Sökning: "mayflies"
Visar resultat 1 - 5 av 6 avhandlingar innehållade ordet mayflies.
1. The function of seasonal habitat shifts in two congeneric mayflies in a boreal river
Sammanfattning : Unregulated North Swedish rivers show large seasonal variations in their physical characteristics. During winter the whole littoral zone freezes solid, and in spring the water flow increases rapidly and the same areas become flooded. The two mayflies Parameletus chelifer and P. minor are common in the North Swedish river Vindelälven. LÄS MER
2. Vattenfysikalisk-kemiska och bottenfaunaförhållanden i ett norrländskt vattendrag påverkat av utsläpp från sulfidmalmbrytning och anrikning
Sammanfattning : Gruvbrytnings- och anrikningsverksamheten av komplexa zink-och kopparsulfidmalmer orsakar på flera håll i Västerbottens län vattenföroreningsproblem. För att studera effekterna av utsläppen i recipienten, har undersökningar och utvärderingar gjorts av de fysikalisk-kemiska och biologiska förhållandena i Vormbäcken 1971 - 1975. LÄS MER
3. Ecology of freshwater mussels in disturbed environments
Sammanfattning : The number of species extinctions is increasing at an alarming rate. Long-lived freshwater mussels of the order Unionoida, which include a parasitic stage on a host fish, are highly threatened. Habitat degradation by turbidity and sedimentation is thought to be one major reason for their decline. LÄS MER
4. Visual ecology of insect superposition eyes
Sammanfattning : In the superposition compound eye each rhabdom (light sensitive unit) receives light through many ommatidial facets, while in the apposition compound eye every rhabdom receives light from a single facet. The superposition design increases photon capture, which is an advantage in dark environments. LÄS MER
5. Molecular phylogenetics and taxonomic issues in dragonfly systematics (Insecta: Odonata)
Sammanfattning : Dragonflies (Odonata) are one of the ancestral groups of extant insects. They represent one of the three most basal branches in the phylogeny of winged insects. The other two groups are the Ephemeroptera, mayflies, and Neoptera, the latter which covers the remaining winged insects. LÄS MER