Morphometrische Differenzierung von Anoplocephalidae-Zystizerkoiden mit einem Beitrag zur Reproduktionsfähigkeit experimentell infizierter Oribatiden

Abstract

Oribatid mites of the genus Scheloribates (Oribatei) were experimentally infected with eggs of Anoplocephala perfoliata, Paranoplocephala mamillana, Moniezia benedeni and Moniezia expansa (Cestoda: Anoplocephalidae). The series of tests were maintained in an incubator at 28°C for 28 days to accelerate the development of cysticercoids in the oribatid mites. After this period the surviving mites were dissected. The length and the width of isolated cysticercoids and oribatid mites were microscopally measured and the prevalence of mite eggs were revealed.

The infection rates of mites with cysticercoids of A. perfoliata, P. mamillana, M. benedeni and M. expansa amounted to 27,2%, to 11,8%, to 37,3% and to 36,5% respectively; the number of cysticercoids per mite ranged from 1 to 9, from 1 to 3, from 1 to 5 and from 1 to 4 respectively.

9,5% of the infected oribatid mites and 22,6% of the non-infected mites harboured mite eggs. Non-infected mites had more eggs than infected mites.

The volumes of each cysticercoid and each oribatid mite body cavity were computed from their length and width. This was the basis for the examinations of the dependence of the cysticercoid volume on the mite body cavity volume, the influence of infection intensity on cysticercoid volume and for the comparison of the cysticercoid volumes of the 4 examined Anoplocephalidae species.

A correlation between cysticercoid volume and mite body cavity volume was not found. Both large and small cysticercoids were isolated from large oribatid mites.

The infection intensity distinctly influenced the cysticercoid volume. At increasing infection intensity the cysticercoid volumes of A. perfoliata, P. mamillana and M. expansa were smaller, the variation of them decreased. On the other hand, cysticercoids of M. benedeni were smaller at lower infection intensity and conversely. The variation of the volumes got bigger, as the number of cysticercoids in the mite rose.

For the first time the cysticercoid volume of different Anoplocephalidae species was compared. P. mamillana and A. perfoliata (cestodes of Equidae) occasionally developed larger cysticercoids in oribatid mites than M. expansa and M. benedeni (cestoda of ruminants). The cysticercoid volumes of P. mamillana, A. perfoliata, M. expansa and M. benedeni ranged from 0,980 * 106 to 3,730 * 106 µm3, from 0,825 * 106 to 3,360 * 106 µm3, from 0,567 * 106 to 3,222 * 106 µm3 and from 0,445 * 106 to 1,590 * 106 µm3 respectively.

Cysticercoids of these Anoplocephalidae species can not be differentiated alone by their volumes. Other characteristics of Anoplocephalidae cysticercoids like diameter of scolex and suckers or the structure of cyst wall should be examined and tested for the differentiation.