Volvatella pyriformis
Pease, 1868

Superfamily: OXYNOOIDEA
Family: Volvatellidae


Pease (1868): Plate 7, figure 5. Volvatella pyriformis. Drawn by A.J.Garrett.

According to Edwin Cruz-Rivero [see message] V. pyriformis is a specialist feeder on Caulerpa sertularioides

Originally reported from Huaheine [Tahiti Ids]. I have copied below the original description from Pease (1868) based on notes and illustrations from Andrew Garrett:
"Animal uniform pale orange; as seen through the shell, freckled with red, which assumes transverse bands. Head subquadrate, slightly emarginate in front and provided with small lateral crests. Eyes black, inserted in a fissure on the side of the head. Foot oblong, truncated and widest in front, and gradually tapering to a rounded tip behind. Motions active; when disturbed discharging a viscid white fluid from the vent. Descriptions of the shells of this genus cannot be relied on for the reason of the distorted change that takes place soon after they are removed from the animal and become dry. The shell resembles that of Lophocerus vigourouxii, Montr."

• Pease, W.H. (1868). Descriptions of marine Gasteropodae, inhabiting Polynesia. American Journal of Conchology, 4(2): 71-80, Pls. 7-10.

Authorship details
Rudman, W.B., 2000 (May 27) Volvatella pyriformis Pease, 1868. [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/volvpyri

Related messages

Re: Feeding ecology of Volvatella

May 31, 2000
From: Kathe R. Jensen

Dear Edwin & Bill,

Concerning Edwin's inquiry I'll be happy to supply whatever info I can. Volvatella is one of the poorest studied sacoglossan genera as far as ecology and biology goes - because usually only 2-3 specimens are found at any one time. Now that you are so lucky as to have recurring recruitments in Guam, you should certainly take the opportunity. I will list some of my papers containing observations on feeding, spawning and copulation in some species of Volvatella. However, it would be very interesting to have some experimental data on these processes.

For reproduction and development, I don't think anything is known for V. pyriformis. So you could start with describing the shape of the egg masses, counting the number of eggs contained, measuring the diameters of uncleaved eggs and egg capsules (surrounding individual eggs), recording the time from deposition to hatching (and if possible of various developmental stages in between). It should also be possible to determine the type of development (planktotrophic, lecithotrophic or encapsulated). If your supply of animals is big enough, you could try to identify minimum size for spawning and total number of egg masses produced over the reproductive period.

For feeding ecology: You are probably aware that all shelled sacoglossans feed exclusively on species of Caulerpa, but whether there is any species specific preference has never been experimentally studied. I have a hunch that "green" species (i.e. with digestive gland tubules in the mantle fold) are more species specific in their diet choice than are the "white" species. But I have never been in a situation where I had enough animals to do the experiments. There have also been claims in the literature that Volvatella feeds preferentially on the rhizoids of Caulerpa. Again this has never been corroborated by experiments. It would also be interesting to see if there is a difference in feeding activity in the light and in the dark (i.e. a possible preference for actively photosynthesizing algae or parts of the alga).

For biochemistry: As far as I know, no species of Volvatella has been included in the studies of bioactive chemicals. If you do decide to study this, please look for both diet-derived and de novo synthesized substances. Most studies deal with only one of these types.

• Jensen, K.R. 1997. Sacoglossa (Mollusca, Opisthobranchia) from the Darwin Harbour Area, Northern Territory, Australia. Pp. 163-186 in: The Marine Flora and Fauna of Darwin Harbour, Northern Australia.
• Jensen, K.R. 1997. Sacoglossa (Mollusca, Opisthobranchia) from the Houtman Abrolhos Islands and central Western Australia. Pp. 307-333 in: The Marine Flora and Fauna of the Houtman Abrolhos Islands, Western Australia, Vol. 2.

Good luck with your studies,


Jensen, K.R., 2000 (May 31) Re: Feeding ecology of Volvatella. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/2476

Feeding ecology of Volvatella

May 28, 2000
From: Edwin Cruz-Rivera

Hello all,
I am looking for information on the genus Volvatella. In particular, I am interested in papers dealing with feeding preferences of different species, reproductive biology (reproductive anatomy included), and chemical ecology of the critters. I am aware of only one paper on this last subject done by Cimino's group in Italy, and published in 1999.

In Guam, some species of Volvatella recruit in large numbers ever so often, but I have not found any articles documenting this here or elsewhere. I am currently working on some aspects of the feeding and chemical ecology of V. pyriformis (a specialist on Caulerpa sertularioides)and would greatly appreciate information on this or other related species. Your input is most valuable.



University of Guam Marine Laboratory
UOG Station
Mangilao, GU 96923


Cruz-Rivera, E., 2000 (May 28) Feeding ecology of Volvatella. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/2460

Dear Edwin,
I have listed below some references which get you into the literature. I am sure there is also relevant literature on the similarly shelled Oxynoe as well. I am sure Kathe Jensen and Cynthia Trowbridge should be able to suggest more.

Any background natural history information on Volvatella in Guam, and if possible, photos of it and its food would be very welcome.

Best wishes,
Bill Rudman.

• Clark, K.B. & Busacca, M (1978) Feeding specificity and chloroplast retention in four tropical ascoglossa, with a discussion of the extent of chloroplast symbiosis and the evolution of the order. J. Moll. Stud. 44: 272-282,Figs1-3.
• Clark, K.B. & DeFreese, D. (1987) Population ecology of Caribbean ascoglossa (Mollusca: Opisthobranchia): a study of specialized algal herbivores. Am. Malacol. Union Bull. 5(2): 259-280.
• Jensen, K.R. & Wells, F.E. (1990) Sacoglossa (= Ascoglossa) (Mollusca, Opisthobranchia) from southern Western Australia. In: Wells, F.E., Walker, D.I., Kirkman, H. & Lethbridge, R. Proceedings of the Third International Marine Biological Workshop: The Marine Flora and Fauna of Albany, Western Australia. Western Australian Museum, Perth, Vol. 1: 297-331.
• Jensen, K.R. (1981) Observations on feeding methods in some Florida ascoglossans. J. Moll. Stud. 47: 190-199.
• Jensen, K.R. (1983) Factors affecting feeding selectivity in herbivorous ascoglossa (Mollusca: Opisthobranchia). J. Exp. Mar. Biol. Ecol., 66: 135-148.
• Jensen, K.R. (1992): Evolution of buccal apparatus and diet radiation in the Sacoglossa (Opisthobranchia). Abstracts, 11th International Malacological Congress, Siena 1992: 280-281.
• Thompson,T.E. (1979) Biology and relationships of the South African sacoglossan mollusc Volvatella laguncula. Journal of Zoology, London, 189(3): 339-347
• Trowbridge, C.D. (1991) Group membership facilitates feeding of the herbivorous sea slug Placida dendritica. Ecology, 72(6): 2193-2203.
• Trowbridge, C.D. (1992) Mesoherbivory: the ascoglossan sea slug Placida dendritica may contribute to the restricted distribution of its algal host. Mar. Ecol. Prog. Ser. 83(16 July): 207-220.
• Trowbridge, C.D. (1993) Local and regional abundance patterns of the Ascoglossan (=Sacoglossan) Opisthobranch Alderia modesta (Loven, 1844) in the Northeastern Pacific. The Veliger 36(4): 303-310.
• Trowbridge, C.D. (1994) Defensive Responses and palatability of specialist herbivores: predation on NE Pacific ascoglossan gastropods. Mar. Ecol. Prog. Ser. 105: 61-70.
• Jensen, K.R. (1994) Behavioural adaptations and diet specificity of sacoglossan opisthobranchs. Ethology, Ecology & Evolution, 6: 87-101.
• Gavagnin, M; Marin, A; Castelluccio, F; Villani, G; Cimino, G (1994) Defensive realtionships between Caulerpa prolifera and its shelled sacoglossan predators. J. Exp. Mar. Biol. Ecol., 175: 197-210.

Rudman, W.B., 2000 (May 28). Comment on Feeding ecology of Volvatella by Edwin Cruz-Rivera. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/2460