MEPS 218:303-309 (2001)  -  doi:10.3354/meps218303

Larval energy metabolism and physiological variability in the Asian shore crab Hemigrapsus sanguineus

Adam G. Marsh*, Sahrye Cohen**, Charles E. Epifanio

College of Marine Studies, University of Delaware, Lewes, Delaware 19958, USA
*E-mail: **Present address: Department of Biology, Tufts University, Medford, Massachusetts 02155, USA

ABSTRACT: Larvae of the Asian shore crab Hemigrapsus sanguineus were reared in the laboratory during zoeal development (Stages I to V, ~15 d at 25°C and 30” S). Measurements of respiration rates, lactate dehydrogenase activity (LDH) and total protein content were made daily on individual larvae (n = 181) in order to assess the level of individual variance in energy metabolism during development. On average, zoeal development in H. sanguineus was estimated to require 43.8 J of metabolic energy to reach a megalope stage; however, the level of individual variance in metabolic rates resulted in a range of 23.8 to 67.9 J (~3-fold difference). LDH specific activities also evidenced a wide range in individual values during development (12 to 785 µU µg-1 protein). Although respiration rates were correlated with LDH specific activity (r2 = 0.628), it is more interesting to note the negative correlation between the variance in these measurements (r2 = 0.796), indicating a substantial degree of individual differences in metabolic activities among these larvae. At present, phenotypic variations in physiological rate processes are not considered in life-history models of larval development, which could be an important variable determining the survival and dispersal of a larval cohort.

KEY WORDS: Larvae · Physiology · Life history · Hemigrapsus sanguineus · Lactate dehydrogenase · Respiration

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