Find research datasets worth reusing
Search datasets from major research repositories and use ShareScore to quickly assess how well each record supports discovery, access, and reuse.
303
datasets available to search
ShareScore release 0.7.1
Dataset results
303 results for “sex ratio”
Sperm limitation produces male biased family sex ratios
<p>Haplo-diploid sex determination in the parasitoid wasp, <em>Nasonia vitripennis</em> (Walker), allows females to adjust their brood sex ratios. Females influence whether ova are fertilized, producing diploid females, or remain unfertilized, producing haploid males. Females appear to adjust their brood sex ratios to minimize "local mate competition," <em>i.e.</em>, competition among sons for mates. Because mating occurs between siblings, females may optimize mating opportunities for their offspring by producing only enough sons to inseminate daughters when ovipositing alone and producing more sons when superparasitism is likely. Although widely accepted, this hypothesis makes no assumptions about gamete limitation in either sex. Because sperm is used to produce daughters, repeated oviposition could reduce sperm supplies, causing females to produce more sons. In contrast, if egg-limited females produce smaller broods, they might use fewer sperm, making sperm limitation less likely. To investigate whether repeated oviposition and female fertility influence gamete limitation within females, we created two treatments of six mated female wasps, which received a series of six hosts at intervals of 24 or 48 hrs. All females produced at least one mixed-sex brood (63 total broods; 3,696 offspring). As expected, if females became sperm limited, in both treatments, brood sex ratios became increasingly male-biased with increasing host number. The interhost interval did not affect brood size, total offspring number or sex ratio, indicating females did not become egg limited. Our results support earlier studies showing sperm depletion affects sex allocation in <em>N. vitripennis</em>¸ and could limit adaptive sex ratio manipulation in these parasitoid wasps.</p>
Dataset for: Mating competition and adult sex ratio in wild Trinidadian guppies
<p><span>Most experimental tests of mating systems theory have been conducted in the laboratory, using operational sex ratios (ratio of ready-to-mate male to ready-to-mate female) that are often not representative of natural conditions. Here, we first measured the range of adult sex ratio (proportion of adult males to adult females; ASR) in two populations of Trinidadian guppies (<em>Poecilia reticulata</em>) differing in ambient predation risk (high vs. low). We then explored, under semi-wild conditions, the effect of ASR (i.e. 0.17, 0.50, 0.83) on mating competition patterns in these populations. ASR in the wild was female-biased and did not significantly differ between the two populations. The range of ASR in our experiment was representative of natural ASRs. As expected, we observed an increase in intrasexual aggression rates in both sexes as the relative abundance of competitors increased. In support of the risky competition hypothesis, all measured behaviors had lower rates in a high vs. low predation-risk population, likely due to the costs of predation. In terms of mating tactics, a male-biased ASR did not lead males to favor forced mating over courtship,</span><span> </span><span>indicating that males did not compensate for the cost of competition by switching to a less costly alternative mating tactic</span><span>. </span><span>Overall, this study highlights the need for field experiments using natural ranges of ASRs to test the validity of mating systems theory in a more complex, ecologically relevant context.</span></p>
Wolf pup sex ratios and covariates, Idaho, USA 2008-2018
<p>Wolf pup sex ratio data and associated covariates in Idaho USA (2008-2018).</p>
Variance in offspring sex ratio and maternal allocation in a highly invasive mammal
<p>Skewed sex ratios at birth are widely reported in wild populations, however the extent to which parents are able to modulate the sex ratio of offspring to maximize their own fitness remains unclear. This is particularly true for highly polytocous species as maximizing fitness may include trade-offs between sex ratio and the size and number of offspring in litters. In such cases, it may be adaptive for mothers to adjust both the number of offspring per litter and offspring sex to maximize individual fitness. Investigating maternal sex allocation in wild pigs (<em>Sus scrofa</em>) under stochastic environmental conditions, we predicted that, under favorable conditions, high quality mothers (larger, older) would produce male-biased litters and invest more in producing larger litters with more males. We also predicted sex ratio would vary relative to litter size, with a male-bias among smaller litters. We found evidence that increasing wild boar ancestry, maternal age and condition, and resource availability may weakly contribute to male-biased sex ratio, however, unknown factors not measured in this study are assumed to be more influential. High quality mothers allocated more resources in litter production, but this relationship was driven by adjustment of litter size, not sex ratio. There was no relationship between sex ratio and litter size. Collectively, our results emphasized that adjustment of litter size appeared to be the primary reproductive characteristic manipulated in wild pigs to increase fitness rather than adjustment of offspring sex ratio.</p>
Fig. 1 in Seasonal Changes In The Sex Ratio Of Nyctalus Species In North-East Hungary
Fig. 1. The numbers of males and females of N. leisleri grouped into 15 day periods
Fig. 2 in Seasonal Changes In The Sex Ratio Of Nyctalus Species In North-East Hungary
Fig. 2. The numbers of males and females of N. noctula grouped into 15 day periods
Figure 2 in Sex ratio estimations of Chelonia mydas hatchlings at Samandağ Beach, Turkey
Figure 2. Frequency of incubation durations in examined nests at Samandağ Beach.
Figure 1 in Sex ratio estimations of Chelonia mydas hatchlings at Samandağ Beach, Turkey
Figure 1. Map showing study area of Samandağ Beach.
Figure 3 in Population dynamics, age structure and sex ratio of the bromeliad-dwelling jumping spider, Psecas chapoda (Salticidae)
Figure 3. Climatic data from Itauna farm (5 km from the study site), from May 1998 to April 2000.
Data from: Are brood sex ratios adaptive? The effect of experimentally altered brood sex ratio on nestling growth, mortality, and recruitment
<p><span>Brood sex ratios (BSRs) have often been found to be non-random in respect of parental and environmental quality, and many hypotheses suggest that non-random sex ratios can be adaptive. To specifically test the adaptive value of biased BSRs, it is crucial to disentangle the consequences of BSR and maternal effects. In multiparous species, this requires cross-fostering experiments where foster parents rear offspring originating from multiple broods, and where the interactive effect of original and manipulated BSR on fitness components are tested. To our knowledge, our study on collared flycatchers (<em>Ficedula albicollis</em>) is the first that meets these requirements. In this species, where BSRs had previously been shown to be related to parental characteristics, we altered the original BSR of the parents shortly after hatching by cross-fostering nestlings among trios of broods, and examined the effects on growth, mortality, and recruitment of the nestlings. We found that original and experimental BSR, as well as the interaction of the two were unrelated to the fitness components considered. Nestling growth was related only to background variables, namely brood size and hatching rank. Nestling mortality was related only to hatching asynchrony. Our results therefore do not support that the observed BSRs are adaptive in our study population. However, we cannot exclude the possibility of direct effects of experimentally altered BSRs on parental fitness, which should be evaluated in the future. In addition, studies similar to ours are required on various species to get a clearer picture of the adaptive value of non-random BSRs.</span></p>
The presence of a guard vicariously drives split sex ratios in a facultatively social bee
<p>Split sex ratios provide broad insights into how reproductive strategies evolve and historically have special relevance to the evolution of eusociality. Yet almost no attention has been directed to situations where split sex ratios may potentially decrease the payoffs for worker-like behaviour, increasing selective thresholds for eusociality. We examined sex ratios in a facultatively social colletid bee, <em>Amphylaeus morosus</em>. Sex ratios in this bee vary strongly with the presence of a nest guard and in a pattern that does not conform to assumptions of previous models in which split sex ratios facilitate altruism. While the production of daughters was constant across social and solitary nests, mothers produced more brood when a non-reproductive guard was present, but these extra brood were all male. This leads to split sex ratios, vicariously driven by guards that are unable to manipulate sex ratios in their favour. Importantly, if guarding becomes more common in a population this would lead to an excess of males and lower the genetic value of these extra males to guards, effectively putting a brake on selection for worker-like behaviour.</p>
Dietary fat supplements influence weight gain and egg production but not offspring sex ratios in Japanese quail
<p>Sex ratio theory suggests that females should bias offspring sex ratios based on maternal condition and the availability of critical food resources. Work in birds indicates that females do, indeed, bias sex ratios according to maternal condition and food quality and quantity. Yet it is unknown whether these sex ratio skews occur due to fluctuations in particular micro- or macro-nutrients, caloric content overall, or even the perception of food availability. We hypothesized that dietary fats may drive biases in offspring sex ratios, because measures of maternal condition often reflect fat reserves, and fats are critical for the process of egg-laying in birds. To test this, we provided breeding Japanese quail, a species that biases sex ratios in response to maternal condition, with either a control breeding diet or a diet supplemented with two oils (safflower oil and flaxseed oil). These oils were chosen for their high omega-3 and omega-6 fatty acid content as well as their importance in mammalian sex allocation. We then measured influences of these diets on the sex ratio of offspring, the change in maternal weight, and the laying rates of female quail. The dietary oil supplements increased weight gains in quail but decreased the number of eggs laid during the experiment. There was no influence of the oil supplements on offspring sex ratios. This indicates that fat may not be a macro-nutrient involved in the process of sex ratio adjustment in quail.</p>
Data for: Mechanisms that can cause population decline under heavily skewed male-biased adult sex ratios
<ol> <li><span>While adult sex ratio (ASR) is a crucial component for population management, there is still a limited understanding of how its fluctuation affects population dynamics. To demonstrate mechanisms that hinder population growth under a biased ASR, we examined changes in reproductive success with ASR using a decapod crustacean exposed to female-selective harvesting. </span></li> <li> <span>We examined the effect of ASR on the spawning</span><span> success </span><span>of females. A laboratory experiment showed that the number of eggs carried by females decreased as the proportion of males in the mating groups increased. Although the same result was not observed in data collected over 25 years in the wild, the negative effect of ASR was suggested when success in carrying eggs was considered as a spawning success. These results indicate that a surplus of males results in females failing to carry eggs, probably due to sexual coercion, and</span> <span>the negative effect of ASR can be detected at the population level only when the bias increases because failure in spawning success occurs in part of population.</span> </li> <li><span>We experimentally examined how male-biased sex ratios affected the maintenance of genetic diversity in a population. The diversity of paternity in a clutch increased with the number of candidate fathers. However, over 50% of a clutch was fertilised by a single male regardless of the sex ratio, and the degree of diversity was less than half of the highest diversity expected in each mating group. </span></li> <li><span>We also experimentally examined the mating ability of males during the breeding season. The experiment showed that multiple mating by males could not compensate for the risk that their genotypes would be lost when multiple males competed for one female. These results suggest that a male-biased ASR could trigger a decline of genetic diversity in a population.</span></li> <li><span>We show that ASR skewed by female-selective harvesting decreases reproductive success not only of males that have few mating opportunities but also of females. We discuss that we may still underestimate the significance of ASR on population persistence due to the difficulty of revealing the effect of ASR.</span></li> </ol>
Multiple paternity is related to adult sex ratio and sex determination system in reptiles
<p><span>The adult sex ratio (ASR, the proportion of males in the adult population) is an emerging predictor of reproductive behaviour, and recent studies in birds and humans suggest it is a major driver of social mating systems and parental care. ASR may also influence genetic mating systems. For instance, male-skewed ASRs are expected to increase the frequency of multiple paternity (defined here as a clutch or litter sired by two or more males) due to higher rates of coercive copulations by males and/or due to females exploiting the opportunity of copulation with multiple males to increase genetic diversity of their offspring. Here we evaluate this hypothesis in reptiles that often exhibit high frequency of multiple paternity, although its ecological and life-history predictors have remained controversial. Using a comprehensive dataset of 81 species representing all four non-avian reptile orders, we show that increased frequency of multiple paternity is predicted by more male-skewed ASR, and this relationship is robust to simultaneous effects of several life-history predictors. Additionally, we show that the frequency of multiple paternity varies with the sex determination system: species with female heterogamety (ZZ/ZW sex chromosomes) exhibit higher levels of multiple paternity than species with male heterogamety (XY/XX) or temperature-dependent sex determination. Thus, our across-species comparative study provides the first evidence that genetic mating system depends on ASR in reptiles. We call for further investigations to uncover the complex evolutionary associations between mating systems, sex determination systems and ASR.</span></p>
Fig. 8 in Sex-ratio and body size plasticity in two cold-adapted ground beetles co-occurring in a periglacial area of the European Alps (Coleoptera: Carabidae)
Fig. 8 – Linear regression graph between elytra width of Nebria castanea females and the soil pH.
Fig. 1 in Sex-ratio and body size plasticity in two cold-adapted ground beetles co-occurring in a periglacial area of the European Alps (Coleoptera: Carabidae)
Fig. 1 – Sampling plan: distribution of pitfall traps at the Lazaunkar site.
Offspring sex ratio is affected by pre-breeding rainfall and hatching order in a cooperative breeding bird
<p><span>Selection may favour sex ratio adjustment when the fitness benefits of producing male or female offspring vary. In birds, sex ratio bias at hatching has been particularly well-studied in cooperative breeding species, primarily in helper-at-the-nest systems wherein young remain with their parents and help raise subsequent broods. In these systems, breeding females are expected to skew offspring sex ratio in favour of the helping sex if sufficient resources exist. In communal laying systems multiple group members breed and raise the young and offspring dispersal varies, making it difficult to predict whether and how breeders should skew offspring sex ratio. We tested for sex ratio bias in smooth-billed anis (<em>Crotophaga ani</em>), a communal laying cuckoo with low within-group relatedness, high offspring dispersal, and high annual turnover in group membership. One male performs nocturnal incubation and sires more offspring, suggesting these males may have higher reproductive variance and thus that it may be beneficial for his mate to produce more male offspring. We hypothesized that pre-breeding rainfall influences food availability and thus offspring sex ratio, predicting that breeding females skew production towards the more beneficial sex (i.e., males) in high food years, consistent with the Trivers-Willard hypothesis. Females may also adjust sex ratio across the hatching order, so we predicted a male-bias in first hatched chicks in larger broods that should experience greater competition. Contrary to our first prediction, more male chicks hatched when pre-breeding rainfall was lower. In partial support of our second prediction, marginally more first hatched chicks were male in larger broods. Based on these results, we propose the nestling competition hypothesis and predict that when nestling competition is high (i.e., in poor years and in large joint broods), mothers should produce more of the more competitive sex. </span></p>
How does the weekend catch-up sleep ratio affect the health and lifestyle of Korean adults? An age- and sex- matched study
<p>The purpose of this study was to investigate the association between various levels of physical activity, self-perception, cardiometabolic risk factors, and weekend catch-up sleep ratio (CSR). Using raw data from the Korea National Health and Nutrition Examination Survey 2018 – 2021, all participants were divided into three groups (< 1.0, 1.0 ≤ CSR < 1.5, or ≥ 1.5) by CSR, which is the value calculated by dividing weekend sleep time by weekday sleep time. After matching age and sex, 2,484 Korean adults were selected as study participants. Descriptive statistics, chi-square test, ANOVA, and multinomial logistic regression analysis were performed to analyze the data. The results showed a significant association between weekend CSR and socioeconomic status, physical activity, self-perception levels, and cardiometabolic risk factors. Specifically, compared to the reference group (1 ≤ CSR < 1.5), those with a CSR < 1 were 2.42 times more likely to live in a single-family house (OR = 2.42, 95% CI = 1.77 – 3.32) and 1.71 times more likely to engage in vigorous physical activity meeting WHO guidelines (OR = 1.71, 95% CI = 1.20 – 2.46). They were also 1.33 times more likely to perceive themselves as 'obese' (OR = 1.33, 95% CI = 1.00 – 1.76). Conversely, those in the CSR ≥ 1.5 group were 3.93 times more likely to be 'pink-collar' workers (OR = 3.93, 95% CI = 2.70 – 5.71), 1.72 times more likely to perceive their stress levels as 'quite' (OR = 1.72, 95% CI = 1.20 – 2.47), and 1.87 times more likely to have diabetes (OR = 1.87, 95% CI = 0.97 – 3.60). Alterations in CSR could indicate changes in physical activity levels, sedentary behavior duration, and other health indicators, ultimately influencing overall well-being. Therefore, a comprehensive healthcare approach incorporating CSR considerations is increasingly essential.</p>
Data from: Contrasting patterns of X-chromosome divergence underlie multiple sex-ratio polymorphisms in stalk-eyed flies
Open the record for dataset details and reuse information.
How does the weekend catch-up sleep ratio affect the health and lifestyle of Korean adults? An age- and sex- matched study
Open the record for dataset details and reuse information.
ScienceDex guides
Understand access before you commit
These curated guides explain access requirements, typical timelines, costs, and reuse considerations for widely used research datasets.
Allen Brain Atlas
Allen Brain Atlas is an Allen Institute collection of brain map atlases, datasets, APIs, and analysis tools covering mouse, human, and non-human primate brain resources.
Annotated Behaviour and Observability Dataset (ABODe)
ABODe is a University of Edinburgh DataShare dataset for behavior classification in group-housed mice using home-cage video, identities, bounding boxes, ground-plate positions, and annotator labels.
DANDI Archive for NWB datasets
DANDI is a BRAIN Initiative archive for publishing and sharing neurophysiology data, including electrophysiology, optophysiology, and behavioral data packaged as NWB and related standards.
International Brain Laboratory public data
The International Brain Laboratory public data releases expose standardized mouse decision-making experiments, including Neuropixels recordings, widefield calcium imaging, behavior, and session metadata accessed through the ONE API.
OpenNeuro
OpenNeuro is a free, open platform for sharing neuroimaging datasets, with public search, dataset pages, and download paths for web, S3, DataLad, and the OpenNeuro CLI.