Table S1. General description of the symbiotic association between Lysmata pederseni and the host tube sponge Callyspongia vaginalis at different localities in the Caribbean Sea. Shown are: the frequency of occurrence of shrimp on hosts (%), the total number of hosts sampled and shrimp collected per locality (Sn and Ss respectively), the density of shrimp (number of shrimps per host: mean [X] ± standard deviation [sd], and range) and the results of specific Chi-square test of goodness-of-fit (χ2 statistic and one-tailed P values) conducted to detect significant differences between the observed frequency of hosts harboring pairs of shrimps and that predicted by a random Poisson distribution. For all Chi-square tests, degrees of freedom = 1.

% / Sn / Ss / Density / Poisson
Locality / X ± sd / range / χ2 / P
Florida Keys, FL, USA / 12.61 / 111 / 26 / 0.24 ± 0.54 / 0 – 2 / 3.08 / 0.129
Carrie Bow Caye, BLZ / 29.03 / 124 / 81 / 0.72 ± 1.34 / 0 – 5 / 4.59 / 0.043
Kunayala, Panama / 10.00 / 110 / 18 / 0.16 ± 0.54 / 0 – 3 / 16.15 / 0.003