The marine goby - alpheid shrimp symbiosis does not correlate with larger fish eye size

The symbiosis between marine gobies and Alpheid shrimp is based on an exchange of sensory performance (look-out for predators) by the goby versus muscular performance (burrow digging) by the shrimp. Using a comparative approach, we estimate the excess investment by the goby into its visual system as a consequence of the symbiosis. When correlating eye size with fish length for both shrimp-associated and solitary gobies, we find that the shrimp-associated gobies do not have larger eyes than size-matched solitary gobies.\n\nWe do find a trend, however, in that the shrimp-associated gobies live at shallower depths than the solitary gobies, indicative of the visual nature of the symbiosis. We discuss the implications of symbiosis based on large and small energy investments, and the evolutionary modifications likely necessary to include shrimp-goby communication into the behavior of the goby.