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Pregnant women may be at higher risk of severe complications associated with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which may lead to obstetrical complications. We performed a case control study comparing pregnant women with severe coronavirus disease 19 (cases) to pregnant women with a milder form (controls) enrolled in the COVI-Preg international registry cohort between March 24 and July 26, 2020. Risk factors for severity, obstetrical and immediate neonatal outcomes were assessed. A total of 926 pregnant women with a positive test for SARS-CoV-2 were included, among which 92 (9.9%) presented with severe COVID-19 disease. Risk factors for severe maternal outcomes were pulmonary comorbidities [aOR 4.3, 95% CI 1.9-9.5], hypertensive disorders [aOR 2.7, 95% CI 1.0-7.0] and diabetes [aOR2.2, 95% CI 1.1-4.5]. Pregnant women with severe maternal outcomes were at higher risk of caesarean section [70.7% (n = 53/75)], preterm delivery [62.7% (n = 32/51)] and newborns requiring admission to the neonatal intensive care unit [41.3% (n = 31/75)]. In this study, several risk factors for developing severe complications of SARS-CoV-2 infection among pregnant women were identified including pulmonary comorbidities, hypertensive disorders and diabetes. Obstetrical and neonatal outcomes appear to be influenced by the severity of maternal disease. ispartof: SCIENTIFIC REPORTS vol:11 issue:1 ispartof: location:England status: published

Lagomorphs show extensive seasonal variation in their reproduction. However, the factors causing this large variation have so far mostly been investigated intraspecifically and therefore provide only some exemplary comparisons of lagomorph reproductive seasonality. The present study applies both a categorical description (birth season categories 1–5) and a quantitative measure (birth season length in months) to summarize the degree of birth seasonality in the wild of 69 lagomorph species. Using a comparative approach, I tested the influence of 13 factors, comprising six habitat, five life history and two allometric variables on birth season length in lagomorphs. Leporids mainly show non-seasonal birthing patterns with high intraspecific variation. Their opportunistic breeding strategy with high reproductive output and their large distribution areas across wide latitude and elevation ranges might be the reasons for this finding. Ochotonids reproduce strictly seasonally, likely because they live at northern latitudes, are high-altitude specialists, and occur in limited distribution areas. The most important factors associated with variation in lagomorph birth seasonality are mid-latitude, mean annual temperature and precipitation of a species’ geographical range and life history adaptations including fewer but larger litters in seasonal habitats. Birth seasons become shorter with increasing latitude, colder temperatures, and less precipitation, corresponding to the decreasing length of optimal environmental conditions. Leporid species with shorter breeding seasons force maternal resources into few large litters to maximise reproductive output while circumstances are favourable. Since allometric variables were only weakly associated with reproductive seasonality, life history adaptations and habitat characteristics determine birth seasonality in Lagomorpha.

Background: Recent evidence suggests that pregnant women might be at higher risk of severe disease associated with the emerging pandemic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), while exposed fetuses/newborns could suffer from preterm birth, growth restriction and neonatal infections. The magnitude of this increased risk and specific risk factors for severity remains unclear. Methods: We performed a case control study comparing pregnant women with severe coronavirus disease 19 (case) to pregnant women with a milder form (controls) enrolled in COVI-Preg international registry cohort between from March 24 to July 26, 2020. Risk factors for severity, obstetrical, fetal and neonatal outcomes were assessed. Findings: A total of 926 pregnant women with a positive test for SARS-CoV-2 were included, among which 92 (9.9%) presented a severe COVID-19 disease. Risk factors for severe maternal outcomes were pulmonary comorbidities [aOR 4.3, 95% CI 1.9-9.5], hypertensive disorders [aOR 2.7, 95% CI 1.0-7.0] and diabetes [aOR2.2, 95% CI 1.1-4.5]. Pregnant women with severe maternal outcomes were at higher risk of cesarean sections [70.7% (n=53/75)], preterm deliveries [62.7% (n= 32/51)] and newborns requiring admission to the neonatal intensive care unit [41.3% (n=31/75)]. Interpretation: Pregnant women, particularly those with associated comorbidities, seem to be at higher risk of severe complications of SARS-CoV-2 infection. Obstetrical and neonatal outcomes appear to be influenced by the severity of maternal disease; complications include cesarean sections, prematurity and neonatal admission to the intensive care unit. Funding Statement: None. Declaration of Interests: The authors declare that they have no conflicts of interest. Ethics Approval Statement: The study was approved by both the Swiss Ethical Board (CER-VD- 2020-00548) and the local ethics boards at each participating center.

Rodents show an immense variation in reproductive seasonality, spanning the whole spectrum from strictly seasonal to continuous reproduction throughout the year. However, the factors causing this variation have so far mostly been investigated in single‐species studies that could not address phylogenetic constraints. By applying both a categorical description and a quantitative measure, the present study characterises the degree of reproductive seasonality in the wild of 272 rodent species. Using a comparative approach, the relationships of 12 variables, comprising five life‐history variables, three abiotic variables, two niche variables and two allometric variables, with reproductive seasonality in rodents, were tested. The majority of rodents reproduced non‐seasonally and had particularly high intraspecific variation in reproductive seasonality compared to other mammalian groups. Their opportunistic breeding strategies, their large geographic ranges with wide latitude and elevation ranges, and their ability to live in human‐made environments may be related to this broad intraspecific variation of birth season length in rodents. The most important variables associated with rodent reproductive seasonality were mid‐latitude of the species’ geographical range, temperature, litters per year, weaning age, age at sexual maturity and sexual size dimorphism. Birth seasons become shorter with increasing latitude and colder temperatures, corresponding to the decreasing length of the favourable season. Species with more pronounced birth seasonality have fewer litters, which are weaned earlier and reach sexual maturity later, corresponding to the shorter period of optimal environmental conditions for reproduction. Sexual size dimorphism was weakly associated with birth seasonality, with more seasonal species having a higher degree of male‐biased sexual dimorphism, potentially because male–male competition and female monopolisation are more likely to evolve in species with short mating seasons. In conclusion, habitat seasonality and life‐history adaptations are most strongly associated with reproductive seasonality in rodents, which has important implications for zoo husbandry and for the effects of climate change on rodents.

The strictly cumulative emergence of manipulative skills in primates constrains the evolution of complex technology., Neural development is highly conserved across distantly related species of different brain sizes. Here, we show that the development of manipulative complexity is equally cumulative across 36 primate species and also that its ontogeny recapitulates phylogeny. Furthermore, larger-brained species reach their adult skill levels later than smaller-brained ones, largely because they start later with the simplest techniques. These findings demonstrate that these motor behaviors are not modular and that their slow development may constrain their evolution. Complex foraging techniques therefore critically require a slow life history with low mortality, which explains the limited taxonomic distribution of flexible tool use and the unique elaboration of human technology.

Background: Pregnant women represent a vulnerable population at higher risk of complications of infectious diseases. Data regarding the consequences of the emerging pandemic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during pregnancy are scarce. Recent evidence suggests that pregnant women might be at higher risk of severe disease, while exposed fetuses and newborns could suffer from preterm birth, growth restriction and neonatal infections. Methods: We developed an international web registry to allow structured data collection. Pregnant women at any stage during gestation tested for SARS-CoV-2 infection were enrolled. Maternal, obstetrical and neonatal outcomes were recorded. Findings: 1033 pregnant women tested for SARS-CoV-2 were included, among which 926 tested positive and 107 tested negative. Positive pregnant women were at higher risk of severe maternal outcomes compared to negative women [aRR 5.6, 95% CI 1.4-22.7]. Risk factors for severe maternal outcomes among positive women were pulmonary comorbidities [aOR 4.3, 95% CI 1.9-9.5], hypertensive disorders [aOR 2.7, 95% CI 1.0-7.0] and diabetes [aOR2.2, 95% CI 1.1-4.5]. No difference in term of obstetrical and neonatal outcomes were observed between positive and negative women. Positive pregnant women with severe maternal outcomes were at higher risk of cesarean sections [70.7% (n=53/75)], preterm deliveries [62.7% (n= 32/51)] and newborns requiring admission to the neonatal intensive care unit [41.3% (n=31/75)]. A positive neonatal SARS-CoV-2 test was observed in 2.9% (n=11/384) of newborns with an available test at birth. Interpretation: Pregnant women, particularly those with associated comorbidities, seem to be at higher risk of severe complications of SARS-CoV-2 infection. Preliminary data regarding obstetrical and neonatal outcomes among women with a mild disease are reassuring. Funding Statement: None. Declaration of Interests: The authors declare that we have no conflicts of interest. Ethics Approval Statement: The study was approved by both the Swiss Ethical Board (CER-VD-2020-00548) and the local ethics boards at each participating center.

Humans stand out among non-aquatic mammals by having both an extremely large brain and a relatively large amount of body fat. To understand the evolution of this human peculiarity we report a phylogenetic comparative study of 120 mammalian species, including 30 primates, using seasonal variation in adult body mass as a proxy of the tendency to store fat. Species that rely on storing fat to survive lean periods are expected to be less active because of higher costs of locomotion and have increased predation risk due to reduced agility. Because a fat-storage strategy reduces the net cognitive benefit of a large brain without reducing its cost, such species should be less likely to evolve a larger brain than non-fat-storing species. We therefore predict that the two strategies to buffer food shortages (storing body fat and cognitive flexibility) are compensatory, and therefore predict negative co-evolution between relative brain size and seasonal variation in body mass. This trade-off is expected to be stronger in predominantly arboreal species than in more terrestrial ones, as the cost of transporting additional adipose depots is higher for climbing than for horizontal locomotion. We did, indeed, find a significant negative correlation between brain size and coefficient of variation (CV) in body mass in both sexes for the subsample of arboreal species, both in all mammals and within primates. In predominantly terrestrial species, in contrast, this correlation was not significant. We therefore suggest that the adoption of habitually terrestrial locomotor habits, accompanied by a reduced reliance on climbing, has allowed for a primate of our body size the unique human combination of unusually large brains and unusually large adipose depots.

Primates, like other mammals, exhibit an annual reproductive pattern that ranges from strictly seasonal breeding to giving birth in all months of the year, but factors mediating this variation are not fully understood. We applied both a categorical description and quantitative measures of the birth peak breadth based on daily observations in zoos to characterise reproductive seasonality in 141 primate species with an average of 941 birth events per species. Absolute day length at the beginning of the mating season in seasonally reproducing species was not correlated between populations from natural habitats and zoos. The mid-point of latitudinal range was a major factor associated with reproductive seasonality, indicating a correlation with photoperiod. Gestation length, annual mean temperature, natural diet and Malagasy origin were other important factors associated with reproductive seasonality. Birth seasons were shorter with increasing latitude of geographical origin, corresponding to the decreasing length of the favourable season. Species with longer gestation periods were less seasonal than species with shorter ones, possibly because shorter gestation periods more easily facilitate the synchronisation of reproductive activity with annual cycles. Habitat conditions with higher mean annual temperature were also linked to less-seasonal reproduction, independently of the latitude effect. Species with a high percentage of leaves in their natural diet were generally non-seasonal, potentially because the availability of mature leaves is comparatively independent of seasons. Malagasy primates were more seasonal in their births than species from other regions. This might be due to the low resting metabolism of Malagasy primates, the comparatively high degree of temporal predictability of Malagasy ecosystems, or historical constraints peculiar to Malagasy primates. Latitudinal range showed a weaker but also significant association with reproductive seasonality. Amongst species with seasonal reproduction in their natural habitats, smaller primate species were more likely than larger species to shift to non-seasonal breeding in captivity. The percentage of species that changed their breeding pattern in zoos was higher in primates (30%) than in previous studies on Carnivora and Ruminantia (13 and 10%, respectively), reflecting a higher concentration of primate species in the tropics. When comparing only species that showed seasonal reproduction in natural habitats at absolute latitudes ≤11.75°, primates did not differ significantly from these two other taxa in the proportion of species that changed to a less-seasonal pattern in zoos. However, in this latitude range, natural populations of primates and Carnivora had a significantly higher proportion of seasonally reproducing species than Ruminantia, suggesting that in spite of their generally more flexible diets, both primates and Carnivora are more exposed to resource fluctuation than ruminants.

Although it is generally assumed that among mammals and within mammal groups, those species that rely on diets consisting of greater amounts of plant fiber have larger gastrointestinal tracts (GIT), statistical evidence for this simple claim is largely lacking. We compiled a dataset on the length of the small intestine, caecum, and colon in 42 strepsirrhine, platyrrhine, and catarrhine primate species, using specimens with known body mass (BM). We tested the scaling of intestine length with BM, and whether dietary proxies (percentage of leaves and a diet quality index) were significant covariates in these scaling relationships, using two sets of models: one that did not account for the phylogenetic structure of the data, and one that did. Intestine length mainly scaled geometrically at exponents that included 0.33 in the confidence interval; Strepsirrhini exhibited particularly long caeca, while those of Catarrhini were comparatively short. Diet proxies were only significant for the colon and the total large intestine (but not for the small intestine or the caecum), and only in conventional statistics (but not when accounting for phylogeny), indicating the pattern occurred across but not within clades. Compared to terrestrial Carnivora, primates have similar small intestine lengths, but longer large intestines. The data on intestine lengths presented here corroborate recent results on GIT complexity, suggesting that diet, as currently described, does not exhaustively explain GIT anatomy within primate clades.

The expensive brain hypothesis predicts that the lowest stable level of energy input sets the upper limit to a species’ brain size. This prediction receives comparative support from the effects of experienced seasonality (including hibernation) and diet quality on mammalian brain size. Here, we test another prediction, which concerns the temporal stability of energy inputs. Allomaternal care in mammals can be provided by breeding males or other helpers (usually earlier offspring). Male care should be stable and reliable since otherwise no breeding would occur. Care by others, in contrast, should fluctuate, as the availability of helpers often varies. One would therefore predict, other things being equal, that the presence of male care in addition to maternal care should show positive correlated evolution with brain size, whereas care by others would not. However, because females can readily respond through litter size adjustments to variable amounts of energy inputs, helper inputs may be used to increase fertility. A detailed comparative analysis of a large sample of mammals (N = 478 species) showed that male help is correlated with the evolution of larger brains, whereas alloparental help is correlated with higher fertility, but only in species where male care is also present (as in cooperative breeders). Humans evolved an unusual form of multi-family cooperative breeding, which involves stable and reliable care by both fathers and alloparents. This combination helps to explain why humans differ from the other apes in having both an extremely large brain and a relatively high reproductive output. Allomaternal care provides breeding females with energy, directly or indirectly, and so would be expected to affect fertility and/or brain size. Which path evolution actually took remains controversial, partly because previous studies did not separate between care provided by the breeding male (paternal care) and care by non-breeding helpers (alloparental care). We distinguish between them because we expect that selection only favours increased brain size if the increase in energy available to the female is predictable and constant. Using a sample of 478 mammals, we show that paternal care, which is both reliable and stable, shows correlated evolution with brain size, whereas alloparental care, which fluctuates with varying availability of helpers, is correlated with higher fertility. Thus, constraints on brain size, imposed by its high-energy costs, may predict brain size better than the fitness benefits of improved cognitive abilities per se.

Background Fat deposits enable a female mammal to bear the energy costs of offspring production and thus greatly influence her reproductive success. However, increasing locomotor costs and reduced agility counterbalance the fitness benefits of storing body fat. In species where costs of reproduction are distributed over other individuals such as fathers or non-breeding group members, reproductive females might therefore benefit from storing less energy in the form of body fat. Results Using a phylogenetic comparative approach on a sample of 87 mammalian species, and controlling for possible confounding variables, we found that reproductive females of species with allomaternal care exhibit reduced annual variation in body mass (estimated as CV body mass), which is a good proxy for the tendency to store body fat. Differential analyses of care behaviours such as allonursing or provisioning corroborated an energetic interpretation of this finding. The presumably most energy-intensive form of allomaternal care, provisioning of the young, had the strongest effect on CV body mass. In contrast, allonursing, which involves no additional influx of energy but distributes maternal help across different mothers, was not correlated with CV body mass. Conclusions Our results suggest that reproducing females in species with allomaternal care can afford to reduce reliance on fat reserves because of the helpers’ energetic contribution towards offspring rearing. Electronic supplementary material The online version of this article (doi:10.1186/s12983-017-0214-0) contains supplementary material, which is available to authorized users.

Patterns of reproductive seasonality in the Carnivora are difficult to study comparatively, due to limited numbers of species for which information is available. Long-term databases of captive populations could overcome this difficulty. We apply a categorical description and a quantitative high-resolution measure (birth peak breadth, the number of days in which 80% of all births occur) based on daily observations in captivity to characterize the degree of reproductive seasonality in the Carnivora for 114 species with on average 1357 births per species. We find that the majority of species retained the birth seasonality displayed in the wild. Latitude of natural origin, delayed implantation, and induced ovulation were the main factors influencing reproductive seasonality. Most species were short-day breeders, but there was no evidence of an absolute photoperiodic signal for the timing of mating or conception. The length of the gestation period (corrected for body mass) generally decreased with birth seasonality but increased in species with delayed implantation. Birth seasons become shorter with increasing latitude of geographical origin, likely because the length of the favorable season declines with increasing latitude, exerting a strong selective pressure on fitting both the reproductive cycle and the interval offspring needs for growth following the termination of parental care into the short time window of optimal environmental conditions. Species with induced ovulation exhibit a less seasonal reproductive pattern, potentially because mates do not have to meet during a short time window of a fixed ovulation. Seasonal species of Carnivora shorten their gestation period so reproduction can occur during the short time window of optimal environmental conditions. Alternatively, other Carnivora species lengthen their gestation periods in order to bridge long winters. Interestingly, this occurs not by decelerating intrauterine growth but by delaying implantation.

Background Fat deposits enable a female mammal to bear the energy costs of offspring production and thus greatly influence her reproductive success. However, increasing locomotor costs and reduced agility counterbalance the fitness benefits of storing body fat. In species where costs of reproduction are distributed over other individuals such as fathers or non-breeding group members, reproductive females might therefore benefit from storing less energy in the form of body fat. Results Using a phylogenetic comparative approach on a sample of 87 mammalian species, and controlling for possible confounding variables, we found that reproductive females of species with allomaternal care exhibit reduced annual variation in body mass (estimated as CV body mass), which is a good proxy for the tendency to store body fat. Differential analyses of care behaviours such as allonursing or provisioning corroborated an energetic interpretation of this finding. The presumably most energy-intensive form of allomaternal care, provisioning of the young, had the strongest effect on CV body mass. In contrast, allonursing, which involves no additional influx of energy but distributes maternal help across different mothers, was not correlated with CV body mass. Conclusions Our results suggest that reproducing females in species with allomaternal care can afford to reduce reliance on fat reserves because of the helpers’ energetic contribution towards offspring rearing.

Humans occupy by far the most complex foraging niche of all mammals, built around sophisticated technology, and at the same time exhibit unusually large brains. To examine the evolutionary processes underlying these features, we investigated how manipulation complexity is related to brain size, cognitive test performance, terrestriality, and diet quality in a sample of 36 non-human primate species. We categorized manipulation bouts in food-related contexts into unimanual and bimanual actions, and asynchronous or synchronous hand and finger use, and established levels of manipulative complexity using Guttman scaling. Manipulation categories followed a cumulative ranking. They were particularly high in species that use cognitively challenging food acquisition techniques, such as extractive foraging and tool use. Manipulation complexity was also consistently positively correlated with brain size and cognitive test performance. Terrestriality had a positive effect on this relationship, but diet quality did not affect it. Unlike a previous study on carnivores, we found that, among primates, brain size and complex manipulations to acquire food underwent correlated evolution, which may have been influenced by terrestriality. Accordingly, our results support the idea of an evolutionary feedback loop between manipulation complexity and cognition in the human lineage, which may have been enhanced by increasingly terrestrial habits.