Obligatory And Facultative Goby-Shrimp Partnerships In The Western Tropical Atlantic

The behaviour of an obligatory fish partner Nes longus and a facultative one Bathygobius curacao, when associated with a facultative shrimp partner Alpheus floridanus, was studied off key Biscayne, in southern Florida. Continuous antennal contact was maintained between the shrimp and the two gobies while outside the burrow. The shrimp retreated into the burrow in response to tail-flick warning signals and head-first entries of N. longus. B. curacao warned the shrimp only by head-first entries into the burrow and gave no special warning signals. The time a shrimp spent outside its burrow differed when it was free-living, or when associated with a facultative or obligatory fish partner. A. floridanus without a partner spent very short periods of time outside the burrow. When associated with B. curacao, it spent less than 10% of the time outside the burrow and about 30% when associated with N. longus. The goby-shrimp partnerships in the western tropical Atlantic are compared to those found in the Indo-Pacific region. The possible evolution of the goby-shrimp partnership is discussed.