Maternal effects alter the severity of inbreeding depression in the offspring

A maternal effect is a causal influence of the maternal phenotype on the offspring phenotype over and above any direct effects of genes. There is abundant evidence that maternal effects can have a major impact on offspring fitness. Yet, no previous study has investigated the potential role of maternal effects in influencing the severity of inbreeding depression in the offspring. Inbreeding depression is a reduction in the fitness of inbred offspring relative to outbred offspring. Here, we tested whether maternal effects due to body size alter the magnitude of inbreeding depression in the burying beetle Nicrophorus vespilloides . We found that inbreeding depression in larval survival was more severe for offspring of large females than offspring of small females. This might be due to differences in how small and large females invest in an inbred brood because of their different prospects for future breeding opportunities. To our knowledge, this is the first evidence for a causal effect of the maternal phenotype on the severity of inbreeding depression in the offspring. In natural populations that are subject to inbreeding, maternal effects may drive variation in inbreeding depression and therefore contribute to variation in the strength and direction of selection for inbreeding avoidance.

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Fitness effects and transmission of phoretic nematodes of the burying beetle, Nicrophorus vespilloides

10.1101/193714 ◽

2017 ◽

Author(s):

Yin Wang ◽

Daniel E. Rozen

Keyword(s):

Brood Size ◽

Larval Survival ◽

List Type ◽

Burying Beetle ◽

Negative Effects ◽

Fitness Effects ◽

Nicrophorus Vespilloides ◽

Males And Females ◽

Efficient Mechanisms

AbstractNicrophorus vespilloides is a cosmopolitan social beetle that rears its offspring on decomposing carrion. Wild beetles are frequently associated with two types of macrobial symbionts, mites and nematodes.Although these organisms are believed to be phoretic commensals that harmlessly use beetles as a means of transfer between carcasses, the role of these symbionts on N. vespilloides fitness is poorly understood. Here we show that nematodes have significant negative effects on beetle fitness across a range of worm densities and also quantify the density-dependent transmission of worms between mating individuals and from parents to offspring.Using field-caught beetles, we provide the first report of a new nematode symbiont in N. vespilloides, most closely related to Rhabditoides regina, and show that worm densities are highly variable across individuals isolated from nature but do not differ between males and females. Next, by inoculating mating females with increasing densities of nematodes, we show that worm infections significantly reduce brood size, larval survival and larval mass, and also eliminate the trade-off between brood size and larval mass. Finally, we show that nematodes are efficiently transmitted between mating individuals and from mothers to larvae, directly and indirectly via the carcass, and that worms persist through pupation.These results show that the phoretic nematode R. regina can be highly parasitic to burying beetles but can nevertheless persist because of efficient mechanisms of intersexual and intergenerational transmission.Phoretic species are exceptionally common and may cause significant harm to their hosts, even though they rely on these larger species for transmission to new resources. However, this harm may be inevitable and unavoidable if transmission of phoretic symbionts requires nematode proliferation. It will be important to determine the generality of our result for other phoretic associates of animals.

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Parental care buffers against inbreeding depression in burying beetles

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1500658112 ◽

2015 ◽

Vol 112 (26) ◽

pp. 8031-8035 ◽

Cited By ~ 33

Author(s):

Natalie Pilakouta ◽

Seonaidh Jamieson ◽

Jacob A. Moorad ◽

Per T. Smiseth

Keyword(s):

Parental Care ◽

Inbreeding Depression ◽

Maternal Care ◽

Female Parent ◽

Larval Survival ◽

Environmental Stresses ◽

Fitness Costs ◽

Burying Beetle ◽

Joint Influence ◽

Nicrophorus Vespilloides

When relatives mate, their inbred offspring often suffer a reduction in fitness-related traits known as “inbreeding depression.” There is mounting evidence that inbreeding depression can be exacerbated by environmental stresses such as starvation, predation, parasitism, and competition. Parental care may play an important role as a buffer against inbreeding depression in the offspring by alleviating these environmental stresses. Here, we examine the effect of parental care on the fitness costs of inbreeding in the burying beetle Nicrophorus vespilloides, an insect with facultative parental care. We used a 2 × 2 factorial design with the following factors: (i) the presence or absence of a caring female parent during larval development and (ii) inbred or outbred offspring. We examined the joint influence of maternal care and inbreeding status on fitness-related offspring traits to test the hypothesis that maternal care improves the performance of inbred offspring more than that of outbred offspring. Indeed, the female's presence led to a higher increase in larval survival in inbred than in outbred broods. Receiving care at the larval stage also increased the lifespan of inbred but not outbred adults, suggesting that the beneficial buffering effects of maternal care can persist long after the offspring have become independent. Our results show that parental care has the potential to moderate the severity of inbreeding depression, which in turn may favor inbreeding tolerance and influence the evolution of mating systems and other inbreeding-avoidance mechanisms.

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Inbred burying beetles suffer fitness costs from making poor decisions

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2018.0419 ◽

2018 ◽

Vol 285 (1881) ◽

pp. 20180419 ◽

Cited By ~ 1

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.

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Fitness Traits and Dispersal Ability in the Herb Tragopogon pratensis (Asteraceae): Decoupling the Role of Inbreeding Depression and Maternal Effects

Plant Biology ◽

10.1055/s-2003-44788 ◽

2003 ◽

Vol 5 (5) ◽

pp. 522-530 ◽

Cited By ~ 33

Author(s):

F. X. Picó ◽

N. J. Ouborg ◽

J. M. Groenendael

Keyword(s):

Maternal Effects ◽

Inbreeding Depression ◽

Dispersal Ability ◽

Fitness Traits

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Parental care buffers against effects of ambient temperature on offspring performance in an insect

Behavioral Ecology ◽

10.1093/beheco/arz100 ◽

2019 ◽

Vol 30 (5) ◽

pp. 1443-1450 ◽

Cited By ~ 4

Author(s):

Richard Grew ◽

Tom Ratz ◽

Jon Richardson ◽

Per T Smiseth

Keyword(s):

Ambient Temperature ◽

Parental Care ◽

Female Parent ◽

Larval Survival ◽

Climatic Conditions ◽

Burying Beetle ◽

Offspring Performance ◽

Behavioral Mechanism ◽

Wide Range ◽

Nicrophorus Vespilloides

AbstractUnderstanding how animals respond to and cope with variation in ambient temperature is an important priority. The reason for this is that ambient temperature is a key component of the physical environment that influences offspring performance in a wide range of ectotherms and endotherms. Here, we investigate whether posthatching parental care provides a behavioral mechanism for buffering against the effects of ambient temperature on offspring in the burying beetle Nicrophorus vespilloides. We used a 3 × 2 factorial design where we manipulated ambient temperature (15, 20, or 25 °C) and parental care (presence or absence of a female parent after hatching). We found that the effect of ambient temperature on offspring performance was conditional upon the presence or absence of a caring female. Fewer larvae survived in the absence than in the presence of a caring female at 15 °C while there was no difference in larval survival at 20 and 25 °C. Our results show that parental care buffers against some of the detrimental effects of variation in ambient temperature on offspring. We suggest that posthatching parental care may buffer against such effects by creating a more benign environment or by boosting offspring resilience toward stressors. Our results have important implications for our understanding of the evolution of parental care because they suggest that the evolution of parental care could allow species to expand their geographical range to colonize areas with harsher climatic conditions than they otherwise would tolerate.

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The Influence of Applicant and Reviewer Gender on Resident Selection for Internal Medicine

Journal of Medical Education and Curricular Development ◽

10.1177/23821205211016502 ◽

2021 ◽

Vol 8 ◽

pp. 238212052110165

Author(s):

Steven J Katz

Keyword(s):

Internal Medicine ◽

Gender Bias ◽

Potential Role ◽

Selection Process ◽

Expected Number ◽

Internal Medicine Residency Program ◽

Selection For ◽

Resident Selection ◽

Component Scores

Background: While gender bias in medicine, including physician training, has been well described, less is known about gender bias in the selection process for post graduate residency training programs. This analysis reviews the potential role of gender on resident selection for an internal medicine residency program. Methods: File review and interview overall and component scores were analyzed based on the gender of the applicant. File review scores were further analyzed based on the reviewer’s gender. Results: Women applicants scored higher than men applicants on their file review. There were no differences in any one component score except for leadership in art. Women file reviewers scored applicants higher than men file reviewers, but there was no difference between gender scores. There was no difference in overall or component interview scores between men or women applicants. Scoring did not impact the expected rank performance of applicants based on gender at any stage of the selection process. Conclusions: While higher scores were observed in women applicants upon their file review, and women reviewers provided higher file review scores, this did not appear to impact the expected number of women and men applicants at each stage of the applicant process. This suggests a potential lack of gender bias at these stages of applicant selection.

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Introduction: Ecological impact of parasitism on wildlife host populations

Parasitology ◽

10.1017/s0031182000075788 ◽

1995 ◽

Vol 111 (S1) ◽

pp. S3-S14 ◽

Cited By ~ 20

Author(s):

B. T. Grenfell ◽

F. M. D. Gulland

Keyword(s):

Population Dynamics ◽

Potential Role ◽

Evolutionary Ecology ◽

Ecological Impact ◽

Natural Populations ◽

Parasite Population ◽

Theoretical Studies ◽

Host Parasite

The study of parasite population dynamics has been one of the major developments in ecology over the last 15 years (Kennedy, 1975). The seminal articles of Crofton (1971) and Anderson & May (1978, 1979; May & Anderson, 1978, 1979) began this process by illustrating the potential role of parasites in regulating or destabilizing the dynamics of wildlife host populations. Since then, a variety of empirical and theoretical studies (reviewed by Grenfell & Dobson, 1995) have explored the role of parasites in natural populations. In parallel with these population dynamical developments, a growing interest in the evolutionary ecology of parasites has also led to a large literature, examining the evolutionary impact of parasites and the importance of host-parasite coevolution (Hamilton, 1982; May & Anderson, 1990; Lively & Apanius, 1995; Read et al. 1995; Herre, this volume).

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The potential role of gated myocardial perfusion SPECT imaging in patient selection for cardiac resynchronization therapy

Journal of Nuclear Cardiology ◽

10.1007/s12350-014-9956-7 ◽

2014 ◽

Vol 21 (6) ◽

pp. 1072-1074 ◽

Cited By ~ 1

Author(s):

Nina Ajmone Marsan ◽

Jeroen J. Bax

Keyword(s):

Myocardial Perfusion ◽

Cardiac Resynchronization Therapy ◽

Potential Role ◽

Myocardial Perfusion Spect ◽

Cardiac Resynchronization ◽

Resynchronization Therapy ◽

Gated Myocardial Perfusion Spect ◽

Perfusion Spect ◽

Selection For

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Two-locus identity probabilities and identity disequilibrium in a partially selfing subdivided population

Genetics Research ◽

10.1017/s0016672300004833 ◽

2001 ◽

Vol 77 (1) ◽

pp. 67-81 ◽

Cited By ~ 40

Author(s):

RENAUD VITALIS ◽

DENIS COUVET

Keyword(s):

Gene Flow ◽

Natural Populations ◽

Population Data ◽

Selfing Rate ◽

Measures Of Association ◽

Mutation Model ◽

Subdivided Population ◽

Selection For ◽

The Difference

Measures of association of genes at different loci (linkage disequilibrium) are widely used to determine whether the structure of natural populations is clonal or not, to map genes from population data, or to test for the homogeneity of response of molecular markers to background selection, for example. However, the usual definitions of parameters for gametic associations may not be suitable for all these purposes. In this paper, we derive the recursion equations for one- and two-locus identity probabilities in an infinite island model. We study the role of drift, gene flow, partial selfing and mutation model on the expected association of genes across loci. We define the ‘within-subpopulation identity disequilibrium’ as the difference between the joint two-locus probability of identity in state and the expected product of one-locus identity probabilities. We evaluate this parameter as a function of recombination rate, effective size, gene flow and selfing rate. Within-subpopulation identity disequilibrium attains maximum values for intermediate immigration rates, whatever the selfing rate. Moreover, identity disequilibrium may be very small, even for high selfing rates. We discuss the implications of these findings for the analysis of data from natural populations.

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