Abstract:

Notes on the feeding ecology of an urban population of the bridge spider (Larinioides sclopetarius) in Duisburg, North Rhine-Westphalia. The nocturnal bridge spider (Larinioides sclopetarius) lives near water and builds large colonies of hundreds or thousands of indiviuals if sufficient habitat structure necessary for web-building and artificial light attractive to insects are available. The study deals with a large urban population of this orb-weaver living on an embankment in the inner harbour of Duisburg and gives information on the food quantity and spectrum from spring to autumn 2004. The data were evaluated by counting and determining the prey present in the sticky orb-webs. The highest prey abundance (on average 46,3 insects per 100 cm² of web surface) was found in June which coincides with the main hatching period of L. sclopetarius. The most numerous prey were aquatic insects of the taxa Chironomidae (57 %) and Ephemeroptera (38 %). Taken altogether, the bridge spiders in the inner harbour of Duisburg capture several million flying insects a year.