Disfavored in Life, Favored in Death? Later-Life Mortality Differences (Ages 30+) between Migrants and Natives in Antwerp, Rotterdam and Stockholm, 1850-1930

Differences in adult mortality were studied between natives and domestic and international migrants in three Northwestern European cities during different stages of the epidemiological transition. Event history analysis was conducted for mortality risk at ages 30+ using life course data retrieved from three large historical demographic micro-level databases. Results provide ample evidence of healthy migrant effects in Antwerp, Rotterdam, and Stockholm, and the effect was particularly strong among domestic migrants in Rotterdam. The multivariate analyses show that the early life environment, as well as positive selection effects, contributed to the healthy migrant effect: As migration distance increased, mortality risks declined. Being born in the countryside and moving later in life to a city were also associated with lower mortality risks. Although migrants overall had lower mortality risks than natives, we discovered, four vulnerable sub-groups whose mortality risk not only increased, but eventually exceeded that of natives: (1) rural migrants in the period when major epidemics belonged to the past, (2) international migrants who lost their partner, (3) Italian and Italian-speaking Swiss men in Rotterdam, and (4) medium-distance domestic migrant men in Antwerp

Fish and mussels: importance of fish for freshwater mussel conservation

Co-extinctions are increasingly recognized as one of the major processes leading to the global biodiversity crisis, but there is still limited scientific evidence on the magnitude of potential impacts and causal mechanisms responsible for the decline of affiliate (dependent) species. Freshwater mussels (Bivalvia, Unionida), one of the most threatened faunal groups on Earth, need to pass through a parasitic larval (glochidia) phase using fishes as hosts to complete their life cycle. Here, we provide a synthesis of published evidence on the fish–mussel relationship to explore possible patterns in co-extinction risk and discuss the main threats affecting this interaction. We retrieved 205 publications until December 2015, most of which were performed in North America, completed under laboratory conditions and were aimed at characterizing the life cycle and/or determining the suitable fish hosts for freshwater mussels. Mussel species were reported to infest between one and 53 fish species, with some fish families (e.g., Cyprinidae and Percidae) being used more often as hosts than others. No relationship was found between the breadth of host use and the extinction risk of freshwater mussels. Very few studies focused on threats affecting the fish–mussel relationship, a knowledge gap that may impair the application of future conservation measures. Here, we identify a variety of threats that may negatively affect fish species, document and discuss the concomitant impacts on freshwater mussels, and suggest directions for future studies.The Portuguese Foundation for Science and Technology—FCT through POPH/FSE funds supported VM, MI and MLL under grants (SFRH/BD/108298/2015), (SFRH/BPD/90088/2012), (SFRH/BD/115728/2016), respectively. KD acknowledges the support from the Czech Science Foundation (13-05872S). RS acknowledges the support of the strategic programme UID/BIA/04050/2013 (POCI-01-0145- FEDER-007569) funded by national funds through the FCT I.P. and by the ERDF through the COMPETE2020-Programa Operacional Competitividade e Internacionalização (POCI). This study was conducted as part of the project FRESHCO: Multiple implications of invasive species on Freshwater Mussel co-extinction processes, supported by FCT (contract: PTDC/AGRFOR/1627/2014)

The role of local adaptation in shaping fish-mussel coevolution

1. The survival of affiliate (dependent) species in a changing environment is determined by the interactions between the affiliate species and their available hosts. However, the patterns of spatial and temporal changes in host compatibility are often unknown despite host shifts having direct impact on the persistence of local populations. Bivalves of the order Unionida (freshwater mussels) are a functionally important but declining group of affiliate species, which are dependent on freshwater fish to host their parasitic larvae. The role of local adaptations and host fish resistance in shaping freshwater mussel host relationships remains poorly understood. 2. We used an invasive East Asian unionid bivalve, Sinanodonta woodiana, and its potential host fishes to study the mechanisms shaping fish-mussel coevolution using a combination of laboratory cross-exposure methods and field-collected data. We tested whether generalist host use of S. woodiana is pertinent to native host species, with special attention to bitterling fishes (Cyprinidae: Acheilognathinae) that are characterised by a mutual association with freshwater mussels. We also tested whether the pattern of the parasite–host association varies temporally (between areas of ancient and recent sympatry) and spatially (at a sub-basin level in its native range). 3. Results revealed the ability of S. woodiana to widely exploit non-bitterling host fishes at a global scale. In contrast, the ability of S. woodiana to exploit closely associated bitterling fishes was low in its native range (with ancient sympatry). In areas of recent sympatry (non-native S. woodiana range in Europe), S. woodiana glochidia were demonstrated to readily parasitise local, evolutionarily naive bitterling species at high density. 4. The results of a population-level experiment with three native populations of S. woodiana and rose bitterling, Rhodeus ocellatus, from various sub-basins of the River Yangtze confirmed that mussel populations vary in their compatibility with particular host populations. However, there was no evidence of population-specific adaptive coevolution. 5. This study provides the first evidence for a role of fish counter-adaptations against freshwater mussel glochidia, and documents the importance of population-level variation in shaping compatibility between glochidia and their host fishes. This outcome can inform predictions on the impact of biotic homogenisation on endangered affiliate species in general and freshwater mussels in particular

Modelling the invasion history of Sinanodonta woodiana in Europe: tracking the routes of a sedentary aquatic invader with mobile parasitic larvae

Understanding the invasive potential of species outside their native range is one of the most pressing questions in applied evolutionary and ecological research. Admixture of genotypes of invasive species from multiple sources has been implicated in successful invasions, by generating novel genetic combinations that facilitate rapid adaptation to new environments. Alternatively, adaptive evolution on standing genetic variation, exposed by phenotypic plasticity and selected by genetic accommodation, can facilitate invasion success. We investigated the population genetic structure of an Asian freshwater mussel with a parasitic dispersal stage, Sinanodonta woodiana, which has been present in Europe since 1979 but which has expanded rapidly in the last decade. Data from a mitochondrial marker and nuclear microsatellites have suggested that all European populations of S. woodiana originate from the River Yangtze basin in China. Only a single haplotype was detected in Europe, in contrast to substantial mitochondrial diversity in native Asian populations. Analysis of microsatellite markers indicated intensive gene flow and confirmed a lower genetic diversity of European populations compared to those from the Yangtze basin, though that difference was not large. Using an Approximate Bayesian Modelling approach, we identified two areas as the probable source of the spread of S. woodiana in Europe, which matched historical records for its establishment. Their populations originated from a single colonization event. Our data do not support alternative explanations for the rapid recent spread of S. woodiana; recent arrival of a novel (cold‐tolerant) genotype or continuous propagule pressure. Instead, in situ adaptation, facilitated by repeated admixture, appears to drive the ongoing expansion of S. woodiana. We discuss management consequences of our results

Parental loss and offspring mortality risk: Does the timing of parental death affect child’s post-reproductive survival?

A parent who has had a longer lifespan often increases ego’s own chances to also reach an older age, as evidence suggests longevity is partly hereditary. Socially, kinship relationships, and in particular, intergenerational ties are some of the most profound bonds an individual will have in life. As such, parental presence or loss may have lasting implications on child health and survival in later life. Many findings have suggested that parental loss during the early stages of child development has dire consequences on mortality risk for infants and children. As much research has focused on the short-term mortality risk of offspring, and less so on any lasting effect of parental death on child’s older age mortality risk, the main aim of this study is to examine the relationship between the timing of parental loss (or the effect of continued parental presence) over one’s lifespan and its association with own post-reproductive mortality. Survival analysis was conducted using data from the COR*-sample containing linked micro level demographic data on individual life courses for Antwerp city and surroundings (Flanders, Belgium) from 1846-1920. Individuals were followed from age 45 until death or the end of observation. Main variables of interest are parental circumstances (age of ego at parent death, mother and father ages at birth), controlling for the effects of other factors relating to mortality risk, occurring in both early and later life. Preliminary findings suggested differing mortality risk by age group at parental loss, as well as differing results by parent gender. Further analysis, through the assessment of relative risks in fully standardized models and interaction effects for main variables and offspring gender, revealed attenuating effects of losing a parent in early life, how vulnerable the offspring was when losing a parent in later life (ages 45+), particularly a mother, and that both men and women were affected similarly by parental death.status: publishe

Salmon Bias or Red Herring? Comparing adult mortality risks (ages 30-90) between natives and internal migrants: Stayers, returnees and movers in Rotterdam, the Netherlands, 1850-1940

Purpose: To empirically test the salmon bias hypothesis, which states that the 'healthy migrant' effect - referring to a situation in which migrants enjoy lower mortality risks compared to natives - is caused by selective return migration of the weak, sick and elderly. Methods: Using a unique longitudinal micro-level database - the Historical Sample of the Netherlands - we tracked the life courses of internal migrants after they had left the city of Rotterdam, which allowed us to compare mortality risks of stayers, returnees and movers using survival analysis for the study group as a whole, and also for men and women separately. Results: While migrants who stayed in the receiving society had significantly higher mortality risks than natives, no significant difference was found for migrants who returned to their municipality of birth (returnees). By contrast, migrants who left for another destination (movers) had much lower mortality risks than natives. Natives who left Rotterdam also had significantly lower mortality risks compared to natives who stayed in Rotterdam. Migrants who stayed in the receiving urban society paid a longterm health price, particularly strong for female migrants. Conclusions: The salmon bias hypothesis can be rejected, as the lower mortality effect among migrants was not caused by selective return migration. The healthy migrant effect is real and due to a positive selection effect: Healthier people are more likely to migrate.status: publishe

Rivalry, solidarity, and longevity among siblings: A life course approach to the impact of sibship composition and birth order on later life mortality risk, Antwerp (1846–1920)

BACKGROUND Family composition and household dynamics, both in early and in later life, influence individual health and longevity. Both positive and negative effects can be expected in terms of sibling size and composition. On one hand, siblings compete with each other, which may lead to resource dilution and increased adult mortality risks. On the other hand, siblings protect and care for each other, which may have a positive impact on longevity. OBJECTIVE To investigate the way in which sibling composition (with respect to sibship size, sex,and birth order) in the family of orientation and the proximity of siblings in later life relates to adult mortality risks at ages 50+. METHODS Life courses of 258 men and 275 women from the Antwerp COR*-database were 'reconstructed‘ and analyzed by way of event history analysis using Gompertz shared frailty models. RESULTS Being higher in birth order related to significantly higher mortality risk after age 50 for men. Having older brothers, particularly those present in later life, was associated with very high excess mortality risk for both sexes, though men were more strongly disadvantaged. Having (more) younger sisters present at RP (research person) age 50 was related to significantly lower relative mortality risk for women. CONCLUSIONS Our findings highlight the complex relationships between sibling and gender dynamics and mortality risk in later life. Evidence of a lasting impact of sibling competition on mortality risk over age 50 is found; and competition is only replaced by solidarity in critical times (e.g., widowhood), wherein older sibling presence dissimilarly impacts different social groups.status: publishe

Early life conditions, partnership histories, and mortality risk for Swedish men and women born 1915-1929

This paper investigates the relationship between early life biological and social factors, partnership history, and mortality risk. Mortality risks for Swedish men and women over age 50 in the Uppsala Birth Cohort born 1915-1929 were estimated using survival analysis. Relative mortality risk was evaluated through nested multiplicative Gompertz models for 4348 men and 3331 women, followed from age 50 to the end of 2010. Being born to an unmarried mother was associated with higher mortality risk in later life for men and women, and relative to married individuals, being unmarried after age 50 was associated with elevated mortality risk. Single women and divorced men were the highest risk groups, and women were negatively impacted by a previous divorce or widowhood, while men were not. Both genders showed direct effects of early life variables on later life mortality and were vulnerable if unmarried in later life. However, in this study, previous marital disruptions appeared to have more (negative) meaning in the long-term for women.publisher: Elsevier articletitle: Early life conditions, partnership histories, and mortality risk for Swedish men and women born 1915–1929 journaltitle: Social Science & Medicine articlelink: http://dx.doi.org/10.1016/j.socscimed.2014.02.036 content_type: article copyright: Copyright © 2014 Elsevier Ltd. All rights reserved.status: publishe

The effect of widowhood on mortality in polygamous marriages: evidence from the Utah Population Database

Although the increase in mortality following widowhood has been widely studied, much less is known about how this pattern varies across less common household structures. Polygamous marriages are still prevalent across much of the world, but whether and how mortality varies following the death of a partner has not been studied in polygamous relationships. In this study we use data from the Utah Population Database to examine the relationship between marital status and mortality in polygamous marriages in 19th century Utah. With data on 110,952 women and 106,898 men, we particularly focus on whether the widowhood mortality effect varies between monogamous and polygamous marriages. We examine how the number of wife deaths affects male mortality in polygamous marriages, how the death of a sister wife, meaning other women with whom they share a husband, affects female mortality relative to the death of a husband, as well as how marriage order amongst sister wives affects the mortality of women in polygamous marriages. For women we find that the death of a husband in polygamous marriages increases mortality to a similar extent as in monogamous marriages, while the death of a sister wife does not have a qualitatively different effect on mortality than the death of the husband. Marriage order does not play a role in the mortality of women in polygamous marriages in this historical context. For men we find that the death of one wife in a polygamous marriage increases mortality to a lesser extent than it does for men in monogamous marriages. For men there is a dose-response effect to losing additional wives. We discuss these findings in relation to theories regarding the mechanisms driving the widowhood mortality effect

Mortality Clustering in the Family. Fast Life History Trajectories and the Intergenerational Transfer of Infant Death in Late 19th- and Early 20th-Century Antwerp, Belgium

In this article, we investigate to what degree infant mortality risk was transferred from grandmothers to mothers in the Antwerp district, Belgium, during the late nineteenth and early twentieth century. We also investigate some of the determinants of infant mortality and explore the role of the family - paternal factors (presence, age, and social class), mother’s childcare experience, and infant household location - in the survival of infants. The data for this research were retrieved from the Antwerp COR*-database and were transferred into the Intermediate Data Structure (IDS). The results of the survival models show that women whose mother experienced three or more infant deaths had a 77% higher risk of experiencing the loss of an infant themselves, compared to women whose mother experienced zero infant deaths in the past. These results remained robust after controlling for potential mediating and moderating factors. The results on the age of the mother at birth, her marital status, as well as the living environment suggest that at least part of the intergenerational transfer in infant mortality can be explained on the basis of life history theory: women who grew up in a high-risk family tended to reproduce earlier and faster, and often raised their children without a partner. In this way they unconsciously created riskier conditions for the raising of their own infants: the mothers had little life experience, limited resources, and often no assistance from a partner. As a result, their own children were also at an increased risk of dying in infancy.status: publishe