 5 yr. Unexpectedly, longitudinal analyses showed no age-related change within individuals in any immune index, despite sufficient power to detect within-individual change. Between individuals, we found age-related declines in natural antibodies and increases in heterophil-lymphocyte ratios. However, selective disappearance could not adequately explain between-individual age effects, and longitudinal models could not explain our data better than cross-sectional analyses. The lack of clear within-individual immunosenescence is itself notable. Persistent levels of haptoglobin, complement activity, and natural anti- bodies into old age suggests that these immune components are maintained, potentially with adaptive significance

More than kin:Subordinates foster strong bonds with relatives and potential mates in a social bird

Social interactions shape relationships between individuals in complex societies. Affiliative interactions are associated with benefits and strengthen social bonds, while aggressive interactions are costly and negatively affect social bonds. Individuals may attempt to reduce aggressive encounters through submissive displays directed at higher-ranking individuals. Thus, fine-scale patterns of affilia-tive, aggressive, and submissive interactions may reflect costly and beneficial social relationships within groups, providing insight into the benefits of group living and the mechanisms of conflict resolution. So far, however, most studies have looked at social interactions and benefits of group living in isolation. We investigated how the strength of social bonds (affiliative vs. aggressive interactions) and submissive displays varied with kin-selected and potential mating benefits, and with reproductive conflict in the cooperatively breeding purple-crowned fairy-wren, Malurus coronatus. Our results revealed that subordinates formed equally strong social bonds with kin and potential mates (unrelated opposite-sex individuals) while they formed antagonistic relationships with reproductive competitors that offered no kin-selected or mating benefits (unrelated same-sex individuals). Submissive displays were directed exclusively at same-sex breeders, regardless of relatedness. Affiliation and submission were associated with reduced foraging time when food was limited, indicating a cost to maintaining positive relationships. Together, our results suggest that the strength of social bonds is determined by (potential) benefits obtained from group members, while submission likely serves to reduce conflict. Our findings highlight the importance of time-costly social interactions for maintaining relationships with group members, providing insight into how social groups of individuals with (partly) divergent interests can remain stable.</p

PCV23: VARIATION IN COSTS OF TREATING HYPERCHOLESTEROLEMIC PATIENTS IN FRANCE

The evolution of male ornamentation has long been the focus of sexual selection studies. However, evidence is accumulating that sexually selected traits can also be lost, although the process is ill-understood. In male fairy-wrens (Malurus spp.), early molt into the seasonal breeding plumage is critical for obtaining extra-pair paternity (EPP), which reaches very high levels in these socially monogamous songbirds. A notable exception is the purple-crowned fairy-wren, Malurus coronatus, which, like its congeners, breeds cooperatively, but where EPP is very rare. Nevertheless, males develop a conspicuous seasonal breeding plumage at highly variable times. Based on 6 years of molt data collected for 137 individuals, we investigated the adaptive significance of pre-breeding molt timing as a sexual signal under (near) genetic monogamy. Molt timing varied between and within individuals with age and climate: molt was completed earlier in older males and after wetter years. Despite its potential to act as a sexual signal of male quality, fitness benefits and costs of early molt appear limited: molt timing did not correlate with 1) the likelihood of gaining a breeding position; 2) female mate preference (EPP/cuckoldry, divorce); 3) female reproductive investment (breeding timing, clutch size, number of clutches); 4) breeding performance (hatching success, fledging success, fledgling survival, annual reproductive success); and 5) male survival. However, although molt timing did not predict which subordinates would become breeders, breeders molted earlier than subordinates. The lack of EPP in this species might imply relaxed sexual selection on early molt with potential to lead to trait disappearance

Telomere length declines with age, but relates to immune function independent of age in a wild passerine

Telomere length (TL) shortens with age but telomere dynamics can relate to fitness components independent of age. Immune function often relates to such fitness components and can also interact with telomeres. Studying the link between TL and immune function may therefore help us understand telomere-fitness associations. We assessed the relationships between erythrocyte TL and four immune indices (haptoglobin, natural antibodies (NAbs), complement activity (CA) and heterophil-lymphocyte (HL) ratio; n = 477-589), from known-aged individuals of a wild passerine (Malurus coronatus). As expected, we find that TL significantly declined with age. To verify whether associations between TL and immune function were independent of parallel age-related changes (e.g. immunosenescence), we statistically controlled for sampling age and used within-subject centring of TL to separate relationships within or between individuals. We found that TL positively predicted CA at the between-individual level (individuals with longer average TL had higher CA), but no other immune indices. By contrast, age predicted the levels of NAbs and HL ratio, allowing inference that respective associations between TL and age with immune indices are independent. Any links existing between TL and fitness are therefore unlikely to be strongly mediated by innate immune function, while TL and immune indices appear independent expressions of individual heterogeneity.</p

From ornament to armament or loss of function?:Breeding plumage acquisition in a genetically monogamous bird

The evolution of conspicuous male traits is thought to be driven by female mate choice or male-male competition. These two mechanisms are often viewed as distinct processes, with most studies focusing on female choice. However, both mechanisms of sexual selection can act simultaneously on the same trait (i.e., dual function) and/or interact in a synergistic or conflicting way. Dual-function traits are commonly assumed to originate through male-male competition before being used in female choice; yet, most studies focusing on such traits could not determine the direction of change, lacking phylogenetic information. We investigated the role of conspicuous male seasonal plumage in male-male competitive interactions in the purple-crowned fairy-wren Malurus coronatus, a cooperatively breeding bird. Male breeding plumage in most Malurus species is selected by female choice through extra-pair mate choice, but unlike its congeners, M.coronatus is genetically monogamous, and females do not seem to choose males based on breeding plumage acquisition. Our study shows that, within groups, subordinate males that were older, and therefore higher-ranked in the queue for breeder position inheritance, produced a more complete breeding plumage. In line with this, subordinate males that were older and/or displayed a more complete breeding plumage were more successful in competitively acquiring a breeder position. A role as a signal of competitive ability was experimentally confirmed by presenting models of males: in breeding colours, these received more aggression from resident breeder males than in nonbreeding colours, but elicited limited response from females, consistent with competitors in breeding plumage being perceived as a bigger threat to the breeder male. The role of the conspicuous breeding plumage in mediating male-male interactions might account for its presence in this genetically monogamous species. As phylogenetic reconstructions suggest a past female choice function in M.coronatus, this could represent a sexual trait that shifted functions, or a dual-function trait that lost one function. These evolutionary scenarios imply that intra- and intersexual functions of ornaments may be gained or lost independently and offer new perspectives in understanding the complex dynamics of sexual selection

Early-life telomere length predicts lifespan and lifetime reproductive success in a wild bird

Poor conditions during early development can initiate trade-offs that favour current survival at the expense of somatic maintenance and subsequently, future reproduction. However, the mechanisms that link early and late life-history are largely unknown. Recently it has been suggested that telomeres, the nucleoprotein structures at the terminal end of chromosomes, could link early-life conditions to lifespan and fitness. In wild purple-crowned fairy-wrens, we combined measurements of nestling telomere length (TL) with detailed life-history data to investigate whether early-life TL predicts fitness prospects. Our study differs from previous studies in the completeness of our fitness estimates in a highly philopatric population. The association between TL and survival was age-dependent with early-life TL having a positive effect on lifespan only among individuals that survived their first year. Early-life TL was not associated with the probability or age of gaining a breeding position. Interestingly, early-life TL was positively related to breeding duration, contribution to population growth and lifetime reproductive success because of their association with lifespan. Thus, early-life TL, which reflects growth, accumulated early-life stress and inherited TL, predicted fitness in birds that reached adulthood but not noticeably among fledglings. These findings suggest that a lack of investment in somatic maintenance during development particularly affects late life performance. This study demonstrates that factors in early-life are related to fitness prospects through lifespan, and suggests that the study of telomeres may provide insight into the underlying physiological mechanisms linking early- and late-life performance and trade-offs across a lifetime.</p

Multiple hypotheses explain variation in extra-pair paternity at different levels in a single bird family

Extra‐pair paternity (EPP), where offspring are sired by a male other than the social male, varies enormously both within and among species. Trying to explain this variation has proved difficult because the majority of the interspecific variation is phylogenetically based. Ideally, variation in EPP should be investigated in closely related species, but clades with sufficient variation are rare. We present a comprehensive multifactorial test to explain variation in EPP among individuals in 20 populations of nine species over 89 years from a single bird family (Maluridae). Females had higher EPP in the presence of more helpers, more neighbours or if paired incestuously. Furthermore, higher EPP occurred in years with many incestuous pairs, populations with many helpers and species with high male density or in which males provide less care. Altogether, these variables accounted for 48% of the total and 89% of the interspecific and interpopulation variation in EPP. These findings indicate why consistent patterns in EPP have been so challenging to detect and suggest that a single predictor is unlikely to account for the enormous variation in EPP across levels of analysis. Nevertheless, it also shows that existing hypotheses can explain the variation in EPP well and that the density of males in particular is a good predictor to explain variation in EPP among species when a large part of the confounding effect of phylogeny is excluded

Tapping into non-English-language science for the conservation of global biodiversity.

The widely held assumption that any important scientific information would be available in English underlies the underuse of non-English-language science across disciplines. However, non-English-language science is expected to bring unique and valuable scientific information, especially in disciplines where the evidence is patchy, and for emergent issues where synthesising available evidence is an urgent challenge. Yet such contribution of non-English-language science to scientific communities and the application of science is rarely quantified. Here, we show that non-English-language studies provide crucial evidence for informing global biodiversity conservation. By screening 419,679 peer-reviewed papers in 16 languages, we identified 1,234 non-English-language studies providing evidence on the effectiveness of biodiversity conservation interventions, compared to 4,412 English-language studies identified with the same criteria. Relevant non-English-language studies are being published at an increasing rate in 6 out of the 12 languages where there were a sufficient number of relevant studies. Incorporating non-English-language studies can expand the geographical coverage (i.e., the number of 2° × 2° grid cells with relevant studies) of English-language evidence by 12% to 25%, especially in biodiverse regions, and taxonomic coverage (i.e., the number of species covered by the relevant studies) by 5% to 32%, although they do tend to be based on less robust study designs. Our results show that synthesising non-English-language studies is key to overcoming the widespread lack of local, context-dependent evidence and facilitating evidence-based conservation globally. We urge wider disciplines to rigorously reassess the untapped potential of non-English-language science in informing decisions to address other global challenges. Please see the Supporting information files for Alternative Language Abstracts

Conexão entre comportamento reprodutivo e estrutura da paisagem : o caso do tiziu (volatinia jacarina – linnaeus, 1766) no Distrito Federal

Dissertação (mestrado)—Universidade de Brasília, Instituto de Ciências Biológicas, Departamento de Ecologia, Programa de Pós-Graduação em Ecologia, 2012.As agregações territoriais em aves têm sido documentadas para várias espécies e existem muitas hipóteses para explicar as vantagens dos padrões de agregação. O tiziu (Volatinia jacarina) é um ave neotropical que estabelece territórios para alimentação, exibição e nidificação durante a época reprodutiva. Este estudo foi feito numa paisagem perturbada no Cerrado durante a temporada chuvosa de 2010. Foi testado se o tamanho do território e o número de machos nos agregados influenciavam parâmetros comportamentais das aves e o sucesso de nidificação. Também, foi testado se os parâmetros comportamentais ou o sucesso de nidificação era influenciado pelas características da paisagem (filtro grosso) ou da vegetação local (filtro fino). Os resultados mostram que o tamanho de território não tem relação com o número de machos dentro de um agregado, mas existe uma relação significativa entre o tamanho de território e o sucesso de nidificação. A taxa de exibição não teve relação com número de machos dentro dos agregados, mas houve uma tendência no aumento da taxa nos machos que chegaram à área no final da estação reprodutiva. Na escala maior, os resultados mostram que o padrão agregado foi influenciado pela proximidade dos corpos de água, pela maior complexidade da estrutura da vegetação e maior quantidade de árvores, sendo esses alguns dos preditores utilizados para avaliar o sucesso de nidificação. A taxa de exibição teve uma relação negativa com a altura do capim. Os resultados indicam que os elementos dominantes da paisagem influenciam a escolha do habitat pelas aves (filtro grosso), mas a estrutura da vegetação (filtro fino) destaca a influência da mesma no sucesso de nidificação e no comportamento reprodutivo. É importante entender as vantagens das agregações territoriais para os indivíduos dentro da população e como estas observações apoiam a ideia de uma estratégia mista na escolha de habitat: primeiramente baseada nas características físicas do habitat e depois na presença dos conspecíficos. ______________________________________________________________________________________ ABSTRACTTerritorial clustering has been documented in various bird species and several hypotheses have been proposed to explain aggregation patterns. The Blue-black Grassquit is a neotropical bird that establishes all-purpose territories during the breeding season. This study was conducted in a modified landscape within the Brazilian Cerrado during the 2010 rainy season. We examined whether territory size and/or density of male aggregations influence some behavioral parameters for nesting success. Also, we examined if male’s behavioral parameters or nesting success was influenced by landscapeor territory’s vegetation characteristics. Our results show that the number of displaying males within a cluster has no relation with territory size. However, we found a significant relation between territory size and nesting success. Display rate was not related with number of males in clusters but it increased in the males established at the end of the season. These results suggest territory size is a good predictor of pair formation. The results show that the clustered pattern is influenced by water proximity; also, more complex strata of vegetation and higher amount of trees are good predictors for nesting success. We also found a negative relation between display rate and height of grass cover. All these findings could explain the influence of dominant landscape elements in habitat selection by birds, and also how micro scale vegetation analysis might influence reproductive behavior. It is important to understand the benefits of territorial clustering for each individual within a population and how these observations might support the combined strategy in habitat selection: first based on habitat physical characteristics and then by the presence of conspecifics