Gunnar Bergström

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Ips typographus beetles were collected in the field, separated into eight attack phases (from beetles walking on the trunk of a tree under attack to those excavating gallery systems with a mother gallery longer than 4 cm), and immediately frozen in liquid nitrogen. 2-Methyl-3-buten-2-ol,cis- andtrans-verbenol, verbenone, myrtenol, trans-myrtanol, ipsenol,(More)
The literature is reviewed and new evidence presented that pollen produces odors, which serve multiple functions in pollination and defense. Pollen odor, which originates from pollenkitt, comprises volatiles that belong to the same chemical classes found in flower scents, that are in species-specific mixtures, and that contrast with odors of other floral(More)
Storm-fallen Scots pines with broken roots and trees with severed tops exude wound oleoresin. These trees are susceptible to bark beetles due to an injured vascular system that can not provide adequate oleoresin in order to resist new attacks by beetles [I]. Once a tree is attacked, most bark beetles use pheromone attractants to locate mates and often to(More)
The total amounts of, and proportions among, components of the aggregation pheromone produced byIps typographus were found to vary considerably among individuals excised from attacks on standing spruce trees. Chemical analyses of 392 individual male beetles were made by GC-MS. Both unmated and mated males had log-normal frequency distributions in their(More)
cause the method applied did not allow its quanti tat ive determination. The use of modif ied methods suitable for also detecting low-boiling organic compounds made it possible to obta in vertical concentrat ion profiles for this class of compounds, too. The close relationship shown by the seasonal and spatial distr ibution of both compounds, benzene and(More)
Identical chemical compounds are present in the Dufour gland secretion of female Andrena bees and in the cephalic secretion of many male Nomada bees. Females of Nomada parasitize the nests of Andrena. Many Nomada species confine their attacks to a single host species. In two such host-parasite pairs, Andrena haemorrhoa-Nomada bifida and Andrena(More)
The main component of the sex pheromone secretion of femaleDiprion pini L. (Hymenoptera: Diprionidae) from insects collected both in Finland and in France has been identified as athreo-3,7-dimethyl-2-tridecanol (8 ng per female) stereoisomer by GC-MS and synthesis. The secretion also contains lower and higher homologues in small amounts (1–4% of the main(More)
The marking behavior and the scent-marking compounds in males of two Scandinavian bumblebee species Bombus pratorum and Bombus lapidarius were studied. There are characteristic differences in the behavior and in the chemistry of the two species. Males of B. pratorum scent marked small areas of the edges of birch leaves in a quick and unpredictable manner,(More)
Six yeast strains have been isolated and identified from the spruce bark beetle,Ips typographus. We have studied the ability of the yeasts to interconvertcis-verbenol,trans-verbenol, and verbenone. (1S)-cis-Verbenol is an active component in the aggregation pheromone ofIps typographus. The isolatedCandida molischiana/ Hansenula capsulata strain can convert(More)
Six compounds previously identified from hindguts of unmated maleIps typographus (L.) during host colonization: 2-methyl-3-buten-2-ol (MB),cis-verbenol (cV),trans-verbenol (tV), myrtenol (Mt),trans-myrtanol (tM), and 2-phenylethanol (PE), were tested for their attractivity in the field with a subtractive method. The amounts of MB and cV released from a pipe(More)