Publication Date:
2021-05-25
Description:
Background: Trophic interactions are key processes, which determine the ecological function and performance of
organisms. Many decapod crustaceans feed on plant material as a source for essential nutrients, e.g.
polyunsaturated fatty acids. Strictly herbivorous feeding appears only occasionally in marine decapods but is
common in land crabs. To verify food preferences and to establish trophic markers, we studied the lipid and fatty
acid composition of the midgut glands of two marine crab species (Grapsus albolineatus and Percnon affine), one
semi-terrestrial species (Orisarma intermedium, formerly Sesarmops intermedius), and one terrestrial species
(Geothelphusa albogilva) from Taiwan.
Results: All species showed a wide span of total lipid levels ranging from 4 to 42% of the dry mass (%DM) in the
marine P. affine and from 3 to 25%DM in the terrestrial G. albogilva. Triacylglycerols (TAG) were the major storage
lipid compound. The fatty acids 16:0, 18:1(n-9), and 20:4(n-6) prevailed in all species. Essential fatty acids such as
20:4(n-6) originated from the diet. Terrestrial species also showed relatively high amounts of 18:2(n-6), which is a
trophic marker for vascular plants. The fatty acid compositions of the four species allow to clearly distinguish
between marine and terrestrial herbivorous feeding due to significantly different amounts of 16:0, 18:1(n-9), and
18:2(n-6).
Conclusions: Based on the fatty acid composition, marine/terrestrial herbivory indices were defined and compared
with regard to their resolution and differentiating capacity. These indices can help to reveal trophic preferences of
unexplored species, particularly in habitats of border regions like mangrove intertidal flats and estuaries.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Article
,
isiRev
Format:
application/pdf
Permalink
