Seasonal and daily protandry in a cyprinid fish

Marek Šmejkal,Roman Baran,Petr Blabolil,Zuzana Sajdlová,Daniel Ricard,Lucie Vebrová,Jan Kubečka,Lukáš Vejřík,Ivana Vejříková,Tomáš Mrkvička,Marie Prchalová

doi:10.1038/s41598-017-04827-x

Abstract

In polygynandrous mating systems, in which females limit reproductive success, males can increase their success by investing in courtship. Earlier arrival at the spawning ground compared to when females arrive may increase their opportunities in competitive mating systems. In this study, we used passive telemetry to test whether a male minnow known as the asp, Leuciscus aspius, times its arrival at spawning grounds relative to the arrival of females. Males arrived in a model stream approximately five days earlier than females on average and left four to five days later than females over two years. Both sexes performed a daily migration between a staging ground (standing water, low energy costs) and the fluvial spawning ground (high energy costs). Fish abundance peaked twice a day, with a major peak at sunset and a minor peak at sunrise and with the evening peak abundance for males occurring 1 hour 40 minutes earlier than that of females. The number of females on the spawning ground never exceeded the number of males. While the degree of protandry is hypothesized to be influenced by the operational sex ratio (ranging from 0.5 to 1 in our study), our data did not support this theory.

Highlights

In polygynandrous mating systems, in which females limit reproductive success, males can increase their success by investing in courtship
The single likelihood tests demonstrated that the slow site was significantly different than the fast site (Wald test: χ2 = 73.4, p < 0.001) and the medium site (Wald test: χ2 = 32.4, p < 0.001)
We conclude that studied reproducing asps had a spatially delimited spawning ground and that the spawners had to pass at least one antenna to enter the spawning ground (Fig. 1)

Summary

Introduction

In which females limit reproductive success, males can increase their success by investing in courtship. In species in which mating occurs at the gathering site and that have conventional sex roles, males exhibit protandry, generally arriving at the breeding ground before females during the breeding season[16,17,18]. This early arrival is used to establish intra-sexual hierarchies and territories in many types of reproductive gatherings and lek mating systems, and early arriving males may achieve a higher rank and have access to more females (rank advantage hypothesis)[16, 19, 20]. In male Atlantic salmon, Salmo salar, the energetic costs of mating counterbalance the six-times-higher investment in gonadal development by females[10, 28]

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