Department of Environmental and Biological Sciences

Scots pine ( Pinus sylvestris L., Pinaceae) produces a terpenoid resin which consists of monoterpenes and resin acids that offer protection against herbivores and pathogen attacks. Methyl jasmonate (MJ) is a potential plant elicitor which induces a wide range of chemical and anatomical defence reactions in conifers and might be used to increase resistance against biotic damage. Different amounts of MJ (control, 10 m  , and 100 m  ) were applied to Scots pine to examine the vigour, physiology, herbivory performance, and induction of secondary compound production in needles, bark, and xylem of 2year-old Scots pine seedlings. Growth decreased significantly in both MJ treated plants, and photosynthesis decreased in the 100 m  MJ treated plants, when compared to 10 m  MJ or control plants. The large pine weevil ( Hylobius abietis L.) (Coleoptera: Curculionidae) gnawed a significantly smaller area of stem bark in the 100 m  treated plants than in the control or 10 m  treated plants. The 100 m  MJ treatment increased the resin acid concentration in the needles and xylem but not in the bark. Furthermore, both MJ treatments increased the number of resin ducts in newly developing xylem. The changes in plant growth and chemical parameters after the MJ treatments indicate shifts in carbon allocation, but MJ also affects plant physiology and xylem development. Terpenoid resin production was tissue-specific, but generally increased after MJ treatments, which means that this compound may offer potential protection of conifers against herbivores.

When plants are exposed to ozone they exhibit changes in both primary and secondary metabolism, which may affect their interactions with herbivorous insects. Here we investigated the performance and preferences of the specialist herbivore Pieris brassicae on the wild plant Brassica nigra under elevated ozone conditions. The direct and indirect effects of ozone on the plant-herbivore system were studied. In both cases ozone exposure had a negative effect on P. brassicae development. However, in dual-choice tests larvae preferentially consumed plant material previously fumigated with the highest concentration tested, showing a lack of correlation between larval preference and performance on ozone exposed plants. Metabolomic analysis of leaf material subjected to combinations of ozone and herbivore-feeding, and focussing on known defence metabolites, indicated that P. brassicae behaviour and performance were associated with ozone-induced alterations to glucosinolate and phenolic pools.

Carabid data compiled from six independent studies, consisting of 97 799 individuals trapped by pitfalls from Finnish agricultural fields and identified to 111 species were analyzed. Shannon-Wiener H' diversity index was typically around 2.5 and expected species number rarefied to 600 trapped individuals was typically around 30 species. The five most abundant species accounted for 42% of the total catch, and the thirty most abundant species made up 98% of the total catch. Percentage similarities among the assemblages by PS-index were from 16% to 48%. In comparison to published data about carabid diversity in boreal forests, which form the dominating habitat matrix in which Finnish farmland is embedded as relatively small patches, arable fields harbor more species rich assemblages, with more even rank-abundance distributions but variable species composition. Importance of landscape (regional) level, instead of spatial level of crop fields, in understanding carabid diversity in farmland is discussed. Inclusion of carabids into monitoring schemes of agro-biodiversity at landscape level is suggested.

When plants are exposed to ozone they exhibit changes in both primary and secondary metabolism,
which may affect their interactions with herbivorous insects. Here we investigated the performance and
preferences of the specialist herbivore Pieris brassicae on the wild plant Brassica nigra under elevated
ozone conditions. The direct and indirect effects of ozone on the plant-herbivore system were studied. In
both cases ozone exposure had a negative effect on P. brassicae development. However, in dual-choice
tests larvae preferentially consumed plant material previously fumigated with the highest concentration
tested, showing a lack of correlation between larval preference and performance on ozone exposed
plants. Metabolomic analysis of leaf material subjected to combinations of ozone and herbivore-feeding,
and focussing on known defence metabolites, indicated that P. brassicae behaviour and performance
were associated with ozone-induced alterations to glucosinolate and phenolic pools.

... and subsequent performance of litter-feeding soil macrofauna Anne Kasurinen Æ Petri A. Peltonen Æ Riitta Julkunen-Tiitto Æ Elina Vapaavuori Æ Visa Nuutinen Æ Toini Holopainen Æ Jarmo K. Holopainen ... (1999) reported that wood-lice (Porcellio scaber and Oniscus asellus ...

Mycorrhizas are mostly beneficial to host plant growth and survival, e.g., due to improved water and nutrient uptake and enhanced pathogen protection, but also a significant amount of host plant carbon is allocated below-ground to support the mycorrhizal growth. These facts and on the other hand the possibility of mycorrhizas to mediate changes in above-ground defensive chemistry may affect performance of above-ground insect herbivores with different feeding guilds. To see the functionality of complex interaction between mycorrhizal status of plants, host plant chemical quality and insect herbivore performance in a wider ecological scale, studies should be conducted in field conditions and factors contributing to global climate change, such as elevated tropospheric ozone (O 3 ), should also be considered. We recently demonstrated in laboratory study, that insect herbivore response to ectomycorrhizal status of birches was dependent on the fungal species forming ectomycorrhiza and the degree of specialization and feeding guild of insects. In this addendum we provide results from the field study where silver birch (Betula pendula Roth.) seedlings were, in addition to mycorrhizal manipulation, exposed to low-level O 3 and the host plant growth and chemical quality was analysed as well as the performance of two insect herbivores with different feeding guilds was tested.

This review summarizes the main results from a 3-year open top chamber experiment, with two silver birch (Betula pendula Roth) clones (4 and 80) where impacts of 2X ambient [CO2] (EC) and [O-3] (EO) and their combination (EC + EO) were examined. Growth, physiology of the foliage and root systems, crown structure, wood properties, and biological interactions were assessed to

Climate warming is having an impact on distribution, acclimation and defence capability of plants. We compared the emission rate and composition of volatile organic compounds (VOCs) from silver birch (Betula pendula (Roth)) provenances along a latitudinal gradient in a common garden experiment over the years 2012 and 2013. Micropropagated silver birch saplings from three provenances were acquired along a gradient of 7° latitude and planted at central (Joensuu 62°N) and northern (Kolari 67°N) sites. We collected VOCs emitted by shoots and assessed levels of herbivore damage of three genotypes of each provenance on three occasions at the central site and four occasions at the northern site. In 2012, trees of all provenances growing at the central site had higher total VOC emission rates than the same provenances growing at the northern site; in 2013 the reverse was true, thus indicating a variable effect of latitude. Trees of the southern provenance had lower VOC emission rates than trees of the central and northern provenances during both sampling years. However, northward or southward translocation itself had no significant effect on the total VOC emission rates, and no clear effect on insect herbivore damage. When VOC blend composition was studied, trees of all provenances usually emitted more green leaf volatiles at the northern site and more sesquiterpenes at the central site. The monoterpene composition of emissions from trees of the central provenance was distinct from that of the other provenances. In summary, provenance translocation did not have a clear effect in the short-term on VOC emissions and herbivory was not usually intense at the lower latitude. Our data did not support the hypothesis that trees growing at lower latitudes would experience more intense herbivory, and therefore allocate resources to chemical defence in the form of inducible VOC emissions.

Some insectivorous birds orient towards insect-defoliated trees even when they do not see the foliar damage or the herbivores. There are, however, only a few studies that have examined the mechanisms behind this foraging behaviour. Previous studies suggest that birds can use olfactory foraging cues (e.g. volatile organic compounds (VOCs) emitted by defoliated plants), indirect visual cues or a combination of the two sensory cues. VOCs from insect-defoliated plants are known to attract natural enemies of herbivores, and researchers have hypothesized that VOCs could also act as olfactory foraging cues for birds. We conducted three experiments across a range of spatial scales to test this hypothesis. In each experiment, birds were presented with olfactory cues and their behavioural responses or foraging outcomes were observed. In the first experiment, two different
VOC blends, designed to simulate the volatile emissions of mountain birch (Betula pubescens ssp. czerepanovii) after defoliation by autumnal moth (Epirrita autumnata) larvae, were used in behavioural experiments in aviaries with pied flycatchers (Ficedula hypoleuca). The second experiment
was a field-based trial of bird foraging efficiency; the same VOC blends were applied to mountain birches, silver birches (B. pendula) and European white birches (B. pubescens) with plasticine larvae attached to the trees to serve as artificial prey for birds and provide a means to monitor predation rate. In the third experiment, the attractiveness of silver birch saplings defoliated by autumnal moth larvae versus intact controls was
tested with great tits (Parus major) and blue tits (Cyanistes caeruleus) in an aviary. Birds did not orient towards either artificial or real trees with VOC supplements or towards herbivore-damaged saplings when these saplings and undamaged alternatives were hidden from view. These findings do not support the hypothesis that olfactory foraging cues are necessary in the attraction of birds to herbivore-damaged trees.