title: Barnacle larvae actively select flow environments supporting post-settlement growth and survival.
abstract: Many marine dispersive propagules select specific settlement sites based on a range of environmental cues. However, the link between larval choice and post-settlement growth and survival is still poorly understood. Here we show that cypris larvae of the barnacle Balanus improvisus actively reject surfaces exposed to local flow speeds exceeding 5-10 cm/s. Field experiments show that post-settlement growth and survival decline in freestream flows above 15 cm/s. Moreover, studies in flume flow at local speeds exceeding 10 cm/s reveal that early juveniles show reduced feeding rates caused by deformation of the cirral fan, reduced retention efficiency, and a decrease in time spent feeding. We conclude that cypris larvae actively reject flow environments that will be suboptimal for suspension feeding in the early post-settlement phase. Our study suggests that larval choice can be adaptively connected to a specific part of the life cycle, in this case the very sensitive time after metamorphosis.
authors.affiliation: Tjärnö Marine Biological Laboratory, Department of Marine Ecology, Göteborg University, SE-452 96 Strömstad, Sweden. ann.larsson@tmbl.gu.se
authors.forename: Ann I
authors.initials: AI
authors.lastname: Larsson
authors.forename: Per R
authors.initials: PR
authors.lastname: Jonsson
mesh_terms: D000818:Animals; D005247:Feeding Behavior; D007814:Larva / Q000502:physiology; D016019:Survival Analysis; D001468:Thoracica / Q000502:physiology*; D014872:Water Movements