BackgroundThe insecticides dichlorvos, paradichlorobenzene and naphthalene have been commonly used to eradicate pest insects from natural history collections. However, it is not known how these chemicals affect the DNA of the specimens in the collections. We thus tested the effect of dichlorvos, paradichlorobenzene and naphthalene on DNA of insects (Musca domestica) by extracting and amplifying DNA from specimens exposed to insecticides in two different concentrations over increasing time intervals.ResultsThe results clearly show that dichlorvos impedes both extraction and amplification of mitochondrial and nuclear DNA after relatively short time, whereas paradichlorobenzene and naphthalene do not.ConclusionCollections treated with paradichlorobenzene and naphthalene, are better preserved concerning DNA, than those treated with dichlorvos. Non toxic pest control methods should, however, be preferred due to physical damage of specimens and putative health risks by chemicals.

The brown carpet beetle Attagenus smirnovi, Zhantiev 1973 (Coleoptera: Dermestidae) is an important pest of objects of organic origin in museums of cultural and natural history in Europe. Future climate changes are expected to lead to increasing temperatures, which will affect the pest status of this species. In the present study a laboratory investigation was conducted to elucidate the effect of temperature and humidity on the amounts of organic material consumed by larvae of A. smirnovi. In the case of new and old skin, consumption was approximately twice as high at 28 • C compared to 20 • C. Wool was consumed in the greatest amounts: 169 mg of wool was consumed in three months by 30 A. smirnovi larvae. The expected future climate changes in Scandinavia are assumed to lead to higher temperatures in museums and stores where climate is not regulated. Updated data on the present distribution of A. smirnovi in Europe show that it is widespread and common, also in regions with a climate that does not support its survival out of doors. Thus, dispersal of this pest probably only rarely occurs by flight, but usually with human activity. Due to the widespread distribution of A. smirnovi, it is likely that damages in museums and collections in Scandinavia due to this pest will increase as climate changes come into effect.

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SummaryContinuous recordings of VLF electromagnetic radiation were statistically compared with physical conditions of the atmosphere. The VLF level is closely associated with the distance to thunderstorms and therefore related to the dynamical weather processes. In agreement with previous studies, we found that the movement of the VLF sources is associated with the frontal system and especially with the passage of cold fronts. The VLF level is increased mainly by cold fronts of the anatype. The rainfall intensity is closely correlated to the electric discharge formation and thereby also to the VLF activity in the anafronts, while the katafronts often give rise to slight precipitation and few flashes of lightning. The atmospheric pressure changes accompanying the anafronts are largely correlated with the VLF level and the precipitation intensity. The mean diurnal and annual variations of the VLF level are determined by the occurrence of lightning activity. During the summer the daily trend is pronounced due to the insolation effect. The present study shows that the VLF level is determined to a high degree by fairly well defined areas with lightning discharges, which can be localized with automatic lightning location systems or forecasted by the weather services.