8 July 2009 09:45
|Already 4 years, a French team is studying aphids in the fjord. They visit all areas and
make long hours behind binoculars. Time for a visit to learn about their research.
There are two species of aphids on Spitsbergen, one feeding on Dryas octopetala, the other on Salix polaris. The French team studies the species on Dryas, which has two colour morphs: brown and green. Kongsfjorden is the northern limit of their distribution.
The aphids have parasites and even these parasites are parasitized, making a four trophic level: plant-aphid-parasite-parasite of parasite. They also discovered the first individuals of this species who was winged.
On Spitsbergen, the aphid has three generations. The first gemeration emerges from eggs directly after snow melt. The second generation is produced asexual. The third generation is a mixture of asexual and sexual reproduction.
|green aphid||winged aphid||parasitized aphid|
Parasitic wasps lay their eggs inside aphids, which are eaten from the inside by the larvae.
They showed us such a mummy, which was dead but you could see the movements of the larvae inside.
I also learned something about Dryas, the food plant. In autumn the leaves turn brown and dead, but the same leaf will become green again in the next summer. A beautiful adaptration to the harsh climate.
The team in 2009: Maurice Hullé, Jean Christophe Simon and Yannick Outreman.
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