Abstract Dietary restriction (DR) is a well-established intervention to extend lifespan across taxa. Recent studies suggest that DR-driven lifespan extension can be cost-free, calling into question a central tenant of the evolutionary theory of aging. Nevertheless, boosting parental longevity can reduce offspring fitness. Such intergenerational trade-offs are often ignored but can account for the “missing costs” of longevity. Here, we use the nematode Caenorhabditis remanei to test for effects of DR by fasting on fitness of females and their offspring. Females deprived of food for 6 days indeed had increased fecundity, survival, and stress resistance after re-exposure to food compared with their counterparts with constant food access. However, offspring of DR mothers had reduced early and lifetime fecundity, slower growth rate, and smaller body size at sexual maturity. These findings support the direct trade-off between investment in soma and gametes challenging the hypothesis that increased somatic maintenance and impaired reproduction can be decoupled.

For methods on data collection, please see Mautz et al. (2019) Dietary restriction improves fitness of ageing parents but reduces fitness of their offspring in nematodes. The Journals of Gerontology: Series A (in press). 10.1093/gerona/glz276 

FILE: female_reproduction_lifespan_data.csv

           Variable            description

            line                  row number in dataset

            treatment       AL = ad libitum, constant access to food; TF = temporary fasting, no food first 6 days after sexual maturity

            individual        number of individual by treatment

            gen                  Generation marker. F0 for treatment/control females. F1 for offspring of treatment/control females

            D0                    Date of birth

            trtIDgen           unique identifier for each individual. Treatment-Identification number - Generation

            plate                plate number

            day                  day of reproduction

            date                 date of reproduction

            alr                    Age at last reproduction. ‘date’ column with last non-zero value for ‘larvae’ column minus “D0’ column.

            lifespan           Length of life.

            larvae              Number of larvae produced for that respective plate/day

            matcensor       Maternal censoring for lifespan analysis. For females that were still producing eggs on death date.

 

 

FILE: female_heat-shock_data.csv

          Variable          description

            treatment       AL = ad libitum, constant access to food; TF = temporary fasting, no food first 6 days after sexual maturity

            plate                plate number. Each plate had 10 females

            hour                 time at which knock down was assessed. Knock-down was assessed every hour for 7 hours.

            a                      Freely moving or normal movement after being prodded gently by scorer

            b                      Abnormal, non-sinusoidal movement or not freely moving (i.e. only anterior portion of body moving) after being prodded gently by scorer

            c                      not moving even after being stimulated by scorer, but with buccal pump moving or completely non-response

                                    NB: categories b, c were combined in analysis.

           

FILE: offspring_reproduction_lifespan_data.csv

             Variable           description

            line                  row number in dataset

            treatment        AL = ad libitum, constant access to food; TF = temporary fasting, no food first 6 days after sexual maturity

            individual        number of individual by treatment

            gen                  Generation marker. F0 for treatment/control females. F1 for offspring of treatment/control females

            D0                    Date of birth

            plate                plate number

            day                  day of reproduction

            colldate           date that plate of larvae was collected

            alr                    Age at last reproduction. ‘colldate’ column with last non-zero value for ‘larvae’ column minus “D0’ column.

            lifespan           Length of life. max(collate) - D0

            larvae              Total count of larvae on the plate

            matcensor       Maternal censoring for lifespan analysis. For females that were still producing eggs on death date.

 

FILE: offspring_development_size_data.csv

           Variable            description

            treatment        AL = ad libitum, constant access to food; TF = temporary fasting, no food first 6 days after sexual maturity

            plate                plate number

            female           

            date1               date which eggs were laid     

            time1              time at which plates were generated (plates were generated in two blocks).

            comb1             combination of date1 and time1 to calculate development time

            comb2             combination of date2 and time2 to calculate development time

            date2               date at which individuals becamesexually mature

            time2              time at which individual became sexually mature

            pic                   reference number for picture of that individual

            size                  measurement of size (in mm sq).

 

FILE: offspring_heat-shock_data.csv

           Variable            description

            treatment       AL = ad libitum, constant access to food; TF = temporary fasting, no food first 6 days after sexual maturity

            f0_plate          plate on which the test worm developed

            f1_plate          plate on which worm was placed for heat shock treatment (worms from development plates were randomized across treatment plates)

            time                Hour at which knock down was assessed. Knock-down was assessed every hour for 7 hours.

            a                      Freely moving or normal movement after being prodded gently by scorer

            b                      Abnormal, non-sinusoidal movement or not freely moving (i.e. only anterior portion of body moving) after being prodded gently by scorer

            c                      not moving even after being stimulated by scorer, but with buccal pump moving or completely non-response

                                    NB: categories b, c were combined in analysis.

 

FILE: Temporary fasting nematodes data analysis.Rmd

            NB: R code used to analyze above data files