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Certain traits of recipient environments, such as the availability of limiting resources, strongly determine the establishment success and spread of non-native species. These limitations may be overcome through behavioral plasticity, allowing them to exploit alternative resources. Here, we show how a secondary cavity nester bird, the rose-ringed parakeet Psittacula krameri, innovates its nesting behavior as a response to the shortage of tree cavities for nesting in its invasive range in Tenerife (Canary Islands). We observed that some breeding pairs excavated their own nest cavities in palms, thus becoming primary cavity nester, whereas others occupied nests built with wood sticks by another invasive species, the monk parakeet Myiopsitta monachus. The use of these novel nesting strategies increased the number of breeding pairs by up to 52% over 6 years, contributing to a 128.8% increase of the whole population. Innovative nests were located at greater heights above ground and were more aggregated around conspecifics but did not result in greater breeding success than natural cavities. Occupation of monk parakeet colonies by rose-ringed parakeets also benefited the former species through a protective-nesting association against nest predators. Our results show how an invasive species innovate nesting behaviors and increase nest-site availability in the recipient environment, thus facilitating its population growth and invasion process. Potential behavioral innovations in other invasive rose-ringed parakeet populations may be overlooked, and should be considered for effective management plans.

Intra-specific coloration polymorphism coupled with an ancient process of lineage differentiation in Berberomeloe majalis (Linnaeus, 1758) offers the opportunity to analyse the temporal scenario in which the correlation between toxicity and coloration might have evolved. Based on phylogenetic and phylogeographic analyses, we identified the timing for the split between red-striped and entirely black morphotypes of B. majalis. To evaluate whether coloration patterns and toxicity are related in this species, we quantified the concentration of cantharidin across morphotypes and phylogeographic lineages. Phylogenetic analyses based on cox1 mitochondrial DNA sequences recovered three major clades where both morphotypes were intermingled, indicating a multiple homoplastic origin for the entirely black coloration. Our analyses showed that cantharidin content did not differ between morphs of B. majalis; however, it significantly increased in haemolymph in females kept isolated from males, which reveals the females’ ability either to concentrate cantharidin towards haemolymph or to synthesize cantharidin themselves. Lack of monophyly and absence of genetic isolation in both morphotypes favour the hypothesis of a recent homoplastic phenomenon to explain the loss of the striped pattern. Our phylogenetic and phylogeographic analyses show that changes in coloration are recent, suggesting that the ancient pressures that fixed and maintained red-striped colorations are no longer acting today on B. majalis. The absence of change in cantharidin content (i.e. entirely black and red-striped specimens are equally poisonous) suggests that the evolution of colour polymorphisms in B. majalis is probably decoupled from toxicity., CGL2010-15786, CGL2008-02567, CGL2012-36345, y CGL2015-66571-P

We studied the effect of capture and handling on free-living red-billed choughs Pyrrhocorax pyrrhocorax. We analysed the association between bird behavioural response and individual health, breeding status, sex, and age. Active responses (aggression towards the ringer, screaming) were more common in the breeding period, and in individuals with a high heterophils to lymphocytes ratio, indicating poor physiological condition and/or high chronic stress. Adults were more aggressive than juveniles and yearlings, and females were more aggressive than males. Sex, age, and condition differences were also recorded in the spectrotemporal output of distress calls. Birds with a screaming/active response appeared to be more stress-susceptible than passive and silent individuals, and this response was stronger during the energy demanding period of reproduction. The results obtained suggest that the response of the red-billed chough during capture might primarily reflect stress-susceptibility, although a number of potential alternative explanations are discussed. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 96, 846–855.

Studies of sibling competition within brood hierarchies have rarely assessed simultaneously the effects of sex and rank in the brood hierarchy on traits other than offspring mortality and differential growth. We studied the expression of heat-shock proteins (Hsps) to assess the physiological stress response to different combinations of sex and position within competitive brood hierarchies in the black kite Milvus migrans (Bodd.), a sexually dimorphic raptor showing facultative siblicide. Senior males showed higher stress levels than did senior females and younger siblings of each sex as revealed by Hsp60 values. The analysis of Hsp70 levels indicated that nestlings from broods in which the senior chick was a male showed higher stress levels than did nestlings from broods in which the senior chick was a female. In addition, levels of Hsp60 were related negatively to nutritional condition expressed as levels of plasmatic albumin. This suggests that the sex of senior chicks may be key in determining their stress level and that of their siblings, which is probably associated with sibling competition by fighting within brood hierarchies. The comparatively higher stress levels of senior males (and their siblings) may be a consequence of their ability to exploit their potential advantage from being the head start while avoiding a possible competitive disadvantage from being the smaller sex, independent of environmental conditions determining the probability of brood reduction. Differential stress levels depending on sex and rank in the brood hierarchy may be a consequence of parental control of offspring behaviour through differential resource allocation (e.g. yolk androgens) or it may reflect adaptations of particular chicks (senior males) to enhance their competitive ability within brood hierarchies.

We assessed the potential control of female Scops owls (Otus scops) over the production of daughters and sons in relation to their order in the laying sequence, and investigated the possible adaptive value of such control on the survival and growth of nestlings. The population sex ratio at fledging was not significantly biased. A relationship between ovulation order and egg sex was found, which was mostly due to the strong male biased sex ratio among initial eggs, as 17 of 18 first-hatched chicks (94%) from first-laid eggs were males. Asynchronous laying and subsequent asynchronous hatching resulted in a decreasing survival of chicks with increasing hatching order. Female chicks fledged with a higher mass than males and fledging mass decreased with hatching order due to male biased hatching order and its influence in the growth of the single first-hatched female. These results suggest that female Scops owls may be able to adjust the sex of their offspring at egg production to invest differentially in their survival and growth. © 2002 The Linnean Society of London, Biological Journal of the Linnean Society, 2002, 76, 1–7.

The immune system has high costs of maintenance and production and expression of immune function should be dependent on the condition of the individual. The fitness cost that parasites impose on hosts may then be reflected in the investment that hosts make in immunity. Little is known about sources and consequences of intra- and interspecific variation in the presence and size of organs of the immune system in relation to ectoparasitism. Variation in the presence and size of the bursa of Fabricius and spleen size was measured to assess potential relationships between immune defence, nutritional condition and ectoparasites in the Magpie Pica pica. We found three species of lice (Mallophaga), two species of louse flies (Hippoboscidae), and the larvae of a tick (Ixodidae) infecting magpies. Age explained a significant proportion of variation in prevalence and number of parasite species, first-year birds being more parasitized than adults. Spleen size increased with nutritional condition, and the level of ectoparasitism negatively affected nutritional condition. Only one species of lice (Philopterus picae) was involved; the negative effect of this species on nutritional condition was more pronounced in males than females. These results are consistent with the hypotheses of condition-dependent investment in the immune system and sexual differences in susceptibility to parasite effects. Ectoparasites may thus play a role in modulating the relationship between condition and immune defence. We also found evidence for an interaction between the bursa and the spleen. Magpies with bursa had larger spleens than those where it had atrophied. This interaction did not affect ectoparasitism or nutritional condition.

The authors’ previous study showed the presence of follicular dendritic cell (FDC) networks—though altered—in neoplastic areas, not only in the nodular lymphocyte predominance type, but also in other types of Hodgkin’s disease. The present retrospective study was performed on 102 patients to determine whether the presence or absence of FDC networks, or parts of them, in neoplastic areas has prognostic relevance in Hodgkin’s disease. Follicular dendritic cells were visualized with the monoclonal antibody Ki-FDCl P, which selectively stains FDCs in paraffin- embedded tissues. Univariate statistical analysis, in which nodular sclerosis (NS) and mixed cellularity (MC) types were combined, showed three prognostically different groups: the best prognosis was associated with nodular lymphocyte predominance cases; the worst with FDC-negative NS or MC cases; and an intermediate prognosis with FDC-positive NS or MC cases. In the NS group, the prognosis of FDC-positive cases was better than that of FDC-negative cases. After multivariate analysis, stepwise modeling identified three prognostic factors at diagnosis: stage ( P = .001), FDC status ( P = .001), and age ( P = .06). The authors conclude that in the most common types of Hodgkin’s disease (nodular lymphocyte predominance, NS, and MC), FDC status in the neoplastic area(s) bears prognostic relevance, a positive FDC status predicting a favorable prognosis and a negative FDC status an unfavorable one.

In previous studies, Epstein–Barr virus was considered a possible etiologic factor in Hodgkin’s disease. Two hundred twenty-nine cases of Hodgkin’s disease were investigated for the presence of Epstein–Barr virus DNA using the polymerase chain reaction technique on formalin-fixed, paraffin-embedded lymph node tissue to clarify the clinical importance of the incidence of this genome. In 42 cases (18.3%), genomic DNA was not amplifiable. The remaining 187 cases included the following subtypes: lymphocyte-predominant type (n = 13), nodular sclerosis type (n = 98), mixed cellularity type (n = 68), and lymphocyte-depleted type (n = 8). Sixty-six cases (35.2%) were positive for Epstein–Barr virus DNA. In the statistical analysis of available follow-up data from 130 patients, no influence of a positive Epstein–Barr virus DNA finding on length of survival time was revealed. This was true within the cohort of all patients and within the histologically defined subtypes of Hodgkin’s disease. In this investigation, detection of Epstein–Barr virus DNA by polymerase chain reaction showed no prognostic relevance for patients with Hodgkin’s disease.