The work demonstrates the clear presence of ageing aspects in the postembryonic development of the song thrush in regard to its linear dimensions and body proportions. It is proposed to distinguish the stages of early nesting, mid-nesting and late nesting. At each stage, the mostly developed body parts and organs are those which are needed for the growing organism to provide its best functionality at the current period of its postembryonic development.
We study size-at-age and sexual variability of morphometric characteristics of the marsh frog. According to the size of the body, males were divided into three size-age groups (juvenis, subadultus, adultus), females — into four groups (juvenis, subadultus, adultus, adultus-I). We found that the chronological age of frogs (skeletochronology) does not always correspond to their biological age (size and proportions of the body). We noted that the semi-adult males are reliably larger than females by mean values of 26 studied morphometric characters. Males and females of “adultus” group do not differ by linear body size, significant differences were found in body proportions (7 characters). For the females of “adultus-I” group, the mean values of 26 characters are significantly larger than for “adultus” males. The results of our study showed that with the age of the marsh frog, the level of exhibition, directionality and structure of morphometric sex differences changes.
Interrelations Between Different Forms of Group Variability of Quantitative Traits in Microtus socialis (Cricetidae, Mammalia) in the Peak Phase of Population Abundance. Peskov V. N., Sinyavskaya I. A., Emelyanov I. G.- The amount of input and the interrelation of various forms of group variability of quantitative traits in general morphological disparity of M. socialis in the peak phase of the population abundance was studied. It was found that the variability of 4 exterior and 11 interior traits are determined primarily by the age of the animals, whereas the influence of sex and the season is very low. With ageing, the intensity of sexual differences and seasonal variability increase. The correlated variability of morphological traits was almost the same (Rs = 0.820-0.98) in males and females during different seasons.
Sex differences and the ability to determine the sex of Scorpaena porcus (Linnaeus, 1758) on morphological characters were studied in the population inhabiting coastal waters of the Black Sea near the southern coast of Crimea. These differences were revealed in size (females are larger than males) and in proportions of the body. It is found that variation of the absolute and relative values in plastic characters is higher in females compared with males. It is shown that in 92 % of individuals belonging to S. porcus we can determine the sex using morphological characters with a probability of 99.9-100 %.
Comparative analysis of morphometric characters of small-scaled scorpionfish from the Black Sea (near the southern coast of the Crimea) and from the eastern part of the Adriatic Sea showed significant differences in males and females on thirteen plastic and three meristic characters. These differences may be due to unequal abiotic and biotic habitat conditions, and refer about the geographical variability of the species, indicating the presence of two different populations in the study area.
The paper explores the possibility of implementing the methods of multivariate statistics into studying the growth processes on the example of song thrushes, Turdus philomelos, Brehm, 1831, during their postnatal development as nestlings. The developmental trends in 12 morphometric traits in T. philomelos in the course of postembryogenesis is shown to be explained for 99.3 % by the first two principal components (PC). The major developmental trend (PC1 - 95.1 %) is defined by a highly correlative though irregular growth of linear forms of nestlings’ body parts, the two other trends relate to the body proportion formation (PC2 - 4.2 %). Th ere have been discovered the two growth stages: (1) of fast growth: from birth up to the 8th day with relative increment in growth of traits equal in average to 91.9 %, and (2) of slow growth: from the 8th to the 14th day, characterized by a reduction of an average growth increment being five times lower, and by intense feather cover development. There have been demonstrated that all the variables can be structured into the four groups or growth correlation pleiads (groups comprising similarly growing traits). The growth is shown to be most specific for the song thrush’s body, head and bill, being a part of a single pleiad. While still forming the three different growth pleiads the properties of the bird’s wing, leg, the 3rd and the 4th toes differ significantly less in respect to their growth characteristics.