Fisheries Science

, Volume 75, Issue 3, pp 641–648 | Cite as

Prediction of timing of mating and egg extrusion in the coconut crab Birgus latro judged from female pleonal expansion

  • Taku Sato
  • Kenzo Yoseda
Original Article Biology


A temporal pattern of reproductive activities of biological resources is essential information for the implementation of specific seasonal closures. First we investigated the relationship between the female pleonal expansion and female reproductive condition (i.e., non-ovigerous, ovigerous, or with spermatophores) to clarify the morphological characteristics of female coconut crabs that were able to mate. Second, we mated females with males in captivity to examine the relationship between the degree of female pleonal expansion and mating success. The index of pleonal expansion (ratio of inter-tergite distances to thoracic length) was significantly different among female reproductive conditions; females with spermatophores just before egg extrusion had the most expanded pleon. In the mating trials, all females showing index values higher than 0.35 mated with males. These results indicate that the female pleonal expansion has a strong relation to reproductive activities of females and can be applied as a morphological criterion for selecting females being able to mate. Next, we investigated whether reproductive activities of female coconut crabs are related to the lunar cycle. The reproductive activities were synchronized with the lunar cycle, and most females mated and extruded eggs around the new moon phase. These results have considerable implications for resource management and aquaculture for this species.


Birgus latro Coconut crab Egg extrusion Lunar cycle Mating Pleonal expansion Seasonal closures 



This work was possible thanks to the generous hospitality and cooperation of residents of Hatoma Island. We thank the editor, anonymous reviewers, Dr. K. Okuzawa, and members of the Ishigaki Tropical Station, Seikai National Fisheries Research Institute, for helpful comments and discussions. This study was supported by a Grant-in-aid for Science Research (no. 20710184 to T.S.) from the Ministry of Education, Culture, Sports, Science and Technology.


  1. 1.
    Berry AJ (1986) Semi-lunar and lunar spawning periodicity in some tropical littorinid gastropods. J Mollusc Stud 52:144–149CrossRefGoogle Scholar
  2. 2.
    Christy J (1986) Timing of larval release by intertidal crabs on an exposed shore. Bull Mar Sci 39:176–191Google Scholar
  3. 3.
    Giese AC, Kanatani H (1987) Maturation and spawning. In: Giese AC, Pearse JS, Pearse VB (eds) Reproduction of marine invertebrates, vol IX. Blackwell, Palo Alto, pp 252–313Google Scholar
  4. 4.
    Morgan SG (1995) The timing of larval release. In: McEdward LR (ed) Ecology of marine invertebrate larvae. CRC Press, Boca Raton, pp 157–191Google Scholar
  5. 5.
    Harrison PL, Babcock RC, Bull GD, Oliver JK, Wallance CC, Willis BL (1984) Mass spawning on tropical reef corals. Science 223:1186–1189PubMedCrossRefGoogle Scholar
  6. 6.
    Caspers H (1984) Spawning periodicity and habitat of the Palolo worm Eunice viridis in the Samoan Island. Mar Biol 79:229–236CrossRefGoogle Scholar
  7. 7.
    Colin PL (1992) Reproduction of the Nassau grouper, Epinephelus striatus (Pisces: Serranidae) and its relationship to environmental conditions. Environ Biol Fishes 34:357–377CrossRefGoogle Scholar
  8. 8.
    Samoilys MA, Squire L (1994) Preliminary observation on the spawning behavior of coral trout, Plectropomus leopardus (Pisces: Serranidae), on the Great Barrier Reef. Bull Mar Sci 54:332–342Google Scholar
  9. 9.
    Pears RJ, Choat JH, Mapstone BD, Begg GA (2007) Reproductive biology of a large, aggregation-spawning serranid, Epinephelus fuscoguttatus (Forsskål): management implication. J Fish Biol 71:795–817CrossRefGoogle Scholar
  10. 10.
    Mercier A, Ycaza RH, Hamel JF (2004) Aquaclture of the Galapagos sea cucumber, Isostichopus fuscus. In: Lovatelli A, Conand C, Purcell S, Uthicke S, Hamel JF, Mercier A (eds) Advances in sea cucumber aquaculture and management. FAO Fisheries Technical Paper No. 436, FAO, Rome, pp 347–358Google Scholar
  11. 11.
    Amesbury SS (1980) Biological studies on the coconut crab (Birgus latro) in the Mariana Islands. Univ Guam Mar Lab Techn Rep 66:39Google Scholar
  12. 12.
    Wells SM, Pyle RM, Collins NM (1983) Coconut or robber crab. In: I.U.C.N invertebrate red data book, I.U.C.N., Gland, Switzerland, p 632Google Scholar
  13. 13.
    Fletcher WJ (1993) Coconut crabs. In: Wright A, Hill L (eds) Nearshore marine resources of the south Pacific, Institute of Pacific Studies. University of the South Pacific, FFA, and ICOD, pp 643–681Google Scholar
  14. 14.
    Sato T, Yoseda K (2008) Reproductive season and female maturity size of coconut crab Birgus latro in Hatoma Island, southern part of Japan. Fish Sci 74:1277–1282CrossRefGoogle Scholar
  15. 15.
    Brown IW, Fielder DR (1991) Project overview and literature survey. In: Brown IW, Fielder DR (eds) The coconut crab: aspects of Birgus Latro biology and ecology in Vanuatu, ACIAR Monograph, vol 8, pp 1–11Google Scholar
  16. 16.
    Helfman GS (1977) Copulatory behavior of the coconut or robber crab Birgus latro (L.) (Decapoda, Anomura, Paguridea, Coenobitidae). Crustaceana 33:198–202CrossRefGoogle Scholar
  17. 17.
    Sato T, Yoseda K (2009) Egg extrusion site of coconut crab Birgus latro: direct observation of terrestrial egg extrusion. Mar Biodiver Rec 2:e37CrossRefGoogle Scholar
  18. 18.
    Matthews DC (1956) The probable method of fertilization in terrestrial hermit crabs based on comparative study of spermatophores. Pac Sci 10:303–309Google Scholar
  19. 19.
    Tudge CC (1991) Spermatophore diversity within and among the hermit crab families, Coenobitidae, Diogenidae, and Paguridae (Paguridae, Anomura, Decapoda). Biol Bull 181:238–247CrossRefGoogle Scholar
  20. 20.
    Fletcher WJ, Brown IW, Fielder DR (1990) Growth of the coconut crabs Birgus latro in Vanuatu. J Exp Mar Biol Ecol 127:245–251CrossRefGoogle Scholar
  21. 21.
    Barnes RD (1980) Invertebrate Zoology. Saunders College, Holt, Rinehart and Winston, PhiladelphiaGoogle Scholar
  22. 22.
    Sato T, Yoseda K, Abe O, Shibuno T (2008) Male maturity, number of sperm and spermatophore size relationships with male size in coconut crab Birgus latro in Hatoma Island, southern part of Japan. J Crust Biol 28:663–668CrossRefGoogle Scholar
  23. 23.
    Schiller C, Fielder DR, Brown IW, Obed A (1991) Reproduction, early life-history and recruitment. In: Brown IW, Fielder DR (eds) The coconut crab: aspects of Birgus latro biology and ecology in Vanuatu, ACIAR Monograph, vol 8, pp 13–35Google Scholar
  24. 24.
    Forward RBJ (1987) Larval release rhythms of decapod crustaceans: an overview. Bull Mar Sci 41:165–176Google Scholar
  25. 25.
    Morgan SG, Christy JH (1994) Plasticity, constraint, and optimality in reproductive timing. Ecology 75:2185–2203CrossRefGoogle Scholar
  26. 26.
    Johannes RE (1978) Reproductive strategies of coastal marine fishes in the tropics. Environ Biol Fishes 3:65–84CrossRefGoogle Scholar
  27. 27.
    Palmer JD (1995) The biological rhythms and clocks of intertidal animals. Oxford University Press, OxfordGoogle Scholar
  28. 28.
    Morgan SG (1996) Influence of tidal variations in reproductive timing. J Exp Mar Biol Ecol 206:237–251CrossRefGoogle Scholar
  29. 29.
    Skov MW, Hartnoll RG, Ruwa RK, Shunula JP, Vannini M, Cannicci S (2005) Marching to a different drummer: crabs synchronize reproduction to a 14-month lunar-tidal cycle. Ecology 86:1164–1171CrossRefGoogle Scholar

Copyright information

© The Japanese Society of Fisheries Science 2009

Authors and Affiliations

  1. 1.Ishigaki Tropical StationSeikai National Fisheries Research Institute, Fisheries Research AgencyIshigakiJapan

Personalised recommendations