PECKIANA Volume 8 (2012) pp. 203 207 ISSN 1618-1735 The reactions of the common dormouse (Muscardinus avellanarius) and the yellow-necked mouse (Apodemus flavicollis) to the odour of nest Abstract Arboreal rodents can identify details of intraspecific and interspecific odours of nests and react accordingly to them. The common dormouse is a relatively weak dormouse species and more often shows the reaction of avoidance when confronted with a nest of the yellow-necked mouse. The yellownecked mouse, as a strong competitor in relation to dormice, more often shows the reaction of attraction or neutral response to the odour of dormouse nests. Meanwhile, the intraspecific reaction of the common dormouse was neutral, but for the yellow-necked mouse was avoidance. Keywords: arboreal rodents, intraspecific test, interspecific test, attraction, avoidance 1. Instruction Forest rodents spend much time in different hollows and holes that make it difficult to get visual information about the environment. Odour signals are their main source of environmental information (Rozenfeld & Le Boulenge 1987, Andrzejewski et al. 1997). Rodents use scent to find food, to orientate and to avoid predators. They also mark territory using urine and excrement to provide an odour map and for protection of their individual area (Sokolov et al. 1979, Łopucki & Szymroszczyk 2003). Such odour marks can be found on branches, stubs, stones and on the ground. Odour signals play an important role in intraspecific identification of familiar and unfamiliar individuals and their social status in a population. Odour is important in a rodent s behaviour to find partners in the reproductive period and they are able to identify sex, age and physiological state of different individuals (Łopucki & Szymroszczyk 2003, Sun et al. 2007). Also odour signals are significant in the regulation of interspecific relationships in the forest community of small rodents. Such signals help to avoid unwanted direct contacts and to increase tolerance during actual meetings (Sokolov et al. 1979, Łopucki & Szymroszczyk 2003, Mrόz 2007). The tendency to avoid interspecific contacts is one of the evolutionary mechanisms for population isolation (Sun et al. 2007). Investigations of reactions to the odour of rodents have been carried out mostly in laboratory conditions using direct contact of individuals. Olfactory identification between individual rodents has been shown and suggests that they use it in natural conditions (Łopucki & Szymroszczyk 2003). The role of olfactory signals for rodents in the wild has not been investigated until now (Andrzejewski et al. 1997).
204 The arboreal rodents common dormouse (Muscardinus avellanarius) and yellow-necked mouse (Apodemus flavicollis) were the subjects of our study. They live in the same ecosystems of deciduous and mixed forests. Both inhabit artificial nests and there is a high level of interaction between these species in the wild. They use mainly odour and audio communication, especially in the breeding period. The aim of our study was to investigate the reactions of the common dormouse and the yellow-necked mouse to odour signals of each other and other rodents in semi-natural conditions. The first task was to determine the presence and type of the common dormouse and the yellow-necked mouse reactions to intraspecific odour of nest. The second task was to determine the presence and type of interspecific reactions to odour of nest belonging to other selected rodents. 2. Material and methods The investigations were carried out in the Podole region (Ukraine) and Jura region (Poland) during 2007 2008. Oak (Quercus robur), hornbeam (Carpinus betulus), spruce (Picea abies) and pine (Pinus sylvestris) were the main tree species in the Ukrainian study areas. Beech (Fagus sylvatica), pine and spruce were the main tree species in the study areas in Poland. Simple nest-boxes and nest-tubes made by W. Nowakowski were used in the investigations (Zaytseva & Nowakowski 2009). In the Podole region, 100 nest-tubes and 105 nest-boxes were positioned in trees. In the Jura region 175 nest-tubes and 62 nest-boxes were used. They were monitored monthly from April to October. Nest-boxes and nest-tubes were used to capture animals for testing and for odour samples of nesting material. We used odour of nest of native species such as the common dormouse, the fat dormouse (Glis glis), and the yellow-necked mouse. Also we used the nest odour of the African species woodland dormouse (Graphiurus murinus) kept in captivity. Sex of the animals built a nest has not been determined. Only adult individuals of both sexes were used in testing and one animal was tested once in Poland and twice in Ukraine (to different nest odours). In our investigation the olfactory tester constructed by W. Nowakowski was used (Fig. 1, Fig. 2). The odour of nest sample of nesting material was in one chamber, another chamber was empty and the animal had a choice between the two. The empty chamber was chosen randomly and the chamber with the nest material was washed out between tests. A positive test was recorded when the experimental animal chose to approach the box with odour of nest. The type of reaction was defined by the percentage of positive tests in which the animal reacted by attraction to the test sample. All results from Ukraine and Poland are combined. In total 916 tests were made, 766 with the common dormouse (240 intraspecific tests, 172 with the fat dormouse, 261 with the yellow-necked mouse and 93 with the woodland dormouse) and 150 with the yellow-necked mouse (37 intraspecific tests, 29 with the fat dormouse, 66 with the common dormouse and 18 with the woodland dormouse). 3. Results and Discussion Intraspecific reactions of the common dormouse to odour of nest were neutral or equivalent (46 % of tests were positive, χ 2 = 0.83, р = 0.3609). This is probably because in their natural habitat the common dormouse constantly meets odours of other individuals of their species and the test samples may be familiar (Owadowska 1999). The spatial and ethological structure of dormouse populations also plays an important role. The common dormice are territorial
Reactions to the odour of nest 205 rodents, but overlapping home ranges are quite common. In addition, young individuals live in areas used by adults and sometimes they form a temporary ethological group (Airapetjanc 1983, Juškaitis 2008). A relatively high tolerance to odour of nest may be due to all these reasons. Interspecific reactions of the common dormouse to odour of nest were diverse and speciesspecific. The reaction to the odour of nest of the fat dormouse was statistically significant avoidance (only 37 % of tests were positive, χ 2 = 5.72, р = 0.0168). In the forest ecosystems in Ukraine and Poland these two species frequently share the same tree space, have the same daily activity pattern and use the same food sources so that their ecological niches are partly overlapped. Their spatial competition shows in colonization or destruction of the common dormouse nests by the fat dormouse during the spring-summer period (Lozan et al. 1990). The fat dormouse is a bigger, aggressive and dominant rodent that has strongly negative impacts on individuals of the common dormouse and even can kill those (Juškaitis 2008). Fig. 1 The olfactory tester constructed by W. Nowakowski (photo H. Zaytseva-Anciferova). Fig. 2 Diagram of the olfactory tester constructed by W. Nowakowski.
206 The reaction to odour of nest belonging to the woodland dormouse was neutral (53 % of tests were positive, χ 2 = 0.13, р = 0.7145). This African species was unknown to the common dormouse, and test animals were disoriented and reacted differently. Odour of nest of the woodland dormouse was recognized as odour of familiar family, but unknown relative, because it is considered that all species within the whole family have the odour core in common (Mrόz 2007). The reaction of the common dormouse to odour of nest of the yellow-necked mouse was avoidance (only 35 % of tests were positive, χ 2 = 11.59, р = 0.0007), representing a strong and statistically significant aversion. The yellow-necked mouse is an aggressive and dominant species of rodent, so the common dormouse prefers to avoid it. A similar negative reaction was also observed in other interspecific relations between the yellow-necked mouse and smaller and weaker species, such as voles (Andrzejewski & Olszewski 1963, Sokolov et al. 1979, Łopucki & Szymroszczyk 2003, Mrόz 2007). Although this mouse is a granivore, sometimes it eats arthropods, small birds and mammals. In such cases, the urine and excrement of the yellow-necked mouse may have an odour of predator (Lozan et al. 1990, Grüm & Bujalska 2000, Nowakowski, personal report). In addition, this bigger and stronger rodent can destroy the common dormouse nests and kill young dormice also (Airapetjanc 1983, Lozan et al. 1990, Juškaitis 2008). The intraspecific reaction of the yellow-necked mouse to odour of nest was neutral with tendency to avoidance, but statistically non-significant (38 % of tests were positive, χ 2 = 1.1, р = 0.2951). Aggressive interactions are possible between different species of rodents and also between individuals of one species (Sokolov et al. 1979). The yellow-necked mouse is a territorial species and it shows aggressive reactions in direct contact (Grüm & Bujalska 2000), which is why these rodents tend to avoid each other when using shared space. Interspecific reactions of the yellow-necked mouse to odour of nest were diverse and species specific. The reaction to the fat dormouse was neutral (48 % of tests were positive, χ 2 = 0.02, р = 0.8964). Both species are quite aggressive and their ecological niches only some overlap. The yellow-necked mouse lives in the lower and middle levels of the forest, while the fat dormouse occupies mainly the highest level of trees and seldom comes down. The reaction of the yellow-necked mouse to odour of nest of the common dormouse was neutral with tendency of attraction (59 % of tests were positive, χ 2 = 1.1, р = 0.2943), but statistically non-significant. The positive response to the common dormouse is typical behaviour for the yellow-necked mouse, which is an aggressive and dominant species relative to other forest rodents (Čiháková & Frynta 1996, Grüm & Bujalska 2000). It often occupies the nests of small dormice and may even displace them (Andrzejewski & Olszewski 1963, Čiháková & Frynta 1996, Juškaitis 2008). The reaction of the yellow-necked mouse to odour of nest of the woodland dormouse was neutral with tendency of attraction (67 % of tests were positive, χ 2 = 1.03, р = 0.3105), but statistically non-significant. This odour was unknown to the yellow-necked mouse. But the odour core could have been recognized by rodents (Mróz 2007). Therefore, it could make moderate concern of the yellow-necked mouse. All our results were in accord with behaviour described for these species in the literature suggesting consistency despite differing study methods. The details of each intraspecific and interspecific reaction to the odour of nest need further investigation.
Reactions to the odour of nest 207 4. References Airapetjanc, A. (1983): Dormice. Leningrad University Publishers, Leningrad: 192 pp. (in Russian). Andrzejewski, R., Babińska-Werka, J., Liro, A., Owadowska, E. & Szacki, J. (1997): The attractiveness of conspecific and interspecific odour for bank voles Clethrionomys glareolus. Acta Theriologica 42: 231 234. Andrzejewski, R. & Olszewski, J. L. (1963): Social behavior and interspecific relations in Apodemus flavicollis (Melchior, 1834) and Clethrionomys glareolus (Schreber, 1780). Acta Theriologica 7: 155 168. Čiháková, J. & Frynta, D. (1996): Intraspecifics and interspecific behavioral interactions in the wood mouse (Apodemus sylvaticus) and the yellow-necked mouse (Apodemus flavicollis) in a neutral cage. Folia Zoologica 45: 105 113. Grüm, L. & Bujalska, G. (2000): Bank voles and yellow-necked mice: what are interrelations between them? Polish Journal of Ecology 48, Supplement: 141 145. Juškaitis, R. (2008): The common dormouse Muscardinus avellanarius: Ecology, population structure and dynamics. Institute of Ecology of Vilnius University Publishers, Vilnius: 164 pp. Łopucki, R. & Szymroszczyk, P. (2003): Recognition of interspecific familiar versus unfamiliar odours among bank voles and yellow-necked mice. Acta Theriologica 48: 167 176. Lozan, M., Belik, L. & Samarskij, S. (1990): Dormice (Gliridae) of south-west of SSSR. Shtiintsa. Kishinev: 146 pp. (in Russian). Mrόz, I. (2007): Response of the bank vole Clethrionomys glareolus (Schreber, 1780) to the odour and presence of geterospecifics as measured be scent marking behavior and trapping in double traps in an alder forest. Polish Journal of Ecology 55: 559 570. Owadowska, E. (1999): The range of olfactory familiarity between individuals in a population of bank voles. Acta Theriologica 44: 133 150. Rozenfeld, F. M. & Le Boulenge, E. (1987): Urine marking by male bank voles (Clethrionomys glareolus, Schreber, 1780. Microtine. Rodentia) in relation to their social rank. Canadian Journal of Zoology 65: 2594 2601. Sokolov, V. E., Skurat, L.N. & Vasilieva, N. Yu. (1979): Some aspects of olfactory behavior of the bank vole (Clethrionomys glareolus) and yellow-necked mouse (Apodemus flavicollis). Zoological Journal LVIII 12: 1864 1871 (in Russian). Sun, P., Zhao, Y., Zhao, X. & Wang, D. (2007): Behavioural reaction of root vole (Microtus oeconomus Pallas) males of different social ranks to familiar and novel odour of conspecific males. Polish Journal of Ecology 55: 571 578. Zaytseva, H. & Nowakowski, W. K. (2009): Using of new type of nest-boxes in ecological investigation of arboreal rodents. Pryrodnychiy Almanah: Biological Scienses. Kherson 12: 81 93 (in Ukrainian). Accepted 16 May 2012 Authors addresses: Hanna Zaytseva-Anciferova* Army Academy named after hetman Petro Sahaydachnyi Gwardiyska str., bld. 32 79007 Lviv, Ukraine Wojciech Nowakowski University of Nature and Humanity, Department of Zoology ul. Prusa 12 08-110 Siedlce, Poland *Corresponding author: Hanna Zaytseva-Anciferova (e-mail: zaitsevasonia@yahoo.com)