Gregarine Stylocephalus oblongatus (Apicomplexa, Eugregarinida, Gregarinidae) from the Intestine of Opatrum sabulosum (Coleoptera, Tenebrionidae) in the Reclamation Areas of Pokrovsky Mining and Processing Plant: the First Report and Morphometric Variabil

Abstract

The peculiarities of variability of forms and sizes of the gregarine Stylocephalus oblongatus (Hammerschmidt, 1838) Watson, 1916 in the intestines of the Opatrum sabulosum (Linnaeus, 1761) from the sites of reclamation of lands disturbed by mining industry in the south of the area of the Steppe Dnipro were investigated. This is a new record for the protozoan fauna of Ukraine. The prevalence of host infection was 7.44 %. To determine the limits of variability, a sample of 71 specimens was used. Gamonts of S. oblongatus were analysed by 15 linear characteristics and 18 indices of the ratio of these characteristics. For linear parameters, the average coefficient of variation was 33 %. The minimum values of the coefficient of variation were characteristic for the lengths of the gamont, protomerite and their ratio. The principal component analysis identified 4 principal components, the value of which was greater than 1. Together they explained 73 % of the variability. Cluster analysis identified 4 clusters that can be explained as 2 morphotypes and 2 morphosubtypes. The greatest contribution to the overall variability of S. oblongatus gamonts is made by the position of the cell nucleus of the gamont in relation to the septum, the width of the septum and protomerite and the distance from the posterior end of the deuteromerite to the axis of its maximum width. The observed morphological differences can be explained by different degrees of host infection. It is important to compare the obtained information on intraspecific variability of S. oblongatus with similar data from natural ecosystems, as well as from agrocenoses and urban populations of O. sabulosum.