Sustained effects of larval blackfly settlement on further substrate colonisers
Kiel, E.; Böge, F.; Rühm, W.
Archiv für Hydrobiologie Volume 141 Number 2 (1998), p. 153 - 166
published: Feb 19, 1998
ArtNo. ESP141014102007, Price: 29.00 €
Artificial substrates and histological staining procedures have been used to study interference effects among blackfly larvae. Colonising larvae apply silk to the substratum to attach themselves for filter feeding, locomotion or pupation. We have hypothesised that species might react differently to alterations of the substratum caused by the silk of previously colonisers and have therefore compared Simulium noelleri Friederichs and Simulium vernum Macquart, which are characteristic of different habitats. The number of larval colonisers and the number and position of their silk pads on previously colonised and new control substrates were recorded after 24 h of exposure in streams. The results support our hypothesis that blackfly species react to surface properties differently and are thus affected differently by previous colonisers. Whereas S. noelleri seems to prefer previously colonised substrates or, at least, is not negatively affected by silk remnants on the surfaces, S. vernum appears to avoid areas covered by the silk of other larvae. We conclude that interference caused by silk remnants and species-specific differences in tolerance concerning surface properties affect simuliid density, distribution and colonisation dynamics.