| Alder fly (Sialis lutaria (Linnaeus 1758)) |
|
|
Scientific name: Sialis lutaria (Linnaeus 1758) Common name: Alder fly French name: Sialis de la vase Order: Megaloptera Family: Sialidae Wingspan : 20-35 mm. Biotope: Banks of ponds and lakes with stagnant water and mud. Geographic area: Europe and Asia. Observation period : May to June. |
Sialidae are blackish brown insects which hold their wings roof-like over the abdomen when they are landed. They have a very hesitating flight and only live about two weeks in the adult stage. The wings show large cells and the upper edge of the fore wings is bordered with an alignment of square-shaped cells (less than fifteen). There are three Sialidae species in France and experts will tell you that you can only tell them apart with a close exam of the genitalia under a binocular microscope. However here is some additional information. Sialis lutaria is mainly found near stagnant or slow running water. Sialis fuliginosa is found near running water like mountain torrents. Sialis nigripes, which is rarer, is found near large rivers but also near lakes where you can also find Sialis lutaria. You can also use the colour of the costal vein, near the base. It is yellow on Sialis lutaria and dark on Sialis fuliginosa (and what about Sialis nigripes??) Sialidae lay their eggs on the vegetation near water's edge. The larvae are aquatic. They live in silt and feed on small invertebrates. |
| [To know more about the Alder fly] [Top] |
|
Sialidae have a very hesitating flight and will land on the first found support. You just need to straighten the hand. The identification of this species is not confirmed. It is only based on the location of the observation, the bank of a pond with stagnant water. I have not shot this picture with great care either. I will replace it in a more or less near future. |
André Bon April 2011
Home
Home