Variation in erythrocyte morphology in alpine accentors (Prunella collaris Scop.) from Tian Shan, Rila and the High Tatra mountains and effects of molting

Abstract

The birds inhabiting the high-altitude mountains have several physiological adaptations to environmental conditions. In this study, we try to investigate if are the morphological changes in erythrocytes caused by adaptation to a different condition in Eurasian mountain ranges and molt period. In a comparison of morphology of erythrocytes in alpine accentors from three different regions (Central Tian Shan (Kyrgyzstan), the Rila Mountains (Bulgaria) and the High Tatras (Slovakia)) variations were found in size and shape. Birds from the High Tatras had the largest and most elliptical cells, while erythrocytes from Tian Shan´s birds have the smallest and roundest shape. We also found that individuals from spatially separated populations of alpine accentors vary in size. The largest birds are found in the High Tatras, with smaller birds in the Rila Mountains and the smallest in the Tian Shan. Changes in erythrocyte morphology were studied in birds during the molt period (September–October). The cells elongate during the molt and do not reach their pre-molt size even after the molt. These morphology differences likely reflect their adaptation to environmental conditions such as climate and temperature as well as individual metabolic processes during the molt and preparation for autumn migration. In addition to their essential function (respiratory gas transport), nuclear erythrocytes can also participate in the transcription and translation of proteins, extending their other functions. Thus, it seems that changes in morphology must not affect these functions.