Slowest of the slow: latitudinal insensitivity of burrowing capacity in the bivalve Laternula
- 149 Downloads
Low temperature limits the rate of biochemical reactions and aerobic scopes of cold water ectotherms. To compensate for this limiting effect, animals living in cold environments often possess physiological or morphological adaptations to maintain vital functions. Cross-latitudinal comparison of aerobic capacities is one method to test which factors constrain activity in thermally distinct environments particularly when congeneric studies are carried out on related species with conservative ecology and habitat. Burrowing is a major aerobic activity of bivalve molluscs that is described here for the first time for the tropical mangrove species Laternula truncata and Laternula boschasina and then compared with their Antarctic congener Laternula elliptica. About 80% of L. truncata (16.3–46.1 mm shell length) and 63% of L. boschasina (11.3–27.7 mm shell length) buried within 24 h at 28°C. The burrowing rate index (BRI = [3√wet weight/time to bury]×104) ranged between 1.1 and 20.2 for L. boschasina and 1.1–32.9 for L. truncata. These values are 2–3 orders of magnitude less than other tropical bivalve molluscs and are amongst the lowest recorded for any bivalve. Comparisons with the Antarctic L. elliptica showed little or no differences in BRI (Q10 of 1.0–1.2 for specimens of the same size). This is contrary to the general pattern over a wide range of bivalves, where BRI increases with a Q10 of between 2.9 and 6.4 between high latitudes and the equator. L. elliptica has 25–30% longer relative foot length than tropical congeners of the same size, which could be a morphological adaptation compensating for reduced burrowing speeds in a colder environment. Burrowing rates within the genus Laternula could, however, also be maintained by differing habitat, ecological and physiological constraints on burrowing capability.
KeywordsBivalve Shell Length Temperature Compensation Mitochondrial Density Aerobic Scope
We thank the staff of Biodiversity Centre and Sungei Buloh Wetland Reserve, National Parks Board, Singapore for facilitating this project. S.A.M was funded by Antarctic Funding Initiative grant 2/34 awarded to L.S.P. The studies undertaken comply with the laws of UK and Singapore. Two anonymous reviewers provided comments which greatly improved this manuscript.
- Ansell AD (1983) Species of Donax from Hong Kong: morphology, distribution, behaviour and metabolism. In: Morton B, Dudgeon D (eds) Proceedings of the Second International Workshop on the Malacofauna of Hong Kong and Southern China, B. Hong Kong University Press, Hong Kong, pp 19–47Google Scholar
- Ansell AD, Trueman ER (1967) Burrowing in Mercenaria mercenaria (L.) (Bivalvia, Veneridae). J Exp Biol 46:105–115Google Scholar
- Clarke A (1983) Life in cold water: the physiological ecology of polar marine ectotherms. Oceanogr Mar Biol 21:341–453Google Scholar
- Harper E, Peck LS (2003) Feeding characteristics and metabolic costs in the Antarctic muricid gastropod Trophon longstaffi. Polar Biol 26:208–217Google Scholar
- Morton B (1976) The structure, mode of operation and variation in form of the shell of the Laternulidae (Bivalvia: Anomalodesmata: Pandoracea). J Molluscan Stud 42:261–278Google Scholar
- Quayle DB (1949) Movements in Venerupis (=Paphia) pullastra (Montagu). Proc Malac Soc Lond 28:31–37Google Scholar
- Stanley SM (1970) Shell form and life habits in the Bivalvia (Mollusca). Geol Soc Am Mem 125:1–296Google Scholar
- Tan KS, Oh TM (2002) Feeding habits of Chicoreus capucinus (Neogastropoda: Muricidae) in a Singapore mangrove. Boll Malacol Suppl 4:43–50Google Scholar
- Trueman ER, Ansell AD (1969) The mechanisms of burrowing into soft substrata by marine animals. Ocenogr Mar Biol Ann Rev 7:315–366Google Scholar
- Trueman ER, Brand AR, Davis P (1966) The dynamics of burrowing in some common littoral bivalves. Proc Malac Soc Lond 37:97–109Google Scholar