Niche and life-history differences in five highly sympatric species of Trithemis dragonflies (Odonata: Libellulidae)
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Date
1995
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Abstract
Niche and life-history differences in five species of Trithemis were investigated
to determine the extent of interspecific competition. Interspecific competition
was mostly avoided because species favoured different habitats and
microhabitats. There was the possibility of competition between larvae under
conditions of lowered food concentration, where they occurred in the same
habitat and microhabitat. Larvae of different species preferred specific prey taxa,
but chose to feed on a different prey taxon once it was more readily available.
Because species were restricted more by food size than taxon, competition for
food was unlikely. Interspecific competition may have occurred between adults
because the niche breadth of some species became contracted as the density of
other species increased. Interspecific competition among larvae was unlikely
because individuals of different sizes were present together, allowing for food
partitioning. Asynchronous development therefore ensured that competition for
food of the same size was reduced. Competition was also reduced by species
showing peaks in abundance at different times of the year.
Description
Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1995.
Keywords
Dragonflies--Ecology., Dragonflies--KwaZulu-Natal--Pietermaritzburg., Trithemis., Competition (Biology), Theses--Entomology.