الفهرس 
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Abstract
Some arthropod species are associated with termites, the most numerous and least studied are the mites (Acari). Some mite species are only incidentally found in termite nests, while others are obligate associates.
Generally, most mites associated with termites are considered as saprophagous or phoretic (Wang et al., 2002). These mites do not have any significant effects on the health of their hosts in nature. Few mite species feed on termites. Some, Such as: Acotyledon formosani Phillipsen and Coppel and certain species of the genus Australhpopus, are abundant in weak termite colonies and cause death (Phillipsen and Coppel, 1977a,b). Conversely, termite-associated mites may benefit the termites by scavenging on other arthropods or fungi (Eickwort, 1990). Despite the abundant and diverse mite fauna existing with termites, little is known for their diversity, biology, ecology and the nature of their associations.
In the present study, the diversity and abundant of some mite and insect species associated with the sand termite, P. hypostoma together, with the simultaneous effects of certain environmental variables on the population density of mites species when they accompany termite workers during the surface activity were studied. The possibility of using the new recommend insecticides for termite control has also achieved through the current study.
The present course of investigation therefore had to be accomplished in three basic topics:
1. Taxonomical and morphological studies of the Acarididia mite species extracted from termite nests, located in Upper Egypt and the New Valley Governorates.
2. The exploration of the ecological trends of some mite and insect species associated with the sand termite, P. hypostoma which attacks wooden construction, trees and any cellulosic materials in the New Valley Governorate.
3. Toxicological studies, using some selected neonicotinoid pesticides to combat termite workers in the laboratory and below the soil surface in areas infested with the sand termite.
The present study showed the following results:
5.1. Taxonomical studies:
1. Certain morphological characteristics were used to separate the mite species from each other.
2. Description of two new Acarididia mites of the total species extracted from the nest of the sand termite, P.hypostoma, the two new species proved to be new to science.
3. Establishment of an identification key for 21 Acarididia mites, of these 19 species were previously described from the nest of the Amitermes desertorum (Desneux) (Aswan Governorate) and the Psammotermes hypostoma Desneux (New Valley, Assiut and Qena Governorates).
5.2. Ecologyical studies:
5.2.1. General survey of the mite species extracted from the sand termite nest:
Thirty six species of mites pertaining to eighteen families and three orders (Astigmata, Mesostigmata, and Prostigmata) were identified from the nests of the sand termite, P. hypstoma, El-Kharga, New Valley, during 2012 to 2014. Of these, 17 species are belonged to Astigmata mite (10 species pertaining to the Acarididia and 7 species affiliating to the Oribatei); the Mesostigmata (16 species) and Prostigmata (3 species).
5.2.2. General survey of insect species associated with the sand termite, P. hypostoma:
Nineteen insect species pertaining to ten insect families and seven orders were identified from the sand termite nest, El-Kharga, New Valley during the two studied years (2012 to 2014).
5.2.3. Seasonal and monthly abundance of mite groups in relation to the surface foraging activity of the sand termite:
Spring and summer were found to be more favorable for the three mite groups through both years of study. The peak numbers were recorded during July and August identical with the census of the termite individuals, whereas winter and autumn seasons were found to be less suitable for mites and termites activities.
5.2.4. Simultaneous effect of certain weather factors in addition to mite individuals on the surface foraging activity of the sand termite:
The maximum and minimum temperature and the maximum and minimum temperature of soil temperature (10 cm of soil depth) showed highly significant positive correlations (r = 0.7748**; 0.7553**; 0.8117** and 0.7511**), respectively. However, the maximum relative humidity had highly significant negative one (r=-0.6176**), and the minimum relative humidity had insignificant negative correlation (r=-0.3931). On the other side, the relationship between the number of the termite individuals versus the number of all mite groups showed highly significant positive correlation (r=0.8587**). All studied factors were responsible for 86.74% on the surface activity of the sand termite, P. hypostoma. It can be concluded that mite individuals, temperature and soil temperature were the most important variable factors affecting the surface foraging activity of the sand termite workers.
5.3. Toxicological studies
5.3.1. Laboratory studies:
5.3.1.1. The LC50 values of termite workers when used workers dip bioassay method after 3 h exposure period of Chlorpyrifos (48% EC), Imidacloprid (20% SL), Acetamiprid (20% SP), and Thiamethoxam (18.6% SC) were 15.07, 34.42, 48.42, and 76.72 ppm, respectively. While, after 12 h, these values were decreased to be 1.24, 2.55, 3.82 and 5.95, and 0.21, 0.66, 0.81and 1.11, after 24 h of treatment for the above mentioned pesticides, respectively. Thiamethoxam (49%WG) was not applicant after 3h of treatment, its mortality percentage was significantly below 50%. The LC50 values of this compound were 11.84 and 5.75 after 12 and 24 h of treatment.
The toxicities of the tested pesticides increased significantly after exposure periods from 3 h to 24 h. The toxicity index of Chlorpyrifos (48% EC) was 100%, after 3h of treatment, and for the selected neonicotinoid pesticides, Imidacloprid (20% SL), Acetamiprid (20% SP) and Thiamethoxam (18.6% SC) were 43.46%, 31.21%, 19.63%, respectively. However, the same trend was also observed after each time period (6, 12, 24 h).
5.3.1.2. When used the cardboard-dip bioassay, the LC50 values after 3 h of treatment were: 28.29, 50.95, 52.18, 83.36 for Chlorpyrifos (48% EC), Imidacloprid (20% SL), Acetamiprid (20% SP), and Thiamethoxam (18.6% SC), respectively. Thiamethoxam (40% WG) was not applicant, its mortality percentage was significantly below 50%. While, these values were: 7.20, 19.15. 21.55, 27.50 ppm; 2.10, 4.08, 4.57, 7.77, 14.80 and 0.36, 0.82, 1.02, 1.33, 6.21 after 6, 12 and 24 hours for chloropyrifos (48% EC), Imidacloprid (20% SL), Acetamiprid (20% SP), Thiamethoxam (18.6% SC), Thiamethoxam (40% WG), respectively. The current study revealed that, Chlorpyrifos (48% EC) was the most toxic compound among the tested pesticides, while, Imidacloprid (20% SL) was the most potent neonicotinoid among the four tested neonicotinoid pesticides. Moreover, the toxicity increased dramatically for all tested pesticides after exposure from 3 h to 24 h. The toxicity index of Chlorpyrifos (48% EC) was 100% after 3 hours exposure period. While, these values were: 55.52%, 54.21% and 33.93% for the selected neonicotinoid pesticides: Imidacloprid (20% SL), Acetamiprid (20% SP), Thiamethoxam (18.6% SC), respectively. Thiamethoxam (40% WG) was not applicant. Further, similar trends were also observed after each time period (6, 12, 24 h). from the above mentioned toxicity results, it can be observed that, the use of termite workers dip bioassay method gave better results of the tested pesticides as compared with the cardboard-dip bioassay. The LC50 values decreased after 24 h as compared with the 3 h exposure period to the tested pesticides. Furthermore, Chlorpyrifos (48% EC) is considered the most potent pesticides among all pesticides tested whereas Imidacloprid (20% SL) is considered the most potent one among the neonicotinoid pesticides tested under laboratory conditions. The formulation of Thiamethoxam (18.6% SC) was more toxic than the formulation of Thiamethoxam (40% WG) in both bioassay methods.
5.3.2. Field studies:
The reduction percentages in palm fronds recorded as the height of termite sandy clay formed by termite workers on the palm frond surface when treated with the concentration of 0.1 mg/L of Chlorpyrifos (48% EC), Acetamprid (20% SP), Imidacloprid (20% SL), Thiamethoxam (18.6% SC), and Thiamethoxam (40% WG) were: 45, 41.67, 18.42, 20.00 and 01.96% after 15 days exposure period, respectively and when used 1.00 mg/L, these values were: 67.5, 64.58, 44.74, 42.00 and 17.65%, respectively. At concentration 10 mg/L, the reduction percentages were: 87.50, 79.17, 68.42, 60.00 and 41.18% for the above mentioned pesticide, respectively. However, at high concentrations (100 and 1000 mg/L) the reduction percentages were: 100, 100, 86.84, 80.00 and 60.78, respectively. Whereas in the control treatment, the reduction percentages were 0% for all insecticides used. After 30 days exposure period, the reduction percentages were increased. At the concentration of 0.1 mg/L of Chlorpyrifos (48% EC), Acetamprid (20% SP), Imidacloprid (20% SL), Thiamethoxam (18.6% SC), and Thiamethoxam (40% WG), the percentages of reduction were: 58.67, 51.43, 45.78, 35.00 and 14.28%, respectively. When used the concentration of 1.00 mg/L the reduction percentages were: 70.67, 60.00, 56.63, 48.75, and 25.71%, respectively. At concentration of 10 mg/L, the reduction percentages were: 78.67, 70.00, 67.47, 62.50 and 42.86%, respectively. Furthermore, at high concentrations (100 and 1000 mg/L), the reduction percentages were: 89.33, 85.71, 78.31, 75.00, and 57.14%, respectively. Whereas in the control treatment, the reduction percentages were 0% for all insecticides used. The same trends of results were observed after 45 and 60 days exposure periods. It can be concluded that, the reduction percentages on palm fronds increased significantly with an increase of the exposure period (from 15 to 60 days) as a result of the surface foraging activity of the sand termite workers.