CONOR and CONOR: BEHAVIOR IN LARVAL PORCELLANID CRABS 



when the structures used first resemble those 

 of the adult, but before the adult mode of life 

 is adopted. Attempted swimming by abdominal 

 clapping is an example of the development of an 

 adult behavior pattern before the adult structure 

 is completed. Megalopae of these four species 

 clean the body with the fifth legs in the adult 

 manner, a feature also observed for other por- 

 cellanid megalopae by Lebour (1943) and 

 Knight (1966). 



At the molt to megalopa there is an abrupt 

 change from carnivorous to a filter-feeding, 

 herbivorous habit. As Nicol (1932) first noted, 

 adult Porcellanidae are specialized for filter feed- 

 ing on suspended material. Adults of the two 

 Petrolisthes species studied here will also some- 

 times accept pieces of mussel as food, but the two 

 Pachycheles species will not. The observations 

 on the megalopae of these species and those of 

 Lebour on Porcellana species, indicate that the 

 acquisition of morphological and behavioral 

 adaptations to filter feeding in the Porcellanidae 

 involve both the adult and megalopa stages. 

 Although many other anomuran adults feed on 

 particulate material by some mode of filter feed- 

 ing, it is not known whether this also involves 

 the late larval stages. No information could be 

 found in the literature on feeding by their post- 

 zoeal stages. In hermit crabs, which are more 

 generalized detrital-feeding Anomura, both zoea 

 and postzoeal stages can be reared on Artemia 

 nauplii, as found for example by Provenzano 

 (1962). 



Since population and species success depends 

 upon the megalopae locating a suitable adult 

 habitat, settling behavior is a critical part of 

 later larval development. Settling behavior of 

 barnacles, bryozoa, and some other forms has 

 been studied; however, similar settling behavior 

 in decapod Crustacea has not been studied, with 

 the exception of shell selection by the glaucothoe 

 stage of hermit crabs (Reese, 1962; Hazlett, 

 1971) and the coconut crab Birgus latro (Reese, 

 1968). For the megalopae studied here, the 

 behavioral sequence of the true planktonic pe- 

 riod, the settling and swimming period, and the 

 period of final settlement seems to be highly spe- 

 cialized for substrate selection. Possession of this 

 behavioral mechanism would permit, under na- 



tural conditions of turbulent water movement, 

 older megalopae to select or reject substrates 

 encountered by random contact. No information 

 is available on how settled megalopae reach the 

 final adult habitat after initial settlement, , but 

 postsettling megalopae and very young juveniles 

 have been found clinging to the base of surf 

 grass and under stones with adults. 



LITERATURE CITED 



FoxoN, G. E. H. 



1934. Notes on the swimming methods and habits 

 of certain crustacean larvae. J. Mar. Biol. Assoc. 

 U.K., New Ser. 19:829-849. 

 GONOR, S. L., AND J. J. GONOR. 



1973. Descriptions of the larvae of four North 

 Pacific Porcellanidae (Crustacea: Anomura). 

 Fishery Bull., U.S. 71: 

 Gore, R. H. 



1968. The larval development of the commensal 

 crab Polyonyx gibbesi Haig, 1956 (Crustacea: 

 Decapoda). Biol. Bull. (Woods Hole) 135:111- 

 129. 

 Greenwood, J. G. 



1965. The larval development of Petrolisthes elon- 

 gatiLS (H. Milne Edwards) and Petrolisthes 

 novaezelandiae Filhol (Anomura, Porcellanidae) 

 with notes on breeding. Crustaceana 8:285-307. 



GURNEY, R. 



1942. Larvae of decapod Crustacea. Ray Soc. 

 (Lond.) Publ. 129, 306 p. 



Haig, J. 



1960. The Porcellanidae of the eastern Pacific 

 (Crustacea Anomura). Allan Hancock Pac. Ex- 

 ped. 24, 440 p. 

 Hazlett, B. A. 



1971. Influence of rearing conditions on initial 

 shell entering behavior of a hermit crab (Deca- 

 poda, Paguridae). Crustaceana 20:167-170, 

 Knight, M. D. 



1966. The larval development of Polyonyx quad- 

 riungulatus Glassell and Pachycheles rudis Stimp- 

 son (Decapoda, Porcellanidae) cultured in the 

 laboratory. Crustaceana 10:75-97. 



Knudsen, J. W. 



1960. Reproduction, life history and larval ecology 

 of the California Xanthidae, the pebble crabs. 

 Pac. Sci. 14:3-17. 

 1964. Observations of the reproductive cycles and 

 ecology of the common Brachyura and crablike 

 Anomura of Puget Sound, Washington. Pac. Sci. 

 18:3-33. 

 Lebour, M. V. 



1943. The larvae of the genus Porcellana (Crusta- 

 cea Decapoda) and related forms. J. Marine Biol. 

 Assoc. U.K. 25:721-737. 



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