Abstract: In this study, reproductive biology of Glis glis (Linnaeus, 1766) and weight gaining of pups were studied in four localities by using wooden nestboxes and tattoo pliers method in mixed deciduous forest of Istranca Mountains in Turkish Thrace. By considering morphological peculiarities, body weight gaining and reproductive signs of adults, mating behaviors and breeding times were measured from specimens captured in nestboxes. Results showed that females were mated between June 15 and August 18 and gave a birth between July 14 and September 16. The litter size ranged from 1 to 12 (Mean 6.05, n = 100) and the least weight of newborn is 2 g. Female to male ratio were in the range of 48.2 to 51.8%, respectively (n = 82). Over wintering adult yearlings reached maturity in mid June. Yearlings arising hibernation after May gained weight during September and October and they entered hibernation at the end of November. The litters at bird gained weight daily from 0.83-1.19 g and reached to 25.16-35.7 g at mean within 30 days during August and September.
Introduction
The fat dormouse Glis glis (Linnaeus, 1766) is an arboreal and nocturnal glirid species inhabited in deciduous forest of Europe, Northern Anatolia, the Caucasus and North-Eastern Iran (Corbet, 1978; Storch, 1978).
In Turkey, it has been reported from Thrace by Kahmann (1962), Doğramacü and Tez (1991), Kurtonur (1975), Kurtonur (1992) Civitelli et al. (1995) and Simson et al. (1995) and Northern Anatolia (Osborn, 1965; Kumerloeve, 1975; Kock, 1990; Çolak et al., 1994, 1997). Among these records only the paper of Çolak et al. (1997) contains the reproductive knowledge of the fat dormouse. They describe the postnatal development of 8 pups born from a captive female obtained from Rize, North- Eastern Anatolia and give the litter size as 3-8 (Mean: 5.7, n:8).
So, there is no available information on the reproductive biology of the fat dormouse living in Turkish Thrace. The aim of this study was to summarize the reproductive data collected over five years (1998-2002) by monthly checks of 216 nestboxes, which placed in deciduous forest of Istranca (Yüldüz) Mountains of Turkish Thrace.
Materials and Methods
Data of breeding Glis glis were collected four study areas chosen in the mixed deciduous forest of North-East Turkish Thrace. The name, altitude, latitude, area, number of nestboxes, dominated trees and durations of the monthly controls of the study areas as fallows:
| 1 | Demirköy. 530 m a.s.l. 41 48 N 27 44 E. 2 ha 60 nestboxes. Fagus orientalis, July 1998 - October 2002. |
| 2 | Çakmaktepe. 130 m a.s.l. 41 48 N 27 46 E. 1.2 ha. 37 nestboxes. Malus sylvestris, Corylus avellanarius, July 1998 - December 2000. |
| 3 | Kastro.10 m a.s.l. 41 36 N 28 06 E. 1.5 ha. 48 nestboxes Quercus spp. July 1998 - November 2001. |
| 4 | Çilingoz.. 30 m a.s.l.. 41 34 N 28 10 E. 2.4 ha 71 nestboxes, Quercus spp., July 1998 - December 2000. |
In total, 216 wooden nestboxes (20x18x14 cm, hole 5 cm) were tied to tree trunk according to Morris et al. (1990). Nestboxes density was 30 per ha. They were sited 3 - 4 m above the ground.
In total, 891 fat dormice have been captured of which 531 marked by ear tattooing (tattoo pliers). Captured dormice after etherized were weighted, sexed, external measurements (head and body, tail, ear and hind foot) and breeding conditions were recorded.
Female with litters, sizes of litters, sex ratio, weight, external measurements (head and body and tail length) and morphological development (separations of digits, fur development, eye and ear opening) of the nestling were recorded.
In estimation of the mating day and the day of birth of young, the procedures of Bieber’s (1998) were fallowed. The age and from hence, birth date of the young was calculated by their external measurements, morphological development and body weight according to Koenig (1960), Vietinghoff-Riesch (1960), Gaisler et al. (1976). In calculation of the mating date, 30-31 days of pregnancy was taken by Koenig (1960).
Results
Breeding Time
During the study, in total, 531 fat dormice were marked in 891 captures.
In these animals 88 females with litters have been recorded of which 22 have
been recaptured. In certain years, lacking of the females with litters shows
that reproduction does not occur in same pattern in every year (Table
1). In the monthly checking period, we observed progress in the morphological
sexual characters of both males and females after May 13.
The dates of females with litters that found in the nestboxes in the whole study areas were between 9 August and 25 September. Estimated dates of birth of these nestlings, by using their morphological parameters and body weights, were scattered 14 July and 16 September (Table 2). Within this period, most breeding occurs in the last week of July (36% of all litters recorded) and in the first week of August (24%) (Fig. 1). The mating period can be estimated from the dates of birth minus duration of pregnancy (30-31 days) Koenig (1960). In this case, mating occur between 15 June and 18 August, mostly in the last week of June and first week of July (Table 2 and Fig. 1).
| Table 1: | Durations of monthly checks of four study areas and the numbers of captured = marked + recaptured fat dormice in which the numbers of females with litters (♂+♀) given in parenthesis |
| ♂ + ♀ (male and female symbols) | |
| Table 2: | Estimated birth and mating dates of females with pups in Istranca Mountains |
| Table 3: | Litter sizes and sex rations of pups |
The unreproductive year in Demirköy, that is 2000 and the unfruiting beech trees confirm the notion of Bieber (1998) that Glis glis foresee the time that the trees around will not give fruit and thus they don’t breed.
Litter Sizes and Sex Ratio
Total litter size varied between 1 and 12 (mean = 6.1, N = 90) (Table
3). Litters of 5-8 young were most frequent (75% of all litters recorded)
(Fig. 2).
| Table 4: | The body weight gaining of captured and recaptured pups in August, September and October 1998 and 2001 (n = 25). (*) = New born) |
| Table 5: | The first breeding ages of the female that marked when yearlings and recaptured in the following year with litters (n=14) |
At all study areas the average proportion of the males among the litters were significantly male based. In the whole sample the proportion of males was 54.1%. There is no statistically significant difference between the sex ratios of the pups in all four localities (ANOVA df 3 p>0.05) (Table 3).
| Fig. 1: | Weekly distributions of birth rate frequencies and pup numbers |
| Fig. 2: | Weekly weight gains of the pups after birth |
Body Weight Gaining of the Young
The pups weigh 2 g at birth. The newborns reached a body weight of 20 g
by the 26th day of their lives, gaining about 0.78 g a day. During this study,
we found that the pups were 1-36 days old when they were first observed in the
next boxes and that their daily weight gains was 0.76-1.22 g with an average
of 0.93 g (n = 25). The same pups were 21-56 days old when they were catched
for the second time. They increased their weights by 18-82 g since the first
observation and their daily weight gains was 0.54-1.92 g (Table
4).
All the pups’ body weight gains were tracked weekly till the 9th week and their average weights were found to reach 78 g (Fig. 2) The average weekly and daily weight gains of the pups were 8.6 and 1.2 g, respectively.
Table 5 shows that the daily body weight gains of the marked pups were 1.04-1.42 g with a mean of 1.14 g.
The weight gains of both adults and pups were at the highest levels in September, October and November due to fat deposition as preparation for hibernation. Adults and pups continued to use the next boxes until 20th of November. The individual with the highest body weight was catched on 4th of October with 286 g.
First Delivery of Young Females
The pups catched in the nestboxes during our controls were marked if they
weighed 40 g or more. The female individuals among them were recaptured in the
following year with their pups. The females gave birth after 351-380 days. The
ones that gave their first births were observed to perform this task when they
reached to a body weight of 102 g (Table 5).
Acknowledgements
I thank to Prof. Dr. Cengiz Kurtonur, Tansel Türkyülmaz and Sinan Çünarkök for their contributions to the manuscript and their kind helps for the long field study. This study was supported by The Scientific Research Fund of Trakya University (Project No. TUBAP-171).