Marisia - Maros Megyei Múzeum Évkönyve 36/1. (2016)

Zoology

Alina LARION, Victoria NISTREANU, Veaceslav SÍTNIC, Vlad POSTOLACHI

The duration of mound construction varies depending on the biotope and climatic conditions. Despite the fact that mound construction process is similar, they differ in form, size, weight of food reserves and the number of individuals they inhabit it [5]. After the form of its base the mound resembles most often with irregular ellipse (65%), rarely it is round (35%). On wheat and maize stubbles and on fallow ground double mounds were found (4%). The biggest mounds have been identified in the area of ecotone fallow - wheat stubble and fallow - corn stubble, while the lowest — on the fields of alfalfa (Tab. 1). On fallow and on a strip of weedy not harvested corn particularly large mounds have been found. The length of this strip was about 1.4 km and width of 7 m. It has investigated only a portion of 0,07ha (100x7m), where 11 mounds were observed and investigated. The distance between the mounds varied between 8 and 25 m. Some of them were very high — 45-49 cm and nears om at about 0,5-1 m food reserves non-covered ground were found, in spite of the fact that it was already late October. Thus, the climatic conditions were favorable, food was plentiful and it has allowed longer duration of mound construction.

At the ecotone fallow-agrocoenoses the mounds are the largest, because only in this area there are many seed of both crops and spontaneous plants. Mound size depend not only on the seed abundance, but also on the number of individuals participating in construction (r = 0.99). The number of individuals in mounds with smaller diameter, up to 100 cm, is of 5—6 individuals, with a diameter of 150—200 cm — is of 9—10 individuals and with diameter of higher than 200 cm - is of 12- 14 individuals. As it can be observed, the number of individuals in mounds is the largest at ecotone and in fallow.

Table 1: Dimensions of mounds depending on biotope and number of individuals in autumn

Biotope Large diameter, m Small diameter, m Height, m Ni.ind./mound

min. max. mean min, max. mean min, max. mean________mean_____

Maize stubble 0.8 7 1.28±0.15 0.8 1.33 1.04±0.06 0.20 0.35 0.25±0.02 8.9±0.62

Unharvested 0.8 2.2 1.40±0.10 0.8 1.6 1.19±0.07 0.18 0.49 0.35+0.03 9.8+0.58

maize__________________________________________________________________________________________

Wheat stubble 0.8 1.55 1.21+0.09 0.7 1.55 1.13+0.09 0.2 0,37 0.28+0.02 8.3+0.07

Sunflower 1.0 1.98 1.34+0.06 0.8 1.57 1.23+0.06 0.2 0.54 0.36+0.02 8.9+0.42

stubble_________________________________________________________________________________________

Alfalfa 0.74 1.2 0.99+0.05 0-74 1.2 0.97+0.05 0.16 0.32 0,22+0.02 6.5+0.27

Fallow 0.9 2.3 1.50+0.07 0.8 1,76 1.28+0.05 0.18 0.56 0.36+0.02 10.1+0.47

Ecotone 1.2 2.4 1.68+0.1 0.95 1.5 1.29+0.06 0.3 0.45 0.38+0.02 11.1+0.46

fallow-wheat____________________________________________________________________________________

Econote 1.15 1.99 1.67+0.08 1.15 1.8 1.45+0.06 0.24 0.52 0.35+0.02 10.2+0.35

fallow-maize ____________________________________________________________

In wheat crops the highest density was recorded up to the harvest, followed by number decrease of population. In maize crops the number of individuals increases along with crop growth until the harvest, followed by a sharp decrease of density and the complete renewal of the population. In alfalfa crops the maximum density was recorded during the growing season (May-June), then, depending on agro-technical works, the number of individuals varies significantly and the population is renewing 2-3 times per year. On fallow and at ecotone zones the reproductive activity is also high in other months, because there are no agricultural works and the trophic base is always abundant. On cereal fields in the first half of the summer the reproduction is the most intense (73.1% of reproductive females) compared to the land with perennial plants

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