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Vol. 52, 2013
Feeding spectra of bivalve mollusks Unio and Dreissena from Kanevskoe Reservoir,
Ukraine: are they food competitors or not?
Olesia
N Makhutova1*, Alexander A Protasov2, Michail I
Gladyshev1,3, Anzhelika A Sylaieva2, Nadezhda N
Sushchik1,3, Irina A Morozovskaya2 and Galina S
Kalachova1
1Institute
of Biophysics of Siberian Branch of Russian Academy of Science,
Akademgorodok, Krasnoyarsk 660036, Russia
2Institute of Hydrobiology, National Academy of
Sciences of Ukraine, pr. Geroyev Stalingrada 12, Kiev 04210, Ukraine
3Siberian Federal University, Svobodny av. 79,
Krasnoyarsk 660041, Russia
Abstract
Background: One of the most
abundant freshwater invaders is Dreissena
polymorpha which provide
wide-ranging direct and indirect impacts on the invaded ecosystems. A
particularly notable impact on benthic communities is the extinction of
native mollusks of the order Unionida. However, the settlement of D. polymorpha on unionid's shells
in Kanevskoe Reservoir did not increase native unionid mortality. Since
the reason for the successful coexistence of native unionids and
invading dreissenids in Kanevskoe Reservoir is unknown, we hypothesized
that these mollusks have different feeding spectra. To evaluate this
hypothesis, we compared feeding spectra of the mollusks using a fatty
acid (FA) marker analysis.
Results: Significant differences in the number and
percentages of FAs were found among the mollusks and theirfood sources,
seston, and sediments. Analyses of FA trophic markers in mollusk
tissues showed that U. tumidus
and Dreissena species mainly
consumed algae (greens, diatoms, and dinoflagellates), cyanobacteria,
and detritus particles enriched with bacteria. According to the
multivariate statistical analysis, the mollusks had different feeding
spectra: Dreissena species
fed on planktonic sources, while U.
tumidus mostly consumed food sources of benthic origin, mainly
detritus. In addition, U. tumidus
and Dreissena species
differed in percentages of long-chain polyunsaturated FAs of n-3 and
n-6 families and specific FAs which they could synthesize (20:1n-13 and
22:3 Δ7,13,16).
Conclusions: U. tumidus and Dreissena species obviously
obtained foods of different qualities. Dreissena consumed plankton
species, i.e., more-valuable food, while U. tumidus fed on detritus and
phytobenthic species which were of a lower food quality in terms of
levels of physiologically important eicosapentaenoic and
docosahexaenoic fatty acids. We concluded that the different feeding
spectra of mollusks and adaptations of U. tumidus, the synthesis of
specific FAs, might be the basis for the successful coexistence of
native species and invaders for a long time.
Key words: Invertebrates; Fatty acids; Ration;
Invader.
*Correspondence: E-mail: makhutova@ibp.krasn.ru
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