Spiders in Ecological Webs: References

Nanotoxicology is argued and considered one of the emerging topics. In this study, polyaniline (PANI)/2-acrylamido-2-methylpropanesulfonic acid (AMPSA) capped silver nanoparticles (NPs)/graphene oxide (GO) quantum dots (QDs) nanocomposite (PANI/Ag (AMPSA)/GO QDs NC) as a nanoadsorbent has a potential for removal of toxic hexavalent chromium (Cr(VI)) ions from water. The acute toxicity of this NC was evaluated on Artemia salina and freshwater Ostracods (Cypridopsis vidua) larvae for 48 h. The measurements were made at 24 and 48 h with 3 repetitions. The 50% effective concentration (EC50) values of the NC were determined after the exposure of these organisms. According to the results of the optical microscope, it was found that both experimental organisms intake the NC. In the toxicity results of Ostracods, the NC had a highly toxic effect only at 250 mg/L after 48 h and the EC50 value was 157.6 ± 6.4 mg/L. For Artemia salina individuals, it was noted that they were less sensitive than the Ostracods and EC50 value was 476 ± 25.1 mg/L after 48 h. These results indicated that PANI/Ag (AMPSA)/GO QDs NC has low toxicity towards both investigated organisms.

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Acute toxicity assessment of polyaniline/Ag nanoparticles/graphene oxide quantum dots on Cypridopsis vidua and Artemia salina

The present communication is aimed at assessing the molluscan diversity and distribution under the impact of some physico-chemical variables on them in Gho-Manhasan stream (a distributory of Chenab), Jammu (J & K).  The study involved bottom sampling for 12 months (June, 2010 to July, 2011) from the banks of the stream and registered a total of 11 taxa of freshwater molluscs from class Gastropoda and Bivalvia representing 54.453 and 45.546% of the total population of molluscs. Numerically, Pissidium mitchelli (Bivalvia) was the most abundant taxa followed by Melanoides tuberculata (Gastropoda). Lymnea luteola, Bellamya bengalensis, Physella acuta, Gyraulus ladacensisshowed less frequent appearance whereas Lamellidens corrianus and Corbicula cashmeriensis were recorded as rare taxa. Analysis of the data revealed that the physico-chemistry of the stream exercised profound effect on the diversity and distribution of the malacofauna. Significant changes in molluscan assemblages were primarily due to changes in the stream water quality. Coefficient of correlation (r) between molluscs and physico-chemical parameters revealed significant relationship with bivalves.

	 

	Key words: Physico-chemical profile, distributory, gastropoda, bivalvia, malacofauna and correlation.

Diversity and distribution of Mollusca in relation to the physico-chemical profile of Gho-Manhasan stream, Jammu (J K)

Community structure of molluscans in River Nile and its branches in Assiut governorate, Egypt

Knowledge of the distribution and habitat preference of freshwater snail intermediate hosts can provide information to initiate and set-up effective snail control programmes. However, there is limited research conducted on the factors driving the occurrence and abundance of freshwater snail intermediate hosts in the Ethiopian Rift Valley. Hence, in this study, we investigated how environmental and biotic factors influence the occurrence and abundance of the snail intermediate hosts in Ethiopian Rift Valley region. Data on freshwater snails, physico-chemical water quality parameters, physical characteristics of habitat, predators and competitors, and anthropogenic activity variables were collected from 174 sampling sites during the wet season of 2017 and 2018. Generalized linear models were used to identify the main environmental and biotic factors affecting the occurrence and abundance of the snail species. It was found that Bulinus globosus (31.7%) was the most abundant snail species followed by Lymnaea natalensis (21.6%), Lymnaea truncatula (15.1%) and Biomphalaria pfeifferi (14.6%). Generalized linear models indicated that physico-chemical parameters (water temperature, turbidity, chlorophyll-a, dissolved oxygen, chemical oxygen demand, alkalinity, calcium, magnesium, nitrate and ammonia), physical habitat characteristics (water depth, canopy cover, macrophyte cover and substrate type) and biotic factors (abundance of predators and competitors) were found to be the main variables determining the occurrence and abundance of snail species in the Ethiopian Rift Valley region. In terms of anthropogenic activities, human settlement, farming, bathing and swimming, clothes washing, grazing, drainage of land, car washing, boating, fishing and silviculture were also important variables determining the occurrence and abundance of snail species in the region. The findings reported herein suggest that integrated snail control strategies should be considered to control snails via protection of water bodies from disturbance by anthropogenic activities. In this way, it is possible to reduce the concentration of organic matter and dissolved ions in aquatic ecosystems which are conducive for the presence of snails.

/pdf/environmental-and-biotic-factors-affecting-freshwater-snail-11r9kknvgg.pdf

Environmental and biotic factors affecting freshwater snail intermediate hosts in the Ethiopian Rift Valley region

Monthly and seasonal fluctuations in densities of freshwater snails were recorded in six different sites at Qena Governorate during the period of March 2009 February 2010. The study revealed the occurrence of 13 species of freshwater snails belonging to 9 families of class Gastropoda. The snail species and their total catch were: Cleopatra bulimoides (1704 specimens), Lanistes carinatus (1468 specimens), Melanoides tuberculata (1036 specimens), Gabbiella senaariensis (731 specimens) Theodoxus niloticus (670 specimens), Bellamya unicolor (588 specimens), Physa acuta (213 specimens), Lymnaea natalensis (145 specimens), Succinea cleopatra (85 specimens), Bulinus truncatus (73 specimens), Biomphalaria alexandrina (41 specimens), Gyraulus ehrenbergi (12 specimens) and Helisoma duryi (2 specimens) in a descending order. The densities of the recorded snails varied seasonally and the general seasonal peak was recorded during Autumn while the lowest density observed during Winter. Ecological factors which may influence the distribution of the recorded snails were also determined (water temperature, pH, dissolved oxygen conductivity, total hardness, total dissolved salts, water depth and percentage of macrophytes).

http://zoology.eajbs.eg.net/pdf/vol3-num1/2.pdf

Population dynamics of freshwater snails (Mollusca: Gastropoda) at Qena Governorate, Upper Egypt

Spiders are one of the more diverse arthropod taxa, ranking seventh in global diversity, which makes them a fascinating group to study [1]. The correct identification of many spider species is considered problematic due to complex variation in morphology [2]. The Egyptian spider fauna are incompletely known due to scarcity of studies on this group especially in Upper Egypt. So, the present key for identifying terrestrial spiders at Qena Governorate is a part of a comprehensive study conducted at the region to study the ecology and taxonomy of this group. The present key was designed to facilitate identification of terrestrial spiders at Qena Governorate using their morphological characteristics. Samples of spiders were collected during a period of one year (from February, 2012 till January, 2013) from six different sites covering Qena governorate. Qena (15-260 N, 32-500 E) is located at Upper Egypt about 600 Km south of Cairo and 60 Km north of Luxor and 260 Km west of the Red Sea. Climate of Qena is hot, dry in summer and cold in winter. It rarely rains. Also, it receives a large quantity of solar radiation; especially in summer. Sampling methods of spiders included hand picking, sweep net and pitfall trap. Survey results revealed the occurrence of 14 families that included 23 genera and 23species. The present key for the collected families and species was designed and illustrated using taxonomic characteristics of each species.

/pdf/a-key-for-identification-of-spiders-at-qena-governorate-2sepzexsfr.pdf

A Key for Identification of Spiders at Qena Governorate, Upper Egypt

Spiders are one of the more diverse arthropod taxa, ranking seventh in global diversity, which makes them a fascinating group to study (Coddington, 1986). The Egyptian spider fauna still incompletely known due to scarcity of studies on this group especially in Upper Egypt. So, the present study was focused on Qena Governorate (15-26 N, 32-50 E) to make a survey of spiders in different habitats of this region and to study its abundance of this group as well as the effects of some physical factors on the abundance of the collected taxa. Samples were collected every 2 weeks during a period of one year (from February, 2012 till January, 2013) from six different sites covering Qena governorate. Sampling methods include hand picking, sweep net and pitfall trap. Also, physical factors (temperature, relative humidity, evaporation and wind velocity) were recorded during the period of study. Survey results revealed the occurrences of 1247 specimens belonging to 14 families that included 23 genera and 23species. Families recorded were: Agelenidae, Araneidae, Eutichuridae, Gnaphosidae, Linyphiidae, Lycosidae, Oecobiidae, Oxyopidae, Philodromidae, Pholcidae, Salticidae, Sparassidae, Theridiidae and Thomisidae. Family Salticidae was represented by the highest number of specimens during the whole period of study (22.29 % from the total number of collected taxa), while family Agelenidae was represented by the lowest number. The maximum number of spiders was collected during autumn (29.11 % from the total number) while the minimum number was collected during winter. By using statistical analysis, it could be concluded that the total relative abundance of all species was affected by temperature followed by relative humidity.

https://cat.journals.ekb.eg/article_18015_ea55e50801719fafc0aa880ee0d7558e.pdf

Ecology of spiders at qena governorate, egypt

T present work deals with the ecology of eight species of freshwater ostracods (Cypridopsis vidiui, Potamocypris variegattf. Hemicypris dematomarginata, llyocypris gibha, Uyocypris hiplicata, Fabaeformisccmdona holzkampfu Pseudocandona semicognita and Limnocythere inopinata) collected from Qena Govemorate. Monthly samples were collected for a period of one year (from July, 2000 till June, 2001) from four sites. Some ecological factors were measured during the period of investigation and correlated with the density of the ostracod species studied. Statistical analysis was performed by using SPSS software package (version 9) and the model equations controlling the density and the physical factors measured for the studied species were deduced.

/pdf/ecology-of-eight-species-of-freshwater-ostracods-crustacea-3viirsoklj.pdf

Amal A. Mahmoud

Papers

Population dynamics of freshwater snails (Mollusca: Gastropoda) at Qena Governorate, Upper Egypt

A Key for Identification of Spiders at Qena Governorate, Upper Egypt

Ecology of spiders at qena governorate, egypt

Ecology of eight species of freshwater ostracods (crustacea) from qena governorate, upper egypt

Survey and Ecological Studies Onspiders at Qena Governorate , Egypt