Xu, X., Wei, K., Zhang, W. P., Lin, L., Wang, X. F., Shen, F. J., Zhang, L., Zhang, Z. H. & Yue, B. S. 2007: A novel method for sex determination of giant panda. — Ann. Zool. Fennici 44: 401–404.

A fast, inexpensive, and reliable method for sex determination of giant panda was developed using amplification of giant panda zinc finger alleles (ZFX/ZFY). Two sets of primers targeted a conserved region in the exon of the ZFX/ZFY genes worked in a single PCR process, and provided positive results for both males and females. Sexes of individuals were revealed by sex-specific banding patterns (females: 447 bp, 146 bp; males: 447 bp, 350 bp, 146 bp). This method was successfully tested on blood sample from pandas of known sex. Non-invasive tests revealed that this method can also be applied to non-invasive samples such as hair or feces.

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Franzén, M. & Larsson, M. 2007: Pollen harvesting and reproductive rates in specialized solitary bees. — Ann. Zool. Fennici 44: 405–414.

Andrena humilis is an endangered oligolectic solitary bee and has declined in recent decades throughout western Europe. The aim of this study was to explore the pollen harvesting pattern and to determine the reproductive rate in specialized andrenid bees. We measured the amount of pollen required to produce one brood-cell, the pollen harvesting rate and compared our results with data for other specialized andrenid bee species. Pollen-foraging trips were registered and the activity events (entering, leaving or digging) recorded at the nests. The mean number of pollen-foraging trips per day was 5.3 and an average bee nest was active (and open) 88 min day^–1. The bees were highly efficient in harvesting pollen and spent on average 10.7 min to complete one pollen-foraging trip. Most pollen-foraging trips (77%) were completed in less than 15 min. The duration of pollen-foraging trips increased over the day, presumably because pollen became more costly to harvest. Based on pollen counts (pollen loads on bees and pollen provisions) an average bee required 3.85 foraging trips to complete one brood cell and one bee managed to accomplish 1.37 brood cells in one day with suitable weather. In the literature we found data on an additional 19 specialized andrenid bee species. Andrena humilis seems to be extremely efficient compared with most other species, with an average trip for pollen lasting almost one hour (average for andrenid bees = 46 min). An extremely low reproductive rate seems to be a common trait among specialized bees in the family Andrenidae with an average 0.9 offspring produced per day and less than ten offspring produced during the whole lifetime. The high degree of specialisation and the low reproductive rate among andrenid bees can explain the severe decline in many species today.

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Hoset, K. S. & Steen, H. 2007: Relaxed competition during winter may explain the coexistence of two sympatric Microtus species. — Ann. Zool. Fennici 44: 415–424.

Root voles (Microtus oeconomus) are competitively superior during summer and locally displace field voles (M. agrestis). Since the two species co-exist in many areas, competition may be relaxed or reversed during winter. To assess the competitive interaction during winter, we used PIT tags to study activity patterns and home range overlap of the two species in two enclosures with food-supplemented and non-supplemented plots during the winter of 2002–2003. Additionally, we established single species systems of root-vole and field-vole populations in the winter of 2004. Home-range size was smaller and activity lower in field voles than in root voles, and food supplementation caused an increase in activity in both species. Activity and home-range size in either species was not affected by the presence of the other. Despite the different activity patterns of the two species, home range overlap between field voles and root voles did not differ from random in the food-supplemented plots. In the non-supplemented plots daily overlap was higher than expected. As predicted, we were not able to detect any interference competition between field and root voles during winter. This supports our hypothesis that coexistence between the two may be caused by relaxed contest competition during winter.

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Benesh, D. P., Valtonen, E. T. & Jormalainen, V. 2007: Reduced survival associated with precopulatory mate guarding in male Asellus aquaticus (Isopoda). — Ann. Zool. Fennici 44: 425–434.

Precopulatory mate-guarding in aquatic crustaceans is known to have immediate costs for the guarding male. The extent to which guarding behavior may reduce future reproductive opportunities, however, is less established. We examined the survival and antennae length, suggested to be important in detecting receptive females, in male freshwater isopods (Asellus aquaticus) collected paired or unpaired. Antennae length to body size relationships suggested that large, paired males had broken antennae more commonly than large, unpaired males. Moreover, broken antennae seem to be associated with increased mortality. Males collected paired had lower survival than males collected unpaired, and this reduction in survival was greatest in larger individuals. In pairing trials, males usually attempted pair formation regardless of their size, female size, or previous pairing status. Our results suggest that some costs associated with male guarding behavior may extend beyond the actual guarding episode, though the consequences for mating decisions remain to be determined.

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Kaefer, Í. L., Boelter, R. A. & Cechin, S. Z. 2007: Reproductive biology of the invasive bullfrog Lithobates catesbeianus in southern Brazil. — Ann. Zool. Fennici 44: 435–444.

We studied the reproductive biology of an invasive population of the bullfrog Lithobates catesbeianus by analyzing individuals captured in the central Rio Grande do Sul state, southern Brazil. Specimens were collected during 12 field trips held from May 2002 to June 2003. We analyzed gonad development stages in 216 individuals to evaluate the fecundity, reproductive effort, size–fecundity relationships, and seasonal distribution of individuals. Reproductive activity was potentially continuous, and was more intense during the spring and summer. The smallest mature male was 90.25 mm in snout–urostyle length (SUL); the SUL of the smallest mature female was 120.83 mm. The invasive potential of L. catesbeianus is probably associated with reproductive traits such as continuous gonad development, extended reproduction period, high fecundity, and early sexual maturity. The data presented here form a basis for future studies on the impacts and management of bullfrogs in invaded ecosystems.

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Nygrén, T., Pusenius, J., Tiilikainen, R. & Korpelainen, J. 2007: Moose antler type polymorphism: age and weight dependent phenotypes and phenotype frequencies in space and time. — Ann. Zool. Fennici 44: 445–461.

We provide the first detailed description of the phenotypic polymorphism of the European moose (Alces alces) bulls with three different antler types: cervina, intermediate and palmated. We assess how the frequencies of bulls with different antler types as well as antler spread and tine numbers are related to age, body weight, region and time. Our results indicate that antler type phenotypes are linked to other body and antler size characteristics. The cervina type had the smallest and the palmated the largest carcass weight, antler spread and tine numbers. The youngest age groups were predominantly of cervina type. At the prime age of 6.5–10.5 years, the prevalent types were intermediate and palmated. At an older age, the cervina type increased and the other types decreased. We propose that the penetrance of inherited antler type is best at prime age when it is important for a bull to be successful in mating competition. The cervina type was most prevalent in the southern zone and the palmated type in the northern zone. The mean age, mean carcass weight, antler spread and tine numbers all decreased from 1976–1986 to 1996–1999. The results were similar in the age-standardized prime age bulls. We hypothesize that intensive selective hunting as well as possible fitness differences between antler types in managed forests may have been involved in the decrease of the palmated antler type.

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Goropashnaya, A. V., Fedorov, V. B., Seifert, B. & Pamilo, P. 2007: Phylogeography and population structure in the ant Formica exsecta (Hymenoptera, Formicidae) across Eurasia as reflected by mitochondrial DNA variation and microsatellites. — Ann. Zool. Fennici 44: 462–474.

Phylogeography and population structure of the ant Formica exsecta was studied across Eurasia by using mtDNA sequences and microsatellite genotypes. The phylogeny based on 1.5 kb mtDNA fragment including the cytochrome b and part of the ND6 gene showed significant division (1.63% of nucleotide divergence) between a haplotype from Tibet and all other haplotypes. Similar to findings in diverse array of species associated with forest in Eurasia, the mtDNA phylogeny revealed no evidence for vicariant events due to separation in different forest refugia over glacial periods. The haplotype network includes several small clades (with 2–4 haplotypes in each) with geographically limited distribution, but one geographical region may have received haplotypes from two or more of such clades. This pattern could indicate mixing of different gene pools during postglacial colonization of Europe from different forest refugia or from an ancestral source with some spatial genetic differentiation. The genealogy and the haplotype frequencies suggest postglacial colonization of Siberia from a single refugial source of limited size. Maternal and biparental DNA markers indicated a moderate but significant level of population differentiation (mtDNA [PHI]_ST = 0.42, microsatellite F_ST = 0.13) across Eurasia. However, no correlation between genetic differentiation estimated for mtDNA and microsatellites was found among the populations. Considerable reduction in microsatellite genetic diversity was found in the small population of F. exsecta in England, giving some basis to classify this population as near threatened.

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Oja, H. & Pöysä, H. 2007: Spring phenology, latitude, and the timing of breeding in two migratory ducks: implications of climate change impacts. — Ann. Zool. Fennici 44: 475–485.

We studied whether the timing of hatching in the mallard (Anas platyrhynchos) and the common goldeneye (Bucephala clangula) is associated with the timing of lake ice break-up (a local climate index) and the North Atlantic Oscillation (NAO, a large-scale climate index), and if the strength of these associations differ between southern and northern populations of the species. In both species, the date of hatching was associated with the date of ice break-up; more clearly so in northern Finland than in southern Finland. The date of hatching was neither associated with the winter NAO (December–March) nor with the spring NAO (March–May). There was no difference between southern and northern populations in terms of the annual differences (in days) between the timing of ice break-up and the timing of hatching. However, in both species, this difference decreased with increasing lateness of the spring in the north, the corresponding trend being less clear in the south.

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Sjöberg, K., Pettersson, R. B., Ball, J. P. & Sundström, T. 2007: Seed crops of Norway spruce and winter habitat quality for boreal birds: old-growth compared with managed forests. — Ann. Zool. Fennici 44: 486–495.

We compared the winter bird community in 5 old-growth coniferous forests and adjacent managed forests in northern Sweden. Norway spruce seeds on snow (available to birds) were sampled during late winter and differed about 13-fold between 1990 and 1992. There were no significant differences between the old-growth and managed forest in the seed-rich (mast) year, but during the seed-poor (normal) year there were more birds in total, and more birds belonging to the biogeographical group Northern taiga species in the old-growth forests. Our analysis suggests that differences in habitat quality between old-growth and managed forests may be small in the rare years with high spruce seed production, but in an average year, old-growth forests seem to be better for wintering birds. This pattern, although needing further study to determine its generality, is consistent with suggestions that forestry may negatively influence the avian community by reducing winter habitat quality.

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