Phaeomelanin matters: Redness associates with inter-individual differences in behaviour and feather corticosterone in male scops owls (Otus scops).

Individuals within populations often show consistent variation in behavioural and physiological traits which are frequently inter-correlated, potentially leading to phenotypic integration. Understanding the mechanisms behind such integration is a key task in evolutionary ecology, and melanin based colouration has been suggested to play a pivotal role. In birds, most of plumage colour variation is determined by two types of melanin, eumelanin and phaeomelanin, but the role of phaeomelanin in avian phenotype integration has been barely investigated. Here, we test for covariation between phaeomelanin-based colouration, behavioural traits (i.e. nest territoriality, aggressiveness, breath rate and parental behaviour) and corticosterone in feathers in the polymorphic scops owl Otus scops, a bird species in which more phaeomelanic individuals display reddish colourations. In males, we observed that reddish males took longer to return to their nests and showed higher levels of feather CORT than more greyish ones. Behaviour and feather CORT were not associated to plumage colour in females. The found associations between redness, behaviour and feather CORT in males, but not in females, might suggest the existence of a sex-specific integrated phaeomelanic phenotype in scops owls.

Six Collective Challenges for Sustainability of Almería Greenhouse Horticulture.

Globally, current food consumption and trade are placing unprecedented demand on agricultural systems and increasing pressure on natural resources, requiring tradeoffs between food security and environmental impacts especially given the tension between market-driven agriculture and agro-ecological goals. In order to illustrate the wicked social, economic and environmental challenges and processes to find transformative solutions, we focus on the largest concentration of greenhouses in the world located in the semi-arid coastal plain of South-east Spain. Almería family farming, predominantly cooperative, greenhouse intensive production, commenced after the 1960s and has resulted in very significant social and economic benefits for the region, while also having important negative environmental and biodiversity impacts, as well as creating new social challenges. The system currently finds itself in a crisis of diminishing economic benefits and increasing environmental and social dilemmas. Here, we present the outcomes of multi-actor, transdisciplinary research to review and provide collective insights for solutions-oriented research on the sustainability of Almeria's agricultural sector. The multi-actor, transdisciplinary process implemented collectively, and supported by scientific literature, identified six fundamental challenges to transitioning to an agricultural model that aims to ameliorate risks and avoid a systemic collapse, whilst balancing a concern for profitability with sustainability: (1) Governance based on a culture of shared responsibility for sustainability, (2) Sustainable and efficient use of water, (3) Biodiversity conservation, (4) Implementing a circular economy plan, (5) Technology and knowledge transfer, and (6) Image and identity. We conclude that the multi-actor transdisciplinary approach successfully facilitated the creation of a culture of shared responsibility among public, private, academic, and civil society actors. Notwithstanding plural values, challenges and solutions identified by consensus point to a nascent acknowledgement of the strategic necessity to locate agricultural economic activity within social and environmental spheres.This paper demonstrates the need to establish transdisciplinary multi-actor work-schemes to continue collaboration and research for the transition to an agro-ecological model as a means to remain competitive and to create value.

Avian and rodent responses to the olfactory landscape in a Mediterranean cavity community.

Animals rely on cues informing about future predation risk when selecting habitats to breed in. Olfactory information may play a fundamental role in the assessment of predation threats, because predators produce characteristic body odours, but the role of odours in habitat selection has seldom been considered. Here, we test whether fear of predation induced by odour cues may affect the settlement pattern of a Mediterranean cavity-dependent community of rodents and non-excavator hole-nesting birds. To test this hypothesis, we experimentally manipulated the perception of predation risk on a scale of patch by applying either odours of a carnivore predator (risky odour treatment), lemon essence (non-risky odour treatment) and a control non-odorous treatment and studied bird and rodent settlement patterns. Nest-box occupation probability differed across treatments so that species in the community settled in more numbers in control than in non-risky and than in risky odour-treated nest boxes. Concerning settlement patterns, control nest boxes were occupied more rapidly than nest boxes with odour information. Birds and rodents settled earlier in control than in risky odour-treated nest boxes, but their settlement pattern did not significantly vary between risky odour and non-risky odour-treated nest boxes. Our findings demonstrate that olfactory cues may be used to assess habitat quality by settling species in this community, but we cannot pinpoint the exact mechanism that has given rise to the pattern of preference by nest boxes.

Receivers matter: the meaning of alarm calls and competition for nest sites in a bird community.

Animal communities may constitute information networks where individuals gain information on predation risk by eavesdropping on alarm calls of other species. However, communities include species in different trophic levels, and it is not yet known how the trophic level of the receiver influences the informative value of a call. Furthermore, no empirical study has yet tested how increased competition may influence the value of alarm calls for distinct receivers. Here, we identify the importance of alarm calls emitted by a small owl, the little owl (Athene noctua), on the structure of a cavity-nesting bird community including mesopredators and primary prey under variable levels of competition for nest holes. Competitors sharing top predators with the callers and prey of the callers interpreted alarm and non-alarm calls differently. Competitors chose preferentially alarm and non-alarm patches over control patches to breed, while prey selected alarm patches. In contrast, competition for nest sites affected habitat selection of prey species more than that of competitors of the callers. This study provides support for a changing value of alarm calls and competition for nest sites for distinct receivers related to niche overlapping among callers and eavesdroppers, therefore, calling attention to possible cascading effects by the use of information in natural communities.

An experimental test of host's life history traits modulation in response to cuckoo parasitism risk.

Hosts can counteract parasites through defences based on resistance and/or tolerance. The mechanistic basis of tolerance, which involve defensive mechanisms minimizing parasite damage after a successful parasitic attack, remains poorly explored in the study of cuckoo-host interactions. Here, we experimentally explore the possibility that the risk of great spotted cuckoo Clamator glandarius parasitism may induce tolerance defences in magpie Pica pica hosts through plasticity in life-history traits. We predict that magpies exposed to auditory cues indicating high parasitism risk will more likely exhibit resistance and/or modify their life-history traits to minimize parasitism costs (i.e. tolerance) compared to magpies under low parasitism risk. We found that manipulating the perceived parasitism risk did not affect host resistance (i.e. rejection of parasitic eggs) nor host life-history traits. Unexpectedly, host's egg volume increased over the season in nests exposed to auditory cues of control non-harmful hoopoes Upupa epops. Our results do not provide support for inducible defences (either based on resistance or tolerance) in response to risk of parasitism in magpie hosts. Even so, we encourage studying plastic expression of breeding strategies in response to risk of cuckoo parasitism to achieve a better understanding of the mechanistic basis of tolerance defences.

Exploratory behaviour modulates the relationship between colony familiarity and helping in a cooperative bird.

Individuals within animal groups may differ in personality and degree of familiarity raising the question of how this influences their social interactions. In Iberian magpies Cyanopica cooki, a portion of first-year males engage in cooperative behaviours and dispersal, allowing addressing this question. In this study, we first investigate the relationship between colony familiarity (native versus foreign) and reproductive status (breeding versus helping) of males during 21 years. Secondly, we measure the exploratory behaviour and monitor reproductive status of a sample of individuals with different colony familiarity during 2 years. Long-term monitoring revealed that foreign individuals were more likely breeders. The analysis on the subset of individuals in which exploratory behaviour was measured revealed a mediatory effect of exploratory behaviour in the association between colony familiarity and helping behaviour. Specifically, among foreign individuals, higher explorative males were more frequently involved in helping behaviour than lower explorative ones. Conversely, among native males, breeders were more explorative than helpers. Our results suggest that aspects of personality may mediate the value of familiarity in reproductive tasks in social species.