Male alternative reproductive behaviours in a Mediterranean wrasse, Symphodus ocellatus: Evidence from otoliths for multiple life-history pathways

Although alternative reproductive behaviours have been studied extensively, it has only been possible in a few cases to document the underlying life-history pathways and factors that determine their expression. In Symphodus ocellatus, a Mediterranean wrasse, males adopt a variety of behaviours. Within a season, they may invest in territory defence, nest building and broodcare (nesting males); join nesting males in their defence against reproductive parasites, but also participate in spawning (satellites); parasitize nesting males’ spawns (sneakers); or refrain from reproduction (non-reproductives). To examine the life-history patterns of these alternatives, we observed individual males during a reproductive season and categorized their behaviour as sneakers, satellites, nesting males or non-reproductives. We then used their otoliths to estimate age and growth patterns. Males are sneakers, satellites or non-reproductives in their first reproductive season, while they behave as satellites or nesting males when 2 years old. Differences in early growth and behaviour suggest three alternative pathways: switching between reproductive seasons from being non-reproductive directly to nesting, changing from satellite to nesting behaviour between seasons, or from sneaking to adopting satellite behaviour. The adoption of a behaviour is apparently related to growth before reproduction in the first year of life. The existence of four age-dependent alternative behaviours within three separate life-history pathways indicates that we need to determine the life-history pathways that occur before we can infer the underlying mechanisms allowing the stable co-existence of alternative reproductive behaviours in a given species.