DOI: 10.5061/dryad.pg4f4qrwr
title: Data from: Age at first reproduction and senescence in Eastern chipmunks (Tamia striatus)

description: 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.
description: 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.
description: # Age at first reproduction and senescence in Eastern chipmunks (Tamia
 striatus)
 [https://doi.org/10.5061/dryad.pg4f4qrwr](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