Association between parity and fistula location in women with obstetric fistula: a multivariate regression analysis.

OBJECTIVE: To compare primiparous and multiparous women who develop obstetric fistula (OF) and to assess predictors of fistula location. DESIGN: Cross-sectional study. SETTING: Fistula Care Centre at Bwaila Hospital, Lilongwe, Malawi. POPULATION: Women with OF who presented between September 2011 and July 2014 with a complete obstetric history were eligible for the study. METHODS: Women with OF were surveyed for their obstetric history. Women were classified as multiparous if prior vaginal or caesarean delivery was reported. The location of the fistula was determined at operation: OF involving the urethra, bladder neck, and midvagina were classified as low; OF involving the vaginal apex, cervix, uterus, and ureters were classified as high. MAIN OUTCOME MEASURES: Demographic information was compared between primiparous and multiparous women using chi-squared and Mann-Whitney U-tests. Multivariate logistic regression models were implemented to assess the relationship between variables of interest and fistula location. RESULTS: During the study period, 533 women presented for repair, of which 452 (84.8%) were included in the analysis. The majority (56.6%) were multiparous when the fistula formed. Multiparous women were more likely to have laboured <1 day (62.4 versus 44.5%, P < 0.001), delivered a live-born infant (26.8 versus 17.9%, P = 0.026), and have a high fistula location (37.5 versus 11.2%, P < 0.001). Multiparity [adjusted odds ratio (aOR) = 4.55, 95% confidence interval (CI) 2.27-9.12)] and history of caesarean delivery (aOR = 4.11, 95% CI 2.45-6.89) were associated with development of a high fistula. CONCLUSIONS: Multiparity was common in our cohort, and these women were more likely to have a high fistula. Additional research is needed to understand the aetiology of high fistula including potential iatrogenic causes. TWEETABLE ABSTRACT: Multiparity and caesarean delivery were associated with a high tract fistula in our Malawian cohort.

The relationship between handling time and cortisol release rates changes as a function of brain parasite densities in California killifish Fundulus parvipinnis.

This study validated a technique for non-invasive hormone measurements in California killifish Fundulus parvipinnis, and looked for associations between cortisol (a stress hormone) and 11-ketotestosterone (KT, an androgen) release rates and the density or intensity of the trematode parasites Euhaplorchis californiensis (EUHA) and Renicola buchanani (RENB) in wild-caught, naturally infected F. parvipinnis. In experiment 1, F. parvipinnis were exposed to an acute stressor by lowering water levels to dorsal-fin height and repeatedly handling the fish over the course of an hour. Neither parasite was found to influence cortisol release rates in response to this acute stressor. In experiment 2, different F. parvipinnis were exposed on four consecutive days to the procedure for collecting water-borne hormone levels and release rates of 11-KT and cortisol were quantified. This design examined whether F. parvipinnis perceived the water-borne collection procedure to be a stressor, while also exploring how parasites influenced hormone release rates under conditions less stressful than those in experiment 1. No association was found between RENB and hormone release rates, or between EUHA and 11-KT release rates. The interaction between EUHA density and handling time, however, was an important predictor of cortisol release rates. The relationship between handling time and cortisol release rates was negative for F. parvipinnis harbouring low or intermediate density infections, and became positive for fish harbouring high densities of EUHA.

Behavioural syndromes in fishes: a review with implications for ecology and fisheries management.

This review examines the contribution of research on fishes to the growing field of behavioural syndromes. Current knowledge of behavioural syndromes in fishes is reviewed with respect to five main axes of animal personality: (1) shyness-boldness, (2) exploration-avoidance, (3) activity, (4) aggressiveness and (5) sociability. Compared with other taxa, research on fishes has played a leading role in describing the shy-bold personality axis and has made innovative contributions to the study of the sociability dimension by incorporating social network theory. Fishes are virtually the only major taxon in which behavioural correlations have been compared between populations. This research has guided the field in examining how variation in selection regime may shape personality. Recent research on fishes has also made important strides in understanding genetic and neuroendocrine bases for behavioural syndromes using approaches involving artificial selection, genetic mapping, candidate gene and functional genomics. This work has illustrated consistent individual variation in highly complex neuroendocrine and gene expression pathways. In contrast, relatively little work on fishes has examined the ontogenetic stability of behavioural syndromes or their fitness consequences. Finally, adopting a behavioural syndrome framework in fisheries management issues including artificial propagation, habitat restoration and invasive species, may promote restoration success. Few studies, however, have examined the ecological relevance of behavioural syndromes in the field. Knowledge of how behavioural syndromes play out in the wild will be crucial to incorporating such a framework into management practices.

Corrigendum to: "Task syndromes: linking personality and task allocation in social animal groups" by J. C. Loftus, A. Perez, and A. Sih. 32:1-17.

[This corrects the article DOI: 10.1093/beheco/araa083.].

Task syndromes: linking personality and task allocation in social animal groups.

Studies of eusocial insects have extensively investigated two components of task allocation: how individuals distribute themselves among different tasks in a colony and how the distribution of labor changes to meet fluctuating task demand. While discrete age- and morphologically-based task allocation systems explain much of the social order in these colonies, the basis for task allocation in non-eusocial organisms and within eusocial castes remains unknown. Building from recent advances in the study of among-individual variation in behavior (i.e., animal personalities), we explore a potential mechanism by which individuality in behaviors unrelated to tasks can guide the developmental trajectories that lead to task specialization. We refer to the task-based behavioral syndrome that results from the correlation between the antecedent behavioral tendencies and task participation as a task syndrome. In this review, we present a framework that integrates concepts from a long history of task allocation research in eusocial organisms with recent findings from animal personality research to elucidate how task syndromes and resulting task allocation might manifest in animal groups. By drawing upon an extensive and diverse literature to evaluate the hypothesized framework, this review identifies future areas for study at the intersection of social behavior and animal personality.

Optimal behavior: can foragers balance two conflicting demands?

According to much current theory, organisms should be able to balance the conflicting demands of the need to feed efficiently and the need to avoid preadtors while feeding. In an experimental conflict situation, it was possible to evaluate the relative fitnesses associated with the available choices and to compare the observed behaviors with predictions derived from fitness considerations. A backswimmer, Notonecta hoffmanni, was capable of balancing these two conflicting factors adaptively.

Behavioural type in newly emerged steelhead Oncorhynchus mykiss does not predict growth rate in a conventional hatchery rearing environment.

Behavioural assays were conducted on newly emerged steelhead Oncorhynchus mykiss to investigate the presence of behavioural syndromes and to determine whether behavioural type in young fish predicts growth rate in a conventional hatchery rearing environment. Individual fry were consistent in their position choice and activity behaviours across safe and unsafe contexts, as well as among assays conducted on different days. Position choice and activity behaviours, however, were not necessarily correlated to each other. Both behaviours predicted feeding rates during behavioural assays, but there was no relationship between fry behaviour and subsequent growth rate or survival during the first 3 months of hatchery rearing. These results support the hypothesis that selection in captivity may be relaxed with respect to behavioural type rather than directional, allowing for increased behavioural variance in domesticated populations. Modest magnitudes of correlations among fry behaviours, however, suggest that behavioural type may be unstable at the onset of the juvenile feeding stage.

Parasitism, personality and cognition in fish.

It is well established that parasites can have profound effects on the behaviour of host organisms, and that individual differences in behaviour can influence susceptibility to parasite infections. Recently, two major themes of research have developed. First, there has been a growing interest in the proximate, mechanistic processes underpinning parasite-associated behaviour change, and the interactive roles of the neuro-, immune, and other physiological systems in determining relationships between behaviour and infection susceptibility. Secondly, as the study of behaviour has shifted away from one-off measurements of single behaviours and towards a behavioural syndromes/personality framework, research is starting to focus on the consequences of parasite infection for temporal and contextual consistency of behaviour, and on the implications of different personality types for infection susceptibility. In addition, there is increasing interest in the potential for relationships between cognition and personality to also have implications for host-parasite interactions. As models well-suited to both the laboratory study of behaviour and experimental parasitology, teleost fish have been used as hosts in many of these studies. In this review we provide a broad overview of the range of mechanisms that potentially generate links between fish behaviour, personality, and parasitism, and illustrate these using examples drawn from the recent literature. In addition, we examine the potential interactions between cognition, personality and parasitism, and identify questions that may be usefully investigated with fish models.

Stream drift, size-specific predation, and the evolution of ovum size in an amphibian.

A stream-breeding race of small-mouthed salamanders (Ambystoma texanum) in central Kentucky produces ova that are twice as large as those of a pond-breeding race found nearby. Embryos of stream-breeders also hatch at a more advanced developmental stage than those of pond-breeders. Morphological evidence indicates that stream-breeders were derived from pond-breeding stock. Assuming that differences between stream and pond-breeders reflect evolutionary change, and that the ancestral pond stock that invaded streams was similar to extant pond-breeders, we examined three hypotheses that might explain changes in ovum size and stage at hatching following the invasion of streams. (1) Larger ovum size evolved indirectly as a consequence of selection for rapid development which minimizes mortality risk from stream drying. (2) Increased ovum (hatchling) size and stage at hatching of stream-breeders are adaptations to resist stream current. (3) Increased ovum (hatchling) size and stage at hatching are adaptations to reduce predation on hatchlings from stream invertebrates. The results of field and laboratory studies only support hypotheses (2) and (3). Hatchlings that were relatively large or at a more advanced developmental stage had slower drift rates and were less vulnerable to predation by Phagocata gracilis, a flatworm abundant in streams in central Kentucky. Developmental and growth parameters were not correlated significantly with ovum size in populations of either geographic race. Differences in degree of parental care among races also cannot explain variation in ovum size since both races abandon their eggs immediately after oviposition.