Fox, C. W. 2006: Colonization of a new host by a seed-feeding beetle: Genetic variation, maternal experience, and the effect of an alternate host. — Ann. Zool. Fennici 43: 239–247.

Human introductions of non-native plants, and subsequent colonization of these plants by herbivores, can be used to study the ecological processes influencing the evolution of insect diet. The seed beetle Stator limbatus has colonized non-native Texas ebony (Ebenopsis ebano) that is grown as an ornamental in Arizona (USA). Texas ebony is not used as a host by S. limbatus where the beetle and plant are naturally sympatric but is used by the sister species to S. limbatus (S. beali). Lines created in an artificial selection experiment were used to test for genetic variation in the ability of S. limbatus larvae to survive on Texas ebony and to examine the role that a native host (blue paloverde, P. florida) plays in facilitating the colonization of Texas ebony. Genetic variation in survival on Texas ebony was present in this S. limbatus population, but the major factor affecting survival was maternal experience with the alternate host — females that encountered paloverde during egg maturation produced offspring that survived > 10-times better on Texas ebony as compared with offspring of females that did not encounter paloverde. This difference was because paloverde stimulated a plastic change in egg composition. Absence of paloverde in the community will reduce larval survival and limit the ability of S. limbatus populations to incorporate Texas ebony into their range of suitable hosts. Blue paloverde provides a stepping stone for colonization of Texas ebony; exposure of mothers to P. florida seeds during egg maturation can increase offspring survival enough that populations do not go extinct before evolving increased survival on the new host, Texas ebony.

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Klemme, I., Eccard, J. A., Gerlach, G., Horne, T. J. & Ylönen, H. 2006: Does it pay to be a dominant male in a promiscuous species? — Ann. Zool. Fennici 43: 248–257.

In many species male dominance leads to an increased access to mates through male-male competition and/or female choice. However, for promiscuous species, in which both males and females mate several times with different partners, male mating success is not necessarily correlated with male reproductive success. We conducted an enclosure study on the promiscuous bank vole (Clethrionomys glareolus) to investigate the influence of male social status on reproductive success. We assessed male dominance in the laboratory from urine marking behavior. Thereafter, we released male pairs of either a clearly different dominance relationship or an equal dominance along with four unrelated females to outdoor enclosures for 10 to 12 days and followed their reproductive output. On average 2.1 females per enclosure were breeding, i.e. the mean operational sex ratio was 1. Paternity analyses revealed no correlation between male dominance and reproductive success. Male body mass, which was not correlated to social status, was also not related to reproductive success. We suggest that, in bank vole males, sexual selection for dominance or body mass may not be strong. The benefit of multi-male mating in promiscuous species may therefore override the benefit of mating with high quality males.

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Kojola, I. & Heikkinen, S. 2006: The structure of the expanded brown bear population at the edge of the Finnish range. — Ann. Zool. Fennici 43: 258–262.

Based on the geographic location of male and female bears shot in Finland in 1954–2003, we examined regional differences in the population structure of peripheral brown bear (Ursus arctos). More bears were shot in western and northern locations in 1954–1963 than in 1993–1998. Between 1954–1963 male and female bears were shot in equal proportions, whereas between 1993–2003 more males than females were shot in western and northern locations. During 1968–1995, the population growth rate was strikingly higher in southern than in northern parts of Finland. Our results provide evidence that the peripheral Finnish brown bear population increases towards both the north and west, which may occur because of a higher harvesting rate in the north and a recent population expansion from the east.

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Laakkonen, M. V. M. 2006: The effects of long-term predator exposure on body composition and condition of young Arctic charr (Salvelinus alpinus). — Ann. Zool. Fennici 43: 263–270.

Non-lethal energetic and physiological costs of severe predation risk in aquatic prey are poorly understood. Knowledge of this matter would be especially valuable in life-skills training programs for hatchery-reared fish, where long-term predator conditioning is one potential method to improve the antipredator skills of naïve fish. In this study I examined the effects of long-term (72 days) predator exposure on the body composition (whole-body lipid and water content) and body condition of hatchery-bred Arctic charr (Salvelinus alpinus) young. The chemical cues from charr-fed pikeperch (Sander lucioperca) were used as the exposure stimuli. My results revealed that the predator-exposed charr had a lower body condition and water content but higher lipid content than the non-exposed conspecifics, demonstrating that long-term predation risk causes serious physiological changes. Since predator conditioning can evidently result in marked physiological changes in prey fish, future studies should take into further consideration not only behavioural but also physiological effects of life-skills training.

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Liukkonen, T. 2006: Finnish native grey partridge (Perdix perdix) population differs clearly in mitochondrial DNA from the farm stock used for releases. — Ann. Zool. Fennici 43: 271–279.

The mitochondrial DNA (mtDNA) control region I (CR1) of 138 wild and 36 captive grey partridges (Perdix perdix) was sequenced. Representing two major mitochondrial DNA lineages that differed by 15 nucleotide substitutions (3.7%), the Finnish lineage dominated in the wild, whereas the European lineage dominated in the captive stock. Most individuals represented a single haplotype in each lineage. Nucleotide and haplotype diversities were high in mixed subpopulations with individuals of both lineages. Analysis of molecular variance (AMOVA) showed that when the captive stock was excluded, about 80% of the total variation could be explained by the variation within subpopulations. When captive stock was included, 67% of the variation was explained by the variation between subpopulations. According to [PHI]_ST values, captive stock differed from the wild subpopulations. These results clearly show that the native stock in Finland differs in mtDNA CR1 from the farm stock. In the area of large-scale captive rearing and releasing, only one bird represented the same mitochondrial lineage as the farm stock. It is evident that released farm birds have left only minor marks in the native population in Finland.

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Palagi, E. & Dapporto, L. 2006: Urine marking and urination in Lemur catta: a comparison of design features. — Ann. Zool. Fennici 43: 280–284.

The "design features" of a signal are strictly shaped by selective forces since they affect the optimality of the signal form. In Lemur catta urine deposition can be combined with the following tail configurations: (1) tail held up in an evident display (Urine Marking, UM); (2) tail slightly raised to avoid its impregnation with urine (Urinating, UR). It has recently been demonstrated that only UM has marking functions and the visual tail display is only one of the features facilitating detection of the signal by the receiver. Other features help senders to increase the probability of signal detection (e.g. site of deposition and association with other scent depositions). In this paper, we ranked using a multivariate general linear model and logistic regression the relative importance of such features in shaping the two kinds of depositions. Furthermore, we demonstrated that both UM and UR have constant depositional features probably in order to improve the detectability of the urine marking and the animals' safety during urine excretion.

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Ratkiewicz, M. & Jaroszewicz, B. 2006: Allopatric origins of sympatric forms: the skippers Carterocephalus palaemon palaemon, C. p. tolli and C. silvicolus. — Ann. Zool. Fennici 43: 285–294.

The taxonomic status and evolutionary origin of subspecies is often controversial. The Carterocephalus palaemon (Pallas, 1771) subspecies complex (Chequered skipper; Lepidoptera, Hesperiidae) may be a model for taxonomic clarification by means of genetic studies. We analysed two subspecies: Carterocephalus palaemon palaemon and C. palaemon tolli (the latter one endemic to the Bia?owie?a Primeval Forest, Poland) at 34 allozyme loci and compared them with the northern chequered skipper Carterocephalus silvicolus (Meigen, 1829), a well-defined species. The overall F_ST value between C. palaemon complex and C. silvicolus was significant (0.700, P < 0.001). Significant genetic differentiation (F_ST = 0.191, P < 0.001) was found between sympatrically occurring forms: C. p. palaemon and C. p. tolli, confirming their phenotypic distinction. PCA and admixture analyses revealed the existence of three distinct gene pools (C. silvicolus, C. p. palaemon and C. p. tolli). The genetic differentiation between C. palaemon complex and C. silvicolus was similar to that found among the other well-defined species, while the F_ST value between the two genetic lineages of C. palaemon is typical for a butterfly species with subspecific structure. Observed differentiation between C. p. palaemon and C. p. tolli most likely results from long-lasting isolation between lineages rather than resulting from an initial divergence driven by strong disruptive selection.

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Solonen, T. 2006: Overwinter population change of small mammals in southern Finland. — Ann. Zool. Fennici 43: 295–302.

Patterns and variations in the overwinter population change of small mammals (shrews, voles, and mice) were studied on the basis of long-term data collected using snap trapping in autumn and spring 1981–2005 in southern Finland. In particular, attempts were made to reveal possible negative effects of mild winters on the wintering success of populations. The winter decline in density varied considerably both within and between species and groups. It was not significantly steeper in the coastal than in inland vole populations, but there were significant differences between the local populations of the southern coast. Small mammals seemed to overwinter more successfully in forests than in fields, and the negative effects of mild winters seemed to impact the populations of field habitats. The direct contribution of high ambient temperatures on the overwinter population change seemed to be largely restraining, but especially so in the depth of winter. There seemed to be indirect inverse effects involved. Population density exhibited only minor effects.

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Vetemaa, M., Neumann, E., Thoresson, G. & Pihlak, M. 2006: Trade-off between number and intraovarian growth rate of offspring in Zoarces viviparus. — Ann. Zool. Fennici 43: 303–309.

Trade-off between number and intraovarian growth rate of offspring was studied using 15 samples of females caught at 7 sites in the Baltic Sea and the Skagerrak. The growth of normal embryos appeared to be synchronous within broods, and there was no correlation between the females' size and relative fecundity. Females with higher relative fecundity had significantly smaller average larval length which may suggest existence of offspring competition for maternal energy supplies. Our results also show that reduced offspring size in females with high relative fecundity did not fully compensate for the increase in offspring number: the ratio of embryo mass to female somatic weight was positively correlated with relative fecundity. The negative relationship between female condition and relative fecundity indicates that increased investment in offspring affects the energetic state of the female. However, the last effect was rather moderate.

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