scholarly journals Host traits and lifetime fitness costs of being parasitized in red-breasted mergansers

FACETS ◽  
2021 ◽  
Vol 6 ◽  
pp. 2155-2176
Author(s):  
Shawn R. Craik ◽  
Rodger D. Titman ◽  
Anna M. Calvert ◽  
Gregory J. Robertson ◽  
Mark L. Mallory ◽  
...  
Keyword(s):  
Hatching Success ◽  
Bird Species ◽  
Lifetime Reproductive Success ◽  
Fitness Costs ◽  
Conspecific Brood Parasitism ◽  
Annual Survival ◽  
Fitness Consequences ◽  
Mergus Serrator ◽  
Future Reproduction ◽  
Nest Initiation

The addition of eggs to a nest by a conspecific is known for approximately 250 bird species. Understanding the evolution of conspecific brood parasitism (CBP) requires assessment of fitness consequences to the egg recipient (host). We addressed host traits and the effects of CBP on future reproduction (i.e., annual survival) and hatching success of hosts by following the nesting of 206 red-breasted mergansers ( Mergus serrator) for a colony in which an average of 41% of nests was parasitized annually. Each host was tracked for ≥2 seasons and up to seven seasons. The proportion of a host’s nesting attempts that was parasitized averaged 43% and varied considerably across individuals (range 0%–100%). Probability of parasitism, however, was not repeatable across a host’s nests. Rather, rates of CBP throughout a host’s lifetime increased with earlier dates of nest initiation. CBP had no effect on annual survival of a host. Hatching success throughout a host’s lifetime declined with a greater number of foreign eggs added to the individual’s nests. This study revealed that there may be measurable costs of CBP to lifetime reproductive success in red-breasted mergansers, although our observations suggest that costs to hosts are limited to the most heavily parasitized clutches.

scholarly journals Glucocorticoids, state-dependent reproductive investment and success in the face of danger in a long-lived bird

2020 ◽  
Author(s):  
Kristina Noreikienė ◽  
Kim Jaatinen ◽  
Benjamin B. Steele ◽  
Markus Öst
Keyword(s):  
Predation Risk ◽  
Telomere Length ◽  
Clutch Size ◽  
Body Condition ◽  
Nest Predation ◽  
Hatching Success ◽  
Reproductive Investment ◽  
Trade Off ◽  
Relative Telomere Length ◽  
Future Reproduction

AbstractGlucocorticoid hormones may mediate trade-offs between current and future reproduction. However, understanding their role is complicated by predation risk, which simultaneously affects the value of the current reproductive investment and elevates glucocorticoid levels. Here, we shed light on these issues in long-lived female Eiders (Somateria mollissima) by investigating how current reproductive investment (clutch size) and hatching success relate to faecal glucocorticoid metabolite [fGCM] level and residual reproductive value (minimum years of breeding experience, body condition, relative telomere length) under spatially variable predation risk. Our results showed a positive relationship between colony-specific predation risk and mean colony-specific fGCM levels. Clutch size and female fGCM were negatively correlated only under high nest predation and in females in good body condition, previously shown to have a longer life expectancy. We also found that younger females with longer telomeres had smaller clutches. The drop in hatching success with increasing fGCM levels was least pronounced under high nest predation risk, suggesting that elevated fGCM levels may allow females to ensure some reproductive success under such conditions. Hatching success was positively associated with female body condition, with relative telomere length, particularly in younger females, and with female minimum age, particularly under low predation risk, showing the utility of these metrics as indicators of individual quality. In line with a trade-off between current and future reproduction, our results show that high potential for future breeding prospects and increased predation risk shift the balance toward investment in future reproduction, with glucocorticoids playing a role in the resolution of this trade-off.

scholarly journals Drivers and Consequences of Partial Migration in an Alpine Bird Species

2021 ◽  
Author(s):  
Øyvind Lorvik Arnekleiv ◽  
Katrine Eldegard ◽  
Pål Fossland Moa ◽  
Lasse Frost Eriksen ◽  
Erlend B. Nilsen
Keyword(s):  
Body Weight ◽  
Small Body ◽  
Bird Species ◽  
Nesting Success ◽  
Partial Migration ◽  
Individual State ◽  
Migratory Behaviour ◽  
Willow Ptarmigan ◽  
Fitness Consequences ◽  
Migratory Strategy

1. Partial migration, where a portion of the population migrates between winter and summer (breeding) areas and the rest remain year-round resident, is a common phenomenon across several taxonomic groups. Yet, although several hypotheses have been put forward to explain why some individuals migrate while others stay resident – as well as the fitness consequences of the different strategies – the drivers and consequences of the decision to migrate or not are poorly understood. 2. We used data from radio-tagged female (n=73) willow ptarmigan Lagopus lagopus in an alpine study area in Central Norway to test if i) the decision to migrate was dependent on individual state variables (age and body size), ii) individuals repeated migratory behaviour between seasons, and iii) the choice of migratory strategy was related to nesting performance.3. Partially supporting our prediction that migratory strategy depends on individual state, we found that juvenile birds with small body sizes were more likely to migrate whereas large juveniles stayed resident. For adult females, we found no relationship between migratory strategy and body weight. We found strong evidence for high individual repeatability of migratory strategy between seasons. Migratory strategy did not explain variation in nesting performance among individuals, suggesting no direct influence of the chosen strategy on nesting success. 4. Our results indicate that partial migration in willow ptarmigan is determined by juvenile body weight, and that migratory behaviour becomes a part of the individual life history as a fixed strategy. Nesting success was not affected by migratory strategy in our study population, but future studies should assess other traits to further test potential fitness consequences.

scholarly journals The Role of the Immune System from an Evolutionary Perspective

2019 ◽  
pp. 198-209
Author(s):  
Carsten Schradin ◽  
Rainer H. Straub
Keyword(s):  
Evolutionary Medicine ◽  
Future Generations ◽  
Lifetime Reproductive Success ◽  
Life History Stage ◽  
Evolutionary Perspective ◽  
Lifetime Fitness ◽  
Fitness Consequences ◽  
Reproductive Life ◽  
Fitness Benefits

“Nothing in Biology makes sense, except in the light of evolution.” This famous citation of Theodosius Dobzhansky also underlies the integrative field of evolutionary medicine, which faces the challenge to combine (patho-)physiological mechanisms with evolutionary function. Here we introduce a concept from the study of animal behavior, which are the four questions of Tinbergen that consider: 1. the ontogeny of an individual describing its development, 2. its physiological machinery, which 3. has fitness consequences influencing 4. the evolutionary history (phylogeny) of future generations. It is shown how this concept can be applied to infectious disease and to chronic inflammatory systemic diseases. Evolutionary medicine takes lifetime reproductive success into account. The hypothesis to be tested is that mechanisms underlying a disease in old age might have higher fitness benefits in the pre-reproductive and/or reproductive life history stage, leading to an overall increased lifetime fitness.

scholarly journals Inbred burying beetles suffer fitness costs from making poor decisions

2018 ◽  
Vol 285 (1881) ◽  
pp. 20180419 ◽  
Author(s):  
Jon Richardson ◽  
Pauline Comin ◽  
Per T. Smiseth
Keyword(s):  
Decision Making ◽  
Inbreeding Depression ◽  
Resource Availability ◽  
Environmental Conditions ◽  
Fitness Costs ◽  
Individual Decision ◽  
Burying Beetle ◽  
Individual Decision Making ◽  
Fitness Consequences ◽  
Nicrophorus Vespilloides

There is growing interest in how environmental conditions, such as resource availability, can modify the severity of inbreeding depression. However, little is known about whether inbreeding depression is also associated with differences in individual decision-making. For example, decisions about how many offspring to produce are often based upon the prevailing environmental conditions, such as resource availability, and getting these decisions wrong may have important fitness consequences for both parents and offspring. We tested for effects of inbreeding on individual decision-making in the burying beetle Nicrophorus vespilloides, which uses the size of a carrion resource to make decisions about number of offspring. Both inbred and outbred females adjusted their initial decisions about number of eggs to lay based on carcass size. However, when we forced individuals to update this initial decision by providing them with a different-sized carcass partway through reproduction, inbred females failed to update their decision about how many larvae to cull. Consequently, inbred females reared too many larvae, resulting in negative fitness consequences in the form of smaller offspring and reduced female post-reproductive condition. Our study provides novel insights into the effects of inbreeding by showing that poor decision-making by inbred individuals can negatively affect fitness.

scholarly journals Negative Fitness Consequences and Transmission Dynamics of a Heritable Fungal Symbiont of a Parasitic Wasp

2009 ◽  
Vol 75 (10) ◽  
pp. 3115-3119 ◽  
Author(s):  
Cara M. Gibson ◽  
Martha S. Hunter
Keyword(s):  
Competitive Ability ◽  
Horizontal Transmission ◽  
Parasitic Wasp ◽  
Experimental Tests ◽  
Bacterial Symbionts ◽  
Fitness Costs ◽  
Fungal Symbiont ◽  
Fitness Consequences ◽  
Single Host ◽  
Host Ecology

ABSTRACT Heritable bacterial symbionts are widespread in insects and can have many important effects on host ecology and fitness. Fungal symbionts are also important in shaping their hosts' behavior, interactions, and evolution, but they have been largely overlooked. Experimental tests to determine the relevance of fungal symbionts to their insect hosts are currently extremely rare, and to our knowledge, there have been no such tests for strictly predacious insects. We investigated the fitness consequences for a parasitic wasp (Comperia merceti) of an inherited fungal symbiont in the Saccharomycotina (Ascomycota) that was long presumed to be a mutualist. In comparisons of wasp lines with and without this symbiont, we found no evidence of mutualism. Instead, there were significant fitness costs to the wasps in the presence of the yeast; infected wasps attacked fewer hosts and had longer development times. We also examined the relative competitive abilities of the larval progeny of infected and uninfected mothers, as well as horizontal transmission of the fungal symbiont among larval wasps that shared a single host cockroach egg case. We found no difference in larval competitive ability when larvae whose infection status differed shared a single host. We did find high rates of horizontal transmission of the fungus, and we suggest that this transmission is likely responsible for the maintenance of this infection in wasp populations.

scholarly journals Early and adult social environments have independent effects on individual fitness in a social vertebrate

2015 ◽  
Vol 282 (1813) ◽  
pp. 20151167 ◽  
Author(s):  
Vérane Berger ◽  
Jean-François Lemaître ◽  
Dominique Allainé ◽  
Jean-Michel Gaillard ◽  
Aurélie Cohas
Keyword(s):  
Social Environment ◽  
Lifetime Reproductive Success ◽  
Social Environments ◽  
Long Term Effects ◽  
Delayed Effects ◽  
Individual Fitness ◽  
Fitness Consequences ◽  
Dominant Female ◽  
The Social ◽  
Independent Effects

Evidence that the social environment at critical stages of life-history shapes individual trajectories is accumulating. Previous studies have identified either current or delayed effects of social environments on fitness components, but no study has yet analysed fitness consequences of social environments at different life stages simultaneously. To fill the gap, we use an extensive dataset collected during a 24-year intensive monitoring of a population of Alpine marmots ( Marmota marmota ), a long-lived social rodent. We test whether the number of helpers in early life and over the dominance tenure length has an impact on litter size at weaning, juvenile survival, longevity and lifetime reproductive success (LRS) of dominant females. Dominant females, who were born into a group containing many helpers and experiencing a high number of accumulated helpers over dominance tenure length showed an increased LRS through an increased longevity. We provide evidence that in a wild vertebrate, both early and adult social environments influence individual fitness, acting additionally and independently. These findings demonstrate that helpers have both short- and long-term effects on dominant female Alpine marmots and that the social environment at the time of birth can play a key role in shaping individual fitness in social vertebrates.

scholarly journals When more is less: the fitness consequences of predators attacking more unpalatable prey when more are presented

2010 ◽  
Vol 6 (6) ◽  
pp. 732-735 ◽  
Author(s):  
Hannah M. Rowland ◽  
Elizabeth Wiley ◽  
Graeme D. Ruxton ◽  
Johanna Mappes ◽  
Michael P. Speed
Keyword(s):  
Empirical Support ◽  
Warning Signal ◽  
Fixed Number ◽  
Visual Signal ◽  
Fitness Costs ◽  
Avian Predators ◽  
Fitness Consequences ◽  
Unpalatable Prey

In 1879, Fritz Müller hypothesized that mimetic resemblance in which defended prey display the same warning signal would share the costs of predator education. Although Müller argued that predators would need to ingest a fixed number of prey with a given visual signal when learning to avoid unpalatable prey, this assumption lacks empirical support. We report an experiment which shows that, as the number of unpalatable prey presented to them increased, avian predators attacked higher numbers of those prey. We calculated that, when predators increase attacks, the fitness costs incurred by unpalatable prey can be substantial. This suggests that the survival benefits of mimicry could be lower than Müller proposed. An important finding is, however, that these costs decline in importance as the total number of available prey increases.

scholarly journals Observed heterospecific clutch size can affect offspring investment decisions

2011 ◽  
Vol 8 (3) ◽  
pp. 341-343 ◽  
Author(s):  
Jukka T. Forsman ◽  
Janne-Tuomas Seppänen ◽  
Inka L. Nykänen
Keyword(s):  
Clutch Size ◽  
Bird Species ◽  
Investment Decisions ◽  
Optimal Investment ◽  
Migratory Bird ◽  
Lifetime Reproductive Success ◽  
Egg Mass ◽  
Artificial Nests ◽  
Fine Tune

Optimal investment in offspring is important in maximizing lifetime reproductive success. Yet, very little is known how animals gather and integrate information about environmental factors to fine tune investment. Observing the decisions and success of other individuals, particularly when those individuals initiate breeding earlier, may provide a way for animals to quickly arrive at better breeding investment decisions. Here we show, with a field experiment using artificial nests appearing similar to resident tit nests with completed clutches, that a migratory bird can use the observed high and low clutch size of a resident competing bird species to increase and decrease clutch size and egg mass, accordingly. Our results demonstrate that songbirds can discriminate between high and low quantity of heterospecific eggs, and that social information can have long-term physiological consequences affecting reproductive strategies. Such behaviour may help animals to better adapt to changing environments and lead to convergent traits with competitors.

Fitness costs of resource overlap among coexisting bird species

Nature ◽  
1996 ◽  
Vol 380 (6572) ◽  
pp. 338-340 ◽  
Author(s):  
Thomas E. Martin
Keyword(s):  
Bird Species ◽  
Fitness Costs ◽  
Resource Overlap

scholarly journals Low hatching success in the critically endangered kākāpō (Strigops habroptilus) is driven by early embryo mortality not infertility

2020 ◽  
Author(s):  
James L. Savage ◽  
Jodie M. S. Crane ◽  
Nicola Hemmings ◽  
Keyword(s):  
Hatching Success ◽  
Wild Population ◽  
Bird Species ◽  
Early Embryo ◽  
Critically Endangered ◽  
Major Barrier ◽  
In The Wild ◽  
Underlying Causes ◽  
First Time ◽  
Effective Conservation

AbstractIn many endangered species, reproductive failure is a major barrier to recovery. The critically endangered kākāpō (Strigops habroptilus) exemplifies this challenge: 61% of their eggs fail to hatch, and of these 73% show no sign of development. Undeveloped eggs have previously been attributed to male infertility, but recent studies of non-threatened bird species suggest fertilisation failure is rare in the wild. The underlying causes of fertilisation failure and embryo death differ, so distinguishing between them is essential for effective conservation management. Here we show that the majority (72%, n=124) of undeveloped kākāpō eggs are fertilised, and combine this with conservation programme data on natural copulations, artificial inseminations, and paternity of developed eggs, to generate the most precise estimate to date of fertility in a wild population. We also demonstrate, for the first time in a wild bird, that artificial insemination results in greater numbers of sperm reaching the egg.

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