Barlow, G. W. & Lee, J. S. F. 2005: Sex-reversed dominance and aggression in the cichlid fish Julidochromis marlieri. — Ann. Zool. Fennici 42: 477–483.

The plesiomorphic breeding system of the large fish family Cichlidae is a monogamous, biparental pair that cares for eggs and extends care to shepherding and protecting tiny fry. Typically, the male is larger than his mate and dominates her. Julidochromis marlieri, an African cichlid from Lake Tanganyika, follows this pattern but with an important difference: the female is larger than her mate; one female was reported mated to two males simultaneously (Yamagishi & Kohda 1996). We asked whether the female also dominates her mate, as in polyandrous, sex-role reversed birds. Additionally, documenting an inherent difference in aggressiveness would clarify the behavioral mechanisms that support pair-bonding in monogamous species. We staged contests between males and females of various relative sizes. When equal in size, females regularly won contests. Females were also more likely to initiate advancement to more aggressive stages of the fight. Thus dominance and aggression are sex-reversed in Julidochromis marlieri.

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Pollock, M. S., Zhao, X., Brown, G. E., Kusch, R. C., Pollock, R. J. & Chivers, D. P. 2005: The response of convict cichlids to chemical alarm cues: an integrated study of behaviour, growth, and reproduction. — Ann. Zool. Fennici 42: 485–495.

Predation is an important agent leading to the evolution of accurate risk assessment. In fishes, one of the best studied modes of threat assessment is the use of damage release cues from consumed or damaged individuals. These cues act as sources of public information alerting both conspecific and heterospecific individuals in the immediate area of a possible predation threat. Responses to damage release cues can be behavioural (e.g. avoidance of the cue or increased schooling), morphological (e.g. change in body shape), and potentially reproductive (e.g. altered patterns of breeding and reproductive investment). In the current study we documented the response of convict cichlids (Archocentrus nigrofaciatus) to damage release cues from conspecifics, unknown heterospecifics (swordtail, Xiphophorus helleri), and distilled water. In short term behavioural trials we found that cichlids exhibited an antipredator response to injured conspecifics, while they exhibited a foraging response to injured swordtails and no response to distilled water. In longer term trials (41 days) we found that cichlids exposed to conspecific cues grew significantly less than those in the other treatments. Finally, we found that reproductive patterns were influenced by the treatments. Cichlids bred faster in the presence of predation cues (conspecific skin extract) and food cues (swordtail skin extract) than the control treatment (distilled water).

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Pöykkö, H., Rautio, P., Hyvärinen, M., Tuomi, J., Markkola, A., Kuikka, K. & Roitto, M. 2005: Differential performance of two geometrids on previously defoliated Scots pine. — Ann. Zool. Fennici 42: 497–503.

We studied the effect of previous defoliations of Pinus sylvestris on the performance of two geometrid moths, Bupalus piniarius and Macaria liturata, using a field experiment. Prior to the experiment, we found defoliation to increase the concentrations of certain secondary chemicals and reduce the N (nitrogen) concentration of needles. Hence, it was predicted that defoliation-induced changes should decrease the performance of geometrids feeding on P. sylvestris. As B. piniarius is a monophagous species on P. sylvestris, and M. liturata is oligophagous feeding also on Larix and Juniperus species, we predicted that M. liturata should suffer more than B. piniarius from defoliation-induced changes in needle chemistry. As predicted, defoliation had a negative effect on the performance, the oligophagous M. liturata being more vulnerable. Defoliation resulted in decreased sex-specific survival of M. liturata, but did not affect the survival of B. piniarius. In M. liturata, no males survived to the pupal stage in previously defoliated trees. Defoliation also resulted in lower pupal weights in both species. We conclude that defoliation-induced changes on the performance of insects with different host ranges merit more attention.

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Selonen, V., Painter, J. N. & Hanski, I. K. 2005: Microsatellite variation in the Siberian flying squirrel in Finland. — Ann. Zool. Fennici 42: 505–511.

The Siberian flying squirrel (Pteromys volans) is an arboreal rodent that inhabits spruce-dominated boreal forest. The species has declined in Finland, probably due to modern forestry. We studied genetic variation in the flying squirrel (n = 159) between eight sampling sites in Finland using seven microsatellite loci. Heterozygosity levels were similar in the flying squirrel as found for other Sciurid species. There were slight heterozygote excesses over all loci. Isolation by distance was clear and genetic differentiation between sampling sites was high (overall F_ST = 0.115). In addition, geographical isolation of one site was observed as increased differentiation and low allele richness. Radio telemetry studies have revealed that the dispersal abilities of flying squirrels are good. However, the high differentiation between sampling sites indicates that the actual gene flow over large distances is low. Thus our results emphasize the importance of landscape-level management in the conservation of the flying squirrel.

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Camargo, A., Naya, D. A., Canavero, A., da Rosa, I. & Maneyro, R. 2005: Seasonal activity and the body size–fecundity relationship in a population of Physalaemus gracilis (Boulenger, 1883) (Anura, Leptodactylidae) from Uruguay. — Ann. Zool. Fennici 42: 513–521.

Two key life history attributes are temporal reproductive patterns and inter- and intraspecific variation in clutch size. In this work, we collected individuals of Physalaemus gracilis in Espinas stream (Maldonado, Uruguay) to analyze the correlation of activity with environmental variables and to evaluate the influence of reproductive investment on the body size-fecundity (BSF) relationship. In contrast to previous reports, the reproductive activity peaked in spring and was not correlated with temperature or rainfall in either sex. Regression analysis showed that the BSF relationship varied with size, and that larger females had a steeper slope than smaller females. Reproductive investment data indicate that smaller females invested less energy in their offspring than larger females, which is probably due to the imposed cost of continued growth.

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Kaartinen, S., Kojola, I. & Colpaert, A. 2005: Finnish wolves avoid roads and settlements. — Ann. Zool. Fennici 42: 523–532.

The avoidance of roads and human settlements by wolves (Canis lupus) in a harvested population was studied in boreal woodland landscapes in east-central Finland with a low density of humans (2 km^–2) and roads (0.4 km/km^–2). The abundance of the primary prey, i.e. moose, is moderate with approximately 50 moose per wolf within wolf pack territories. Twelve alpha wolves in six territories were captured, fitted with radiocollars, and ground-tracked during 1998–2002. The number of wolves has recently been increasing in Finland and they have also expanded their range. This in turn has raised a certain degree of concern among people living in the area, and the wolves are often perceived as a safety threat both to people and domestic animals. We found that wolves tended to avoid human constructions. The avoidance distances were highest for buildings (1000 m) and for roads (250 m). Extrapolating from the avoidance distances to give an estimate for the entire study area revealed that 48% of the study area would potentially be subject to reduced use by the wolf.

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Fowler, M. S. 2005: Predicting community persistence based on different methods of species ranking. — Ann. Zool. Fennici 42: 533–543.

Different species in a community can be ranked according to the strength of their effect on the dynamics of the entire community. Despite a considerable research effort on community structure and the "keystone" species concept, there are still unresolved issues in this area. This work addresses the suitability of different methods of characterising community members, either by relative abundance, or different measures of competitive ability. Multi-species competitive communities were simulated to allow comparison of methods that rank community members by either their abundance or competitive ability. Results indicate that characterising species according to their relative density, rather than competitive ability, provides a more refined measure of the importance of each community member. The analysis is extended by assessing which species are most likely to be involved with cascading extinction events, showing that the species with the lowest abundance is most likely to face extinction. Here it is also shown that removal of the most abundant species, i.e. that with the greatest relative density within the community, leads to the highest probability of community collapse, with further loss of community members through cascading extinctions. The asymmetry and non-linearity of between species interactions mean that species' ranking can change unexpectedly following species loss. These results can lead to practical recommendations in management decisions for conservation and other species management problems, e.g. harvesting in marine food-webs, where it may be difficult to assess relative competitive ability between species in the ecosystem.

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Valtonen, A. & Saarinen, K. 2005: A highway intersection as an alternative habitat for a meadow butterfly: effect of mowing, habitat geometry and roads on the ringlet (Aphantopus hyperantus). — Ann. Zool. Fennici 42: 545–556.

The decline of semi-natural grasslands throughout Europe has given rise to the idea that road verges under mowing management could serve as alternative habitats for several meadow species. We studied the distribution and movements of the ringlet butterfly (Aphantopus hyperantus) at a highway intersection and its surroundings. A total of 2113 individuals were marked, and 17% of the individuals recaptured, in 2003. The population densities were generally low in the verge and in sections mown in mid-summer. Mid-summer mowing also delayed the dispersal of individuals to the area until the vegetation had regenerated. The majority of individuals were sedentary but there was more emigration from linear verges and sections with a low population density. A dense network of roads may decrease the movement of the ringlet but a single road is not an absolute barrier to the species. We conclude that intersections and road verges can provide alternative habitats for meadow species, as shown here with the ringlet, but that the quality of these habitats depends on the mowing management.

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