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Vol. 51 No. 2, 2012
Lipid Contents and Fatty Acid Compositions of Idotea baltica and Sphaeroma serratum (Crustacea: Isopoda) as
Indicators of Food Sources
Ermelinda
Prato1,*, Antonio Danieli2, Michele Maffia2,
and Francesca Biandolino1
1CNR
– Institute for Coastal Marine Environment, Section of Taranto, Via
Roma 3, Taranto 74100, Italy
2Laboratory of General Physiology, Department of
Biological and Environmental Science and Technology. Univ. of Lecce,
Monteroni, Lecce I-73100, Italy
Ermelinda Prato, Antonio Danieli, Michele Maffia, and
Francesca Biandolino (2012) The lipid and fatty acid (FA)
compositions of Idotea baltica and Sphaeroma serratum, from Mar Piccolo basin at
Taranto (Ionian Sea), Italy, were analyzed during winter and summer to
assess their feeding habits. The 2 isopods showed strong similarities
in total lipid contents. Phospholipids (PLs) were the major lipid class
in both species, followed by triacylglycerols (TAGs). A low proportion
of energystorage lipids suggested a regular food supply. Twenty-seven
fatty acids were identified in the species studied. Unsaturated FAs
(UFAs) represented the predominant proportion in both species in the
seasons studied. Among them, monounsaturated FAs (MUFAs) showed higher
levels. Regarding FAs corresponding to the potential food of the 2
isopods studied, I. baltica
and S. serratum displayed
different FA profiles. Large amounts of 18:2n-6 and18:3n-3 were found,
especially in S. serratum
suggesting a specific selection of phytodetritus from green algae or
terrestrial material of neighboring vegetation. The FA marker for
diatoms of I. baltica
differed from that of S. serratum,
although both species showed major consumption of diatoms during
summer. Idotea baltica showed
higher levels of 22:6n-3 and 20:4n-6 in winter suggesting a preference
for dinoflagellates and macroalgae in this period. High levels of the
carnivorous marker (the 18:1n-9/18:1n-7 ratio) reflected consumption of
animal materials, especially in winter. Examination of trophic markers
indicated that I. baltica and S. serratum consumed a mixed diet,
showing that they have the ability to choose among available food
sources.
Key words: Idotea baltica, Sphaeroma serratum, Lipids, Fatty acids,
Trophic markers.
*Correspondence: E-mail:linda.prato@iamc.cnr.it
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