Aj. Alverson et Gw. Courtney, Niche overlap of sympatric Blepharicera larvae (Diptera : Blephariceridae)from the southern Appalachian Mountains, J N AMER BE, 20(4), 2001, pp. 564-581
Citations number
65
Categorie Soggetti
Aquatic Sciences
Journal title
JOURNAL OF THE NORTH AMERICAN BENTHOLOGICAL SOCIETY
The southern Appalachian Mountains are home to the greatest diversity of Bl
ephariceridae (Diptera) in North America, with 13 Blepharicera Macquart spe
cies inhabiting the region. Sympatric Blepharicera species seem to occupy a
common ecological niche, in contradiction to the competitive exclusion pri
nciple. Instar IV Blepharicera larvae were studied to determine whether die
tary differences facilitate coexistence of sympatric species. Diatom assemb
lages of Blepharicera diets, total diatom biovolume ingested, and similarit
y between diatom assemblages of larval diets and the forage base were exami
ned. Dietary characteristics were compared among Blepharicera species withi
n and between discrete microhabitats at 3 sites in southern Appalachia. Dat
a showed broad dietary overlap among species that co-occurred in the same m
icrohabitat and strong microhabitat effects on larval dietary assemblages.
In addition, several species ingested disproportionately greater biovolumes
of small, adnate and prostrate diatom species compared to their availabili
ty on the substratum. Sympatric Blepharicera species may not partition food
resources where spatial overlap is most acute.