Data from: Senescence and costs of reproduction in the life history of a small precocial species
Trillmich, Fritz; Geißler, Edda; Guenther, Anja (2019), Data from: Senescence and costs of reproduction in the life history of a small precocial species, Dryad, Dataset, https://doi.org/10.5061/dryad.5k1b239
Species following a fast life history are expected to express fitness costs mainly as increased mortality while slow-lived species should suffer fertility costs. Because observational studies have limited power to disentangle intrinsic and extrinsic factors influencing senescence, we manipulated reproductive effort experimentally in the cavy (Cavia aperea) which produces extremely precocial young. We created two experimental groups: One was allowed to reproduce continuously (CR), the other intermittently (IR) by removing males at regular intervals. We predicted that the CR-females should senesce (and die) earlier and produce either fewer and/or smaller, slower growing offspring per litter than those of the IR group. CR-females had 16% more litters during three years than IR-females. CR-females increased mass and body condition more steeply and both remained higher until the experiment ended. Female survival showed no group difference. Reproductive senescence in litter size, litter mass and reproductive effort (litter mass/maternal mass) began after about 600 days and was slightly stronger in CR- than IR-females. Litter size, litter mass and offspring survival declined with maternal age and were influenced by seasonality. IR females decreased reproductive effort less during cold seasons and only at higher age than CR-females. Nevertheless, offspring winter mortality was higher in IR-females. Our results show small costs of reproduction despite high reproductive effort suggesting that under ad libitum food conditions costs depend largely on internal regulation of allocation decisions.