Meeting Abstract
The discovery that pelagic fish larvae are not just passive particles, but have the ability to demonstrate directional behaviors in the open ocean and locate appropriate settlement sites has intrigued biologists for many years. Yet it is still unclear which sensory modalities foster this capability. Morphological analysis of the ontogeny of the various sensory organs can shed light on their functional capacities. In this study, we reared two neon goby species native to Belizean reefs (Elacatinus lori and Elacatinus colini) in a field laboratory and describe the developmental morphology of the olfactory organ and internal taste buds from day-of-hatch through settlement (~30 days post hatch). Histology and SEM show that both sensory systems develop in a manner consistent with that of other reef fishes, with notable changes around the time of settlement. The olfactory epithelium is present at hatching, and later invaginates and becomes enclosed in a blind sac with two nares at settlement stage. There is no sign of lamellae or accessory nasal sacs, which would otherwise indicate the capacity for active nasal ventilation. Internal taste buds are abundant in the buccal cavity, with the majority on the gill arches (including pharyngeal jaws) and the roof of mouth. The distribution of taste buds shows a “spread” to more rostral positions within the buccal cavity (lips, buccal valves and “tongue”) as the larvae approach settlement. The implications of these ontogenetic trends for larval navigation will be discussed. Funded by NSF grant 1459224 to JFW and 1459546 to PMB.
