Hafiz Muhammad Tahir

Effect of spider silk on the foraging activity of Acrida turrita (Linnaeus, 1758) (Orthoptera: Acridinae)

Abstract Predators hold a position of great importance in agro-ecosystems. Their primary significance is that they deter the prey and reduce their plant foraging behaviour, thereby reducing damage and indirectly enhancing the biomass production. The present study was designed to observe the foraging activity of insects in response to spider silk and the cues deposited by spiders on the plants. Orb-weaving spider, Argiope trifasciata, was used as a silk source while Acrida turrita, the common grasshopper of rice fields was used as model herbivorous insect. Foraging of grasshoppers on the silk/cues-deposited plant leaves was compared with the control leaves. Resultantly, a sharp contrast was observed in the foraging activity. Silk-treated leaves were distinctly avoided by the grasshoppers when they were given a choice between the silk-treated and untreated leaves. Furthermore, the learning behaviour of grasshopper was also examined against fresh spider cues. The grasshoppers exhibited a preference for the clean filter paper; by spending more time on it as compared to the cue-deposited filter paper. Therefore, the study provided conclusive evidences that irrespective of the absence of spider, the presence of silk itself is an effective deterrent in threatening the prey and reducing the herbivory damage.

Lethal effects of λ-cyhalothrin and Emamectin benzoate in Plexippus paykulli (Araneae: Salticidae)

Abstract In the present study, effects of λ-cyhalothrin and emamectin benzoate on survival, locomotion, avoidance behaviour and growth of Plexippus paykulli Savigny Et Audouin, 1827 were studied. P. paykulli was found highly susceptible against the recommended field rate concentration of λ-cyhalothrin. The pesticide affected survival, locomotion and growth of the spiders. On the other hand, emamectin benzoate showed a negligible effect on spiders survival. However, emamectin benzoate significantly affected the locomotion and growth of P. paykulli. It is concluded that although emamectin benzoate is less toxic than λ-cyhalothrin for P. paykulli, it cannot be recommended for IPM programme.

Evaluating the accuracy of morphological identification of insect pests of rice crops using DNA barcoding

Abstract Accurate identification of agricultural pests is key requirement for the successful integrated pest management (IPM) program. However, due to limitations of conventional morphological methods, other molecular method like DNA barcoding is used. The current study was designed to evaluate the accuracy of morphological identification of insect pests using DNA barcoding. Morphologically, a total of 247 insect pests, representing 10 families, 18 genera, 22 species were identified. However, molecular identifications confirmed the presence of 11 families, 16 genera, and 20 species of agricultural pests. A total of 59 specimens were processed for DNA barcoding but genomic sequences of mt COI gene up to 600 bp were revived from 48 samples. Specimens that were misidentified through morphological studies were placed to their appropriate taxon, using this molecular approach. Results revealed the existence of clear barcode gap for different pest species. Moreover, the values of distance with the nearest neighbour recorded were higher than the maximum intra-sequence divergences for all species. It is concluded that DNA barcoding is a reliable technique for identification of agricultural pests, especially for immature stages when morphometric studies are ambiguous and will be helpful in the development of more effective pest management options for regulating pest species.

Use of mitochondrial COI gene for the identification of family Salticidae and Lycosidae of spiders

Abstract In recent years, DNA barcoding has become quite popular for molecular identification of species because it is simple, quick and an affordable method. Present study was conducted to identify spiders of most abundant families, i.e. Salticidae and Lycosidae from citrus orchards in Sargodha district using DNA barcoding. A total of 160 specimens were subjected to DNA barcoding but, sequences up to 600 bp were recovered for 156 specimens. This molecular approach proved helpful to assign the exact taxon to those specimens which were misidentified through morphological characters in the study. We were succeeded to discriminate six species of Lycosidae and nine species of Salticidae through DNA barcoding. Results revealed the presence of clear barcode gap (discontinuity in intra- and inter-specific divergences) for members of both families. Furthermore, the maximum intra-specific divergence was less than NN (nearest neighbour) distance for all species. This suggested the reliability of DNA barcoding for spider’s identification up to species level. We got 98% success in our study. It is concluded from present study that DNA barcoding is more reliable tool especially for immature spiders, when morphological characters are ambiguous.

Effect of Milking Method, Diet, and Temperature on Venom Production in Scorpions

Abstract In the present study, two common buthid scorpions, i.e., Androctonus finitimus (Pocock, 1897) (Scorpiones: Buthidae) and Hottentota tamulus (Fabricus, 1798) (Scorpiones: Buthidae), were maintained in the laboratory for venom recovery. The aim of study was to compare the quantity and quality of venom extracted from scorpions by manual and electrical method. We also recorded the effect of diet and temperature on venom production. Results of our study revealed that electrical method yielded good quality and higher quantity of venom as compared to manual method. The quantity of venom by two studied species differed statistically. We recorded the effect of food on venom production by providing different prey items to the scorpions and found that grasshopper nymphs and adults were the best diet for the scorpions to get maximum yield of venom as compared to other prey types (house crickets, house flies, and moths). Production of venom and activity of scorpions was found to be associated with temperature. During winter season, venom recovery was comparatively low as compared to the hottest part of year; when venom milking and activity of scorpions both were increased.

Toxicological Evaluation of Essential Oils from Some Plants of Rutaceae Family

Essential oils are produced as secondary metabolites by aromatic plants, predominantly belonging to families Apiaceae, Lamiaceae, Myrtaceae, and Rutaceae. The family Rutaceae has great economic importance for its numerous edible fruits and essential oils. In the present study, essential oils of seven plants of family Rutaceae, Aegle marmelos, Murraya koenigii, Citrus reticulata Blanco, Zanthoxylum armatum, Skimmia laureola, Murraya paniculata, and Boenninghausenia albiflora, were used for their toxicological assessment. Seven groups of selected essential oils-treated Wistar rats were established against control group (n = 5) that received water for 14 days; animals were offered feed and water ad libitum and treated with essential oils at 400 mg/kg body weight. Hematological studies revealed significant elevation in TEC in animals treated with essential oils of M. koenigii, S. laureola, and B. albiflora, while an elevation in PCV and depletion in MCV were observed in animals treated with M. paniculata and B. albiflora, respectively. Serological investigations demonstrated significant depletion in triglycerides and elevation in blood sodium level in animals treated with essential oils of A. marmelos and C. reticulata Blanco. Boenninghausenia albiflora affected many markers including RBC, MCV, triglycerides, HDL, LDL, urea, and sodium. In conclusion, all oils except B. albiflora can be considered safe for internal use.

INSECTICIDE RESISTANCE IN THE GROUND SPIDER, Pardosa sumatrana (THORELL, 1890; ARANEAE: LYCOSIDAE).

Elevated levels of insecticides detoxifying enzymes, such as esterases, glutathione S-transferases (GSTs), and cytochrome P-450 monooxygenases, act in the resistance mechanisms in insects. In the present study, levels of these enzymes in the insecticide-resistant ground spider Pardosa sumatrana (Thorell, 1890) were compared with a susceptible population (control) of the same species. Standard protocols were used for biochemical estimation of enzymes. The results showed significantly higher levels of nonspecific esterases and monooxygenases in resistant spiders compared to controls. The activity of GSTs was lower in the resistant spiders. Elevated levels of nonspecific esterases and monooxygenases suggest their role in metabolic resistance in P. sumatrana. The reduced levels of total protein contents revealed its possible consumption to meet energy demands.