DISTRIBUTION OF THE JUVENILE COCONUT CRAB, BIRGUS-LATRO (L.), ON THE ISLAND OF LIFOU, NEW-CALEDONIA

The objective of this study was to examine the distribution of juvenil e Birgus latro (L). The field research was conducted on the terrace of the eastern part of the island of Lifou in the Loyalty Islands. The t errace, which was once the surrounding reef, has since been raised alo ng with the raising of the atoll. Located between the ocean and the fo rmer reef crown, which is now the cliff, the terrace encircles the isl and. juvenile crabs were only found under coconut piles at the foot of coconut trees. The largest juvenile crabs collected had. thoracic len gth (TL) of 28 mm. The number of crabs in coconut piles decreased rapi dly above 23 mm TL, which is approximately the size of sexual maturity . No adults were found under coconut piles, as their principal habitat was in burrows located in the calcareous rock beyond the terrace. The smallest juvenile crabs were found near the ocean and the largest clo se to the cliff-face. During their first terrestrial stages, juvenile coconut crabs carried three kinds of terrestrial gastropod shells acco rding to their size. Those with a TL of less than 2 mm mostly chose Dr aparnaudia sp., those with a TL between 2 and 4 mm preferred Achatina fulica and those between 4 and 7 mm used Achatina fulica and Placostyl us sp. shells with a preference for the latter. All crabs captured les s than or equal to 7 mm TL (n = 32; mean size = 3.7 +/- SD 1.4 mm) had a shell, as opposed to all those over 7.8 mm TL (n = 50; mean size = 16.5 +/- SD 5.2 mm) which no longer did.