The pollen beetle is the most important pest in Danish oilseed rape fields. In 2001, we screened a broad range of pollen beetle populations for pyrethroid and dimethoate resistance. A standard dip-test was used to test insecticide resistance in 18 populations collected from oilseed winter and spring rape fields. The beetles were treated with four different insecticides: the pyrethroids tau-fluvalinate, lambda-cyhalothrin and esfenvalerate, and the organophosphate dimethoate. The results show that up to 99% of the pollen beetles survived Danish standard doses of pyrethroids and up to 36% of the beetles survived standard doses of dimethoate.

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The pollen beetle is the most important pest in Danish oilseed rape crops and it is essential that farmers are able to control this pest, especially in years when the economic damage threshold will be exceeded. About seven years ago, Danish oilseed rape growers began reporting that the pyrethroids seemed to be losing effectiveness towards pollen beetles. In 2001 18 populations collected from winter and spring oilseed rape fields were tested and very high level of insecticide resistance was found. In 2003 100 populations of pollen beetles were tested, using a FAO dip‐test, for resistance to fenitrothion, lambda‐cyhalothrin and tau‐fluvalinate. It can be concluded that many Danish populations of pollen beetles are resistant to the pyrethroid lambda‐cyhalothrin and to a lesser extent to the pyrethroid tau‐fluvalinate. No resistance to the organophosphate fenitrothion was found.

Background: Knowledge of spatiotemporal migration patterns is important for our understanding of migration ecology and ultimately conservation of migratory species. We studied the annual migration schedules of European nightjar, a large nocturnal insectivore and compared it with two other larger migratory insectivores, common swift and common cuckoo. All species breed in North Europe and winter in sub-Saharan Africa, but estimating their spatiotemporal non-breeding distributions from observations is complicated by the occurrence of similar local African species. We used geolocators to track the annual migrations of nightjars and swifts and compared these with satellite tracking of cuckoo migration.Results: Individuals of the three species migrated to wintering grounds centered in Central Africa, except some common swifts that remained in West Africa, crossing or circumventing the Sahara along different routes in spring and fall. Overall, all species showed similar regional and seasonal use of several stopover areas during migration. Among the three species, European nightjars and common cuckoos showed the most similar spatiotemporal migration patterns. The nightjars wintered in SW Central Africa and breeding and wintering made up by far the two longest stationary periods. Swifts were generally more mobile, and some individuals progressively visited areas further east in East Africa during winter and further west in West Africa on spring migration; this species also spent less time on stopovers, but more on wintering areas. Cuckoos were intermediate in their extent of movements. The speed of nightjar spring migration was equal to that of fall migration, in contrast to the two other species where spring return to breeding areas was faster. Conclusions: Ecological requirements are potentially useful for understanding spatiotemporal migration patterns and causes of declines in migratory species.