Live fast, don't die young: Survival–reproduction trade‐offs in long‐lived income breeders

Abstract

Trade‐offs between survival and reproduction are at the core of life‐history theory, and essential to understanding the evolution of reproductive tactics as well as population dynamics and stability. Factors influencing these trade‐offs are multiple and often addressed in isolation. Further problems arise as reproductive states and survival in wild populations are estimated based on imperfect and potentially biased observation processes, which might lead to flawed conclusions.In this study, we aimed at elucidating trade‐offs between current reproduction (both pregnancy and lactation), survival and future reproduction, including the specific costs of first reproduction, in long‐lived, income breeding small mammals, an under‐studied group.We developed a novel statistical framework that encapsulates the breeding life cycle of females, and accounts for incomplete information on female pregnancy and lactation and imperfect and biased recapture rates. We applied this framework to longitudinal data on two sympatric, closely related bat species (Myotis daubentonii and M. nattereri).We revealed the existence of several, to our knowledge previously unknown, trends in survival and breeding of these closely related, sympatric species and detected remarkable differences in their age and costs of first reproduction, as well as their survival–reproduction trade‐offs.Our results indicate that species with this type of life history exhibit a mixture of patterns expected for long‐lived and short‐lived animals, and between income and capital breeders. Thus, we call for more studies to be conducted in similar study systems, increasing our ability to fully understand the evolutionary origin and fitness effects of trade‐offs and senescence.

Low Rates of PIT‐Tag Loss in an Insectivorous Bat Species

“…Bat banding (ringing) has become less popular through time, and is rigorously regulated in Australia because of unacceptable rates of injury in some species (Baker et al 2001). Nevertheless, banding remains one of the most common long-term marking choices for bats (Kunz and Weise 2009, Culina et al 2019, Locatelli et al 2019. There is little information available about band loss and, to our knowledge, this is the first study to report rates of loss from the use of flanged bat bands applied to the forearm.…”

Phenology of reproductive condition varies with age and spring weather conditions in male Myotis daubentonii and M. nattereri (Chiroptera: Vespertilionidae)

“…earlier onset of spermatogenesis, and possibly a shift in mating strategies, with increasing age) is a process that takes several years. Demonstrating that, as small-sized but long-lived mammals, bats exhibit unusual combinations of life-history traits 35 .…”

Exploring the role of life history traits and introduction effort in understanding invasion success in mammals: A case study of Barbary ground squirrels

“…Bat species, for example, may show a combination of life history traits either related to a fast or slow life history (Culina et al 2019). In invasion ecology, fast life history traits are suggested to promote the population growth and spread of introduced species, thus favouring species 'invasiveness': for example, success of mammals at the introduction stage is related to having large, more frequent litters and a longer reproductive lifespan, while establishment success is related to larger litters, longer reproductive lifespan and greater introduction effort, and their spread success is associated with larger, more frequent litters and higher introduction effort (Capellini et al 2015).…”