Lek mating females away from the hotshot. A manipulative experiment using the little bustard, "Tetrax tetrax", was done to test the various lek evolution models. The experiment involved varying the size and sex ratio of leks using decoys. To test whether or not the presence of a hotshot determined lek formation, a hotshot little bustard decoy was placed within a lek. After the fake hotshot was added to the lek, both male and female visitation to the lek increased. The hotspot model considers the female density to be the catalyst for the clustering of males. This model predicts that leks will form
Xylota tarda Xylota tarda Xylota tarda is a Palearctic species of hoverfly. External images For terms see Morphology of Diptera<br> Wing length 5·5-8·5 mm. Large red areas on black abdomen. Wing membrane not infuscated. Dorso-apical white bristle on metatarsus 1. Antero-dorsal pale hairs on the basal half of femur 3 uniform not longer than 1/4 the depth of femur. The male genitalia are figured by Hippa (1968). The larva is illustrated in colour by Rotheray (1994) ). See references for determination (but see Speight for contradiction) Palearctic Fennoscandia South to Spain. Northern Italy (Apennines) Slovenia. Ireland East through Central Europe into European