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Data on reproductive success in traditional cultures suggest that for men, but not for women, range and variance rise as subsistence intensifies. For hunter gatherers, ranges and variances tend to cluster in single digits: they re...
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Data on reproductive success in traditional cultures suggest that for men, but not for women, range and variance rise as subsistence intensifies. For hunter gatherers, ranges and variances tend to cluster in single digits: they reach 15 or 16, at the high end. For herder-gardeners, ranges and variances are more consistently in double digits: they get as high as 80 or 85. And for full-time agriculturalists in the first civilizations, ranges consistently ran to triple digits: emperors from Mesopotamia to Peru were the fathers of hundreds of children. In human societies, as in other animal societies, reproductive skew goes up with a more sedentary life
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The Socotra Cormorant Phalacrocorax nigroogularis is a little studied, regional endemic seabird restricted to the Arabian Gulf region threatened by anthropogenic disturbance. The global population is estimated at 110,000 breeding ...
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The Socotra Cormorant Phalacrocorax nigroogularis is a little studied, regional endemic seabird restricted to the Arabian Gulf region threatened by anthropogenic disturbance. The global population is estimated at 110,000 breeding pairs. The Siniya Island colony, the largest in the United Arab Emirates (15,500 breeding pairs), was studied during the 2011 breeding season to determine baseline reproductive parameters and the effect of exotic trees on reproductive performance. Mean nesting density was 0.92 nests/m2 and shaded areas had significantly higher density (1.05/m2) compared to unshaded areas (0.75/m2). Mean clutch size was 2.4 eggs/nest and did not differ between shaded and unshaded areas. Mean egg volume was significantly higher in shaded (49.56 cm3) compared to unshaded areas (48.5 cm3). Hatching success was significantly higher in shaded (65.1%) compared to unshaded areas (46.6%). Fledging success was 65.6% and did not differ between shaded and unshaded areas. Chicks creched under trees soon after leaving their nests and this likely increased fledging success, regardless of whether chicks came from shaded or unshaded areas. Overall reproductive success was 1.7 chicks/nest. Higher egg volumes and hatching success under shaded areas suggest that plantations had a beneficial effect on the cormorants on Siniya Island and could be of conservation value. Further studies are required to determine what habitat features linked with these trees specifically aid in enhancing reproductive performance.
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Identifying the causes of individual variation in fitness should improve predictions about population dynamics and responses of populations to environmental change. Precise predictions may require long-term studies to parameterize...
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Identifying the causes of individual variation in fitness should improve predictions about population dynamics and responses of populations to environmental change. Precise predictions may require long-term studies to parameterize models when the fitness of individual phenotypes depends on environmental conditions. We used a 37-yr study of a resident Song Sparrow (Melospiza melodia) population to identify traits that predicted individual variation in female lifetime reproductive success and to test for context dependence in trait-fitness relationships. Specifically, we asked how individual inbreeding coefficient, maternal age, and a suite of natal morphological traits influenced 2 components of lifetime reproductive success: (1) the probability of surviving to breed, and (2) the lifetime number of offspring produced, given that a female bred locally. We then tested whether population density influenced trait-fitness relationships. We found that differences in natal traits had life-long impacts on female fitness. Lower maternal age, a higher inbreeding coefficient, later laying date, lower nestling body condition, and longer tarsi were all negatively related to lifetime reproductive success. Maternal age and the inbreeding coefficient influenced both components of lifetime reproductive success, whereas other factors only influenced one. Therefore, traits that predict the probability of surviving to breed locally may differ from those that predict the number of offspring produced. We also observed larger effects of the inbreeding coefficient on fitness in years of low population density, which were often preceded by cool winters. Our findings demonstrate that natal traits and the environment experienced early in a bird's life can have life-long effects on individual fitness, primarily independent of population density.
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Very little information is available for Peucaea botterii texana (Texas Botteri's Sparrow) and nothing is known about its nesting ecology, in part due to its cryptic behavior and nesting strategies. Our goal was to examine the nes...
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Very little information is available for Peucaea botterii texana (Texas Botteri's Sparrow) and nothing is known about its nesting ecology, in part due to its cryptic behavior and nesting strategies. Our goal was to examine the nesting ecology of Texas Botteri's Sparrows and compare reproductive success between exotic and native grasslands. We searched for and monitored nests in 2004 and 2005 on the King Ranch in southern Texas. We found no relationship in reproductive effort, nest characteristics, and plant species richness around the nest between grassland types. Vegetation surrounding Texas Botteri's Sparrow nests was significantly taller and denser in native grasslands than in exotic grasslands. Further research on nesting ecology for the Texas Botteri's Sparrow is necessary to determine its habitat needs and its role as an indicator of grassland quality.
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Female fitness is often influenced by trade-offs in energy allocated to reproduction or self-maintenance that is dependent upon the life history of the organism. Maternal body size and condition are factors that are often positive...
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Female fitness is often influenced by trade-offs in energy allocated to reproduction or self-maintenance that is dependent upon the life history of the organism. Maternal body size and condition are factors that are often positively correlated with clutch size and offspring size. We investigated whether maternal body size (snout-vent length, SVL) and condition (residual of mass on SVL) could predict measures of reproductive success including clutch size, offspring body size (SVL), and offspring survival in the territorial Eastern Red-backed Salamander (Plethodon cinereus). Brooding females and their eggs were collected and then housed in a controlled laboratory setting. We recorded the number of eggs found with each female and separated offspring from females once hatched. At 40 d after hatching, we measured the SVL and mass of females and juveniles. Maternal SVL, but not condition, was positively related to clutch size and offspring SVL; however, there was no significant relationship between clutch size and offspring SVL, indicating no trade-off between number and body size of offspring. In the laboratory, survival of the offspring to 185 d post-hatching was positively related to maternal SVL and negatively related to maternal condition. Also, the mean SVL, measured on day 40, of the offspring that survived to 185 d was significantly greater than the SVL of the offspring that did not survive, indicating a benefit of larger offspring body size. Finally, subsequent egg production (number of new oocytes produced by females following the current reproductive bout) was positively related to maternal SVL and condition (measured 185 d after hatching their previous clutches). These results suggest that larger maternal body size and condition of Eastern Red-backed Salamanders provide increased reproductive success through the number and body size of offspring produced in current or subsequent reproductive bouts and in offspring survival. Large body size in territorial anima
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Motivated by the success of the Janowski starlike function, we consider here closely related functions for log-harmonic mappings of the form f (z) = zh(z)g(z) defined on the open unit disc U. The functions are in the class of the ...
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Motivated by the success of the Janowski starlike function, we consider here closely related functions for log-harmonic mappings of the form f (z) = zh(z)g(z) defined on the open unit disc U. The functions are in the class of the generalized Janowski starlike log-harmonic mapping, S~(1h)(A, B, a) , with the functional zh(z) in the class of the generalized Janowski starlike functions, S* (A, B, a). By means of these functions, we obtained results on the generalized Janowski close-to-starlike log-harmonic mappings, CST_(1h)(A, B, a).
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The reproductive success of predators depends on abiotic environmental conditions, food abundance and population density, and food abundance, density and their interactions may respond to changes in climatic conditions. Timing of ...
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The reproductive success of predators depends on abiotic environmental conditions, food abundance and population density, and food abundance, density and their interactions may respond to changes in climatic conditions. Timing of reproduction by five of the eight numerically most common prey of the sparrowhawk Accipiter nisus advanced significantly since 1971, during a period of temperature increase. There was no evidence that mean laying date or any other reproductive parameter of sparrowhawks changed consistently during the study period 1977–1997. Laying date advanced and percentage of unsuccessful female sparrowhawks decreased with beech mast in the current year, an index of food abundance for avian prey. Mean laying date of sparrowhawks was advanced in warmer springs, and although mean clutch size was not larger in warm than in cold springs, mean brood size of successful pairs and breeding success increased in such springs, showing that sparrowhawks enjoyed a fitness gain when reproducing early. The timing of sparrowhawk reproduction with respect to the peak in abundance of fledgling prey increased, from a good match between mean timing of fledging by prey and maximum demand for food by the predator in 1977, to reproduction occurring later than the peak in fledging prey availability in 1997. The size of the breeding population of sparrowhawks was not predicted by mean spring temperature, the size of the breeding population the previous year or beech mast crop. The size of the post-breeding population was predicted by size of the breeding and post-breeding population the previous year and by the proportion of unsuccessful females the current year. These findings imply that sparrowhawks did not respond to change in climate, although climate changed the timing of reproduction by the main prey species.
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This study investigates dioecious fig species using a pollinator introduction experiment. Our aims were to determine: (1) whether there was a significant difference in foundress distribution between sexes per fig species; (2) whet...
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This study investigates dioecious fig species using a pollinator introduction experiment. Our aims were to determine: (1) whether there was a significant difference in foundress distribution between sexes per fig species; (2) whether fig size and foundress number affect reproductive success of dioecious figs; and (3) who is the 'controlling partner' in the fig/pollinator mutualism. Three dioecious fig species: Ficus semicordata, Ficus hispida and Ficus tinctoria from Xishuangbanna, China, were selected for this experiment. We found that there was no significant difference of the foundress number in female and male figs of F. semicordata, F. hispida and F. tinctoria. Also, the foundress number did not depend on the fig diameter. The numbers and the proportions of fig seeds and female wasp offspring significantly increased with more foundresses; and fig seed number was significantly higher than female wasp offspring in F. semicordata and F. hispida, but not in F. tinctoria. Our results indicate that figs are generally the 'controlling partner' in fig-wasp mutualisms in species with large figs, but not with small figs. Compared with published studies of reproductive success in monoecious figs, the dioecious figs seem to be more efficient in producing both seeds and wasp offspring when there is a high number of foundress.
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The reproductive biology of Hyalella longistila (Faxon, 1876), a freshwater amphipod found in streams in southeastern Brazil, was investigated. We assessed body-size relationships between paired and unpaired males and females as w...
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The reproductive biology of Hyalella longistila (Faxon, 1876), a freshwater amphipod found in streams in southeastern Brazil, was investigated. We assessed body-size relationships between paired and unpaired males and females as well as the egg stage, fecundity, relationship between number of eggs and their stage, number of eggs and female size, and pairing and reproductive success. A positive Spearman rank correlation was observed between the cephalothorax length (CL) of paired males and females. The mean CL of paired males and females was positively related, indicating a size-assortative mating. The mean fecundity was 12.88 +/- 2.00 eggs per female, with peaks in August 2012 and September 2012, with 16.82 and 15.08 eggs per female, respectively. The developmental stage and the number of eggs found on the brood pouch were negatively correlated, indicating that as the embryo developed, fewer eggs remained in the egg pouch (marsupium). Higher values for male pairing success were observed for size classes between 0.59 and 0.67 mm, and both sexes presented higher values for reproductive success between 0.63 and 0.68 mm. Our results could support conservation practices or even studies using such amphipods as model organisms.
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Bateman’s principles of sexual selection predict that the sex with “cheaper” gametes may maximize reproductive efforts by mating multiply and so display greater positive covariance between reproductive and mating success. We co...
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Bateman’s principles of sexual selection predict that the sex with “cheaper” gametes may maximize reproductive efforts by mating multiply and so display greater positive covariance between reproductive and mating success. We conducted a semi-controlled breeding experiment to genetically quantify sexual selection in adult Ambystoma texanum, a sexually monomorphic salamander with simple courtship behaviors. We used four polymorphic microsatellite loci to genotype 57 adults enclosed in a breeding wetland and compared their multilocus profiles to that of 862 embryos collected from the enclosure. The molecular data were used to assign parentage, investigate the mating system, and measure sexual selection intensity. Parentage analyses indicated 36% of dams and 93% of sires were genetically sampled via their gametes but physically unsampled, suggesting that a large number of breeders over-wintered within the enclosure and/or some females released into the enclosure were already inseminated. We used the genetic data to generate estimates of individual reproductive and mating success and we interpret these in light of salamander behavior and sexual selection theory. The incidence of multiple mating in females (86%) was considerably higher than in males (32%) and the standardized variance in mating success was significantly greater in females. The correlations between reproductive and mating success were significant and of similar magnitude between the sexes, indicating that both sexes increased reproductive success through increased mating success. This pattern may be a function of differential opportunities for mating success between the sexes.
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