Reproductive allocation in pulsed-resource environments: a comparative study in two populations of wild boar.
Pulsed resources influence the demography and evolution of consumer populations and, by cascading effect, the dynamics of the entire community. Mast seeding provides a case study for exploring the evolution of life history traits of consumers in fluctuating environments. Wild boar (Sus scrofa) population dynamics is related to seed availability (acorns/beechnuts). From a long-term monitoring of two populations subjected to markedly different environmental contexts (i.e., both low vs. high frequency of pulsed resources and low vs. high hunting pressure in Italy and in France, respectively), we assessed how pulsed resources shape the reproductive output of females. Using path analyses, we showed that in both populations, abundant seed availability increases body mass and both the absolute and the relative (to body mass) allocation to reproduction through higher fertility. In the Italian population, females equally relied on past and current resources for reproduction and ranked at an intermediate position along the capital-income continuum of breeding tactics. In contrast, in the French population, females relied on current more than past resources and ranked closer to the income end of the continuum. In the French population, one-year old females born in acorn-mast years were heavier and had larger litter size than females born in beechnut-mast years. In addition to the quantity, the type of resources (acorns/beechnuts) has to be accounted for to assess reliably how females allocate resources to reproduction. Our findings highlight a high plasticity in breeding tactics in wild boar females and provide new insight on allocation strategies in fluctuating environments.
Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, 7491, Trondheim, Norway. marlene.gamelon@ntnu.no.
Marlène
0000-0002-9433-2369
M
Gamelon
CNR, Istituto per i Sistemi Complessi, via Madonna del Piano 10, 50019, Sesto Fiorentino, Italy.
Stefano
S
Focardi
Office National de la Chasse et de la Faune Sauvage, 2 Bis Rue des Religieuses, BP 19, 52120, Châteauvillain, France.
Eric
E
Baubet
Office National de la Chasse et de la Faune Sauvage, 2 Bis Rue des Religieuses, BP 19, 52120, Châteauvillain, France.
Serge
S
Brandt
Istituto Superiore per la Protezione e la Ricerca Ambientale, Via Ca' Fornacetta 9, 40064, Ozzano dell'emilia, Bologna, Italy.
Barbara
B
Franzetti
Istituto Superiore per la Protezione e la Ricerca Ambientale, Via Ca' Fornacetta 9, 40064, Ozzano dell'emilia, Bologna, Italy.
Francesca
F
Ronchi
Laboratoire de Biométrie et Biologie Évolutive, CNRS UMR 5558, Université Claude Bernard Lyon 1, 69622, Villeurbanne, France.
Samuel
S
Venner
Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, 7491, Trondheim, Norway.
Bernt-Erik
BE
Sæther
Laboratoire de Biométrie et Biologie Évolutive, CNRS UMR 5558, Université Claude Bernard Lyon 1, 69622, Villeurbanne, France.
Jean-Michel
JM
Gaillard
D000818:Animals; D017753:Ecosystem; D004777:Environment; D008098:Litter Size; D012098:Reproduction; D034421:Sus scrofa
Body mass; Breeding tactics; Fluctuating environments; Masting; Path analysis