Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
1998
Abstract
The genus Bryomyia comprises altogether eight species in the Palearctic region, including one new species Bryomyia amurensis Mamaev et Økland described in the present article. A revised key to the species of Bryomyia in the Holarctic region is presented.
1997
Abstract
No abstract has been registered
Authors
Nina JohansenAbstract
Developmental time and survival of eggs, larvae, pupae and adult females of the cabbage moth, Mamestra brassicae (L.) (Lepidoptera: Noctuidae) were investigated at different temperatures within the range of 5 to 23oC. In addition, the influence of temperature during the larval period on the weight of the succeeding pupae was studied, as well as the effect of temperature on fecundity of adult females. The lower developmental thresholds (Tb) and thermal requirement (DD) were established for all developmental stages and the larval instars using linear regression analysis. Tb and DD were 8.6°C and 75 degree-days for eggs, 5.4°C and 496 degree-days for the total larval period, 7.2°C and 304 degree-days for pupae, and 5.0°C and 56 degree-days for adult females, respectively. Pupal mortality was low at all temperatures. The survival of eggs and larvae was highest at 18oC, whereas mortality was 100% at 8.5oC. Larval mortality was highest in the first instar and decreased with increasing age. Pupae gained the highest weight when the larvae were reared at 18oC, and decreased with declining temperature. Temperature had no significant effect on total fecundity or fertility. Fecundity was basically unimodal distributed at all temperatures. At low temperatures the egg deposition period was markedly prolonged.
Authors
Nina JohansenAbstract
No abstract has been registered
Abstract
The subfamily ground midges (Lestremiinae) has been poorly studied in Fennoscandia. Until quite recently (1986) only eight species of this group was known from this area. However, the number of species recorded has increased considerably the few last years. This article surveys new and old records of ground midge from Fennoscandia. The survey is based on a new material collected in 49 localities in various parts of Fennoscandia, and on records in previous publications. A list of altogether 73 species of ground midge is presented, including 25 species which are new to Finland, Norway or Sweden.
Abstract
No abstract has been registered
Abstract
No abstract has been registered
Abstract
No abstract has been registered
1996
Abstract
The diversity in different groups of obligate saproxylic beetles was related to ecological variables at three levels of spatial scale in mature spruce-dominated forest. The variables were connected to: decaying woodwood-inhabiting fungilevel of disturbancelandscape ecologyvegetational structure. Several strong relationships were found at medium (1 km2) and large scales (4 km2), while only weak relationships were found at a small scale (0.16 ha; 1ha=104m2). This may be explained by the local variations in habitat parameters and the high mobilities of many beetle species. Factors connected to decaying wood and wood-inhabiting fungi were clearly the most important factors at all scale levels. In particular, the variables diversity of dead tree parts, number of dead trees of large diameter and number of polypore fungi species increased the species richness of many groups and increased the abundance of many species. Eight species were not recorded below a certain density of decaying wood per 1 or 4 km2. Former extensive cutting was a negative factor at large scale, probably because of decreasing recolonization with increasing distance to source habitats. Thinning reduced the diversity of species associated with birch. The development of guidelines favouring the diversity of saproxylic beetles are discussed below
Abstract
In the present study the predation rate of Chrysoperla carnea (Stephens) on eggs and larvae of the lepidopterous species Mamestra brassicae (L.) was investigated including the prey"s influence on survival and development. The experiments were done at 20 +/- 1 degrees C and L:D = 16:8. C. carnea larvae were fed on eggs and first instar larvae of M. brassicae, respectively. In both cases the daily predation rate of C. carnea increased slowly during the two first instars and reached a peak in the third larval instar. During the third instar 87% and 85% of the total numbers of M. brassicae eggs and larvae, respectively, were consumed. C. carnea preyed on a mean total of 312 M. brassicae eggs and 232 M. brassicae larvae during its larval development. The mean daily predation rate of C. carnea reached a maximum of 106.6 eggs of M. brassicae and 46.1 larvae of M. brassicae. C. carnea consumed a total of 32 mg of M. brassicae eggs and 70 mg of M. brassicae larvae during its larval development. The developmental time of C. carnea fed on M. brassicae eggs and larvae was 27.4 and 21.5 days, respectively. Almost 10% of C. carnea died when reared on M. brassicae eggs and 15% died when reared on M. brassicae larvae. The quality aspect of the prey is discussed.