Life history optimisation drives latitudinal gradients and responses to global change in marine fishes.

Within many species, and particularly fish, fecundity does not scale with mass linearly; instead, it scales disproportionately. Disproportionate intraspecific size-reproduction relationships contradict most theories of biological growth and present challenges for the management of biological systems. Yet the drivers of reproductive scaling remain obscure and systematic predictors of how and why reproduction scaling varies are lacking. Here, we parameterise life history optimisation model to predict global patterns in the life histories of marine fishes. Our model predict latitudinal trends in life histories: Polar fish should reproduce at a later age and show steeper reproductive scaling than tropical fish. We tested and confirmed these predictions using a new, global dataset of marine fish life histories, demonstrating that the risks of mortality shape maturation and reproductive scaling. Our model also predicts that global warming will profoundly reshape fish life histories, favouring earlier reproduction, smaller body sizes, and lower mass-specific reproductive outputs, with worrying consequences for population persistence.

Bioactive Modified Non-Wovens as a Novel Approach of Plants Protection against Invasive Slugs.

Invasive slugs generate significant problems in the area of horticultural and agricultural production. Despite the multitude of methods to reduce the pest population, including preventive, mechanical, agrotechnical, cultivation, biological, and chemical treatments, no effective plant protection strategy has been developed so far. In this paper, a solution based on modified non-woven fabric with bioactive molluscicidal properties using the extract of tansy flower, metaldehyde, and abamectin (Vertigo® 018 EC) was proposed. All modified mats show significant anti-slug properties in comparison to control, and molluscicidal properties depend on the type of active substance. Non-woven modified with commonly used metaldehyde demonstrated fast action against slugs and presents the highest efficiency. The effectiveness of non-woven mats with Vertigo® 018 EC is lower than for the mats with metaldehyde but higher than for the mats modified with tansy flower extract. The proposed solution will enable removing and neutralization of molluscicide from the fields, after the efficient pest control, according to circular economy principles. Moreover, it may allow for better control of the molluscicide release to the environment in comparison to widely used pellets, and contribute to the virtual protection of plants against invasive slugs.

Concerted evolution of body mass, cell size and metabolic rate among carabid beetles.

Alterations in cell number and size are apparently associated with the body mass differences between species and sexes, but we rarely know which of the two mechanisms underlies the observed variance in body mass. We used phylogenetically informed comparisons of males and females of 19 Carabidae beetle species to compare body mass, resting metabolic rate, and cell size in the ommatidia and Malpighian tubules. We found that the larger species or larger sex (males or females, depending on the species) consistently possessed larger cells in the two tissues, indicating organism-wide coordination of cell size changes in different tissues and the contribution of these changes to the origin of evolutionary and sex differences in body mass. The species or sex with larger cells also exhibited lower mass-specific metabolic rates, and the interspecific mass scaling of metabolism was negatively allometric, indicating that large beetles with larger cells spent relatively less energy on maintenance than small beetles. These outcomes also support existing hypotheses about the fitness consequences of cell size changes, postulating that the low surface-to-volume ratio of large cells helps decrease the energetic demand of maintaining ionic gradients across cell membranes. Analyses with and without phylogenetic information yielded similar results, indicating that the observed patterns were not biased by shared ancestry. Overall, we suggest that natural selection does not operate on each trait independently and that the linkages between concerted cell size changes in different tissues, body mass and metabolic rate should thus be viewed as outcomes of correlational selection.

Scaling of organ masses in mammals and birds: phylogenetic signal and implications for metabolic rate scaling.

The persistent enigma of why the whole-body metabolic rate increases hypoallometrically with body mass should be solved on both the ultimate and proximate levels. The proximate mechanism may involve hyperallometric scaling of metabolically inert tissue/organ masses, hypoallometric scaling of metabolically expensive organ masses, a decrease in mass-specific metabolic rates of organs or a combination of these three factors. Although there are literature data on the tissue/organ masses scaling, they do not consider phylogenetic information. Here, we analyse the scaling of tissue/organ masses in a sample of 100 mammalian and 22 bird species with a phylogenetically informed method (PGLS) to address two questions: the role of phylogenetic differences in organ/tissue size scaling and the potential role of organ/tissue mass scaling in interspecific metabolic rate scaling. Strong phylogenetic signal was found for the brain, kidney, spleen and stomach mass in mammals but only for the brain and leg muscle in birds. Metabolically relatively inert adipose tissue scales isometrically in both groups. The masses of energetically expensive visceral organs scale hypoallometrically in mammals, with the exception of lungs, with the lowest exponent for the brain. In contrast, only brain mass scales hypoallometrically in birds, whereas other tissues and organs scale isometrically or almost isometrically. Considering that the whole-body metabolic rate scales more steeply in mammals than in birds, the mass-specific metabolic rate of visceral organs must decrease with body mass much faster in birds than in mammals. In general, studying whole-body metabolic rate is not adequate for explaining its scaling, and measuring metabolic rates of organs, together with their contribution to body mass, is urgently required.

Incidence and etiology of mortality in polytrauma patients: an analysis of material from Multitrauma Centre of the University Teaching Hospital no 1 in Szczecin, over a period of 3 years (2017-2019).

<b>Introduction:</b> The pattern of traumatic death is a subject of great interest in the worldwide literature. Most studies have aimed to improve trauma care and raise awareness of avoidable fatal complications. <br><b>Aim:</b> The objective of the present study was an epidemiological and clinical analysis of causes of traumatic death of patients treated at the Multitrauma Centre of the University Teaching Hospital No 1 in Szczecin, over a period of 3 years (2017-2019). <br><b>Material and methods:</b> The study material comprised medical data of 32 patients with a mean age of 63 years, who died due to polytrauma injury. The time of death form admission to the Multitrauma Centre, primary cause of death, spectrum and sites of injuries, as well as method of treatment (operative or conservative) were variables considered in the analysis. <br><b>Results:</b> The predominant mechanisms of injury were traffic accidents - 22 cases (69%) followed by falls from a height 8 (25%) and other mechanism - 2 cases (6%). The most common primary cause of death was brain injury - 17 patients (53%) followed by pelvic or spinal fractures - 5 (16%). The predominant constituents of polytrauma were bony injuries (pelvis, spine and limbs) - 28 cases (87%), followed by head injuries - 25 (78%), chest - 24 (75%) and abdominal injuries - 17 (53%). Eighteen patients (56%) required operative treatment; craniotomy for brain injuries was the most commonly performed - in 11 patients, followed by laparotomy - in 5. Five other patients underwent an endovascular procedure - pelvic artery embolization. Twelve patients (38%) died in the first two days from admission to the trauma center, 5 (16%) in the first week and 15 over one week form admission. <br><b>Conclusions:</b> Head injuries, pelvic fractures with associated retroperitoneal bleeding and severe injuries affecting several body parts were identified as the most dangerous for the survival of polytrauma patients. A trend to decrease mortality due to hemorrhagic shock was observed, but it remains unchanged for central nervous system injuries.

Effects of thermal and oxygen conditions during development on cell size in the common rough woodlice Porcellio scaber.

During development, cells may adjust their size to balance between the tissue metabolic demand and the oxygen and resource supply: Small cells may effectively absorb oxygen and nutrients, but the relatively large area of the plasma membrane requires costly maintenance. Consequently, warm and hypoxic environments should favor ectotherms with small cells to meet increased metabolic demand by oxygen supply. To test these predictions, we compared cell size (hindgut epithelium, hepatopancreas B cells, ommatidia) in common rough woodlice (Porcellio scaber) that were developed under four developmental conditions designated by two temperatures (15 or 22°C) and two air O2 concentrations (10% or 22%). To test whether small-cell woodlice cope better under increased metabolic demand, the CO2 production of each woodlouse was measured under cold, normoxic conditions and under warm, hypoxic conditions, and the magnitude of metabolic increase (MMI) was calculated. Cell sizes were highly intercorrelated, indicative of organism-wide mechanisms of cell cycle control. Cell size differences among woodlice were largely linked with body size changes (larger cells in larger woodlice) and to a lesser degree with oxygen conditions (development of smaller cells under hypoxia), but not with temperature. Developmental conditions did not affect MMI, and contrary to predictions, large woodlice with large cells showed higher MMI than small woodlice with small cells. We also observed complex patterns of sexual difference in the size of hepatopancreatic cells and the size and number of ommatidia, which are indicative of sex differences in reproductive biology. We conclude that existing theories about the adaptiveness of cell size do not satisfactorily explain the patterns in cell size and metabolic performance observed here in P. scaber. Thus, future studies addressing physiological effects of cell size variance should simultaneously consider different organismal elements that can be involved in sustaining the metabolic demands of tissue, such as the characteristics of gas-exchange organs and O2-binding proteins.

Thermal and oxygen conditions during development cause common rough woodlice (Porcellio scaber) to alter the size of their gas-exchange organs.

Terrestrial isopods have evolved pleopodal lungs that provide access to the rich aerial supply of oxygen. However, isopods occupy conditions with wide and unpredictable thermal and oxygen gradients, suggesting that they might have evolved adaptive developmental plasticity in their respiratory organs to help meet metabolic demand over a wide range of oxygen conditions. To explore this plasticity, we conducted an experiment in which we reared common rough woodlice (Porcellio scaber) from eggs to maturation at different temperatures (15 and 22 °C) combined with different oxygen levels (10% and 22% O2). We sampled animals during development (only females) and then examined mature adults (both sexes). We compared woodlice between treatments with respect to the area of their pleopod exopodites (our proxy of lung size) and the shape of Bertalanffy's equations (our proxy of individual growth curves). Generally, males exhibited larger lungs than females relative to body size. Woodlice also grew relatively fast but achieved a decreased asymptotic body mass in response to warm conditions; the oxygen did not affect growth. Under hypoxia, growing females developed larger lungs compared to under normoxia, but only in the late stage of development. Among mature animals, this effect was present only in males. Woodlice reared under warm conditions had relatively small lungs, in both developing females (the effect was increased in relatively large females) and among mature males and females. Our results demonstrated that woodlice exhibit phenotypic plasticity in their lung size. We suggest that this plasticity helps woodlice equilibrate their gas exchange capacity to differences in the oxygen supply and metabolic demand along environmental temperature and oxygen gradients. The complex pattern of plasticity might indicate the effects of a balance between water conservation and oxygen uptake, which would be especially pronounced in mature females that need to generate an aqueous environment inside their brood pouch.

Coevolution of body size and metabolic rate in vertebrates: a life-history perspective.

Despite many decades of research, the allometric scaling of metabolic rates (MRs) remains poorly understood. Here, we argue that scaling exponents of these allometries do not themselves mirror one universal law of nature but instead statistically approximate the non-linearity of the relationship between MR and body mass. This 'statistical' view must be replaced with the life-history perspective that 'allows' organisms to evolve myriad different life strategies with distinct physiological features. We posit that the hypoallometric allometry of MRs (mass scaling with an exponent smaller than 1) is an indirect outcome of the selective pressure of ecological mortality on allocation 'decisions' that divide resources among growth, reproduction, and the basic metabolic costs of repair and maintenance reflected in the standard or basal metabolic rate (SMR or BMR), which are customarily subjected to allometric analyses. Those 'decisions' form a wealth of life-history variation that can be defined based on the axis dictated by ecological mortality and the axis governed by the efficiency of energy use. We link this variation as well as hypoallometric scaling to the mechanistic determinants of MR, such as metabolically inert component proportions, internal organ relative size and activity, cell size and cell membrane composition, and muscle contributions to dramatic metabolic shifts between the resting and active states. The multitude of mechanisms determining MR leads us to conclude that the quest for a single-cause explanation of the mass scaling of MRs is futile. We argue that an explanation based on the theory of life-history evolution is the best way forward.

Return to Physical Activities after Scarf Osteotomy for Hallux Valgus.

BACKGROUND: Scarf osteotomy is an effective method of surgical treatment of hallux valgus. The final im-pact of the procedure on patients' physical activity has not been assessed so far. Our goals were to evaluate sports and physical activities in patients following the Scarf osteotomy and to compare these with clinical outcomes. MATERIAL AND METHODS: The study included 79 patients who were treated for hallux valgus with a Scarf osteotomy in 2015-2016. The average age in the examined group at the time of surgery was 55.43 (± 11.97) years, while the follow-up was on average 3.13 (± 0.42) years. Physical activity was measured using the UCLA - Activity Score and Author's Sport Specific Questionnaire. Clinical outcomes were evaluated with the Ame-rican Orthopedic Foot and Ankle Score (AOFAS HMI) and compared to sports outcomes. RESULTS: After the procedure, the frequency of undertaking physical activity increased by about 21% (p = 0.0005) and the time spent by patients during the week on sports (minutes per week) increase by about 19% (p = 0.005). The result of the UCLA - Activity Score after surgery increased by an average of about 4.7% (p = 0.016). The average satisfaction with the result of the surgery was 8.2 (1-10 scale). The majority of patients (67%) were able to maintain the amount of physical activity after the surgery and few patients (24%) were able to increase this amount. CONCLUSION: The study suggests that Scarf osteotomy has a positive effect on the ability of patients with hallux valgus to return to sport and physical activity.

An analysis of causes of trauma, spectrum of injuries and treatment outcomes in patients treated at Multitrauma Centre of the University Teaching Hospital No 1 in Szczecin in 2015. Comparison of results from years 2015 and 2007.

INTRODUCTION: Multitrauma is defined as injury involving two or more different body parts, with a condition that at least one of these injuries is life-threatening. They represent serious traumas, requiring treatment in the intensive care units and frequently surgical intervention. AIM: The objective of this study was epidemiological and clinical analysis of patients treated in 2015 year in Multitrauma Centre of the University Teaching Hospital no 1 in Szczecin, and comparison the results with outcomes of similar study conducted in the same Centre in 2007 year. MATERIAL: Clinical material comprised medical notes of 82 patients, 52 men (63%) and 30 women (37%), with a mean age of 44 years, who sustained multitrauma injuries. An analysis included causes of traumas, spectrum of injuries, involvement of body parts, methods and outcomes of the treatment. RESULTS: The most common cause of multitrauma was traffic accident - 45 cases (55%), followed by fall from height - 22 (27%) and other mechanism - 15 (18%). The most frequent component of multitrauma made bone fractures (spine, pelvis, limbs) - 64 cases (78%), followed by head traumas - 63 (77%), chest - 53 (65%) and abdominal 30 (36%) injuries. A total of 48 patients (58%) required surgical intervention, the most frequently fixation of bone fractures - 24 patients (29%), repair of abdominal and head injuries - 18 (22%) either. Of 82 treated patients 64 (78%) survived and 18 (22%) died. A mean period of stay in Multitrauma Centre was 23 days for survived patients and 17 days for those who died. Comparing to similar analysis conducted 8 years earlier, a change in involvement of particular body parts comprising multitrauma injury was observed: number of head injuries increased of 14%, number of chest traumas and bone fractures decreased of 21% and 11%, respectively. The survival rate improved of 10%.

Vanishing benefits - The loss of actinobacterial symbionts at elevated temperatures.

Only a few insect species are known to engage in symbiotic associations with antibiotic-producing Actinobacteria and profit from this kind of protection against pathogens. However, it still remains elusive how widespread the symbiotic interactions with Actinobacteria in other organisms are and how these partnerships benefit the hosts in terms of the growth and survival. We characterized a drastic temperature-induced change in the occurrence of Actinobacteria in the gut of the terrestrial isopod Porcellio scaber reared under two different temperature (15 °C and 22 °C) and oxygen conditions (10% and 22% O2) using 16S rRNA gene sequencing. We show that the relative abundance of actinobacterial gut symbionts correlates with increased host growth at lower temperature. Actinobacterial symbionts were almost completely absent at 22 °C under both high and low oxygen conditions. In addition, we identified members of nearly half of the known actinobacterial families in the isopod microbiome, and most of these include members that are known to produce antibiotics. Our study suggests that hosting diverse actinobacterial symbionts may provide conditions favorable for host growth. These findings show how a temperature-driven decline in microbiome diversity may cause a loss of beneficial functions with negative effects on ectotherms.

Extrinsic Mortality Can Shape Life-History Traits, Including Senescence.

The Williams' hypothesis is one of the most widely known ideas in life history evolution. It states that higher adult mortality should lead to faster and/or earlier senescence. Theoretically derived gradients, however, do not support this prediction. Increased awareness of this fact has caused a crisis of misinformation among theorists and empirical ecologists. We resolve this crisis by outlining key issues in the measurement of fitness, assumptions of density dependence, and their effect on extrinsic mortality. The classic gradients apply only to a narrow range of ecological contexts where density-dependence is either absent or present but with unrealistic stipulations. Re-deriving the classic gradients, using a more appropriate measure of fitness and incorporating density, shows that broad ecological contexts exist where Williams' hypothesis is supported.

Concerted evolution of body mass and cell size: similar patterns among species of birds (Galliformes) and mammals (Rodentia).

Cell size plays a role in body size evolution and environmental adaptations. Addressing these roles, we studied body mass and cell size in Galliformes birds and Rodentia mammals, and collected published data on their genome sizes. In birds, we measured erythrocyte nuclei and basal metabolic rates (BMRs). In birds and mammals, larger species consistently evolved larger cells for five cell types (erythrocytes, enterocytes, chondrocytes, skin epithelial cells, and kidney proximal tubule cells) and evolved smaller hepatocytes. We found no evidence that cell size differences originated through genome size changes. We conclude that the organism-wide coordination of cell size changes might be an evolutionarily conservative characteristic, and the convergent evolutionary body size and cell size changes in Galliformes and Rodentia suggest the adaptive significance of cell size. Recent theory predicts that species evolving larger cells waste less energy on tissue maintenance but have reduced capacities to deliver oxygen to mitochondria and metabolize resources. Indeed, birds with larger size of the abovementioned cell types and smaller hepatocytes have evolved lower mass-specific BMRs. We propose that the inconsistent pattern in hepatocytes derives from the efficient delivery system to hepatocytes, combined with their intense involvement in supracellular function and anabolic activity.

Effects of fat and exoskeletal mass on the mass scaling of metabolism in Carabidae beetles.

The rate at which organisms metabolize resources and consume oxygen is tightly linked to body mass. Typically, there is a sub-linear allometric relationship between metabolic rates and body mass (mass-scaling exponent b < 1). The origin of this pattern remains one of the most intriguing and hotly debated topics in evolutionary physiology. A decrease in mass-specific metabolic rates in larger organisms might reflect disproportionate increases in body components with low metabolic activity, such as storage and skeletal tissues. Addressing this hypothesis, we studied standard metabolic rates, body mass, and fat and exoskeletal mass in males and females from 15 species of Carabidae beetles. There was a sub-linear allometric relationship of metabolic rate with body mass: b = 0.72 (phylogeny not considered), b = 0.54 (phylogeny considered). The latter exponent was significantly lower than 0.75, which is sometimes regarded as a universal exponent value in the mass scaling of metabolic rates. Contrary to our hypothesis, the relative contribution of fat and the exoskeleton to body mass decreased, rather than increased with body mass, as indicated by the sub-linear allometric mass scaling of both components (b < 1). Supporting the role of metabolically inert body components in shaping metabolic scaling, the exponents (b) for metabolism became slightly smaller (b = 0.70, phylogeny not considered; 0.52, phylogeny considered) when we removed lipids and the exoskeleton from body mass calculations and considered only the lean mass of soft tissue in the mass scaling. Overall, our results indicate that, in beetles, the relative content of metabolically inert components changes across species according to species-specific body mass. Nevertheless, we did not find evidence that this changing contribution plays a central role in the origin of interspecific metabolic scaling in carabids. Our findings stress the need for finding alternative explanations, at least in carabids, for the origin of the mass scaling of metabolic rates.

Density-dependence interacts with extrinsic mortality in shaping life histories.

The role of extrinsic mortality in shaping life histories is poorly understood. However, substantial evidence suggests that extrinsic mortality interacts with density-dependence in crucial ways. We develop a model combining Evolutionarily Stable Strategies with a projection matrix that allows resource allocation to growth, tissue repairs, and reproduction. Our model examines three cases, with density-dependence acting on: (i) mortality, (ii) fecundity, and (iii) production rate. We demonstrate that density-independent extrinsic mortality influences the rate of aging, age at maturity, growth rate, and adult size provided that density-dependence acts on fertility or juvenile mortality. However, density-independent extrinsic mortality has no effect on these life history traits when density-dependence acts on survival. We show that extrinsic mortality interacts with density-dependence via a compensation mechanism: the higher the extrinsic mortality the lower the strength of density-dependence. However, this compensation fully offsets the effect of extrinsic mortality only if density-dependence acts on survival independently of age. Both the age-pattern and the type of density-dependence are crucial for shaping life history traits.

Physical mechanism or evolutionary trade-off? Factors dictating the relationship between metabolic rate and ambient temperature in carabid beetles.

The tight association between ambient temperature (T) and metabolic rate (MR) is a common occurrence in ectotherms, but the determinants of this association are not fully understood. This study examined whether the relationship between MR and T is the same among individuals, as predicted by the Universal Temperature Dependence hypothesis, or whether this relationship differs between them. We used flow-through respirometry to measure standard MR and to determine gas exchange patterns for 111 individuals of three Carabidae species which differ in size (Abax ovalis, Carabus linnei and C. coriaceus), exposed to four different temperatures (ten individuals of each species measured at 6, 11, 16 and 21°C). We found a significant interaction between ln body mass and the inverse of temperature, indicating that in a given species, the effect of temperature on MR was weaker in larger individuals than in smaller individuals. Overall, this finding shows that the thermal dependence of MR is not body mass invariant. We observed three types of gas exchange patterns among beetles: discontinuous, cyclic and continuous. Additionally, the appearance of these patterns was associated with MR and T. Evolution in diverse terrestrial environments could affect diverse ventilation patterns, which accommodate changes in metabolism in response to temperature variation. In conclusion, explaining the variance in metabolism only through fundamental physical laws of thermodynamics, as predicted by the Universal Temperature Dependence hypothesis, appears to oversimplify the complexity of nature, ignoring evolutionary trade-offs that should be taken into account in the temperature - metabolism relationship.

Mass scaling of metabolic rates in carabid beetles (Carabidae) - the importance of phylogeny, regression models and gas exchange patterns.

The origin of the allometric relationship between standard metabolic rate (MR) and body mass (M), often described as MR=aMb , remains puzzling, and interpretation of the mass-scaling exponent, b may depend on the methodological approach, shapes of residuals, coefficient of determination (r2) and sample size. We investigated the mass scaling of MRs within and between species of Carabidae beetles. We used ordinary least squares (OLS) regression, phylogenetically generalized least squares (PGLS) regression and standardized major axis (SMA) regression to explore the effects of different model-fitting methods and data clustering caused by phylogenetic clades (grade shift) and gas exchange patterns (discontinuous, cyclic and continuous). At the interspecific level, the relationship between MR and M was either negatively allometric (b<1) or isometric (b=1), depending on the fitting method. At the intraspecific level, the relationship either did not exist or was isometric or positively allometric (b>1), and the fit was significantly improved after the analyzed dataset was split according to gas exchange patterns. The studied species originated from two distinct phylogenetic clades that had different intercepts but a common scaling exponent (OLS, 0.61) that was much shallower than the scaling exponent for the combined dataset for all species (OLS, 0.71). The best scaling exponent estimates were obtained by applying OLS while accounting for grade shifts or by applying PGLS. Overall, we show that allometry of MR in insects can depend heavily on the model fitting method, the structure of phylogenetic non-independence and ecological factors that elicit different modes of gas exchange.

Not all cells are equal: effects of temperature and sex on the size of different cell types in the Madagascar ground gecko Paroedura picta.

Cell size plays a role in evolutionary and phenotypically plastic changes in body size. To examine this role, we measured the sizes of seven cell types of geckos (Paroedura picta) reared at three constant temperatures (24, 27, and 30°C). Our results show that the cell size varies according to the body size, sex and developmental temperature, but the pattern of this variance depends on the cell type. We identified three groups of cell types, and the cell sizes changed in a coordinated manner within each group. Larger geckos had larger erythrocytes, striated muscle cells and hepatocytes (our first cell group), but their renal proximal tubule cells and duodenal enterocytes (our second cell group), as well as tracheal chondrocytes and epithelial skin cells (our third cell group), were largely unrelated to the body size. For six cell types, we also measured the nuclei and found that larger cells had larger nuclei. The relative sizes of the nuclei were not invariant but varied in a complex manner with temperature and sex. In conclusion, we provide evidence suggesting that changes in cell size might be commonly involved in the origin of thermal and sexual differences in adult size. A recent theory predicts that smaller cells speed up metabolism but demand more energy for their maintenance; consequently, the cell size matches the metabolic demand and supply, which in ectotherms, largely depends on the thermal conditions. The complex thermal dependency of cell size in geckos suggests that further advancements in understanding the adaptive value of cell size requires the consideration of tissue-specific demand/supply conditions.

An evolutionary solution of terrestrial isopods to cope with low atmospheric oxygen levels.

The evolution of current terrestrial life was founded by major waves of land invasion coinciding with high atmospheric oxygen content. These waves were followed by periods with substantially reduced oxygen concentration and accompanied by the evolution of novel traits. Reproduction and development are limiting factors for evolutionary water-land transitions, and brood care has probably facilitated land invasion. Peracarid crustaceans provide parental care for their offspring by brooding the early stages within the motherly brood pouch, the marsupium. Terrestrial isopod progeny begin ontogenetic development within the marsupium in water, but conclude development within the marsupium in air. Our results for progeny growth until hatching from the marsupium provide evidence for the limiting effects of oxygen concentration and for a potentially adaptive solution. Inclusion of air within the marsupium compensates for initially constrained growth in water through catch-up growth, and it may explain how terrestrial isopods adapted to short- and long-term changes in oxygen concentration.