Stevanovic Jevrosima
Investigations
of morphometric and chromosomal variability in diversity preserving of
Carniolan honey bee (Apis mellifera
carnica Pollmann, 1879) in Serbia
SUMMARY
The
concept of preservation of biological diversity takes into consideration all
aspects of living nature on Earth, the entire biological resources of genes,
species and ecosystems, as well as the mankind necessity for further prosperity
and survival. At the first plase, within this concept are simple and direct
verification and systematization of the entire biodiversity as a foundation
stone of all present and future human activities.
The
aim of this study was to investigate morphometric and chromosomal diversities
of indigenous populations of the carniolan honeybee A. m. carnica in order to preserve the genetic diversity of this
subspecies. The established aim is achieved by realizing the following tasks:
1. Microecological characterization of regions where honeybees of the Banat,
Timok and Syenichko–Peshterski ecotypes were sampled; 2. Morphometric analysis
of honeybees of the sampled ecotypes; 3. Chromosomal analysis of the honeybees
of the mentioned ecotypes.
For microecological analysis, all climatic data the for three-year
research period (1997-1999) were taken over from the Federal Weather Buerau
and were used for designing climadiagrams. Orographic data were gained from the
topographic maps (1 : 50 000) of the investigated regions, available from the Military Geographic Institute.
The floristic data, for the regions where sampling was done, were obtained by
monitoring the visited localities and comparing the obtained results with the
relevant literature data.
For
morphometric analyses, altogether 900 samples were collected from 30 different
localities (10 localities from
each investigated region). 30 adult workers were
sampled from each locality and their fore wings, hind wings and hind legs were
prepared. The basic parameters of descriptive statistics were calculated for
all 30 analysed morphometric characters (16 lengths and 14 venation angles) –
for the whole specimen, separately, for each ecotype and locality. In order to
ascertain the significance of individual differences between morphometric
characters (between ecotypes and between localities within each ecotype) the
analysis of variance (ANOVA) was performed. The canonical discriminant analysis
(CDA) was applied to morphometric data in order to evaluate level of divergency
and to identify elements of morphometric discrimination between the ecotypes.
For
chromosomal analyses of honeybees, 12 worker prepupae from each locality were
sampled. Since prepupae were collected from 10 localities of each investigated
region (inhabited with Banat, Timok and Syenichko–Peshterski honeybee
ecotypes), it means that 120 prepupae of each ecotype were collected. Only the
cerebral ganglia from living worker prepupae, nine to eleven days old, with
star-like, redish eyes, were used for the cytogenetic analysis. Chromosomes
from the cerebral ganglia were prepared in accordance with the procedure of Hoshiba et al. (1995), adapted to the
requirements of this study. G – banding of chromosomes was done by the
tripsin-method of Ronne
(1991), which is a modification and an improvement of those established by Seabright (1971). The Analysis of distribution of euchromatin and
heterochromatin regions were performed on honeybee chromosomes of Banat, Timok
and Syenichko–Peshterski ecotypes in order to determine the interecotype
chromosomal differences between honeybees in Serbia.
The
results of microecological investigations show orographic, as well as climatic
and floristic differences between the regions inhabited with the investigated
honeybee ecotypes. The results of the descriptive statistics and analysis of
variance of morphometric characters confirmed the existence of inter- and
intraecotype honeybee variabilities in Serbia. The greatest interecotype
differences were recorded between Syenichko–Peshterski and Banat honeybee
ecotypes; less between Timok and Banat and the least differences were noticed
between honeybeees of Syenichko–Peshterski and Timok ecotypes. The greatest
intraecotype variability was registered inside Syenichko–Peshterski ecotype,
less within Timok ecotype and the least within Banat ecotype. The analysis of
variance (ANOVA) indicated that intraecotype variability is minor in relation
to the interecotype variability.
The
Canonical Discriminant Analysis CDA of all the analysed morphometric
characteristics revealed 100% of the total variation in the first two canonical
axes. The values of
standardized coefficients indicated that in total specimen the greatest
proportion of the variance on the first canonical axis was expressed by
differences in value of angles G18, E9 and B4. The greatest contributions to
variance on the second axis were made by differences in fore
wing length (FWLN), femur length (FELN) and in value of angle G18.
Two-dimensional plots of scores of the first two canonical variables
discriminated three groups (ecotypes) from each other: Banat and Syenichko–Peshterski
ecotypes were discriminated on the first canonical axis due to the differences
in values of angles G18, E9 and B4, while Timok ecotype was separated from
Banat and Syenichko–Peshterski ecotypes on the second axis due to the
differences in fore wing length (FWLN), femur length (FELN) and in value of
angle G18.
Chromosomal
analyses revealed differences between Timok and Banat honeybee ecotypes in case
of chromosomes 2, 4, 11 and 13. Between Timok and Syenichko–Peshterski
ecotypes, differences in chromatic region redistribution were observed for
chromosomes 1, 2, 15 and 16. The greatest differences in G-band distribution
were registered between Syenichko – Peshterski and Banat ecotypes in case of
chromosomes 1, 2, 4, 11, 12, 13, 15 and 16.
The
variability in phenotype and genotype of the carniolan honeybee, confirmed
after morphometric and chromosomal analyses is the result of various
environmental factors, due to the fact that samplings were done in regions some
200 km apart, with different climatic, geographic and floristic features. All
the results point to a great inter- and intraecotype variability of the
carniolan honeybee in Serbia. The analysed ecotypes A. m. carnica represent a remarkable genetic resource for a highly
selectioned breed impovement. Therefore, it is necessary to undertake
protection measures for these ecotypes by forming segregated apiaries in their
indigenous regions.