Fallow deer polyandry is related to fertilization insurance

Abstract

Polyandry is widespread, but its adaptive significance is not fully understood. The hypotheses used to explain its persistence have rarely been tested in the wild and particularly for large, long-lived mammals. We investigated polyandry in fallow deer, using female mating and reproduction data gathered over 10 years. Females of this species produce a single offspring (monotocous) and can live to 23 years old. Overall, polyandry was evident in 12 % of females and the long-term, consistent proportion of polyandrous females observed, suggests that monandry and polyandry represent alternative mating strategies. Females were more likely to be polyandrous when their first mate had previously achieved high numbers of matings during the rut or was relatively old. However, polyandry was not related to the following factors: female age, the stage of the rut, the dominance ranks of mates, or the number of daily matings achieved by males. Polyandrous and monandrous multiplemating females were not more likely than single-mating females to be observed with an offspring during the following year, and there were no significant differences in offspring size between these females. These results provide support for a fertility insurance hypothesis, with females remating if fertilization from the first mating was uncertain due to possible sperm depletion. The potential for different female mating strategies among large, polygynous mammals has generally been overlooked. Our findings highlight the complexity of female reproductive strategies and the possible trade-offs between fertilization success, preferences for high-quality males, and potential costs of polyandry, particularly for monotocous species.

The hidden ageing costs of sperm competition

“…Although earlier studies assumed that sperm were particularly cheap to produce (see Dewsbury, 2005), the influence of resource availability on sperm production has been demonstrated in a wide spectrum of organisms. For instance, in fallow deer ( Dama dama ), a species in which females mate with several males during a given reproductive attempt (Briefer et al ., 2013), yearling males with a diet supplemented with protein and amino acids have larger testes, exhibit Sertoli cells – which play a key nutritional function during spermatogenesis – with higher workload capacities, higher concentrations of sperm within the epididymis and sperm with a longer midpiece than do non‐supplemented yearling males (Ros‐Santaella et al ., 2019). This positive effect of an enriched diet on sperm quantity and/or quality has also been repeatedly found in agronomy research (e.g.…”

Evolution of ungulate mating systems: Integrating social and environmental factors

“…Mating systems may be fluid in some species (Isvaran, 2005); we describe the mating behavior based on the most prevalent system (or multiple systems for some species), and the one most closely related to polygynous mating. For example, in fallow deer ( Dama dama ; Briefer, Farrell, Hayden, & McElligott, 2013), white‐tailed deer (DeYoung, Demarais, Gonzales, Honeycutt, & Gee, 2002), sika ( Cervus Nippon ; Endo & Doi, 2002), and pronghorn (Carling, Wiseman, & Byers, 2003) females occasionally accept copulations from multiple males; those giving birth to multiple offspring may have litters of mixed paternity. This outcome might indicate polyandry or promiscuity, but multiple copulations make up only a small part of mating by females and may relate to fertility insurance (Briefer et al, 2013).…”

Damherten in de Manteling van Walcheren en de kop van Schouwen : beheer van damhertpopulaties in relatie tot beheerdoelstellingen en welzijnsaspecten

“…De draagtijd duurt 32-33 weken. In de periode mei tot juli worden de meeste kalfjes geboren, waarbij hindes één kalf krijgen (Briefer et al, 2013). Vrij levende damherten kunnen meer dan 20 jaar oud worden (Langbein & Putman, 1992).…”