Somatic Maintenance Research Articles

Contemporary small-scale subsistence populations offer unique insights into human musculoskeletal health and aging.

Human foragers avoid noncommunicable diseases that are leading causes of mortality, partly because physically active lifestyles promote healthy aging. High activity levels also promote tissue damage accumulation from wear-and-tear, increase risk of injury and disability which compromise productivity, and reduce energetic investments in somatic maintenance given constrained energy expenditure. Constraints intensify when nutrient supply is limited and surplus energy is directed toward pathogen defense and reproduction, as occurred throughout hominin evolution. This paper reviews evidence linking exposomes to musculoskeletal health in subsistence populations, focusing on effects of physical activity, pathogens, diet, and reproduction. Chronic musculoskeletal conditions are common for humans and possibly prehistoric hominins but rarer in quadrupedal apes. We propose that transition to bipedalism ~6 to 8 million years ago constituted an early "mismatch scenario," increasing hominin susceptibility to musculoskeletal conditions vis-à-vis quadrupedal apes due to changes in mechanical loading environments. Mismatched musculoskeletal traits were not targets of selection because of trade-offs favoring bipedal extractive foraging and higher fertility.

PIWIL1 is recruited to centrosomes during mitosis in colorectal cancer cells and is linked to cell cycle progression

PIWI proteins, traditionally associated with germline development, have recently gained attention for their expression in various cancers, including colorectal cancer. However, the molecular mechanisms underlying their reactivation and impact on cancer initiation and progression remain elusive. Here, we found that PIWIL1 is expressed at relatively high levels in CRC-derived samples and cell lines, where it undergoes a dynamic relocalization to the centrosome during mitosis. Knockdown of PIWIL1 induces G2/M arrest associated with disruption of the mitotic spindle and aberrant metaphase events, highlighting its role in cell cycle progression. We also found that the expression of PIWIL1 is lost during the differentiation of Caco-2 cells into enterocytes and that PIWIL1 is expressed in cells at the base of the intestinal crypts in normal human colon tissue, where intestinal stem cells are known to reside. Thus, it is possible that the presence of PIWIL1 in cancer cells reflects a physiological role of this protein in stem cell maintenance, which would argue in favor of the proposed stem cell origin of CRC. Supporting this view, dedifferentiation of human fibroblasts into induced pluripotent stem cells (iPSCs) involves the reactivation of PIWIL2 expression, another member of the PIWI protein family. Overall, our findings suggest a role of PIWIL1 in mediating cell cycle dynamics, both in colorectal cancer cells and possibly also in intestinal stem cells. In a broader aspect, we provide evidence supporting an involvement of PIWI proteins in somatic stem cell maintenance, thus expanding the known non-gonadal functions of this protein family.

The Endogenous Expression of BMI1 in Adult Human Eyes.

BMI1, also known as B lymphoma Mo-MLV insertion region 1, is a protein in the Polycomb group that is implicated in various cellular processes, including stem cell self-renewal and the regulation of cellular senescence. BMI1 plays a role in the regulation of retinal progenitor cells and the renewal of adult neuronal cells. However, the presence, location, and quantification of BMI1 in the adult human eye have never previously been reported. In this study, we collected 45 frozen globes from eye banks, and ocular tissues were dissected. Protein was quantified by utilizing a custom electrochemiluminescence (ECL) assay developed to quantify the BMI1 protein. BMI1 was found in all ocular tissues at the following levels: the retina (1483.6 ± 191.7 pg/mL) and the RPE (296.4 ± 78.1 pg/mL). BMI1 expression was noted ubiquitously in the GCL (ganglion cell layer), the INL (inner nuclear layer), the ONL (outer nuclear layer), and the RPE (retinal pigment epithelium) via immunofluorescence, with higher levels in the inner than in the outer retinal layers and the RPE. These data confirm that BMI1 is expressed in the human retina. Further studies will illuminate the role that BMI1 plays in ocular cells. BMI1 levels are lower in aged retinas, possibly reflecting changes in retinal somatic and stem cell maintenance and disease susceptibility.

A germline-to-soma signal triggers an age-related decline of mitochondrial stress response

The abilities of an organism to cope with extrinsic stresses and activate cellular stress responses decline during aging. The signals that modulate stress responses in aged animals remain to be elucidated. Here, we discover that feeding Caenorhabditis elegans (C. elegans) embryo lysates to adult worms enabled the animals to activate the mitochondrial unfolded protein response (UPRmt) upon mitochondrial perturbations. This discovery led to subsequent investigations that unveil a hedgehog-like signal that is transmitted from the germline to the soma in adults to inhibit UPRmt in somatic tissues. Additionally, we find that the levels of germline-expressed piRNAs in adult animals markedly decreased. This reduction in piRNA levels coincides with the production and secretion of a hedgehog-like signal and suppression of the UPRmt in somatic cells. Building upon existing research, our study further elucidates the intricate mechanisms of germline-to-soma signaling and its role in modulating the trade-offs between reproduction and somatic maintenance within the context of organismal aging.

Reproduction has immediate effects on female mortality, but no discernible lasting physiological impacts: A test of the disposable soma theory

The disposable soma theory (DST) posits that organisms age and die because of a direct trade-off in resource allocation between reproduction and somatic maintenance. DST predicts that investments in reproduction accentuate somatic damage which increase senescence and shortens lifespan. Here, we directly tested DST predictions in breeding and nonbreeding female C57BL/6J mice. We measured reproductive outputs, body composition, daily energy expenditure, and oxidative stress at peak lactation and over lifetime. We found that reproduction had an immediate and negative effect on survival due to problems encountered during parturition for some females. However, there was no statistically significant residual effect on survival once breeding had ceased, indicating no trade-off with somatic maintenance. Instead, higher mortality appeared to be a direct consequence of reproduction without long-term physiological consequences. Reproduction did not elevate oxidative stress. Our findings do not provide support for the predictions of the DST.

The Elephant and the Spandrel

Abstract Comparative oncology has made great strides in identifying patterns of cancer prevalence and risk across the tree of life. Such studies have often centered on elucidating the evolution of cancer suppression mechanisms, especially in large and/or long-lived animals such as elephants, in which cancer risk is assumed to exert a strong selective pressure. There is a worry, however, that we are overinterpreting these conclusions, as the deep evolutionary origins of these mechanisms and their involvement in cancer-unrelated functions suggest that the preeminent functions of the identified mechanisms may be unrelated to cancer. Instead, cancer suppression may be an evolutionary byproduct, or “spandrel”, of selection acting on development and somatic maintenance. Here, we highlight the importance of development and somatic maintenance as the underlying axis of natural selection. We argue that by shifting the focus of study from cancer suppression to development and somatic maintenance as the ultimate cause, we can gain a deeper understanding of the evolutionary pressures that shaped the mechanisms responsible for the observed variation in cancer prevalence across species.

Sex-specific growth and lifespan effects of germline removal in the dioecious nematode Caenorhabditis remanei.

Germline regulates the expression of life-history traits and mediates the trade-off between reproduction and somatic maintenance. However, germline maintenance in itself can be costly, and the costs can vary between the sexes depending on the number of gametes produced across the lifetime. We tested this directly by germline ablation using glp-1 RNA interference (RNAi) in a dioecious nematode Caenorhabditis remanei. Germline removal strongly increased heat-shock resistance in both sexes, thus confirming the role of the germline in regulating somatic maintenance. However, germline removal resulted in increased lifespan only in males. High costs of mating strongly reduced lifespan in both sexes and obliterated the survival benefit of germline-less males even though neither sex produced any offspring. Furthermore, germline removal reduced male growth before maturation but not in adulthood, while female growth rate was reduced both before and especially after maturation. Thus, germline removal improves male lifespan without major growth costs, while germline-less females grow slower and do not live longer than reproductively functional counterparts in the absence of environmental stress. Overall, these results suggest that germline maintenance is costlier for males than for females in C. remanei.

A female-biased gene expression signature of dominance in cooperatively breeding meerkats.

Dominance is a primary determinant of social dynamics and resource access in social animals. Recent studies show that dominance is also reflected in the gene regulatory profiles of peripheral immune cells. However, the strength and direction of this relationship differs across the species and sex combinations investigated, potentially due to variation in the predictors and energetic consequences of dominance status. Here, we investigated the association between social status and gene expression in the blood of wild meerkats (Suricata suricatta; n = 113 individuals), including in response to lipopolysaccharide, Gardiquimod (an agonist of TLR7, which detects single-stranded RNA invivo) and glucocorticoid stimulation. Meerkats are cooperatively breeding social carnivores in which breeding females physically outcompete other females to suppress reproduction, resulting in high reproductive skew. They therefore present an opportunity to disentangle the effects of social dominance from those of sex per se. We identify a sex-specific signature of dominance, including 1045 differentially expressed genes in females but none in males. Dominant females exhibit elevated activity in innate immune pathways and a larger fold-change response to LPS challenge. Based on these results and a preliminary comparison to other mammals, we speculate that the gene regulatory signature of social status in the immune system depends on the determinants and energetic costs of social dominance, such that it is most pronounced in hierarchies where physical competition is important and reproductive skew is large. Such a pattern has the potential to mediate life history trade-offs between investment in reproduction versus somatic maintenance.

Reproductive cycle, fecundity and growth of the freshwater mussel Unio tumidus (Bivalvia: Unionidae) from Lake Viinijärvi, Finland

ABSTRACT Freshwater mussels have a substantial role in aquatic ecosystem function and provide valuable ecosystem services, including water filtration, nutrient cycling, habitat creation and sediment stabilization. While they face population declines globally that can negatively affect an ecosystem's health, such as reducing the water quality and increasing the turbidity, lack of information about the basic reproductive biology for most species makes their conservation much more difficult. Here, we monitored a population of Unio tumidus for a year to study its reproductive biology, gonad-dwelling parasites and growth rate in Lake Viinijärvi, Finland. Our data revealed that this species was dioecious with no evidence of hermaphroditism and was non-significantly female-biased (a male to female ratio of 1:1.3). Both sexes of U. tumidus had continuous gametogenesis during the study period with two peaks in the gonadosomatic index (GSI%) during November and May, followed by two clear declines in December and June. Gravidity period (brooding) of embryos or glochidia in the female's outer gills lasted from June to July. Therefore, this population of U. tumidus can be classified as a short-term breeder (tachytictic). The clear decline of GSI% in December might be a strategy that individuals of U. tumidus use to resorb resources back from the gonad for somatic maintenance during winter. Mean length of glochidia was 391 ± 0.049 µm, being among the largest known glochidia for Unionidae. No gonad-dwelling trematode parasites were detected and the population exhibited high fecundity (numbers of oocytes per female), with an average oocyte production of 242,000 ± 18,000. The studied population had a moderate growth rate with a maximum predicted age of 13 years and asymptotic length (the length at which growth slows down while the mussel continues to age, L∞) of 114 mm. Our study provides the first quantitative data and histological analysis of the reproductive biology of U. tumidus, serving as a basis for future research and conservation.

Sons Shorten Mother's Lifespan in Preindustrial Families with a High Level of Infant Mortality.

AbstractIn dimorphic vertebrates where males are larger than females, the energetic costs of producing and rearing sons can exceed those of daughters. In humans, differences in maternal energy intake suggest that sons require 10% and 7% more energy than daughters during pregnancy and lactation, respectively. Due to a trade-off between reproduction and somatic maintenance, having sons is expected to have a more pronounced detrimental impact on a mother's lifespan than having daughters. A limitation of previous studies investigating this hypothesis is that the increased mortality cost of having sons was assumed to affect all mothers equally. Using a dataset from a preindustrial Quebec population monitored over two centuries, we found that the number of sons decreased postmenopausal lifespan only in mothers experiencing high infant mortality. Our study highlights the importance of interindividual variation in environmental conditions and maternal health when studying effects of offspring sex on reproductive costs.

Male allocation to ejaculation and mating effort imposes different life history trade-offs.

When males compete, sexual selection favors reproductive traits that increase their mating or fertilization success (pre- and postcopulatory sexual selection). It is assumed that males face a trade-off between these 2 types of sexual traits because they both draw from the same pool of resources. Consequently, allocation into mate acquisition or ejaculation should create similar trade-offs with other key life history traits. Tests of these assumptions are exceedingly rare. Males only ejaculate after they mate, and the costs of ejaculation are therefore highly confounded with those of mating effort. Consequently, little is known about how each component of reproductive allocation affects a male's future performance. Here, we ran an experiment using a novel technique to distinguish the life history costs of mating effort and ejaculation for mosquitofish (Gambusia holbrooki). We compared manipulated males (mate without ejaculation), control males (mate and ejaculate), and naïve males (neither mate nor ejaculate) continuously housed with a female and 2 rival males. We assessed their growth, somatic maintenance, mating and fighting behavior, and sperm traits after 8 and 16 weeks. Past mating effort significantly lowered a male's future mating effort and growth, but not his sperm production, while past sperm release significantly lowered a male's future ejaculate quantity, but not his mating effort. Immune response was the only trait impacted by both past mating effort and past ejaculation. These findings challenge the assumption that male reproductive allocation draws from a common pool of resources to generate similar life history costs later in life. Instead, we provide clear evidence that allocation into traits under pre- and postcopulatory sexual selection have different trait-specific effects on subsequent male reproductive performance.

Energetic cost of biosynthesis is a missing link between growth and longevity in mammals

The comparative studies of aging have established a negative correlation between Gompertz postnatal growth constant and maximum lifespan across mammalian species, but the underlying physiological mechanism remains unclear. This study shows that the Gompertz growth constant can be decomposed into two energetic components, mass-specific metabolic rate and the energetic cost of biosynthesis, and that after controlling the former as a confounder, the negative correlation between growth constant and lifespan still exists due to a 100-fold variation in the latter, revealing that the energetic cost of biosynthesis is a link between growth and longevity in mammals. Previously, the energetic cost of biosynthesis has been thought to be a constant across species and therefore was not considered a contributor to the variation in any life history traits, such as growth and lifespan. This study employs a recently proposed model based on energy conservation to explain the physiological effect of the variation in this energetic cost on the aging process and illustrates its role in linking growth and lifespan. The conventional life history theory suggested a tradeoff between growth and somatic maintenance, but the findings in this study suggest that allocating more energy to biosynthesis may enhance the somatic maintenance and extend lifespan and, hence, reveal a more complex nature of the tradeoff.

Selective breeding for high levels of voluntary exercise in mice does not reduce lifetime reproductive success or lifespan

The ways locomotor abilities may interact with life history traits are complicated and may involve shifts in resource allocation. For example, individuals that have large litters may have reduced energy available to support the organ systems required for high locomotor performance abilities. Alternatively, energy spent on excess physical activity might subtract from that available for somatic maintenance, and thus be negatively related to lifespan or to other fitness components that contribute to lifetime reproductive success (LRS). We studied lifetime reproductive successes, life span, and health span in mice from a long-term (>100 generations) artificial selection experiment that includes 4 replicate High Runner (HR) lines bred for voluntary locomotor activity on wheels and 4 lines that serve as non-selected Controls (C). Since reaching selection limits at around generation 17-27 (depending on line and sex), the HR mice have been running ~3-fold farther on a daily basis as compared with C mice, for both sexes, which leads to substantially increased energy expenditure and food consumption. Importantly, when housed without wheels, HR mice are not only more active, but also consume more food than C mice. In the present study, we tested for differences in LRS between the HR and C lines. We are also comparing lifespan (median, maximum) and healthspan (e.g., by measurement of maximal oxygen consumption [VO2max] during forced exercise and maximal sprint speed. Twelve male-female pairs per line from generation 97 (born Oct. 2021) are being maintained until their end of life. In addition to total number of pups weaned per pair, we record components of LRS, such as age at first and last litter for the pairs, number of litters, and inter-birth intervals. Here, we present a subset of results through the first 2+ years of the experiment. Only two of 100 pairs never gave birth to any litters, and 89 of 100 pairs weaned at least one litter. The total number of litters born to pairs ranged from 0 to 12, and the number of litters from which at least one pup was weaned ranged from 0 to 11, with a mean of 3.96+0.73 (SE) for C lines and 3.43+0.65 for HR lines (P=0.61). The total number of pups weaned (our measure of LRS) ranged from 0 to 80, with a mean of 29.1+8.1 (SE) for C lines and 25.8+4.4 for HR lines (P=0.73). Thus, we found no evidence that Darwinian fitness has been reduced by artificial selection for high voluntary exercise. As of 1 Nov. 2023, approximately 17% of the breeders are still alive, and preliminary analyses do not indicate significant differences between the C and HR lines in median or maximum lifespan. Supported by U.S. National Science Foundation grant IOS-2038528. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Are some species more sensitive to environmental change than others? It may all depend on the context.

Research Highlight: Rademaker, M., van Leeuwen, A., & Smallegange, I. M. (2024). Why we cannot always expect life history strategies to directly inform on sensitivity to environmental change. Journal of Animal Ecology, https://doi.org/10.1111/1365-2656.14050. Ecological studies have long delved into how organisms allocate energy between reproduction and somatic maintenance to maximize fitness. This allocation gives rise to various life-history strategies, and these strategies have been shown to predict how populations respond to environmental change, allowing us to generalize potential responses to increasing human pressures. Such predictions have, however, been made for a limited set of terrestrial taxa and typically do not explore how individual differences in life-history responses to environmental change scale to affect population-level responses. Using novel data on diverse fish species, Rademaker etal. (2024) construct models that link individual-level trade-offs in energy allocation under environmental change to population-level life-history strategies. A key finding in their study is that short-lived species are not more sensitive to environmental change-unlike results of previous studies. This study represents a new generation of work that underscores the complexity of predicting population responses to environmental shifts and suggests a need for a broader understanding of individual-level mechanisms. The results of Rademaker etal. (2024) encourage further mechanistic life-history analyses across a wider range of species and populations to validate the exciting findings and explore their implications across diverse ecological contexts.

Late reproduction is associated with extended female survival but not with familial longevity

Research questionAre age at last childbirth and number of children, as facets of female reproductive health, related to individual lifespan or familial longevity? DesignThis observational study included 10,255 female participants from a multigenerational historical cohort, the LINKing System for historical family reconstruction (LINKS), and 1258 female participants from 651 long-lived families in the Leiden Longevity Study (LLS). Age at last childbirth and number of children, as outcomes of reproductive success, were compared with individual and familial longevity using the LINKS dataset. In addition, the genetic predisposition in the form of a polygenic risk score (PRS) for age at menopause was studied in relation to familial longevity using the LLS dataset. ResultsFor each year increase in the age of the birth of the last child, a woman's lifespan increased by 0.06 years (22 days; P = 0.002). The yearly risk for having a last child was 9% lower in women who survived to the oldest 10% of their birth cohort (hazard ratio 0.91, 95% CI 0.86–0.95). Women who came from long-living families did not have a higher mean age of last childbirth. There was no significant association between familial longevity and genetic predisposition to age at menopause. ConclusionsFemale reproductive health associates with a longer lifespan. Familial longevity does not associate to extended reproductive health. Other factors in somatic maintenance that support a longer lifespan are likely to have an impact on reproductive health.

Pregnancy is linked to faster epigenetic aging in young women

A central prediction of evolutionary theory is that energy invested into reproduction comes at the expense of somatic maintenance and repair, accelerating biological aging. Supporting this prediction are findings that high fertility among women predicts shorter lifespan and poorer health later in life. However, biological aging is thought to begin before age-related health declines, limiting the applicability of morbidity and mortality for studying the aging process earlier in life. Here, we examine the relationship between reproductive history and biological aging in a sample of young (20 to 22yo) men and women from the Cebu Longitudinal Health and Nutrition Survey, located in the Philippines (n = 1,735). We quantify biological aging using six measures, collectively known as epigenetic clocks, reflecting various facets of cellular aging, health, and mortality risk. In a subset of women, we test whether longitudinal changes in gravidity between young and early-middle adulthood (25 to 31yo) are associated with changes in epigenetic aging during that time. Cross-sectionally, gravidity was associated with all six measures of accelerated epigenetic aging in women (n = 825). Furthermore, longitudinal increases in gravidity were linked to accelerated epigenetic aging in two epigenetic clocks (n = 331). In contrast, the number of pregnancies a man reported fathering was not associated with epigenetic aging among same-aged cohort men (n = 910). These effects were robust to socioecological, environmental, and immunological factors, consistent with the hypothesis that pregnancy accelerates biological aging and that these effects can be detected in young women in a high-fertility context.

Heatwaves inflict reproductive but not survival costs to male insects.

Climate change is having a dramatic effect on the environment, with rising global temperatures and more frequent extreme climatic events, such as heatwaves, that can hamper organisms' biological functions. Although it is clear that sudden and extreme temperatures can damage reproductive processes, there is limited understanding of the effects of heatwaves on male mating behaviour and reproductive success. We tested for the effects of heat stress induced by ecologically relevant heatwaves (33°C and 39°C for five consecutive days) on the mating behaviour, reproductive success, body mass and survival of male field crickets Gryllus bimaculatus, paired with untreated females. We predicted life-history and reproductive costs would increase with increasing heatwave intensity. Consistent with our expectations, males exposed to the highest heatwave temperature produced the fewest offspring, while having to increase courtship effort to successfully mate. Males also gained relatively more weight following heatwave exposure. Given that we found no difference in lifetime survival, our results suggest a potential trade-off in resource allocation between somatic maintenance and reproductive investment. Taken together, our findings indicate that sublethal effects of heatwaves could reduce the growth and persistence of animal populations by negatively impacting reproductive rates. These findings highlight the need for considering thermal ecologies, life history and behaviour to better understand the consequences of extreme climatic events on individuals and populations.

GCN2 Mediates Access to Stored Amino Acids for Somatic Maintenance during Drosophila Aging

GCN2 Mediates Access to Stored Amino Acids for Somatic Maintenance during Drosophila Aging

Growth and longevity modulation through larval environment mediate immunosenescence and immune strategy of Tenebrio molitor

BackgroundThe Disposable Soma Theory of aging suggests a trade-off between energy allocation for growth, reproduction and somatic maintenance, including immunity. While trade-offs between reproduction and immunity are well documented, those involving growth remain under-explored. Rapid growth might deplete resources, reducing investment in maintenance, potentially leading to earlier or faster senescence and a shorter lifespan. However, rapid growth could limit exposure to parasitism before reaching adulthood, decreasing immunity needs. The insect immunity’s components (cellular, enzymatic, and antibacterial) vary in cost, effectiveness, and duration. Despite overall immunity decline (immunosenescence), its components seem to age differently. We hypothesize that investment in these immune components is adjusted based on the resource cost of growth, longevity, and the associated risk of parasitism.ResultsWe tested this hypothesis using the mealworm beetle, Tenebrio molitor as our experimental subject. By manipulating the larval environment, including three different temperatures and three relative humidity levels, we achieved a wide range of growth durations and longevities. Our main focus was on the relationship between growth duration, longevity, and specific immune components: hemocyte count, phenoloxidase activity, and antibacterial activity. We measured these immune parameters both before and after exposing the individuals to a standard bacterial immune challenge, enabling us to assess immune responses. These measurements were taken in both young and older adult beetles. Upon altering growth duration and longevity by modifying larval temperature, we observed a more pronounced investment in cellular and antibacterial defenses among individuals with slow growth and extended lifespans. Intriguingly, slower-growing and long-lived beetles exhibited reduced enzymatic activity. Similar results were found when manipulating larval growth duration and adult longevity through variations in relative humidity, with a particular focus on antibacterial activity.ConclusionThe impact of growth manipulation on immune senescence varies by the specific immune parameter under consideration. Yet, in slow-growing T. molitor, a clear decline in cellular and antibacterial immune responses with age was observed. This decline can be linked to their initially stronger immune response in early life. Furthermore, our study suggests an immune strategy favoring enhanced antibacterial activity among slow-growing and long-lived T. molitor individuals.

Effect of starvation on physiological and survival traits of Mimachlamys varia (Linneaus, 1758)

In order to better understand Mimachlamys varia (Linneaus, 1758) response to nutritional stress, a controlled-condition experiment was conducted. Two scallop batches (i.e. juveniles and adults) were completely food-deprived for 3 months. Changes in mass and energy content of tissues (adductor muscle, digestive gland, rest of the soft tissues), as well as stable carbon and nitrogen isotope ratios of the adductor muscle were monitored weekly. Both batches exhibited a 3-phase response to starvation. For adults, phase 1, was characterized by a fast loss in mass, an δ15N-enrichment, a stable calorific power, and a low mortality, corresponding to a transitional stage associated with protein-storage consumption. Phase 2 (day 28–42) exhibited a stabilization of mass and δ15N values, coinciding with a digestive gland calorific power drop and an acceleration in mortality. This corresponds to a “protein sparing” stage where highly energetic fuel such as lipids, which are stored especially in the digestive gland in pectinids, are consumed in priority. Juveniles exhibited a distinct response characterized by a significant mass loss and an increase in calorific power during the first phase (day 0–28). This body weight decrease may involve the remobilization of low-caloric biochemical compounds (e.g. proteins) using the structure as internal fuel, thus limiting somatic maintenance costs. During the second month, body mass and calorific power stabilized, indicating a “protein sparing” stage. In a third phase for both age classes, mass decreased again together with a sharp increase in mortality: essential structure was ultimately remobilized. The survival rate of juveniles was higher than that of adults during the first two months of the experiment (97% and 64%, respectively). Although the time required for starvation to deplete of half the cohort is higher for juveniles than for mature individuals, increase in mortality rate after reaching the “Point of No Return”, (e.g. the beginning of the last phase) was higher in juveniles than in adults. These results highlight the potential impacts of starvation at the population level, beyond the direct impact on individual survival. For instance, individuals may not effectively contribute to reproduction during the spawning period if exposed to a prolonged winter starvation episode. In particular, since highly energetic compounds stored in the digestive gland are often used as fuel to initiate gametogenesis in pectinids. Similarly, decrease in somatic weight in juveniles may delay their sexual maturity and hence their ability to contribute to population reproductive potential.