Effect of lifespan and age on reproductive performance of the tardigrade Acutuncus antarcticus: minimal reproductive senescence

Over a century ago microfaunal diversity was first recorded by James Murray in lakes at Cape Royds, Ross Island, Antarctica. The report stands as the seminal study for today’s biodiversity investigations, and as a baseline to evaluate changes in faunal communities and introductions. In the present study, Cape Royds lakes were revisited and the mitochondrial c oxidase subunit I (COI) gene and morphology were used to compare diversity of Rotifera, Tardigrada and Nematoda with the records Murray published in the early 1900s. Cyanobacterial mats and the water column were sampled for microfauna from the five largest lakes using methods described by Murray. Across all five lakes similar patterns were observed for species distribution of all three phyla reported by Murray over 100 years ago. Some changes in species assemblages were identified within and between lakes, but there were no new introductions of named species for the Cape Royds region. Some of the species included by Murray in his monograph have been recently redescribed as Antarctic endemics, but others still retain their original name from the Northern Hemisphere holotypes and are also in need of revision to adequately determine the true endemism for these faunal groups.

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“…2015, Tsujimoto et al . 2016). The other aquatic tardigrade species found by Murray resembles the Scottish Diphascon alpinum .…”

Section: Discussionmentioning

confidence: 99%

100 years on: a re-evaluation of the first discovery of microfauna from Ross Island, Antarctica

Velasco-Castrillón

Hawes²,

Stevens

2018

Antarctic Science

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“…Currently, approximately 1200 species have been reported from various habitats, such as marine, fresh-water, or limno-terrestrial environments, though the real number of tardigrade species is estimated to be much higher [ 4 , 5 ]. Tardigrades were found in harsh environments such as Antarctica as well as in urban area, e.g., from activated sludge in a sewage treatment plant [ 6 , 7 , 8 ]. All tardigrades require surrounding water to grow and reproduce, but some limno-terrestrial species are able to tolerate almost complete dehydration.…”

Section: Tardigrades As Model Animals Tolerant To Various Extreme mentioning

confidence: 99%

DNA Protection Protein, a Novel Mechanism of Radiation Tolerance: Lessons from Tardigrades

Hashimoto

Kunieda

2017

Life

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Genomic DNA stores all genetic information and is indispensable for maintenance of normal cellular activity and propagation. Radiation causes severe DNA lesions, including double-strand breaks, and leads to genome instability and even lethality. Regardless of the toxicity of radiation, some organisms exhibit extraordinary tolerance against radiation. These organisms are supposed to possess special mechanisms to mitigate radiation-induced DNA damages. Extensive study using radiotolerant bacteria suggested that effective protection of proteins and enhanced DNA repair system play important roles in tolerability against high-dose radiation. Recent studies using an extremotolerant animal, the tardigrade, provides new evidence that a tardigrade-unique DNA-associating protein, termed Dsup, suppresses the occurrence of DNA breaks by radiation in human-cultured cells. In this review, we provide a brief summary of the current knowledge on extremely radiotolerant animals, and present novel insights from the tardigrade research, which expand our understanding on molecular mechanism of exceptional radio-tolerability.

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“…Reproductive output is one of the central attributes of life history, and knowledge of age-specific reproduction may enhance the understanding of population performance and dynamics (Tsujimoto et al 2016). The decline in fitness components with age is highly variable among different groups of organisms and includes changes in fertility and brood quality (Jones et al 2014).…”

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confidence: 99%

Effect of multiple spawning on female reproductive output and offspring quality in a freshwater caridean shrimp with direct development

Marciano

Tropea

Greco

2018

Invertebrate Biology

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The decline with age in components of fitness is variable among different taxa and includes changes in fertility and brood quality. In this study, we selected individuals of Neocaridina davidi, a freshwater shrimp with direct development, to analyze juvenile quality and female reproductive performance over successive spawnings, both of which are correlated with female age. Given the high costs of reproduction in species with direct development, we hypothesized that female reproductive performance and juvenile quality decrease in later spawns. Two experiments were performed. In Experiment 1, we evaluated the reproductive performance of females of N. davidi and the quality of juveniles (through a food restriction test) over the first six successive spawnings. In Experiment 2, we analyzed the lipid and protein contents in juveniles from the third, fourth, and fifth spawns, after feeding them daily or starving them for 8 d or 12 d after hatching. Female mortality was observed throughout Experiment 1, along with a decrease in the proportion of ovigerous females over successive spawns. However, the interval between spawnings and the number and size of newly hatched juveniles were similar among spawns. Moreover, females that spawned many times had a reproductive efficiency similar to those that spawned few times, as evidenced by a similar percentage of broods successfully hatched and a similar percentage of broods with more than 28 juveniles among all spawns. Overall, these results may indicate a partial effect of multiple spawning on female reproductive performance. Growth, survival, and biochemical composition of food‐restricted juveniles showed similar or even higher values in later spawns as compared to the first spawns. This is, to our knowledge, the first empirical demonstration in a decapod crustacean with direct development that, although the percentage of ovigerous females decreases over time, other reproductive variables and juvenile performance do not decline in successive spawnings, at least for the initial six consecutive spawns.

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Effect of lifespan and age on reproductive performance of the tardigrade Acutuncus antarcticus: minimal reproductive senescence

Cited by 11 publications

References 47 publications

100 years on: a re-evaluation of the first discovery of microfauna from Ross Island, Antarctica

100 years on: a re-evaluation of the first discovery of microfauna from Ross Island, Antarctica

DNA Protection Protein, a Novel Mechanism of Radiation Tolerance: Lessons from Tardigrades

Effect of multiple spawning on female reproductive output and offspring quality in a freshwater caridean shrimp with direct development

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