الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Survey of spiders in tomato plantations was carried out in Al-Mandara region Fayoum Governorate, from Nov. 2012 till Sept. 2014. Collection of spiders started two weeks after planting and continued weekly to the end of the season. Results revealed the existence of 42 species that belong to 34 genera in 14 families. Population densities and seasonal fluctuations in relation to weather conditions were estimated.
The most dominant families were Theridiidae, Lycosidae and Dictynidae, represented by 36.02%, 21.01% and 20.62%, respectively. In moderate numbers were families Miturgidae and Philodromidae, represented by 8.01% and 5.75%, respectively. The rest of families were found in low or rare numbers as follow; Thomisidae 2.4%, Araneidae 2.3%, Salticidae 1.6%, Pisauridae 0.8%, Gnaphosidae 0.6%, Linyphiidae 0.4%, Pholcidae 0.2%, Clubionidae 0.1% and Mimetidae 0.1%. In general two species Anelosimus aulicus (Theridiidae) and Dictyna segregata (Dictynidae) were most dominant being 32.01% and 20.62% of the population of spiders community inhabiting tomato fields.
Statistics indicated insignificant correlation between spider populations and temp., with negative significant correlation for R.H. during Nili plantation 2012/2013; whereas in 2013/2014, the positive correlation was only for temp., with no significant correlation with R.H. In Summer plantation 2013, a positive significant correlation was found for both temp. and R.H., but in 2014, high positive correlation was found with temp. only, with no significant correlation with R.H.
Anelosimus aulicus (Koch), a comb-footed spider that has a great potential to suppress agricultural pests was dominant species. The use of Lannate®, Reldan® and Match® insecticides affects survival of A. aulicus. The effect of these insecticides on this spider was investigated under laboratory conditions which fed on treated larvae of Spodoptera littoralis.
Furthermore, the ultrastructure of the spider midgut and possible changes due to insecticide treatment were examined using Transmission Electron Microscopy (TEM).
The LC50’s, LC90’s values and slope for these insecticides for prey or predator were evaluated and discussed. Lannate® was the most effective due to high acute toxicity, causing 66.7% mortality for females and 91.6% for males. It was also the most drastically effective on females fecundity with no egg sacs laid under recommended field concentration.
Reldan® caused 58.3% mortality for females and 83.33% for males. Match® caused 50.00% mortality for females and 58.33% for males. Generally, males were more sensitive for insecticides than females. The effect of insecticides on longevity periods, prey consumption, fecundity, % hatch and egg incubation period of spiders which fed on treated prey at different concentrations of insecticides were given.
On the other hand, the ultrastructure of the midgut of females and males revealed similarity in untreated spiders which fed on untreated prey after 48h of treatment. Meanwhile, different changes indicated by the presence or absence of some cell components in this organ on specimens which fed on treated larvae, which might interfere with its function.