Data from: Age at first reproduction and senescence in Eastern chipmunks (Tamia striatus)
Data files
Oct 18, 2023 version files 48.16 KB
Abstract
Senescence is the degradation of biological functions with increasing age. Its existence and relationship with life-history strategies remains poorly studied in short-lived wild vertebrate species. We investigated the relationships between age at first reproduction (AFR), reproductive senescence and longevity in an eastern chipmunk (Tamias striatus) population, where the first opportunity to breed is conditioned by pulses of seed production by trees (i.e., masts). We used 11 years of data from a longitudinal study, in which females breed for the first time at seven, 15, or 22 months of age and males at seven or 15 months of age. We first assessed the effect of age on three traits associated with breeding performance, namely the number of offspring produced, and the probability of weaning or siring a litter. We then tested whether an earlier AFR accelerated reproductive senescence and reduced survival of both males and females. We found sex-specific relationships between AFR and senescence. Females reproducing at 15 or 22 months of age showed reproductive senescence, but early-breeding females did not show any decline in reproductive performance at an older age. Also, although we observed reproductive senescence in males, it was not affected by AFR. Our results are consistent with studies highlighting the existence of reproductive senescence in small, wild mammals. Importantly, we provide the first evidence that AFR can strongly influence the patterns of senescence in small short-lived species and does it in a sex-specific way. Our results highlight the importance of studying life-history strategies in both males and females when studying senescence in the wild.
README: Age at first reproduction and senescence in Eastern chipmunks (Tamia striatus)
https://doi.org/10.5061/dryad.pg4f4qrwr
The data set represent 487 observation of reproduction for individual eastern chipmunks, captured between 2004 and 2018, on four study sites in southern Quebec, Canada.
Description of the data and file structure
ID = individual ID
Age_class = the age of the individual at first capture (J = juvenile ; A = adult)
site = name of the study grid
First_capture = the date of first capture
Year_birth = the year of birth
Cohort_birth = one of the two types of birth cohort (chipmunks breed in the srping or in the summer)
cohort_sexual_maturity = one of the three category representing the age at which the animal first bred
AFR = age at first reproduction (in month)
Last-capture = the last capture of the animal (use to calculate lifespan)
lifespan = in month
weaned_juv = whether the animal weaned juveniles during this reproductive event (note that the individual may have reproduced but did not weaned any offspring)
age = the age of the individual (in months) at the time of the reproductive event
nb_juv = the number of juveniles produced
season = the season during the reproductive event. either pre-mast (i.e. the summer before an American beech tree masting event) or post-mast (i.e. the spring after an American beech tree masting event)
NA = unavailable data for some information (e.g. some animals were still alive at the time of the analyses, for these individuals we added "NA" in the lifespan column)
For more information see Allain et al. 2023. Oikos.
Sharing/Access information
Contact: reale.denis@uqam.ca
Methods
These are data from a long term study on a population of eastern chipmunks in southern Quebec. We have followed individuals over their lifespan, to measure age at first reproduction, reproductive status, the probability of reproducing, number of offspring produced. We used Generalized linear mixed models on different reproductive traits in females and males, and a quadratic function of age, to test whether we could detect senescence patterns and whether age at first reproduction was linked to senescence.