Individual Condition (individual + condition)

Distribution by Scientific Domains

Selected Abstracts

Multiple Ornaments in Male Northern Cardinals, Cardinalis cardinalis, as Indicators of Condition

ETHOLOGY, Issue 2 2004
Jodie M. Jawor
Investigations of male ornaments in the context of sexual selection have tended to focus on single ornaments, although many species of birds possess multiple ornaments. Understanding the evolution of multiple ornaments requires knowledge of correlations among ornaments in the same individual and the extent to which ornament expression reflects individual condition and behavior. Variation in four male ornaments in socially monogamous, biparental northern cardinals (Cardinalis cardinalis) was related to body size, indices of condition, level of paternal care, and reproductive success. Redness of breast plumage positively predicted body size and negatively predicted nestling feeding rate. Bill color predicted current body condition, with birds with redder bills in better condition. Birds with smaller black face masks had greater reproductive success. These results are consistent with the hypothesis that different ornaments in male cardinals provide information on different aspects of condition and behavior. [source]

The functional significance of multiple nest-building in the Australian Reed Warbler Acrocephalus australis

IBIS, Issue 3 2006
The vast majority of bird species build a nest in which to breed. Some species build more than one nest, but the function of most multiple nest-building remains unclear. Here we describe the unusual nest-building behaviour of the Australian Reed Warbler Acrocephalus australis, and test experimentally the hypotheses that multiple nest-building is related to individual condition or territory quality, and plays a role in mate assessment. Australian Reed Warblers built two types of nest structures: ,type I' nests, which were used for eggs and nestlings, and ,type II' nests, which were structurally distinct from type I nests, did not support eggs, nestlings or adults and were not essential for successful breeding. The number of type II nests built in each territory varied. Type II nests were only built before breeding had commenced in a territory and females were not observed participating in their construction, supporting a role in female mate choice. Birds provided with supplementary food built significantly more type II nests than control birds. However, supplementary-fed birds did not have greater pairing success, and the addition of further type II nests to territories did not increase the pairing rate or type II nest construction in those territories. There was no relationship between the presence of type II nests and either reproductive success or likelihood of nest predation. We discuss the implications of these results in light of previous suggestions regarding the function of multiple nest-building in birds. [source]

Breeding habitat selection in cliff swallows: the effect of conspecific reproductive success on colony choice

Charles R. Brown
Summary 1.,One way that animals may select breeding sites is by assessing the reproductive success of conspecifics in one season and settling the next year in those habitat patches where success collectively had been greatest. This sort of habitat assessment may promote the formation of colonies at high quality sites. 2.,We examined whether cliff swallows, Petrochelidon pyrrhonota, in south-western Nebraska used conspecific breeding performance to choose colony sites. 3.,Reproductive success at colony sites varied spatially within seasons and between seasons, and was autocorrelated at a site from one year to the next, but not over longer time intervals. Cliff swallows thus met the conditions for potential use of information on conspecific breeding performance. 4.,Among sites re-used in consecutive years, those with highest collective success in one season showed the greatest rates in colony growth the next season, including the greatest influx of immigrants. 5.,The probability of colony-site re-use in successive years increased with collective reproductive success and average breeder body mass (a measure of individual condition) the previous season. 6.,Cliff swallows probably use conspecific breeding performance in selecting colonies. This mechanism is one component of habitat selection that also includes attraction to conspecifics and assessment of an individual's own success. [source]

Owls and rabbits: predation against substandard individuals of an easy prey

Vincenzo Penteriani
The interactions among the multiple factors regulating predator-prey relationships make predation a more complex process than previously thought. The degree to which substandard individuals are captured disproportionately seems to be better a function of the difficulty of prey capture than of the hunting techniques (coursing vs. ambushing predators). That is, when the capture and killing of a prey species is easy, substandard individuals will be predated in proportion to their occurrence in the prey population. In the present study, we made use of eagle owls Bubo bubo and their main prey, the rabbit Oryctolagus cuniculus: (a) the brightness of the white tails of rabbits seems to be correlated with the physical condition of individuals, (b) by using the tails of predated rabbits as an index of individual condition, we found that eagle owls seem to prefer substandard individuals (characterized by duller tails), and (c) by using information from continuous radiotracking of 14 individuals, we suggest that the difficulty of rabbit capture could be low. Although the relative benefits of preying on substandard individuals should considerably decrease when a predator is attacking an easy prey, we hypothesise that the eagle owl preference for substandard individuals could be due to the easy detection of poor individuals by a visual cue, the brightness of the rabbit tail. Several elements allow us to believe that this form of visual communication between a prey and one of its main predators could be more widespread than previously thought. In fact: (a) visual signalling plays a relevant role in intraspecific communication in eagle owls and, consequently, visual signals could also play a role in interspecific interactions, and (b) empirical studies showed that signals may inform the predator that it has been perceived, or that the prey is in a sufficiently healthy state to elude the predator. [source]

Context-dependent sexual advertisement: plasticity in development of sexual ornamentation throughout the lifetime of a passerine bird

A. V. Badyaev
Abstract Male investment into sexual ornamentation is a reproductive decision that depends on the context of breeding and life history state. In turn, selection for state- and context-specific expression of sexual ornamentation should favour the evolution of developmental pathways that enable the flexible allocation of resources into sexual ornamentation. We studied lifelong variation in the expression and condition-dependence of a sexual ornament in relation to age and the context of breeding in male house finches (Carpodacus mexicanus) , a species that develops a new sexual ornament once a year after breeding. Throughout males' lifetime, the elaboration of ornamentation and the allocation of resources to the development of sexual ornamentation depended strongly on pairing status in the preceding breeding season , males that were single invested more resources into sexual ornamentation and changed ornamentation more than males that were paired. During the initial (post-juvenile) moult, the expression of ornamentation was closely dependent on individual condition, however the condition-dependence of ornamentation sharply decreased throughout a male's lifetime and in older males expression of sexual ornamentation was largely independent of condition during moult. Selection for early breeding favoured greater ornamentation in males that were single in the preceding seasons and the strength of this selection increased with age. On the contrary, the strength of selection on sexual ornamentation decreased with age in males that were paired in the preceding breeding season. Our results reveal strong context-dependency in investment into sexual ornamentation as well as a high flexibility in the development of sexual ornamentation throughout a male's life. [source]

Remodeling of the SCF complex-mediated ubiquitination system by compositional alteration of incorporated F-box proteins

Mitsunori Kato
Abstract Ubiquitination regulates not only the stability but the localization and activity of substrate proteins involved in a plethora of cellular processes. The Skp1,Cullin,F-box protein (SCF) complexes constitute a major family of ubiquitin protein ligases, in each member of which an F-box protein serves as the variable component responsible for substrate recognition, thereby defining the function of each complex. Here we studied whether the composition of F-box proteins in the SCF complexes is remodeled under different conditions. We exploited stable isotope labeling and MS for relative quantification of F-box proteins in the SCF complexes affinity-purified en masse from budding yeast cells at log and post-diauxic phases, and revealed an increment of Saf1, an F-box protein involved in entry into quiescence, during the diauxic shift. Similarly, we found that Met4 overexpression induces a specific increment of Met30, the F-box protein responsible for ubiquitination of Met4. These results illustrate a cellular response to environmental and genetic perturbations through remodeling of the SCF complex-mediated ubiquitination system. Compositional alteration of incorporated F-box proteins may redirect the activity of this system toward appropriate substrates to be ubiquitinated under individual conditions for the maintenance of cellular homeostasis. [source]

Reconstruction of seminal ducts in obstructive azoospermia

ANDROLOGIA, Issue 4 2001
G. Popken
Summary. Depending on the localization of the obstruction of the seminal ducts, either a microsurgical reconstruction (tubulovasostomy, vasovasostomy) or a transurethral resection of the ejaculatory ducts is carried out. We have compared the effectiveness and economic advantages of reconstructive microsurgery of the epididymis and vas deferens with standard procedures in animal experiments. Microsurgical invagination techniques in tubulovasostomy are equal to the standard procedure from the point of view of the patency and fertility rates. They are also easier to learn and carry out. Less time is required for the invagination technique, and also less microsurgical suture material. The double-layer technique in vasovasostomy is equal to the one-layer microsurgical technique from the point of view of patency and fertility rates. The one-layer technique requires less time and suture material. It seems that the discrepancy between the patency and the fertility rate is related to immunological processes after reconstruction of the seminal ducts. In cases of obstructive azoospermia it is necessary to investigate the individual conditions and possibilities of the infertile couple. As a result of the high success rate obtainable today by surgical reconstruction of the seminal ducts, this must constitute the first type of treatment to be considered, before any of the procedures of reproductive medicine are undertaken. [source]

Autoimmune disease in individuals and close family members and susceptibility to non-Hodgkin's lymphoma

Lene Mellemkjaer
Objective Rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and Sjögren's syndrome have been consistently associated with an increased risk of non-Hodgkin's lymphoma (NHL). This study was initiated to evaluate the risks of NHL associated with a personal or family history of a wide range of autoimmune diseases. Methods A population-based case,control study was conducted that included 24,728 NHL patients in Denmark (years 1977,1997) and Sweden (years 1964,1998) and 55,632 controls. Using univariate logistic and hierarchical regression models, we determined odds ratios (ORs) of NHL associated with a personal history of hospital-diagnosed autoimmune conditions. Risks of NHL associated with a family history of the same autoimmune conditions were assessed by similar regression analyses that included 25,941 NHL patients and 58,551 controls. Results A personal history of systemic autoimmune diseases (RA, SLE, Sjögren's syndrome, systemic sclerosis) was clearly linked with NHL risk, both for individual conditions (hierarchical odds ratios [ORh] ranged from 1.6 to 5.4) and as a group (ORh 2.64 [95% confidence interval (95% CI) 1.72,4.07]). In contrast, a family history of systemic autoimmune diseases was modestly and nonsignificantly associated with NHL (ORh 1.31 [95% CI 0.85,2.03]). An increased risk of NHL was found for a personal history of 5 nonsystemic autoimmune conditions (autoimmune hemolytic anemia, Hashimoto thyroiditis, Crohn's disease, psoriasis, and sarcoidosis) (ORh ranged from 1.5 to 2.6) of 27 conditions examined. Conclusion Overall, our results demonstrate a strong relationship of personal history of systemic autoimmune diseases with NHL risk and suggest that shared susceptibility may explain a very small fraction of this increase, at best. Positive associations were found for a personal history of some, though far from all, nonsystemic autoimmune conditions. [source]

Moult speed constrains the expression of a carotenoid-based sexual ornament

Abstract We investigated the effect of moult speed on the expression of a sexually selected, carotenoid-based feather ornament in the rock sparrow (Petronia petronia). We experimentally accelerated the moult speed of a group of birds by exposing them to a rapidly decreasing photoperiod and compared the area and the spectral characteristics of their ornaments with those of control birds. Birds with accelerated moulting rate showed a smaller yellow patch with lower yellow reflectance compared to their slow-moulting counterparts. Considering that the time available for moulting is usually constrained between the end of the breeding season and migration or wintering, carotenoid feather ornaments, whose expression is mediated by moult speed, may convey long term information about an individual's condition, potentially encompassing the previous breeding season. Furthermore, the observed trade-off between moult speed and ornament expression may represent a previously unrecognized selective advantage for early breeding birds. [source]

An update on the honesty of melanin-based color signals in birds

Kevin J. McGraw
Summary The control mechanisms and information content of melanin-based color signals in birds have generated much recent interest and controversy among evolutionary biologists. Initial experimental studies on this topic manipulated coarse metrics of an individual's condition (i.e. food intake, disease state) and failed to detect significant condition-dependence of melanin ornament expression. However, three new lines of research appear profitable and target specific factors associated with the production of melanin pigments. These include the role of (i) metals, (ii) amino acids, and (iii) testosterone and social interactions in shaping the extent and intensity of melanin-colored plumage patches. Here, I review recent studies of and evidence for these honesty-reinforcing mechanisms. [source]