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Intraguild predation and interference competition on the endangered dragonfly Aeshna viridis
Erna Suutari1, Markus J Rantala, Jukka Salmela
1Department of Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, 40014, Jyväskylä, Finland. ermasuut@bytl.jyu.fi
Oecologia
|April 21, 2004
Summary
Intraguild predation and interference competition negatively impact endangered Aeshna viridis dragonfly larvae. These interactions, especially with Aeshna grandis, restrict their microhabitat use in Stratiotes aloides plants.
Area of Science:
- Ecology
- Conservation Biology
- Entomology
Background:
- The endangered dragonfly Aeshna viridis faces population decline in Europe due to habitat loss, specifically the reduction of Stratiotes aloides.
- Stratiotes aloides provides essential oviposition sites and protection from fish predation for A. viridis larvae.
- A. viridis larvae coexist with larvae of Aeshna grandis and Aeshna juncea in European lakes.
Purpose of the Study:
- To investigate the effects of intraguild predation (IGP) and interference competition on A. viridis larvae.
- To assess the susceptibility of A. viridis larvae to predation by similar-sized A. grandis and A. juncea larvae.
- To determine how interference competition influences the spatial distribution of A. viridis within Stratiotes aloides rosettes.
Main Methods:
- Laboratory predation experiments were conducted to test IGP susceptibility.
- Microhabitat use of A. viridis and A. grandis larvae was studied in controlled laboratory settings.
- The spatial distribution of A. viridis within Stratiotes aloides rosettes was observed under varying competitive conditions.
Main Results:
- A. viridis larvae are vulnerable to intraguild predation by similar-sized A. grandis and A. juncea larvae under laboratory conditions.
- Interference competition with A. grandis larvae led to A. viridis larvae being restricted to the inner parts of Stratiotes aloides rosettes.
- In the absence of A. grandis, A. viridis larvae utilized the middle and outer portions of the rosettes, indicating altered microhabitat use due to competition.
Conclusions:
- Asymmetric intraguild predation among similarly sized odonate larvae can be intense.
- Both intraguild predation and interference competition significantly affect A. viridis larvae.
- While habitat complexity may mitigate these effects in nature, these interactions can still influence the distribution and microhabitat selection of A. viridis in Stratiotes aloides habitats.
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