Modern methods for managing pine (Pinus sylvestris) create homogenized forests. This decreases nature?s potential for biodiversity and might threaten species in need of different types of milieu. The main purpose of this study was to investigate how important older pine trees are for biodiversity. In the Hall-Hangvar Reserve in the north-west part of Gotland, insects collected from traps showed that more species were found in old or dead trees compared to younger pine trees.

Släktet Rosa, rosor, är en mycket populär kulturväxt med en lång historia av växtförädling. Tyvärr uppskattas de inte bara utav oss människor, utan även utav flera olika skadegörare. Ordningen steklar, Hymenoptera, innehåller flera arter som angriper rosor. Denna litteraturstudie beskriver de stekelarter som finns i Sverige, deras utbredningsområde, utseende och skadebild samt även om de angriper vissa specifika arter eller sorter utav rosor. Bekämpning utav dessa skadegörare beskrivs.

AHA is a Swedish abbreviation of "reveal threatened park and avenue trees" and is a method to assess the conservation value of individual trees, mainly in the park environments but also in natural stands. This method has previously only been practiced in southern Sweden (Sörensson 2008). To see if this method could provide satisfactory results in northern Sweden, I have studied it in areas around the Umeå River. This was done by studying the relationship between trees with different classifications of conservation value (as classed by the AHA method) and their content of species (species richness and abundance). Insects were collected using trunk window traps in a period of 13 weeks during the summer of 2014.

Delia flies (Diptera: Anthomyiidae) are economically important pests in several horticultural crops. The control is commonly relying on chemical insecticides, though there are possibilities with biological control from the natural enemies in the field. An important natural enemy is the parasitic wasp, Trybliographa rapae Westwood (Hymenoptera: Figitidae) that lays eggs in the Delia fly larvae. The parasitoid larva and the host larva have a parallel development until the host dies within its puparium and an adult parasitoid emerges. The aim of this thesis was to understand the attraction to host- and food-associated plant volatiles of T. rapae, in order to enhance the effectiveness of the parasitic wasp as a biological control agent.

24 years have passed since the Chernobyl accident when radionuclides were spread over largeareas of Europe, including the Scandinavian countries. Today, measurable activities of 137Csare still observed in many Swedish ecosystems.Ants (belonging to the order Hymenoptera) are social insects which collect organic materialfrom a large area around their nests. This study focuses on the 137Cs activity in ant nests andthe cesium accumulation in these nests. The aims were (1) to estimate the 137Cs fall-out in1986, (2) estimate the radiation exposure of ants and (3) find how 137Cs is distributed in an anthill. Seven ant hills (occupied by the species Formica polyctena) were studied near the villageof Hille, situated north of the city of Gävle in central Sweden.

Low stumps represent on their own up to 80% of the dead wood remaining on clear cuts and therefore supply suitable habitat for saproxylic insects i.e. insects depending on dead wood for their survival. Recent stump harvesting activities threaten this substrate of ecological importance and increase the anthropogenic negative impacts on these species. Because of technical and environmental reasons (nutrient leakage, erosion) guidelines for stump harvesting recommend to retain stumps standing in wet parts of clear cuts. However, stumps in wet positions might not be a satisfactory substrate for saproxylic insects and therefore might not be as much used as stumps in dry positions.