Future Reproduction Research Articles

EQUAL PROPORTION REPRODUCTION METHOD OF GROTTO BASED ON POINT CLOUD

Abstract. The rapid development of 3D laser scanning and 3D printing technology provides new technologies and ideas for cultural relic protection and reproduction. Aiming at the requirement of equal proportional reproduction of large-scale grottoes, this paper takes the point cloud data of the 18th Cave of Yungang Grottoes obtained by 3D laser scanning as an example, and proposes a data processing and reproduction block partitioning method for equal proportion reproduction. The Cyclone, Geomagic and AutoCAD software were used to construct the 3D model of the grotto, and the 3D printing technology was used to realize the secondary design and model print. Among them, the research focuses on the modeling of massive point clouds and the method of model partitioning based on voxels. It can meet the requirements of movable and assembly while realizing the equal proportional reproduction of the whole grotto. The research results and application can be a good reference for the future grotto reproduction work.

Primera caracterización de folículos preantrales de ovario de alpaca adulta

It is a fact that while even basic reproductive information on alpacas is unavailable, the normal ovarian reserve of this species in comparison to other species is also unidentified. In this study, the ovarian preantral follicles in healthy adult alpacas were characterized in order to establish a general model to in vitro studies. Ten ovaries were collected from five adult alpacas. The ovarian cortex samples were fixed with paraformaldehyde and histological analysis was done. Normal and degenerated follicles percentages were determined. The normal follicles were measured and classified in primordial, transitional, primary and secondary stages. Most of the preantral follicles present in the ovarian cortex of alpacas were primordial and transitional stages; primary (6.10%) and secondary (0.37%) follicles were rarely found. The primary and secondary follicles were larger in diameter when compared with the primordial and transitional follicles. The largest oocyte diameter was recorded in the secondary follicles (P < 0.05). This study serves to establish a biological model for future reproduction studies in Alpacas or as possible biological model for studies of folliculogenesis in humans.

Validation of a death assay for Angiostrongylus cantonensis larvae (L3) using propidium iodide in a rat model (Rattus norvegicus).

Angiostrongylus cantonensis is a pathogenic nematode and the cause of neuroangiostrongyliasis, an eosinophilic meningitis more commonly known as rat lungworm disease. Transmission is thought to be primarily due to ingestion of infective third stage larvae (L3) in gastropods, on produce, or in contaminated water. The gold standard to determine the effects of physical and chemical treatments on the infectivity of A. cantonensis L3 larvae is to infect rodents with treated L3 larvae and monitor for infection, but animal studies are laborious and expensive and also raise ethical concerns. This study demonstrates propidium iodide (PI) to be a reliable marker of parasite death and loss of infective potential without adversely affecting the development and future reproduction of live A. cantonensis larvae. PI staining allows evaluation of the efficacy of test substances in vitro, an improvement upon the use of lack of motility as an indicator of death. Some potential applications of this assay include determining the effectiveness of various anthelmintics, vegetable washes, electromagnetic radiation and other treatments intended to kill larvae in the prevention and treatment of neuroangiostrongyliasis.

Among-population divergence in personality is linked to altitude in plateau pikas (Ochotona curzoniae)

BackgroundAnimals inhabiting high altitudes consistently show slow life-histories. The pace-of-life syndrome (POLS) hypothesis posits behavioural, physiological and/or morphological traits that mediate the trade-off between current and future reproduction or survival, which have coevolved along a slow-fast life history continuum. Previous studies have shown that the life histories of plateau pikas varied across altitude, high-altitude individuals showed slow pace of life which were characterized by few litters per year with small litter sizes. Thus, we hypothesized that pikas populations at higher altitudes would also express personalities characteristic associated with slow life history, such as high sociability, low activity or aggressiveness. We tested this hypothesis by comparing the activity and docility of three plateau pika (Ochotona curzoniae) populations distributed along an altitudinal gradient of the Tibetan Plateau. We predicted that high-altitude pika would be more docile and less active.ResultsThe behaviour of 556 pikas, from which 120 individuals were measured at least twice, was quantified. We observed that plateau pikas at high altitudes were less active and more docile than pika at lower altitudes. Activity and docility were significantly and negatively correlated in populations from high altitudes but not in populations from low altitudes.ConclusionsOur results support the POLS hypothesis, highlight the existence of personality variation among populations distributed along an altitudinal gradient and emphasise the importance of environmental selection on personality divergence.

Individual heterogeneity in life‐history trade‐offs with age at first reproduction in capital breeding elephant seals

AbstractRecruitment age plays a key role in life‐history evolution. Because individuals allocate limited resources among competing life‐history functions, theory predicts trade‐offs between current reproduction and future growth, survival and/or reproduction. Reproductive costs tend to vary with recruitment age, but may also be overridden by fixed individual differences leading to persistent demographic heterogeneity and positive covariation among demographic traits at the population level. We tested for evidence of intra‐ and inter‐generational trade‐offs and individual heterogeneity relating to age at first reproduction using three decades of detailed individual life‐history data of 6,439 capital breeding female southern elephant seals. Contrary to the predictions from trade‐off hypotheses, we found that recruitment at an early age was associated with higher population level survival and subsequent breeding probabilities. Nonetheless, a survival cost of first reproduction was evident at the population level, as first‐time breeders always had lower survival probabilities than prebreeders and experienced breeders of the same age. However, models accounting for hidden persistent demographic heterogeneity revealed that the trade‐off between first reproduction and survival was only expressed in “low quality” individuals, comprising 35% of the population. The short‐term somatic costs associated with breeding at an early age had no effect on the ability of females to allocate resources to offspring in the next breeding season. Our results provide strong evidence for individual heterogeneity in the life‐history trajectories of female elephant seals. By explicitly modeling hidden persistent demographic heterogeneity we show that individual heterogeneity governs the expression of trade‐offs with first reproduction in elephant seals.

Foraging rates of ram‐filtering North Atlantic right whales

Abstract North Atlantic right whales spend their summer months foraging primarily in American and Canadian Atlantic waters on high‐energy‐density prey. Here, they rapidly accumulate and store energy obtained within a few months to support future migrations and reproduction while fasting. High drag from their ram‐filter foraging strategy places a limit on what prey densities will be energetically efficient to target. Our understanding of the volume of prey‐laden water filtered by right whales during a dive or foraging bout, and what information they use to decide to forage or not, has been limited by the difficulties of measuring when they feed at depth, how fast they swim during continuous ram filtration and how often they might swallow accumulated prey. We used 10 DTAG deployments from right whales in the Bay of Fundy, Canada, to quantify swimming speeds and estimate the volume of prey‐laden water filtered per dive. We used the tag's inertial sensors to evaluate the timing of frequent biomechanical changes that likely indicate the truncation of continuous filtration, and whether the number or timing of these fluking bouts relates to longer feeding dives or other foraging decisions. During foraging dives, right whales descended at 1.4 (±0.2 SD) m/s and slowed to swim at 1.1 (±0.3) m/s while filtering. We found consistent pauses in the fluking behaviour of foraging right whales, every 56 (±22) s. Whales filtered on average 78 (±30) m3 of water per fluking bout and on average 673 (±201) m3 per dive. Right whales filter large volumes of water at low speeds with a high duty cycle, but require sufficiently high prey energy densities to compensate for a high‐drag foraging strategy. Closely related bowhead whales have a larger gape but swim more slowly, filtering greater volumes with lower drag. Our findings highlight that right whales acquire their energy in a relatively short period of intense foraging; even moderate changes in their feeding behaviour or their prey energy density are likely to negatively impact their yearly energy budgets and therefore reduce fitness substantially. A plain language summary is available for this article.

Maternal investment in a bee species with facultative nest guarding and males heavier than females

1. Maternal investment can be influenced by several factors, especially maternal quality and possibilities for future reproduction. Mass provisioning Hymenoptera are an excellent group for measuring maternal investment because mothers distribute food sources to each brood cell for each offspring separately. Generally in aculeate Hymenoptera, larger females produce larger offspring and invest more in female offspring than in male offspring.2. This study investigated patterns of maternal investment in Ceratina chalcites, which has an uncommon type of sexual size dimorphism in Hymenoptera: on average, males are heavier than females. It was found that larger females produce a significantly higher proportion of male offspring, as males are the costlier sex in this species.3. Facultative nest guarding by females was observed. Females can guard offspring until adulthood, as is typical for bees of genus Ceratina (34.43% of nests); however, in the majority of cases (65.56% of nests), females plug and abandon the nest. Significant differences were found in the amount of investment between guarded and unguarded nests. Guarded nests had a greater number of provisioned brood cells and a higher proportion of male offspring. It is suggested that mothers have two facultative strategies – either she makes a large investment in the offspring of one nest or she abandons the first nest and carries out a second nesting elsewhere.

Egg investment in response to helper presence in cooperatively breeding Tibetan ground tits

Life‐history theory predicts a trade‐off between current and future reproduction to maximize lifetime fitness. In cooperatively breeding species, where offspring care is shared between breeders and helpers, helper presence may influence the female breeders’ egg investment, and consequently, survival and future reproductive success. For example, female breeders may reduce egg investment in response to helper presence if this reduction is compensated by helpers during provisioning. Alternatively, female breeders may increase egg investment in response to helper presence if helpers allow the breeders to raise more or higher quality offspring successfully. In the facultatively cooperative‐breeding Tibetan ground tit Pseudopodoces humilis, previous studies found that helpers improve total nestling provisioning rates and fledgling recruitment, but have no apparent effects on the number and body mass of fledglings produced, while breeders with helpers show reduced provisioning rates and higher survival. Here, we investigated whether some of these effects may be explained by female breeders reducing their investment in eggs in response to helper presence. In addition, we investigated whether egg investment is associated with the female breeder's future fitness. Our results showed that helper presence had no effect on the female breeders’ egg investment, and that egg investment was not associated with breeder survival and reproductive success. Our findings suggest that the responses of breeders to helping should be investigated throughout the breeding cycle, because the conclusions regarding the breeders’ adjustment of reproductive investment in response to being helped may depend on which stage of the breeding cycle is considered.

Worth the reward? An experimental assessment of risk‐taking behavior along a life history gradient

Life history theory predicts that species with faster life history strategies should be willing to risk their survival more to acquire resources than those with slower life history strategies. Foraging can be a risky behavior and animals generally face a tradeoff between food consumption and predation risk. We predicted that the degree to which animals invest in current versus future reproduction (i.e. life history strategy) would determine how they approach this tradeoff. We manipulated food abundance in wetlands to assess whether life history theory could explain risk taking among females of five duck species with respect to foraging. We found evidence consistent with our prediction based on life history theory; species with a faster life history strategy were willing to engage in riskier behavior, by feeding more intensively, for a greater food reward. Females from species with faster life history strategies devoted 25% more time to feeding when in high food density treatment plots versus control plots. The percentage of time that females from species with slower life history strategies devoted to feeding was not affected by food density. These findings contribute to our understanding of life history theory and represent a possible mechanism to explain differences in life history strategies among species.

Histological characterization of gonadal development of juvenile Lake sturgeon (Acipenser fulvescens)

Lake Sturgeon (Acipenser fulvescens) hatcheries that produce juveniles to augment natural populations are of increasing importance to management and species recovery. Maintaining balanced sex ratios of juveniles that are released into the wild is important to future natural reproduction. Greater understanding of the chronology of gonadal development of hatchery-reared fish can help managers target ages to conduct surveys, predict cohort sex ratios, and maintain demographically healthy adult populations. We histologically characterized gonadal development of juvenile Lake Sturgeon between the ages of three to 53 months. Gonads of all surveyed fish (N = 56) were undifferentiated and immature at all time-points surveyed until 41 months, although histological changes consistent with gonadal enlargement and development were observed (e.g., increase of adipose tissue, gonadal epithelial ridge thickening). At 41 months, sex could be determined in two (25%) of the eight sampled fish based on presence of ova within the gonadal tissue, and five (62.5%) showed continued gonadal development, but were still undifferentiated (sex could not be assigned). At 53 months, sex could be determined in six (75%) of eight sampled fish. Two (25%) showed advanced development (e.g., epithelial thickening of the germinal ridge), but the gonads were undifferentiated (i.e., no ova or spermatozoa present). Delayed gonadal differentiation is consistent with the delayed sexual maturity generally observed in Lake Sturgeon relative to other teleost species. Sample sizes precluded statistical evaluation, however, sex determination did not appear to be associated with egg incubation temperature.

Pregnancy rate and outcome of pregnancies in long-term survivors of Hodgkin’s lymphoma

Thanks to the increased number of young survivors of Hodgkin's lymphoma (HL), management of the pregnancies of women who have a history of exposure to chemotherapies and radiation therapy is becoming increasingly common. Many patients and clinicians are worried that pregnancy after the diagnosis of HL may increase the risk of relapse, despite a lack of empirical evidence to support such concerns. In the present study, we included 89 women diagnosed with HL between 2006 and 2015 under the age of 50years, who were in complete remission and alive without relapse > 1year after treatment. We determined the pregnancy rate, time to pregnancy, and the disease-free survival. We found no evidence of significant impairment of the fertility of female HL long-term survivors and no evidence that a pregnancy increases the relapse rate among women in remission from HL. Survivors of HL need to consider a range of factors when deciding on future reproduction.

Experimentally induced antipredator responses are mediated by social and environmental factors.

Nest predation is a common cause of reproductive failure for many bird species, and various antipredator defense behaviors have evolved to reduce the risk of nest predation. However, trade-offs between current reproductive duties and future reproduction often limit the parent’s ability to respond to nest predation risk. Individual responses to experimentally increased nest predation risk can give insights into these trade-offs. Here, we investigate whether social and ecological factors affect individual responses to predation risk by experimentally manipulating the risk of nest predation using taxidermic mounts in the cooperative breeding Seychelles warbler (Acrocephalus sechellensis). Our results show that dominant females, but not males, alarm called more often when they confront a nest predator model alone than when they do so with a partner, and that individuals that confront a predator together attacked more than those that did so alone. Dominant males increased their antipredator defense by spending more time nest guarding after a presentation with a nest predator, compared with a nonpredator control, but no such effect was found for females, who did not increase the time spent incubating. In contrast to incubation by females, nest guarding responses by dominant males depended on the presence of other group members and food availability. These results suggest that while female investment in incubation is always high and not dependent on social and ecological conditions, males have a lower initial investment, which allows them to respond to sudden changes in nest predation risk.

Predation risk affects egg-ejection but not recognition in blackbirds

Predation and brood parasitism have critical effects on the fitness of animals, but few studies have focused on the potential interactions between these two important selective forces. For instance, the egg-rejection process, one of the most important defensive responses of hosts against brood parasites, may be affected by variation in predation risk, which might divert their focus from the nest (present reproduction) to self-maintenance (future reproduction). In this study we explore the effect of predation risk on the first two stages of the egg-rejection process (judgment and decision) and if this potential effect changes according to the target of predation (adults vs offspring). To do so, we experimentally parasitized nests of common blackbirds (Turdus merula) with mimetic model eggs simultaneously exposing them to different predation-risk situations: adult predator, egg predator, and control. We found that predation risk did not affect egg recognition. Nevertheless, blackbirds exposed to the adult predation risk showed a significant reduction in the ejection rate, particularly at the end of the breeding season. We discuss our results in relation to the egg-rejection process and life-history theory. Our findings suggest that a predation risk directed to adults of parasitized nests, but not to their offspring, can play an important role in the blackbirds’ decision-making influencing the ejection of parasitic eggs, consequently affecting the outcome of the evolutionary relationship between brood parasites and their hosts. Brood parasitism and predation are two important selective forces in nature, which play a crucial role in the evolutionary process in birds. Despite this, few studies have explored the possible relationships between these two selective pressures. In particular, the possibility that predation risk affects host defenses against brood parasites has usually been neglected. Predation risk could influence the egg-rejection process, which is the main defensive measure adopted by hosts once they have been parasitized. In this study we showed that predation risk seems to modulate host defenses against brood parasites in common blackbirds, but depending on the threat posed by predators. In particular, adult predation risk affects the second stage of the egg-rejection process reducing the ejection rate of parasitic eggs. Our results open a new line of research in brood parasitism studies, demonstrating that external stimuli to brood parasite-host systems can influence egg-rejection decisions.

Sexual conflict in action: An antagonistic relationship between maternal and paternal sex allocation in the tammar wallaby, Notamacropus eugenii.

Sex ratio biases are often inconsistent, both among and within species and populations. While some of these inconsistencies may be due to experimental design, much of the variation remains inexplicable. Recent research suggests that an exclusive focus on mothers may account for some of the inconsistency, with an increasing number of studies showing variation in sperm sex ratios and seminal fluids. Using fluorescent in‐situ hybridization, we show a significant population‐level Y‐chromosome bias in the spermatozoa of wild tammar wallabies, but with significant intraindividual variation between males. We also show a population‐level birth sex ratio trend in the same direction toward male offspring, but a weaning sex ratio that is significantly female‐biased, indicating that males are disproportionately lost during lactation. We hypothesize that sexual conflict between parents may cause mothers to adjust offspring sex ratios after birth, through abandonment of male pouch young and reactivation of diapaused embryos. Further research is required in a captive, controlled setting to understand what is driving and mechanistically controlling sperm sex ratio and offspring sex ratio biases and to understand the sexually antagonistic relationship between mothers and fathers over offspring sex. These results extend beyond sex allocation, as they question studies of population processes that assume equal input of sex chromosomes from fathers, and will also assist with future reproduction studies for management and conservation of marsupials.

Live fast, don't die young: Survival-reproduction trade-offs in long-lived income breeders.

Trade‐offs between survival and reproduction are at the core of life‐history theory, and essential to understanding the evolution of reproductive tactics as well as population dynamics and stability. Factors influencing these trade‐offs are multiple and often addressed in isolation. Further problems arise as reproductive states and survival in wild populations are estimated based on imperfect and potentially biased observation processes, which might lead to flawed conclusions.In this study, we aimed at elucidating trade‐offs between current reproduction (both pregnancy and lactation), survival and future reproduction, including the specific costs of first reproduction, in long‐lived, income breeding small mammals, an under‐studied group.We developed a novel statistical framework that encapsulates the breeding life cycle of females, and accounts for incomplete information on female pregnancy and lactation and imperfect and biased recapture rates. We applied this framework to longitudinal data on two sympatric, closely related bat species (Myotis daubentonii and M. nattereri).We revealed the existence of several, to our knowledge previously unknown, trends in survival and breeding of these closely related, sympatric species and detected remarkable differences in their age and costs of first reproduction, as well as their survival–reproduction trade‐offs.Our results indicate that species with this type of life history exhibit a mixture of patterns expected for long‐lived and short‐lived animals, and between income and capital breeders. Thus, we call for more studies to be conducted in similar study systems, increasing our ability to fully understand the evolutionary origin and fitness effects of trade‐offs and senescence.

Early-life telomere length predicts lifespan and lifetime reproductive success in a wild bird.

Poor conditions during early development can initiate trade-offs that favour current survival at the expense of somatic maintenance and subsequently, future reproduction. However, the mechanisms that link early and late life-history are largely unknown. Recently it has been suggested that telomeres, the nucleoprotein structures at the terminal end of chromosomes, could link early-life conditions to lifespan and fitness. In wild purple-crowned fairy-wrens, we combined measurements of nestling telomere length (TL) with detailed life-history data to investigate whether early-life TL predicts fitness prospects. Our study differs from previous studies in the completeness of our fitness estimates in a highly philopatric population. The association between TL and survival was age-dependent with early-life TL having a positive effect on lifespan only among individuals that survived their first year. Early-life TL was not associated with the probability or age of gaining a breeding position. Interestingly, early-life TL was positively related to breeding duration, contribution to population growth and lifetime reproductive success because of their association with lifespan. Thus, early-life TL, which reflects growth, accumulated early-life stress and inherited TL, predicted fitness in birds that reached adulthood but not noticeably among fledglings. These findings suggest that a lack of investment in somatic maintenance during development particularly affects late life performance. This study demonstrates that factors in early-life are related to fitness prospects through lifespan, and suggests that the study of telomeres may provide insight into the underlying physiological mechanisms linking early- and late-life performance and trade-offs across a lifetime.

Compensatory and additive helper effects in the cooperatively breeding Seychelles warbler (Acrocephalus sechellensis).

In cooperatively breeding species, care provided by helpers may affect the dominant breeders’ investment trade‐offs between current and future reproduction. By negatively compensating for such additional care, breeders can reduce costs of reproduction and improve their own chances of survival. Alternatively, helper care can be additive to that of dominants, increasing the fledging fitness of the current brood. However, the influence helpers have on brood care may be affected by group size and territory quality. Therefore, the impact of helping needs to be disentangled from other factors determining offspring investment before conclusive inferences about the effect of help on additive and compensatory care can be made. We used 20 years of provisioning data to investigate the effect of helping on provisioning rates in the facultative cooperatively breeding Seychelles warbler Acrocephalus sechellensis. Our extensive dataset allowed us to statistically disentangle the effects of helper presence, living in larger groups and different food availability. We show compensatory and additive care (i.e., partial compensation) in response to helper provisioning. Helpers lightened the provisioning load of the dominant male and female and increased total provisioning to nestlings. This was irrespective of group size or territory quality (food availability). Moreover, our results illustrate sex‐specific variation in parental care over the course of the breeding event. We discriminate between temporal variation, group size, and territory quality processes affecting cooperative care and as such, gain further insight into the importance of these factors to the evolutionary maintenance of helping behavior.

Risk of having one lifetime pregnancy and modification by outcome of pregnancy and perinatal loss.

With increasing cesarean section rates, adverse pregnancy outcomes such as preterm delivery and small-for-gestational-age continue to be public health challenges. Besides having high co-occurrence and interrelation, it is suggested that these outcomes, along with preeclampsia, are associated with reduced subsequent fertility. On the other hand, the loss of a child during the perinatal period is associated with increased reproduction. Failure to consider this factor when estimating the effects of pregnancy outcomes on future reproduction may lead to erroneous conclusions. However, few studies have explored to what degree a perinatal loss contributes to having a next pregnancy in various adverse pregnancy outcomes. This was a population-based study of mothers giving birth to their first singleton infant (≥22 gestational weeks) during 1967-2007 who were followed for the occurrence of a second birth in the Medical Birth Registry of Norway until 2014. Relative risks with 95% confidence intervals for having one lifetime pregnancy by preterm delivery, small-for-gestational-age, preeclampsia and cesarean section were obtained by generalized linear models for the binary family and adjusted for maternal age at first birth, education and year of first childbirth. Main outcome measure was having one lifetime pregnancy. Nearly 900000 women gave birth to their first singleton infant in 1967-2007, of which 16% had only one lifetime pregnancy. These women were older at first delivery, had less education and there was a higher proportion of unmarried women than women with two or more births. In women with pregnancy complications where the infant survived the perinatal period, there were the following relative risks for one lifetime pregnancy: increased preterm delivery: 1.21 (1.19-1.22)], small-for-gestational-age: 1.13 (1.12-1.15), preeclampsia: 1.09 (1.07-1.11), cesarean section: 1.24 (1.23-1.25). The risk was significantly reduced if the child was lost (preterm delivery: 0.63 [0.59-0.68], small-for-gestational-age: 0.57 [0.51-0.63], preeclampsia: 0.69 [0.59-0.80], cesarean section: 0.67 [0.56-0.79]), compared with women with no perinatal loss and no adverse outcome. The associations between adverse outcomes of pregnancy and the risk of having one lifetime pregnancy were strongly modified by child survival in the perinatal period.

Brood Size Affects Future Reproduction in a Long-Lived Bird with Precocial Young.

Estimation of trade-offs between current reproduction and future survival and fecundity of long-lived vertebrates is essential to understanding factors that shape optimal reproductive investment. Black brant geese (Branta bernicla nigricans) fledge more goslings, on average, when their broods are experimentally enlarged to be greater than the most common clutch size of four eggs. Thus, we hypothesized that the lesser frequency of brant clutches exceeding four eggs results, at least partially, from a future reduction in survival, breeding probability, or clutch size for females tending larger broods. We used an 8-year mark-recapture data set (Barker robust design) with 5 years of clutch and brood manipulations to estimate long-term consequences of reproductive decisions in brant. We did not find evidence of a trade-off between reproductive effort and true survival or future initiation date and clutch size. Rather, future breeding probability was maximized ( [SE]) for manipulated females tending broods of four goslings and was lower for females tending smaller (one gosling; [SE]) or larger (seven goslings; [SE]) broods. Our results suggest that demographic trade-offs for female brant tending large broods may reduce the fitness value of clutches larger than four and, therefore, contribute to the paucity of larger clutches. The lack of a trade-off between reproductive effort and survival provides evidence that survival, to which fitness is most sensitive in long-lived animals, is buffered against temporal variation in brant.

Iodine Mediator with Anomalously High Redox Potential and Its Application to a Catalytic Cycle for Lithium Carbonate Decomposition toward Future Lithium Reproduction

Lithium carbonate (Li2CO3) is observed in conventional lithium-ion batteries in which cell performance has been reduced. In this paper, a catalyst to electrochemically decompose Li2CO3 was investigated to develop a Li reproduction technology. It has been accepted that iodine with a redox potential below 3.5 V vs Li+/Li cannot decompose Li2CO3, because the decomposition potential of Li2CO3 is 3.82 V vs Li+/Li. Here, we observed that the redox potential of iodine in trimethyl phosphate (TMP) and dimethyl sulfoxide (DMSO) solutions increased up to 4.0 V, and thus Li2CO3 could be chemically decomposed by iodine in these solvents. This unexpectedly high redox potential may be caused by deviation of the electric charges on two iodine atoms due to a 1:1 complex formation of iodine with the solvent. Reaction pathways are discussed with respect to the chemical decomposition of Li2CO3 by iodine. We combined the chemical decomposition behavior with the redox couple of iodine species. A double-chamber type cell with ...