Heterospecific egg destruction by Wattled Starlings and the impact on Pied Babbler reproductive success

Ostrich ◽  
2011 ◽  
Vol 82 (3) ◽  
pp. 201-205 ◽  
Author(s):  
A R Ridley ◽  
A M Thompson
Author(s):  
Gus Mills ◽  
Margaret Mills

This book demonstrates how cheetahs are adapted to arid savannahs like the southern Kalahari, and makes comparisons with other areas, especially the Serengeti. Topics dealt with are: demography and genetic status; feeding ecology, i.e. methods used for studying diet, diets of different demographic groups, individual diet specializations of females, prey selection, the impact of cheetah predation on prey populations, activity regimes and distances travelled per day, hunting behaviour, foraging success and energetics; interspecific competition; spatial ecology; reproductive success and the mating system; and conservation. The major findings show that cheetahs are well adapted to arid ecosystems and are water independent. Cheetah density in the study area was stable at 0.7/100 km2 and the population was genetically diverse. Important prey were steenbok and springbok for females with cubs, gemsbok, and adult ostrich for coalition males, and steenbok, springhares, and hares for single animals. Cheetahs had a density-dependent regulatory effect on steenbok and springbok populations. Females with large cubs had the highest overall food intake. Cheetahs, especially males, were often active at night, and competition with other large carnivores, both by exploitation and interference, was slight. Although predation on small cubs was severe, cub survival to adolescence was six times higher than in the Serengeti. There was no difference in reproductive success between single and coalition males. The conservation priority for cheetahs should be to maintain protected areas over a spectrum of landscapes to allow ecological processes, of which the cheetah is an integral part, to proceed unhindered.


2020 ◽  
Vol 126 (5) ◽  
pp. 957-969
Author(s):  
Enya N Quiroz-Pacheco ◽  
Francisco Mora ◽  
Karina Boege ◽  
César A Domínguez ◽  
Ek del-Val

Abstract Background and Aims The implications of herbivory for plant reproduction have been widely studied; however, the relationship of defoliation and reproductive success is not linear, as there are many interacting factors that may influence reproductive responses to herbivore damage. In this study we aimed to disentangle how the timing of foliar damage impacts both male and female components of fitness, and to assess when it has greater impacts on plant reproductive success. Methods We measured herbivore damage and its effects on floral production, male and female floral attributes as well as fruit yield in three different phenological phases of Casearia nitida (Salicaceae) over the course of two consecutive years. Then we tested two models of multiple causal links among herbivory and reproductive success using piecewise structural equation models. Key Results The effects of leaf damage differed between reproductive seasons and between male and female components of fitness. Moreover, the impact of herbivory extended beyond the year when it was exerted. The previous season’s cumulated foliar damage had the largest impact on reproductive characters, in particular a negative effect on the numbers of inflorescences, flowers and pollen grains, indirectly affecting the numbers of infructescences and fruits, and a positive one on the amount of foliar damage during flowering. Conclusions For perennial and proleptic species, the dynamics of resource acquisition and allocation patterns for reproduction promote and extend the effects of herbivore damage to longer periods than a single reproductive event and growing season, through the interactions among different components of female and male fitness.


2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Sue Anne Zollinger ◽  
Adriana Dorado-Correa ◽  
Wolfgang Goymann ◽  
Wolfgang Forstmeier ◽  
Ulrich Knief ◽  
...  

Abstract The impact of human activity on the acoustic environment is overwhelming, with anthropogenic noise reaching even remote areas of the planet. The World Health Organization has identified noise pollution as one of the leading environmental health risks in humans, and it has been linked to a myriad of short- and long-term health effects in exposed individuals. However, less is known about the health effects of anthropogenic noise exposure on animals. We investigated long- and short-term effects of traffic noise on zebra finches breeding in small communal aviaries, using a repeated measures design. Birds bred in both noise and no-noise conditions, and we measured baseline plasma glucocorticoid levels before, during and after breeding. In addition, we assayed immune function, measured reproductive success and offspring growth and compared rates of extra-pair paternity of breeding adults. Breeding birds had significantly lower baseline plasma corticosterone levels when exposed to traffic noise than when they were not exposed to noise playback. In addition, the nestlings reared during noise exposure were lighter than nestlings of the same parents when breeding in control conditions. Our results suggest that traffic noise poses a more severe hurdle to birds at more vulnerable stages of their life history, such as during reproductive events and ontogeny. While chronic exposure to traffic noise in our birds did not, by itself, prove to be a sufficient stressor to cause acute effects on health or reproductive success in exposed individuals, it did result in disruptions to normal glucocorticoid profiles and delayed offspring growth. However, animals living in urban habitats are exposed to a multitude of anthropogenic disturbances, and it is likely that even species that appear to be thriving in noisy environments may suffer cumulative effects of these multiple disturbances that may together impact their fitness in urban environments.


2019 ◽  
Vol 129 (2) ◽  
pp. 334-346
Author(s):  
Veronika Nezhybová ◽  
Martin Reichard ◽  
Caroline Methling ◽  
Markéta Ondračková

Abstract Parasitic infections may affect the reproductive success of the host either directly, through behavioural modification, or indirectly, by altering their reproductive investment in response to infection. We determined the effects of infection with the eye fluke Diplostomum pseudospathaceum (Trematoda) on the reproductive traits of European bitterling (Rhodeus amarus, Cyprinidae), an intermediate fish host with a resource-based mating system. Male bitterling infected by Diplostomum exhibited a larger but less pronounced red eye spot (sexually selected signal) than control males, suggesting that infected males were less preferred by females. The frequency of female ovulation and number of offspring were comparable between the infected and the control group, although there was a 1–2 week delay in the peak of ovulation and offspring production in infected fish, which is known to coincide with higher juvenile mortality. Chronic eye fluke infection had minimal metabolic costs (measured as oxygen consumption) and, consistent with these results, reproductive activity did not differ between infected and control fish in an experimental test of intersexual selection. Overall, the impact of eye fluke infection on the reproduction of European bitterling was limited. We consider the potential effect of favourable conditions during experiments (abundant food, access to spawning substrate and lack of predators and co-infections) on experimental outcomes and recognize that the effects of chronic eye fluke infection in natural conditions might be more pronounced.


1982 ◽  
Vol 39 (7) ◽  
pp. 968-978 ◽  
Author(s):  
Isaac J. Schlosser

The impact of removing riparian vegetation, channel straightening, and fluctuations in flow regime on trophic structure, reproductive success, and growth rate of fishes was assessed in a natural (Jordan Creek (JC)) and modified (Big Ditch (BD)) headwater stream in east-central Illinois. Shallow habitats and organic substrates increased more in BD than JC during low flow periods in summer. Insect densities in JC were highest in late spring, declining to low levels by late summer. Insect densities in BD were high throughout summer. Fish in JC were predominantly benthic insectivores and insectivore–piscivores; trophic structure, age structure, and biomass were stable between years and seasons; recruits made up a small and stable portion of community biomass and were primarily insectivore–piscivores and generalized insectivores; younger age-classes were in shallow riffle habitats. Adult fish and recruits in BD were predominantly generalized insectivores, omnivores, and herbivore–detritivores; the last two were primarily mid-river species (Carpoides cyprinus and Dorosoma cepedianum). Considerable seasonal and annual variation in trophic structure, total biomass, and age structure occurred in BD associated with annual fluctuations in flow regime, abundance of organic substrates, and reproductive success of mid-river species. Younger age-classes had higher summer growth rates in BD than JC. The temporally variable physical environment and unstable autotrophic energy base created in modified headwater streams are probably major factors responsible for recent shifts in large river fish communities in the midwestern United States from insectivore and insectivore–piscivore species to omnivores and herbivore–detritivores.Key words: community organization, fishes, Illinois, stream continuum, stream alteration, trophic ecology, warmwater stream


Oecologia ◽  
2010 ◽  
Vol 164 (2) ◽  
pp. 411-421 ◽  
Author(s):  
Andrew D. Higginson ◽  
Graeme D. Ruxton ◽  
John Skelhorn

2018 ◽  
Vol 103 ◽  
pp. 1-10 ◽  
Author(s):  
Hanna Ruhmann ◽  
Mareike Koppik ◽  
Mariana F. Wolfner ◽  
Claudia Fricke

Parasitology ◽  
2015 ◽  
Vol 142 (8) ◽  
pp. 1033-1043 ◽  
Author(s):  
M. ZYLBERBERG ◽  
E. P. DERRYBERRY ◽  
C. W. BREUNER ◽  
E. A. MACDOUGALL-SHACKLETON ◽  
J. M. CORNELIUS ◽  
...  

SUMMARYThe impact of haematozoan infection on host fitness has received substantial attention since Hamilton and Zuk posited that parasites are important drivers of sexual selection. However, short-term studies testing the assumption that these parasites consistently reduce host fitness in the wild have produced contradictory results. To address this complex issue, we conducted a long-term study examining the relationship between naturally occurring infection withHaemoproteusandPlasmodium, and lifetime reproductive success and survival of Mountain White-crowned Sparrows. Specifically, we tested the hypothesis that birds infected with haematozoan parasites have reduced survival (as determined by overwinter return rates) and reproductive success. Contrary to expectation, there was no relationship betweenHaemoproteusandPlasmodiuminfection and reproduction or survival in males, nor was there a relationship betweenPlasmodiuminfection and reproduction in females. Interestingly,Haemoproteus-infected females had significantly higher overwinter return rates and these females fledged more than twice as many chicks during their lifetimes as did uninfected females. We discuss the impact of parasitic infections on host fitness in light of these findings and suggest that, in the case of less virulent pathogens, investment in excessive immune defence may decrease lifetime reproduction.


2010 ◽  
Vol 365 (1560) ◽  
pp. 4043-4050 ◽  
Author(s):  
Daniel Nettle ◽  
Lars Penke

The concept of personality has recently begun to attract a great deal of interest in behavioural ecology. However, there is also a large and mature literature on personality within human psychology. These two bodies of work have developed independently and at present make rather little reference to one another. The current paper has two main objectives. First, we seek to acquaint behavioural ecologists with the principal ideas and issues found in the human personality psychology literature. Second, we explore how ideas from the behavioural ecology literature might help advance research in human personality psychology. We suggest strong potential for convergence between the two literatures in the near future. Common themes of this future unified science of personality include the conception of personality traits as reaction norms, a commitment to the importance of direct measurement of behaviour, investigation of both proximate and ultimate explanations for personality variation, and a concern with the impact of personality variation on survival and reproductive success.


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