MEPS 275:175-184 (2004)  -  doi:10.3354/meps275175

Effect of substrate availability and conspecific cues on communal oviposition in the apple murex snail Phyllonotus pomum

Cheryl A. Swanson1,2,*

1Department of Biological Science, Florida State University, Tallahassee, Florida 32306-1100, USA
2Present address: Florida Department of Environmental Protection, 2600 Blair Stone Road MS 6515, Tallahassee, Florida 32399-2400, USA

ABSTRACT: Communal oviposition, the sharing of a single substrate by conspecific individuals for depositing clutches of egg capsules, is common among gastropod molluscs. In soft-bottom habitats, communal oviposition may occur because of a limitation of suitable hard substrate. Conspecific cues may be responsible for aggregating females. This study examined the oviposition behavior of the apple murex snail Phyllonotus pomum in seagrass beds in St. Joseph¹s Bay, Florida. Movement patterns obtained from a mark-recapture study conducted during the 5 mo prior to egg-laying season suggest that females are capable of moving, and often move, farther than the distance at which substrate might become limiting. In field surveys, 1 to greater than 14 possible suitable substrates were available within a 4 m radius of communal oviposition events, yet females still oviposited communally. In a caged field-substrate manipulation experiment, females contributed to a single communal egg-mass even when additional substrates were available within 0.25 m. When given a choice between substrate without and with fresh egg capsules (<8 d old) in a caged field experiment, females deposited an equal number of clutches on each type of substrate. Communal oviposition in P. pomum was not mediated by substrate limitation, and previously laid conspecific egg capsules did not attract females or induce them to oviposit communally. Alternatively, there may be an adaptive advantage to communal oviposition in P. pomum. It is possible that the process of egg-laying from 1 individual attracts, aggregates and induces oviposition in neighboring females.

KEY WORDS: Substrate limitation · Oviposition · Egg-laying · Communal · Phyllonotus pomum · Muricidae · Gastropoda

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