Sh. Alonzo et al., Male alternative reproductive behaviours in a Mediterranean wrasse, Symphodus ocellatus: Evidence from otoliths for multiple life-history pathways, EVOL EC RES, 2(8), 2000, pp. 997-1007
Although alternative reproductive behaviours have been studied extensively,
it has only been possible in a few cases to document the underlying life-h
istory pathways and factors that determine their expression. In Symphodus o
cellatus, a Mediterranean wrasse, males adopt a variety of behaviours. With
in a season, they may invest in territory defence, nest building and broodc
are (nesting males); join nesting males in their defence against reproducti
ve parasites, but also participate in spawning (satellites); parasitize nes
ting males' spawns (sneakers); or refrain from reproduction (non-reproducti
ves). To examine the life-history patterns of these alternatives, we observ
ed individual males during a reproductive season and categorized their beha
viour 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 i
n early growth and behaviour suggest three alternative pathways: switching
between reproductive seasons from being non-reproductive directly to nestin
g, changing from satellite to nesting behaviour between seasons, or from sn
eaking to adopting satellite behaviour. The adoption of a behaviour is appa
rently related to growth before reproduction in the first year of life. The
existence of four age-dependent alternative behaviours within three sepal-
ate life-history pathways indicates that we need to determine the life-hist
ory pathways that occur before we can infer the underlying mechanisms allow
ing the stable co-existence of alternative reproductive behaviours in a giv
en species.