scholarly journals Differences in sibling cooperation in presence and absence of parental care in a genus with interspecific variation in offspring dependence

Evolution ◽  
2021 ◽  
Author(s):  
Madlen A. Prang ◽  
Lena Zywucki ◽  
Maximilian Körner ◽  
Sandra Steiger
2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Alexandra Capodeanu-Nägler ◽  
Eva M. Keppner ◽  
Heiko Vogel ◽  
Manfred Ayasse ◽  
Anne-Katrin Eggert ◽  
...  

The Condor ◽  
2005 ◽  
Vol 107 (4) ◽  
pp. 775-787 ◽  
Author(s):  
Veronika Bókony ◽  
András Liker

Abstract Avian color ornaments produced by different mechanisms (i.e., melanin, carotenoid, and structural colors) can communicate different sets of information due to differences in their condition or developmental constraints. Although this suggests that different color signals should be analyzed separately, few comparative studies have focused on specific types of coloration. In cardueline finches, interspecific variation in overall plumage brightness (which integrates all types of coloration) was previously shown to be affected by sexual selection and to covary with fecundity and parental care. Using a phylogenetic comparative approach, we extended this line of research and tested whether a specific component of plumage ornamentation, the melanin-based black frontal coloration of finches, showed a similar association with reproductive effort. We found that the extent of male melanization and melanin dichromatism increased in species with reduced clutch sizes, whereas female melanization was negatively correlated with incubation length. These results remained significant when we controlled for the effects of several ecological variables, and were also consistent between two alternative multivariate model-selection approaches. Our results are consistent with the hypothesis that interspecific variation in melanization may be related to fecundity and parental care through trade-offs between investment in sexual signals and parental efforts.


2019 ◽  
Author(s):  
Gretchen F. Wagner ◽  
Szymon Marian Drobniak ◽  
Michael Griesser

Reproductive allocation varies greatly across species and is determined by their life-history and ecology. This variation is usually assessed as the number of eggs or propagules (hereafter: fecundity). However, in species with parental care, individuals face trade-offs that affect the allocation of resources among the stages of reproduction as well as to reproduction as a whole. Thus, it is critical to look beyond fecundity to understand the evolution of life-histories and how investment into different reproductive components interact with each other. Here we assessed the influence of species-specific traits and ecological factors on interspecific variation in reproductive performance at each nesting stage of 72 avian populations. Annual productivity was unrelated to annual fecundity. Annual fecundity correlated positively with a fast life-history pace, precociality and non-migratory habits, but these traits were unrelated to reproductive success. Rather, the breeding ecology of a species determined productivity at each stage of nesting, but did not influence fecundity. These results challenge prevailing theory and emphasize that conclusions of interspecific variation in fitness based on numbers of eggs may be equivocal. Moreover, parental decisions regarding reproductive allocation face diverse constraints at different stages of reproduction, influencing the evolution of reproductive tactics in species with parental care.


1977 ◽  
Vol 20 (2) ◽  
pp. 233-240 ◽  
Author(s):  
Sharon F. Garber ◽  
Richard R. Martin

The present study was designed to assess the effects of increased vocal level on stuttering in the presence and absence of noise, and to assess the effects of noise on stuttering with and without a concomitant increase in vocal level. Accordingly, eight adult stutterers spoke in quiet with normal vocal level, in quiet with increased vocal level, in noise with normal level, and in noise with increased level. All subjects reduced stuttering in noise compared with quiet conditions. However, there was no difference in stuttering when subjects spoke with normal compared with increased vocal level. In the present study, reductions in stuttering under noise could not be explained by increases in vocal level. It appears, instead, that reductions in stuttering were related to a decrease in auditory feedback. The condition which resulted in the largest decrease in auditory feedback, speaking in noise with a normal level, also resulted in the largest decrease in stuttering.


1995 ◽  
Vol 5 (12) ◽  
pp. 1689-1695 ◽  
Author(s):  
John Thoms ◽  
Peter Donahue ◽  
Doug Hunter ◽  
Naeem Jan

1998 ◽  
Vol 79 (01) ◽  
pp. 87-90 ◽  
Author(s):  
D. W. Jones ◽  
M. Winter ◽  
M. J. Gallimore

SummaryFactor XII (FXII) levels were determined in plasma samples from 29 normal donors, 10 patients with inherited FXII deficiency (all lupus anticoagulant [LA] negative) and 67 LA positive patients, using clotting (FXIIct), chromogenic substrate (FXIIcs) and immunochemical (FXIIag) assays. Excellent correlations were obtained in the three FXII assays with the LA negative samples and between the FXIIcs and FXIIag assays in the LA positive samples. Correlations between both the FXIIcs and FXIIag with FXIIct in the LA positive patients were poor. Of 67 LA positive samples studied, 25 (37.3%) showed lower values in the FXIIct assay; 13 (19.4%) of these patients were pseudo FXII deficient with values of FXII below the lower limit of normal.These results indicate that a diagnosis of FXII deficiency can be made inappropriately in the presence of phospholipid antibodies and that such a diagnosis should not be made by FXIIct assay alone.


1990 ◽  
Vol 64 (01) ◽  
pp. 061-068 ◽  
Author(s):  
H R Lijnen ◽  
B Van Hoet ◽  
F De Cock ◽  
D Collen

SummaryThe activation of plasminogen by t-PA was measured in the presence and absence of fibrin stimulation, using natural human plasminogen (nPlg) and rPlg-Ala740, a recombinant plasminogen with the active site Ser740 mutagenaed to Ala. Recombinant wild type t-PA (rt-PA) was used as well as rt-PA -Glul275, a recombinant single chain t-PA in which the Arg of the plasmin sensitiv e Arg275- Ile276 peptide bond was substituted with Glu. Conversion of 125I-labeled single chain plasminogen to two-chain plasmin by wild-type or mutant t-PA, was quantitated by SDS gel electrophoresis and radioisotope counting of gel slices, and expressed as initial activation rates (v0 in pM s−1) per 1 μM enzyme. In the absence of fibrin stimulation, the vs for the activation of nPlg and rPlg-Ala740 with the single chain forms of both t-PAs were comparable (0.6 to 2.7 pM s−1) but were lower than with the corresponding two-chain forms (5.3 to 23 pM s−1). In the presence of 1 μM soluble fibrin monomer (desAAfibrin), the v0 for nPlg and rPlg-Ala740 by single chain rt-PA was also comparable (24 and, 33 pM s-1 respectively), whereas with 1 pM CNBr-digested fibrinogen, the vs for nPlg with single chain rt-PA was about 20-fold higher than that of rPlg-Ala740 (135 and 7.5 pM s−1 respectively). In contrast, the vs for nPlg and rPlg-Ala740 by single chain rt-PA- G1u275, two-chain rt-PA-G1u275 or two-chain rt-PA were comparable in the presence of either desAAfibrin or CNBr-digested fibrinogen.These findings confirm and establish: 1) that single chain t-PA is an active enzyme both in the presence and absence of fibrin stimulator; 2) that, in a system devoid of plasmin activity (rPlg- Ala740), the two-chain form of t-PA is about L5 times more active than the single chain form in the absence of fibrin but equipotent in the presence of desAAfibrin; and 3) that the mechanism of stimulation of plasminogen activation with single chain t-PA by CNBr-digested fibrinogen is different from that by soluble fibrin.


Sign in / Sign up

Export Citation Format

Share Document