Birds are known to respond nest-dwelling parasites by altering behaviours. Some bird species, for example, bring fresh plants the nest, which contain volatile compounds that repel parasites. There is evidence some birds living in cities incorporate cigarette butts into their nests, but effect (if any) of this behaviour remains unclear. Butts from smoked cigarettes retain substantial amounts nicotine and other may also act as arthropod repellents. We provide first function a parasite...

Variable environments impose constraints on adaptation by modifying selection gradients unpredictably. Optimal bird development requires an adequate thermal range, outside which temperatures can alter nestling physiology, condition and survival. We studied the effect of temperature nest heat exposure reproductive success a population double‐brooded S potless tarlings turnus unicolor breeding in nestbox colony central Spain with marked intra‐seasonal variation temperature. assessed whether...

The field of androgen deposition in avian eggs and its consequences for offspring development has received a lot attention recent research. However, although variation within clutches yolk androgens is relatively well understood, the adaptive significance patterns between remains rather unclear. Furthermore, it been hypothesized that act as means an maternal effect to adjust given posthatching environment. Thus, are likely depend on specific environment brood. We experimentally manipulated...

Two main substances are responsible for the pigmentation of eggshells birds and reptiles: bluish-green tone comes from biliverdin (BV), protoporphyrin IX (PP) gives brown hues. BV PP can form complexes with metal cations. The objective this investigation is to carry out a theoretical study that analyzes interaction cations (Cu2+, Ag2+, Au2+, Cd2+, Zn2+, Hg2+) PP. divalent ions Cu Ag selected have compounds same charge. Density functional theory (DFT) calculations were used investigate...

Sibling competition has been shown to affect overall growth rates in birds. However, consists on the coordinated development of a multitude structures, and there is ample scope for developmental plasticity trade-offs among these structures. We would expect that structures are used sibling competition, such as gape altricial nestlings, should be prioritized under intense competition. conducted an experiment spotless starling ( Sturnus unicolor ), cross-fostering nestlings nests with different...

The developmental rate of cuckoo embryos and their hatching size is greater than that host species, which may require more nutrient resources in the egg intensive gas exchange during development. In present study, we compared various characteristics a brood parasite, common Cuculus canorus , its frequent host, great reed warbler Acrocephalus arundinaceus . As maternally‐derived testosterone known to enhance growth hatchlings, eggs are expected contain higher concentration eggs. addition,...

Plumage coloration plays an important role in visual communication by signaling aspects of individual quality. It has been proposed that the need for preserving plumage condition and hence content may have promoted a novel mechanism: cosmetic coloration. Here, we investigated whether preen waxes act as cosmetics affecting feathers' ornamental male house finches (Carpodacus mexicanus). We (1) blocked access to uropygial gland group males compared their with control (2) applied wax extracted...

Variation in immunity is influenced by allocation trade-offs that are expected to change between age-classes as a result of the different environmental and physiological conditions individuals encounter over their lifetime. One such trade-off occurs with carotenoids, which must be acquired food involved variety functions. Nonetheless, relationships carotenoids species where these micronutrients scarce due diet poorly studied. Among birds, vultures show lowest concentrations plasma based on...

The role of chemical communication in the social relationships birds is receiving growing attention, but our knowledge still scarce compared to that other taxa. Previous evidence suggests cues emitted by may carry information about their characteristics, which be useful context sexual selection. However, experimental studies are needed investigate bird signalling quality potential partners. We performed an study aimed at disentangling whether female Zebra Finches (Taeniopygia guttata), use...

The intensity of color expression in animals plays a key role social environments as mechanism to signal individual capacities competitive contests. Selective pressures for resource competition differ at different stages life and between sexes; therefore, coloration is expected vary juveniles adults males females. Exploring the covariance other traits may help understand functional significance action natural selection on multivariate phenotypes. Melanin-based plumage was investigated masked...

The objective of this research is to test the effects copper on color pacific white shrimp (Litopenaeus vannamei) in vivo. Forty-eight shrimps (L. were exposed a low concentration (1 mg/L; experimental treatment) and forty-eight used as controls (no added water). As result experiment, it was found that with more are significantly redder than those designated (hue (500–700 nm): P = 0.0015; red chroma (625–700 P<0.0001). These results indicate may from exposure challenge commonly held view...

1. Social and ecological conditions experienced by individuals during early life can strongly influence their development survival. Nestlings of many species present important variations in plasma androgens that be associated with begging sibling competition may translate into fitness effects, since broods higher testosterone (T) production have better body condition fledging success. However, the positive effects counterbalanced a reduction immune defences greater susceptibility to...

Several studies have shown that melanin‐based traits play a crucial role in social contexts as they are associated with dominance, personality and behaviour. However, most of these focused on adults, the juveniles has rarely been explored. Here, we explore association between two nestling Common Kestrels Falco tinnunculus . Our results show female nestlings blacker plumages displayed bolder personalities, providing evidence sex‐dependent phenotypic integration males females. We consider this...

Abstract Knowing how animals adapt their phenotype to local temperature and humidity is key understanding not only ecogeographical rules, but also species will manage climate change, as current models predict changes in global patterns of precipitation. In endotherms, colour adaptations response have been under investigated, acclimatization-the individual capacity reversibly adjust different environments-is unknown. Geographic trends can provide clues about abiotic variables involved...

Abstract The sexually selected egg colour hypothesis (SSECH) proposes that colouration is as a post‐mating signal of female phenotypic quality, maintained by higher allocation paternal care. Similarly, some traits can reflect genetic quality or condition and males could use this information in mate choice modulating parental investment. In our study, we examined the correlation individual variation with expression male ornament how feeding covaried these two spotless starling, which varies...

In birds, female egg allocation patterns have a strong influence in offspring development and differential investment size composition has been shown to respond male attractiveness. this study we experimentally manipulated the perceived attractiveness of starlings Sturnus unicolor by increasing amount green material some nests (a courtship display species). We predicted that, if before laying is related attractiveness, experimental females would increase their reproductive response addition...

Sexual dimorphism (SD) has evolved in response to selection pressures that differ between sexes. Since such change across an individual's life, SD may vary within age classes. Yet, little is known about how on early phenotypes drive the final observed adults. In many dimorphic species, juveniles resemble adult females rather than males, meaning out of selective established by sexual feminized be adaptive. If true, fitness benefits female-like constrain expression male adulthood. Using common...

The detection of predator chemical cues is an important antipredatory behaviour as it allows early assessment predation risk without encountering the and therefore increases survival. For instance, since are often by-products metabolism, olfaction may gather information not only on identity but also about diet predators in vicinity. Knowledge role interactions birds with their environment, contexts avoidance, still scarce. We conducted two two-choice experiments to explore 1) whether house...

The pigments responsible for eggshell color and patterning in birds are protoporphyrin IX (PP) biliverdin (BV). Both involved the catalytic degradation of hemo group. Bilirubin (BR), another pigment, is produced when BV broken down. PP, BV, BR free radical scavengers. In this study, we theoretically investigated antioxidant capacities these three biological meaningful molecules using Density Functional Theory calculations. First, two mechanisms were analyzed BR: electron transfer Hydrogen...