Brommer, J. E. 2004: The range margins of northern birds shift polewards. — Ann. Zool. Fennici 41: 391–397.
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Prinzing, A., Lentzsch, P., Voigt, F. & Woas, S. 2004: Habitat stratification stratifies a local population: ecomorphological evidence from a bisexual, mobile invertebrate (Carabodes labyrinthicus; Acari). — Ann. Zool. Fennici 41: 399–412.
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Pakkasmaa, S. & Laurila, A. 2004: Are the effects of kinship modified by environmental conditions in Rana temporaria tadpoles? — Ann. Zool. Fennici 41: 413–420.
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Heiling, A. M. & Herberstein, M. E. 2004: Floral quality signals lure pollinators and their predators. — Ann. Zool. Fennici 41: 421–428.
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Punttila, P., Niemelä, P. & Karhu, K. 2004: The impact of wood ants (Hymenoptera: Formicidae) on the structure of invertebrate community on mountain birch (Betula pubescens ssp. czerepanovii). — Ann. Zool. Fennici 41: 429–446.
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Päivinen, J., Ahlroth, P., Kaitala, V. & Suhonen, J. 2004: Species richness, abundance and distribution of myrmecophilous beetles in nests of Formica aquilonia ants. — Ann. Zool. Fennici 41: 447–454.
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Pickerell, T., McConnell, S. J. & Skibinski, D. O. F. 2004: Isolation and characterisation of three microsatellite loci from the Chilean scallop Argopecten purpuratus. — Ann. Zool. Fennici 41: 455–457.
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Brommer, J. E. 2004: The range margins of northern birds shift polewards. — Ann. Zool. Fennici 41: 391–397.
The changes in range margins of birds breeding in Finland was analysed from published atlas data for a 12-year period (1974–1979 to 1986–1989). The change in range margin was statistically corrected for changes in species' distribution using linear regression. For species predominantly occurring in southern Finland (n = 116), the expected range margin shift, if their distribution would not have changed, was 18.8 km northwards. Northerly species (n = 34) showed no such significant range margin shift. A similar result was found earlier for UK birds. Recent range margin shifts in birds therefore seem to be a general phenomenon, which may be related to climate change.
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Prinzing, A., Lentzsch, P., Voigt, F. & Woas, S. 2004: Habitat stratification stratifies a local population: ecomorphological evidence from a bisexual, mobile invertebrate (Carabodes labyrinthicus; Acari). — Ann. Zool. Fennici 41: 399–412. Back to the top
Pakkasmaa, S. & Laurila, A. 2004: Are the effects of kinship modified by environmental conditions in Rana temporaria tadpoles? — Ann. Zool. Fennici 41: 413–420. Back to the top
Heiling, A. M. & Herberstein, M. E. 2004: Floral quality signals lure pollinators and their predators. — Ann. Zool. Fennici 41: 421–428. Back to the top
Punttila, P., Niemelä, P. & Karhu, K. 2004: The impact of wood ants (Hymenoptera: Formicidae) on the structure of invertebrate community on mountain birch (Betula pubescens ssp. czerepanovii). — Ann. Zool. Fennici 41: 429–446. Back to the top
Päivinen, J., Ahlroth, P., Kaitala, V. & Suhonen, J. 2004: Species richness, abundance and distribution of myrmecophilous beetles in nests of Formica aquilonia ants. — Ann. Zool. Fennici 41: 447–454. Back to the top
Pickerell, T., McConnell, S. J. & Skibinski, D. O. F. 2004: Isolation and characterisation of three microsatellite loci from the Chilean scallop Argopecten purpuratus. — Ann. Zool. Fennici 41: 455–457.
We present preliminary evidence that local populations may be differentiated among habitat strata also in mobile, sexually reproducing invertebrates. We considered Carabodes labyrinthicus, an oribatid mite species, sampled from the endogeic (below litter layer) and the epigeic stratum in a forest. We found that the endogeion was used by only a few females. Most interestingly, endogeic and epigeic males differed with respect to physiologically relevant traits such as body volume and sensillus shape. Supplementary genetic investigations corroborated this differentiation between strata. Non-parametric tests, jackknife and bootstrap resampling consistently confirmed our findings; indicating that highly robust patterns can be detected even from small samples such as ours. Finally, we found that epigeic males showed a distinctly bimodal distribution of morphology, where one of the two peaks matched the unimodal distribution of endogeic males. We conclude that the population investigated may be gradually differentiated between stratum specialists that are restricted to the epigeion, and stratum generalists.
Kin selection theory predicts that organisms should behave favourably toward their relatives, if the benefits of such behaviour, devaluated by relatedness, are larger than its costs. Under good environmental conditions, the costs of kin-biased behaviour are likely to be low, and kin-biased behaviour may lead to better average performance of related than non-related individuals. However, under poor environmental conditions, individuals should maximise their own fitness, and costly altruistic behaviour should be disfavoured. Consequently, certain environmental conditions could select for kin-biased behaviour. We tested these predictions in a laboratory experiment with common frog (Rana temporaria) tadpoles. We reared full-sib, half-sib and non-kin tadpoles in good and poor environments (constant and decreasing water levels crossed across low and high densities) and recorded time to and size at metamorphosis, both important fitness components in amphibians. Tadpoles metamorphosed earlier and at smaller size at high density. The effects of relatedness on size at metamorphosis interacted with density: positive effects of relatedness were detected at low density, whereas at high density relatedness did not affect metamorph size. Water level treatment did not affect development time, but at low density tadpoles metamorphosed at smaller size in the decreasing water level treatment. There was no interaction between relatedness and water level treatments in any of the traits. Our results indicate that the effects of kinship on fitness-related traits are modified by environmental conditions. Moreover, in the case of R. temporaria tadpoles, interactions with relatedness and density seem to be stronger than interactions with desiccation risk.
Flowers exploit the sensory capabilities of pollinators to lure them. The crab spider Thomisus spectabilis benefits from this system by responding to floral signals that are intended to lure honeybees, Apis mellifera, which they prey upon. We investigated whether honeybees and crab spiders discriminate between flowers of Jasminum mesnyi plants that are either fully rewarding, with two reproductive stamens, or not. We found that both honeybees and crab spiders preferred fully rewarding flowers in the field. Moreover, honeybees preferred small flowers over larger ones, while the height above the ground and the number of petals did not influence flower choice of honeybees and crab spiders. Under experimental conditions, crab spiders showed the same choice pattern as observed in the field. This indicates that they actively search for fully rewarding flowers, which are also preferred by their potential prey. Fully rewarding J. mesnyi lure honeybees through visual, olfactory or a combination of these floral signals and T. spectabilis exploits this communication to enhance their chance of prey encounter.
We studied the effect of wood ants on the mountain birch canopy-invertebrate community by sampling a total of 840 trees at different altitudes on the mountain slopes in northeastern Lapland, Finland. We also estimated the degree of herbivory on birch leaves, and monitored the prey of the wood ants. We addressed three questions: (1) How invertebrates are distributed along the altitudinal gradient and on a larger regional scale, (2) how wood ants (Formica aquilonia) affect the distribution of herbivores and predators in the mountain birch canopy, and (3) how the potential prey of wood ants vary in relation to altitude, season and year. Our results demonstrate that the number of sawfly larvae and the degree of herbivory on birch leaves increases with elevation, with the largest impact on mid elevation areas previously damaged during autumnal-moth (Epirrita autumnata) outbreaks. Wood ants and ant-tended aphids (Symydobius oblongus) were most abundant at lower elevations. Wood ants affected most invertebrate groups negatively at all elevations where the wood ants existed, and the effect was quite stable in time. Further, herbivores were found to comprise a large proportion of prey of wood ants. Because birches are often killed during the outbreak years of moths, trees gain long-term protection by wood ants at reasonably low yearly costs — growth reduction owing to sap sucking by ant-tended aphids. Through this protection, wood ants may prevent the recession of the timberline during outbreak years. Further, defoliated forests may recover substantially faster when birch propagules spread from the green islands of birches surviving around the ant mounds.
Some ecological theories predict a positive relationship between species richness and resource size, resource abundance, or resource concentration. In this study, we tested these three hypotheses with myrmecophilous beetles, which use ant nests as their hosts. The resource concentration hypothesis predicts that patches with a high density of a resource support high richness of species dependent on that specific resource. The resource abundance hypothesis predicts that the hosts offering more resources support more species. The resource size hypothesis predicts that larger hosts support more species than smaller hosts. We collected beetles from nests of the nest building wood ant Formica aquilonia. In 49 F. aquilonia nests, we observed 965 individual beetles and 16 species of myrmecophilous beetle. Both the nearest neighbour distance and the volume of ant nests influenced species richness and beetle number. The beetle species utilising several hosts were more widespread and more abundant than the specialist beetle species. Thus, our findings support the resource concentration, resource size and resource abundance hypotheses.
PCR primers were developed for three microsatellite loci successfully isolated from the Chilean scallop Argopecten purpuratus. One locus was highly variable and therefore suitable for phylogenetic analysis. Heterozygosity was tested in four populations within the natural Chile distribution of the species. This locus will be useful for population genetic analysis if further polymorphic loci are isolated.