What is known

Global distribution:
Alpheid shrimp and gobiid partnerships are widespread across the tropics. Most of the work that has been done on these shrimp-goby relationships has been done in the Red Sea (Luther, 1958; Magnus, 1967; Karplus, 1981; Karplus et al., 1981; Polunin and Lubbock, 1977) and Japan (Harada, 1969; Yanagisawa, 1978, 1982, 1984). There have also been a few smaller studies on an Atlantic association (Karplus, 1992) and only one on the Hawaiian association (Moehring, 1972).

Symbiotic relationship:
Nearly every report of the shrimp and goby relationship has noted that they are symbiotically mutualistic (reviewed by Karplus 1987). The alpheid shrimps dig holes in the predominantly sandy habitats where they live, providing protection for the gobies. The gobies stay at the entrance of the hole during the day, in close enough proximity to dart in for escape and at night for a resting hole. The gobies, which have much keener eyesight, provide a kind of ‘advanced warning system’ by being able to see potential predators earlier. The goby relays this information back to the shrimp through 1) its head-first entries and 2) a series of tail flicks which the shrimp detects through its antenna that are ‘continuously positioned on the fish’s body' (Moehring, 1972; Karplus, 1987, 1992).

Predators of shrimp gobies are …

Daily rhythm patterns show that …

Population dynamics …

Breeding cycles …

Research that still needs to be done

Currently little work has been done how predation effects populations of shrimp gobies. The work that has been done simply compared the activity of shrimp-gobies in areas of low and high predation pressure (Yanigisawa 19.. ). The other works looked at the gobies in a lab when presented a model (Karplus 1979).

It is difficult to ask evolutionary questions because of the difficulty of proving anything. My experiment will not tempt to solve the evolution of the shimp-goby relationship. Instead it may answer a part of the question. It has been hypothesized that shimp-gobies may have evolved in response to predation (Karplus 1987). Yet, no one knows for sure the exact effect of predators on the population. Thus, this study will attempt to fill this very important void in the literature by showing the effect of predators in the short term. It will not be able to make any assumptions of natural selection, because the population is an open population and cannot be tracked over time.