The melanocortin system is a neuroendocrine that regulates range of physiological and behavioural processes. We examined the extent to which simultaneously colour behaviour in cichlid fish Astatotilapia burtoni . found yellow males are more aggressive than blue males, line with previous studies. then exogenous α-melanocyte-stimulating hormone (α-MSH) increases yellowness body dispersal xanthophore pigments both morphs. However, α-MSH had morph-specific effect on aggression, only showing an...

The expression of sexually selected traits, such as ornaments or body coloration, is often influenced by environmental conditions. While phenotypic plasticity thought to precede evolutionary change, itself can also be a target selection. However, the selective forces supporting evolution and persistence in sexual traits are unclear. Using cichlid fish Astatotilapia burtoni , we show that variation level mate competition may promote coloration. In this species, males change between yellow...

The origin and maintenance of phenotypic polymorphisms is a classical problem in evolutionary ecology. Aggressive male–male competition can be source negative frequency-dependent selection stabilizing when aggression biased toward the own morph. We studied experimental assemblages red blue color morphs Lake Victoria cichlid fish Pundamilia. Aggression was investigated mixed-color single-color assemblages. found that indeed males same color, which could theory reduce levels promote...

Abstract Phenotypic plasticity allows organisms to adapt changing environments within their lifetimes. The cost of plastic adaptations may constrain the persistence over evolutionary time. One potential is possibility that phenotypic adjustment specific can cause correlated responses are not necessarily adaptive. Males in African cichlid Astatotilapia burtoni blue or yellow, and males able adjust body coloration color background, presumably increase crypsis. To test whether background...

An animal's ability to adapt a changing environment often requires the coordination of various traits. Across these traits, many covary with one another generate diversity complex phenomes tuned given ecology. While reports have documented trait covariation in populations, less is known about how plastic traits co-vary facilitate adaptation an individual. In African cichlids, morphology and behavior are two hallmarks driving adaptive speciation lineages within East Great Lakes. Here, we...

Male-male competition and female-female can play important roles in the origin maintenance of phenotypic polymorphism speciation. If territory owners bias aggression towards others their own phenotype, rare male phenotypes will be involved fewer costly fights, facilitating evolution diversity, stabilizing coexistence distinct or species. However, mechanisms that regulate biases have received little attention. We discuss how learning plasticity behavioral may dramatically influence evolve,...

Mate preferences on male colour have been implicated in generating and maintaining species diversity among haplochromine cichlid fish. Their lek-like mating system suggests that not only but also territory quality is instrumental mate choice. We assessed the relative importance of choice by testing whether can override female preference for males her own Lake Victoria genus Pundamilia. First, we showed experimental groups dominant preferentially monopolised a large tube to small tube. The...

Sexual selection on male coloration has been implicated in the evolution of colourful species flocks East African cichlid fish. During adaptive radiations, animals diverge multiple phenotypic traits, but role physiology received limited attention. Here, we report how divergence may contribute to stable coexistence two hybridizing incipient fish from Lake Victoria. Males Pundamilia nyererei (males are red) tend defeat those pundamilia blue), yet sibling coexist nature. It suggested that red...

Dominance hierarchies are a fundamental part of social systems in many species and rank can influence access to resources impact health physiology. While subordination is profound stressor, few studies consider the stress experienced by dominant males due constantly needing defend their dominance status through costly aggressive displays. Recent suggest that use body coloration signal status, these costs may also be color morph-specific. Our study examines link between rank, intensity...

Species that exhibit genetic color polymorphism are suitable for studying the evolutionary forces maintain heritable phenotypic variation in nature. Male morphs often differ behavioral dominance, affecting evolution of polymorphisms. However, dominance among female has received far less attention. We studied a polymorphic population cichlid fish Neochromis omnicaeruleus from Lake Victoria, which 3 distinct coexist, black-and-white blotched (WB), orange (OB), and plain (P) morphs. First, we...

It has been suggested that intrasexual competition can be a source of negative frequency-dependent selection, causing agonistic character displacement and facilitating speciation coexistence (sibling) species. In this paper we synthesise the evidence male-male female-female contributes to cichlid diversification, showing is stronger among same-coloured individuals than those with different colours. We argue selection more complex because there are several examples where males do not bias...

A mechanism commonly suggested to explain the persistence of color polymorphisms in animals is negative frequency-dependent selection. It could result from a social dominance advantage rare morphs. We tested for this males red and blue morphs Lake Victoria cichlid, Pundamilia. Earlier work has shown that preferentially attack their own morph, while are more likely win dyadic contests with males. In order study potential contribution both factors morph co-existence, we manipulated proportion...

Social work policy and practice all over the world continue to face impact of neoliberal agenda. Similarly, social education has been subject economic political changes, with an increasing emphasis on a discourse 'evidence-based practice'. However, it is core programs in higher initiate students fundamental values work, as they are recognized global definition work. In order prepare future workers for their assignment, human rights should be given explicit place curricula at Universities...

A study by Rowe et al . reported a winning bias for judo athletes wearing blue outfit relative to those white one during the 2004 Olympics. It was suggested that is associated with higher likelihood of through differential effects colour on opponent visibility and/or an intimidating effect opponent. However, we argue there no in judo. We show alternative factors, namely allocation biases, asymmetries prior experience and differences recovery time are possible confounding factors analysis...