Feeding and Growth of Hermissenda Crassicornis in the Laboratory
Biological factors affecting larval growth in the nudibranch mollusc Hermissenda crassicornis (Eschscholtz, 1831)
Abstract
The nudibranch mollusc Hermissenda crassicornis is used as a biomedical model for studying learning and memory. It is an eurytrophic benthic species with long-term, planktotrophic larvae, and it has been cultured in our laboratory for several years. This paper reports the effects of some dietary factors on H. crassicornis larvae that were investigated in order to establish the conditions for optimal larval growth. Of the several treatments tested, densities of 1–4 larvae ml−1, a diet of Isochrysis galbana Parke and Rhodomonas salina (Wislouch) Butcher at a 1:1 mixture, and an algal density of 10–25×103 cells ml−1 yielded the largest, healthiest larvae, that underwent metamorphosis. Both diet quantity and quality, as well as larval density, had an effect on larval growth and metamorphosis of Hermissenda crassicornis in the laboratory.
Introduction
The nudibranch mollusc Hermissenda crassicornis has been widely used as a biomedical model because of its unique characteristics for the investigation of memory, learning and other neurobiological research (see Alkon, 1983, Alkon, 1989for reviews; Alkon et al., 1993, McPhie et al., 1993). H. crassicornis is an eurytrophic benthic species that has a planktotrophic larval phase (Birkeland, 1974, McDonald and Nybakken, 1978, Harrigan and Alkon, 1978). Its geographic distribution ranges from Alaska to California, and it has also been reported in Japan, living from the intertidal zone down to about 35 m depth (McDonald, 1983). H. crassocornis, like all opisthobranchs, is hermaphroditic, with mandatory sperm exchange. Mating and production of eggs in this species have been described in detail by Rutowski (1983). The number of larvae contained in a single egg mass ranges from 7000 up to a million (Harrigan and Alkon, 1978).
The use of H. crassicornis as a model for biomedical research prompted efforts to culture it in the laboratory. Since the first attempts by Harrigan and Alkon (1978), several studies have been directed at the improvement of the larval culture system (Kuzirian et al., 1989, Tamse et al., 1990), elucidation of adult feeding preferences (Yamoah et al., 1988, Tyndale et al., 1994, Avila and Kuzirian, 1995) and improvement of yields of metamorphosed larvae (Avila et al., 1994, Avila et al., 1996). Aspects such as the best system for larval maintenance, which antibiotics to use, and the optimal light and temperature requirements for the growth of H. crassicornis larvae in the laboratory have been solved in earlier studies (Kuzirian et al., 1989Tamse et al., 1990).
Nutrition of marine invertebrate larvae has recently been reviewed by Boidron-Métairon (1995), and details of physical mechanisms involved in larval feeding have been reviewed by Hart and Strathmann (1995). Both quality and quantity of algal diets can be a limiting factor for growth and development of most planktonic larvae (e.g. Huntley and Boyd, 1984, Olson and Olson, 1989, Rumrill, 1990). Opisthobranch molluscs with long planktonic larval phases have been difficult to culture in the laboratory. Thus, little is known about their larval growth, competence and metamorphosis. Sea hares (Aplysiidae) are probably better known than any other group (Kriegstein et al., 1974, Kriegstein, 1977), but only a few nudibranch species have been studied. Larval survival and metamorphosis in the dendronotid, Tritonia diomedea, which has a planktonic larval life of about 30 days, are affected by the algae in their diet (Kempf and Willows, 1977). In another nudibranch the dorid Hypselodoris infucata, which has a planktonic life of about 18 days, both quantity and quality of algal diet affect larval growth (Hubbard, 1988). Densities higher than 5 larvae ml−1 also increased larval mortality in H. infucata. In the dorid Onchidoris bilamellata, which can extend its larval period for up to 40 days, algal quality also affects larval growth (Todd, 1981).
Harrigan and Alkon (1978)tested the effects of three diets: the combination of Isochrysis galbana Parke and Pavlova (Monochrysis) lutheri (Droop), a second mixture including these two plus Rhodomonas salina (Wislouch) Butcher, and a third diet consisting of only R. salina. They indicated that the addition of R. salina to the two-algae mixture improved the percentage of metamorphosis from 1 to 5%, with respect to the other diets. In a study of the development of Hermissenda crassicornis larvae (Williams, 1980) the larvae were fed Pavlova lutheri, Isochrysis galbana, Dunaliella tertiolecta Butcher, Chlorella clone 580, and Phaeodactylum tricornutum Bohlin, for 48–72 h. Only P. tricornutum was not readily eaten by Hermissenda crassicornis larvae. Williams (1980)suggested that as Hermissenda larvae grow, they may ingest proportionately larger particles, as shown later by Hansen (1991)for the opisthobranch Philine aperta, as well as for some bivalves (Mackie, 1969, Riisgård, 1988). On the other hand, overabundance of food over a period of 10 days stunts larval growth in H. crassicornis (Kuzirian et al., 1990).
The earlier studies of H. crassicornis were carried out either for very short periods of time, or were not clearly directed toward testing the effect of different algal diets on larval growth. We have recently shown that H. crassicornis larval life extends for at least 42 days before competence to metamorphose is achieved (Avila et al., 1996). For this reason, precise information about larval feeding and growth throughout this extended period was needed. Furthermore, no information on the effect of different larval densities in the cultures was available. Therefore, prior to the experiments reported here, it was not known whether biological factors, such as larval density, algal density or even the algal species used as a diet, had an effect on H. crassicornis growth during their larval development.
It was our aim in this study to test the following hypotheses for the aeolid nudibranch H. crassicornis: (1) larval density affects larval growth, (2) algal density affects larval growth, and (3) a combination of algal species will improve larval growth under the culture conditions currently used.
Section snippets
General procedure
H. crassicornis larvae were obtained from animals cultured in our laboratory. The egg masses were laid by individuals of Californian parentage (Sea Life Supply Co., Sand City, CA, USA), except for Experiment 7 in which animals from Oregon were also used. These specimens were collected at Port Oxford (Oregon) at 5–8 m depth. Microalgae for feeding the larvae were cultured at 17 °C following the Guillard (1975)method.
The larvae were cultured at different conditions of density and algal diets, as
The effect of larval density on larval growth
Experiment 1 showed that for two different egg masses, there was no significant difference in larval growth related to larval culture density (Fig. 1). This was true for both egg masses A and B during the entire experiment. At Day 35, larvae at densities of 1 and 2 larvae ml−1 from egg mass A had a larger size than those from the 0.5 and 4 larvae ml−1 treatments; however, this difference was not statistically significant (ANOVA, p=0.07). Common to both egg masses, the highest density (4 larvae ml−1
The effect of larval density on larval growth
There were no significant differences in larval growth at the level of 0.5–4 larvae ml−1, although the highest density cultures (4 larvae ml−1) yielded the smallest larvae in both egg masses (Fig. 1). At the highest larval density used, 15 larvae ml−1, there was a strong effect on growth and size (Fig. 2). These results suggest that there is strong competition for resources at this density. Thus, larval density is not an important factor when using low values (up to 4 larvae ml−1) for culturing H.
Acknowledgements
Dr. M.G. Hadfield, Dr. S.C. Kempf and Dr. R. Sardà gave valuable suggestions during the development of this project, for which we are very thankful. Dr. A.R. Davis and Dr. M. Slattery kindly reviewed the draft of this manuscript. Amy Moran and Bruce Miller from the University of Oregon, very kindly collected and sent us the Oregon specimens for Experiment 6. Diana Franks and Gaspar Taroncher from the Woods Hole Oceanographic Institution generously provided all the algal species other than
References (56)
-
Quantitative studies of feeding and nutrition during larval development of the coral reef asteroid Acanthaster planci (L.)
J. Exp. Mar. Biol. Ecol.
(1982)
-
The Pacific oyster Crassostrea gigas, Part I, Feeding behaviour of larvae and adults
Aquaculture
(1983)
- et al.
La croissance larvaire de Strombus gigas (Mollusque, Gastéropode) en fonction de la nourriture et de la température
Haliotis
(1987)
-
Learning in a marine snail
Science
(1983)
-
Memory storage and neural systems
Sci. Amer.
(1989)
- et al.
GABA-mediated synaptic interaction between the visual and vestibular pathways of Hermissenda
J. Neurochem.
(1993)
- et al.
Natural diets for Hermissenda crassicornis mariculture
Biol. Bull.
(1995)
- et al.
Hermissenda crassicornis larvae metamorphose in laboratory in response to artificial and natural inducers
Biol. Bull.
(1994)
- et al.
Induction of metamorphosis in Hermissenda crassicornis larvae (Mollusca: Nudibranchia) by GABA, choline and serotonin
Inv. Repr. Dev.
(1996)
- et al.
Omnivorous feeding by planktotrophic larvae of the eastern oyster Crassostrea virginica
Mar. Ecol. Prog. Ser.
(1991)
Growth and the delay of metamorphosis of the larvae of Mytilus edulis (L.)
Ophelia
(1965)
Interactions between a sea pen and seven of its predators
Ecol. Monogr.
(1974)
Culture of Mulinia lateralis and Crepidula fornicata embryos and larvae for studies on pollution effects
Thalassia Jugosl.
(1974)
Development and metamorphosis of the planktotrophic larvae of Rostanga pulchra (Mollusca: Nudibranchia)
Mar. Biol.
(1978)
Relative value of ten genera of microorganisms as foods for oyster and clam larvae
Fishery Bull. Fish. Wildl. Serv. U.S.
(1958)
Efficient grazing and utilization of the marine cyanobacterium Synechococcus sp. by the bivalve Mercenaria mercenaria
Mar. Biol.
(1994)
Feeding behaviour in larvae of the opisthobranch Philine aperta. II. Food size spectra and particle selectivity in relation to larval behaviour and morphology of the velar structures
Mar. Biol.
(1991)
Feeding behaviour in larvae of the opisthobranch Philine aperta. I. Growth and functional response at different developmental stages
Mar. Biol.
(1991)
Larval rearing, metamorphosis, growth and reproduction of the eolid nudibranch Hermissenda crassicornis (Eschscholtz, 1831) (Gastropoda, Opisthobranchia).
Biol. Bull.
(1978)
Relationship between body size of the rotifer Brachionus plicatilis and the maximum size of particles ingested
Bull. Jap. Soc. Scient. Fish.
(1980)
Larval growth and the induction of metamorphosis of a tropical sponge-eating nudibranch
J. Moll. Stud.
(1988)
Food-limited growth of marine zooplankton
Am. Nat.
(1984)
Long-lived larvae of the gastropod Aplysia juliana: Do they disperse and metamorphose or just slowly fade away?
Mar. Ecol. Progr. Ser.
(1981)
Cited by (26)
-
A feeding model of oyster larvae (Crassostrea angulata)
2015, Physiology and Behavior
If the microalgal concentration exceeds that threshold, the larva would be unable to capture all the algae that pass through the oral groove, and so k would decrease. On the other hand, an excessively high culture density of larvae would cause a more frequent collision between individuals and influence their swimming and feeding behavior [2,13], which would then influence the filtration coefficient. During larval development, the size of the oral groove does not grow proportionally with velum diameter.
-
Beauties and beasts: A portrait of sea slugs aquaculture
2013, Aquaculture
Cleanliness is the best solution to prevent this problem. Some authors use antibiotics, such as penicillin and streptomycin sulfate (Franz, 1975; Switzer-Dunlap and Hadfield, 1977), anti septic solutions (e.g. poly-iodine complex and fish-grade Trizma (Capo et al., 2009), Chloramphenicol and EDTA (Avila et al., 1997; Harrigan and Alkon, 1978; Sisson, 2005) or keeping cultures in the dark to suppress the growth of unwanted microorganisms. Several studies have already addressed the effect of initial larval density on growth, metamorphic competency and survival of sea slugs larvae (Avila et al., 1997; Capo et al., 2009; Schlesinger et al., 2009; Switzer-Dunlap and Hadfield, 1977).
Recommended articles (6)
Copyright © 1997 Elsevier Science B.V. All rights reserved.
Source: https://www.sciencedirect.com/science/article/abs/pii/S0022098197000774
Post a Comment for "Feeding and Growth of Hermissenda Crassicornis in the Laboratory"