Reduced drift activity of two benthic invertebrate species is mediated by infochemicals of benthic fish
- PDF / 302,241 Bytes
- 9 Pages / 547.087 x 737.008 pts Page_size
- 75 Downloads / 151 Views
Reduced drift activity of two benthic invertebrate species is mediated by infochemicals of benthic fish Michael Scha¨ffer • Carola Winkelmann Claudia Hellmann • Ju¨rgen Benndorf
•
Received: 17 January 2012 / Accepted: 17 January 2013 / Published online: 26 January 2013 Ó Springer Science+Business Media Dordrecht 2013
C. Hellmann e-mail: [email protected]
experiments using gudgeon kairomones were conducted with the results determining significant altered activity in the presence of gudgeon kairomones for both macroinvertebrate species. B. rhodani showed reduced drift activity in the kairomone treatment compared to the kairomone-free control, with a distinct nocturnal pattern being observed for both. G. pulex shifted from a similar day/night movement pattern to a nocturnal movement pattern with decreased activity during the day. Reduce activity during the day, whilst maintaining normal activity at night would not reduce the probability of encountering a nocturnal predator under natural conditions and therefore appears to not be a meaningful anti-predator response. To assess the relevance of these findings under natural conditions, we compared the experimental results with drift measurements from field observations. These show a significant reduction in drift activity for G. pulex and slight tendencies for reduced night-time drift for B. rhodani, under seasonal variations. We conclude that the behaviour in response to the physical contact or the hydrodynamic stimuli of nocturnal predators is the most likely explanation for the differences between the results from our laboratory experiment and the field observation. We further discuss that the observed migration patterns might have different species specific consequences for density stabilisation on a population level.
J. Benndorf Institute of Hydrobiology, Technische Universita¨t Dresden, 01062 Dresden, Germany
Keywords Drift Baetis Gammarus Benthivorous fish Kairomone Streams
Abstract Regulating mobility by actively entering the drift under imminent predation risk is an avoidance strategy employed by aquatic macroinvertebrate species that is widely accepted within the scientific community. This response was most evident with respect to diurnal predators that feed in the water column, such as many salmonids. We investigated the role of the nocturnal benthivorous gudgeon [Gobio gobio (L.)] on the drift activity of two macroinvertebrate species known to display this behaviour: Baetis rhodani (PICTET) and Gammarus pulex (L.). Laboratory drift
Handling Editor: Michael T. Monaghan M. Scha¨ffer (&) Department of Aquatic Ecosystem Analysis and Management, Helmhotz Centre for Environmental Research, UFZ, Bru¨ckstr. 3a, 39114 Magdeburg, Germany e-mail: [email protected] C. Winkelmann C. Hellmann Department of Biology, Institute for Integrated Natural Sciences, University of Koblenz-Landau, Universita¨tsstr. 1, 56016 Koblenz, Germany e-mail: [email protected]
123
100
Introduction Drift behaviour of benthic invertebrates is generally
Data Loading...
