title: [Sizes and sex ratio as indices of inter- and intraspecific relationships of the nematodes from murine rodents].
abstract: On the base of morphometric analysis and investigation of sex ratio in some nematode species from murine rodents the next tendencies were revealed: 1. If the durations of life in nematode males and females are about the same, the sex ratio in a monoinfected host is near 1/3 males and 2/3 females. 2. Presence of other helminth species moves the sex ratio towards males, but in the case of polyinfection the percentage of males decreases again. 3. Solitary helminth specimens have minimal size, and as the parasite number in a host increases, the length and width of nematodes at first in crease, and then begin to decrease. Bounds of these increase and decrease depend on the size, as well as the taxonomic belonging of a nematode. 4. In the presence of other helminths, the decrease of size in a nematode species take place under lesser parasite number than in the case of nomoinfection. Decrease of the absolute size of nematodes and female percentage reduces energy demands of the parasite pool in a host body, because females are larger than males and moreover they spend nutrients and energy for reproduction. It leads to the reciprocal regulation of the helminth species abundance at the level of populations.
authors.forename: N E
authors.initials: NE
authors.lastname: Tarasovskaia
mesh_terms: D000818:Animals; D005260:Female; D006790:Host-Parasite Interactions; D008297:Male; D051379:Mice / Q000469:parasitology*; D009348:Nematoda / Q000033:anatomy & histology / Q000145:classification* / Q000302:isolation & purification; D010270:Parasite Egg Count; D012744:Sex Ratio