Effect of crytocotyle lingua on the ionic concentration of littorina obstusata [L]

The concentration of sodium, potassium and calcium ions [the most important inorganic ions in the body fluid] were determined in both parasitized and uninfected Littorina obtusata [L.]. The ionic concentrations were determined using a Pye Unicam SP atomic absorption spectrophotometer. Sodium and calcium were determined using the absorption mode, while potassium concentration was measured in the emission mode using special potassium filter. The results revealed no significant difference in the concentration of Na+, K+ and Ca++ between parasitized and uninfected L. obtusata. It seems that although the presence of the parasite within the molluscan hosts caused dramatic effects in the tissue and physiology of the snail, the blood ionic concentration of parasitized snail remains isosmotic to that of the surrounding medium

First record of planorbis [Linnaeus] naturally infected with xiphidiocercariae from Derna, Libya

A review of the literature shows that the fresh water snail Planorbis planorbis [Mollusca: Gastropoda] infected with xiphidiocercariae has never been recorded in Derna, Libya. In the present paper the first record was made from Wadi Derna [= Darnah] East Coast of Libya. The snail harbor xiphidiocercariae, the percentage of infection during May 1989 was found to be 7.3%. Morphological description of the snail Planorbis planorbis, xiphidiocercariae is given in the present investigation. The snail possibly acts as an intermediate host of trematode species in Libya. Further studies are needed to investigate and to observe the exact type of trematode in which the fresh water snail P. planorbis acts as an intermediate host in the life-cycle and to determine the definitive host in Libya

Comparative studies on the development of the entomogenous nematodes steinernema feltiae filipjev on spodoptera littoralis [boisduval] and musca domestica linneous

Comparative studies were made at 26°C under laboratory conditions on the development of Steinernema feltiae Filipjev [= Neoaplectana carpocapsae] on the diffrent stages of Spodoptera littoratis [Biosduval] and Musca domestica [Linneous]. In the present investigation the host species influence manifested itself, in a quicker development rate along with the cotton leafworm S. littoralis. Particular development stages took place earlier in the S. littoralis than in M. domestica. As far al the occurrence dates of particular stages of S. feltiae were concerned, the differences in relation to the two host species were significant. The changes in numbers of giant forms in the development course of populations in the caterpillars, pupae and imagos body of both species were studied. The numbers of giant forms correspond with the numbers of invasive larvae, it seems that at first they are growing and then decreasing

Steinernema parasitism of larvae of the housefly musca domestica linneous

The histopathological effect of different dosages 50, 100, 200, 500 and 1000 of Steinernema feltiae Filipjev larvae on the larval tissues of Musca domestica Linneous has been studied. It was found that S. feltiae nematodes invade the fat tissue, gut, cuticle and, muscle tissue of the host. All of these tissues, along with the gut epithelium, show signs of disintegration before death of the host. The tissue of the gut and the fat body are the most severly damaged by the presence of S. feltae. The destructive damages described in this investigation depend mainly upon the time and the intensity of infection

study of the protozoa associated with some harmful insects in the local environment

The present study includes finding resulting from examination of three species of harmful insects, Periplaneta americana, Schistocerca gregaria and Anacanthoterms ochraceus, collected from six cities in the Central Region of Saudi Arabia. Two species of septate gregarines of the genus Gregarina Dufor, were found G. blattarum [Siebold] from mid gut of P. americana and G. rigida from gut of S. gregaria, also six species of Mastigophora in gut of white ant A. ochraceus, Trichonympha campanula, Spirotrichonympha sp., Holomastigoides hartmanni, Rostronympha magna Monocercomonas axostylis and an unidentified species. The seasonal intensity of these Protozoa and percentage of infection together with information about, the holotype, materials are included. At present the holotype materials are deposited at the department of Zoology, Girls College of Education, Riyadh, Saudi Arabia

influence of infection with steinernema feltiae filipjev on the haemocyte picture of the cotton-leaf worm [Spodoptera Littoralis Boisduval]

Infection of Spodoptera littoralis Boisduval larvae with Steinernema feltiae Filipjev nematodes caused sharp variation in proportional percentages of differential hemocyte counts. The mean total hemocyte count per cubic mm of hemolymph in control larvae of S. littoralis was 6000 hemocyte per cubic mm. After infection with 50, 100, 200 and 500 parasitic nematodes of S. feltiae, the mean total count was significantly increased to 17250, 18600, 21000 and 24000 hemocyte per cubic mm, respectively

effect of xiphidiocercarial infection on the ventricular blood pressure of lanistes carinatus

Measurements of the blood pressure from the ventricle of both uninfected Lanistes carinatus and those parasitized with xiphidiocercariae were made in order to determine whether the infection affects the circulatory pressure in L. carinatus. Using ink writing oscillograph [Washington 400 MD 2] the ventricular blood pressures were recorded for 22 uninfected specimens and 16 parasitized with xiphidiocercariae. Parasitized L. carinatus showed a significantly lower ventricular pressure than uninfected ones. The mean ventricular pulse pressure of uninfected snails was 7.79 cm of water compared with a mean of 5.76 cm of water for parasitized specimen

egg mass and growth rate of biomphalaria alexandrina under laboratory conditions

Egg masses of B. Alexandrina are always laid below the water surface in yellowish, rounded to oval, gelatinous masses. The egg mass ranges from 2.5 x 2 mm with 4 eggs to 8 x 5 mm with 39 eggs.The incubation period ranges between 11-15 day in February [15.1-20.3°C] and 6-9 days in August [26.l-31.1°C]. At hatching the shell diameter varies between 0.6-0.7 mm and attains maturity [6.8-7.2 mm] within 80-85 days

Semi-field studies on the bionomics of biomphalaria alexandrina in Egypt

Maximum growth of Biomphalaria alexandrina occured in Spring and minimal growth in Winter. A definite annual cycle in reproductivity and frequency was also recorded. Breeding was intense and mortality was low in Winter oviposition was at a high level in Spring and decreased in Summer. The snail population built gradually in Winter and Spring until a major density peak was reached in June, declined in Summer and breeding started again in Autumn