Study on wing fanning as a signal of sexual response and courtship behavior of Bactrocera papayae

A series of experiments was carried out at the Institute of Biological Sciences, University of Malaya to identify wing fanning as an attraction or signal of sexual response and courtship behavior of Bactrocera papayae. Sexual natures such as signal or attraction and courtship behavior were determined through males and females with modified wings and sensory receptors, respectively. Wing fanning was effective to attract female towards male (42 to 48%) and vice versa (22 to 25%). Sexual attractiveness and signaling by males varied with light intensity. Females were attracted more at 18:20 to 18:55 by frequent wing fanning by males and sharply declined after sunset. Least attraction (10%) was observed by females toward males with modified wings compared to males with non modified wings. Similarly, males were less attracted by females with modified sensory receptors. Significantly, weaker sexual response was found when both the aristae and antennae were removed. Mating rate (12 to 14%) was reduced significantly by males wing removal and clipping (>50%) and wing bases waxed. Modified females mated less than non-modified ones due to the preventive measure of the pheromone receptor. Olfactory signals appear to be more important than acoustic signals in determining whether a female would mate or not. Pheromone along with acoustic receptor modification played a key factor in the success of mating. Acoustic and olfactory signals appear less important when eliminated singly, but combined elimination of olfactory and acoustic signal reduces the mating of females by a greater magnitude.Key words: Attraction, courtship, response, sexual, signaling

Effects of sulfur and nitrogen on nutrients uptake of corn using acidified water

A greenhouse experiment was carried out with elemental sulfur (S) and nitrogen (N) fertilizer using acidified water (pH 6.5) to determine nutrients uptake and growth of maize plants grown in calcareous sandy soil. Four levels of elemental sulfur (0, 1, 5 and 10 t ha-1), two levels of N (0 and 0.34 t N ha-1) were tested at Al Foah Agricultural Experiment Farm, United Arab Emirates (UAE) University. In Al Semaih soil, the pH (1.21-1.33) and electrical conductivity (EC) (7.61 dSm-1) decreased by application of elemental S plus N, while EC rose (3.84 dSm-1) and pH reduced (1.20 to 1.11) in Al Zaid soil. Acidity improved by decreasing soil pH, Na and Cl concentration in both soils. A significant change was observed by application of acidified water at Al Semaih soil causing high levels in the initial status of EC, Na and Cl concentrations in the soil. A negative relationship was observed with soil pH among N, P, S, Fe, Zn and Mn, while uptake availability of sulfur and nitrogen had positive relationship with all nutrients. Elemental sulfur at the rate of 5 t ha-1 and nitrogen had a significant contribution towards uptake availability of N, P, S, Fe, Zn and Mn in both Al Zaid and Al Semaih soils. Based on experimental findings, elemental S at the rate of 5 tha-1 and N fertilizer (0.34 t ha-1) is suitable for the growth of maize at both soils. Al Zaid soil possesses advantages over Al Semaih soil due to its high nutrient uptake ability.Key words: Calcareous soil, corn, elemental sulfur, nitrogen, nutrients uptake

Tropical Legume Crop Rotation and Nitrogen Fertilizer Effects on Agronomic and Nitrogen Efficiency of Rice

Bush bean, long bean, mung bean, and winged bean plants were grown with N fertilizer at rates of 0, 2, 4, and 6 g N m−2 preceding rice planting. Concurrently, rice was grown with N fertilizer at rates of 0, 4, 8, and 12 g N m−2. No chemical fertilizer was used in the 2nd year of crop to estimate the nitrogen agronomic efficiency (NAE), nitrogen recovery efficiency (NRE), N uptake, and rice yield when legume crops were grown in rotation with rice. Rice after winged bean grown with N at the rate of 4 g N m−2 achieved significantly higher NRE, NAE, and N uptake in both years. Rice after winged bean grown without N fertilizer produced 13–23% higher grain yield than rice after fallow rotation with 8 g N m−2. The results revealed that rice after winged bean without fertilizer and rice after long bean with N fertilizer at the rate of 4 g N m−2 can produce rice yield equivalent to that of rice after fallow with N fertilizer at rates of 8 g N m−2. The NAE, NRE, and harvest index values for rice after winged bean or other legume crop rotation indicated a positive response for rice production without deteriorating soil fertility

Growth and nutrient uptake of maize plants as affected by elemental sulfur and nitrogen fertilizer in sandy calcareous soil

This study was carried out to investigate the effect of elemental sulfur (S0) combined with or without N fertilizer on the growth and nutrient uptake such as nitrogen (N), phosphorus (P), sulfur (S), iron (Fe), zinc (Zn) and manganese (Mn) by maize plants grown in sandy calcareous soils. Elemental S at rates of 0, 1, 5 and 10 t ha-1 were tested combined with or without N fertilizer at rates of 0 and 0.34 t ha-1 in pots using normal irrigation water (pH >7.5) under Al Zaid and Al Semaih soils in evaporative cooled greenhouse conditions. Electrical conductivity (EC) increased (2.50 to 2.95 dSm-1) significantly and decreased (5.07 to 6.06 dSm-1) with application of S0 at rates of 5 and 10 t ha-1 combined with N fertilizer in both Al Zaid and Al Semaih soils, respectively. Soil acidity improved by decreasing soil pH (1.41 to1.52 unit) with application of S0 at the rate of 10 t ha-1 combined with N fertilizer. Addition of S0 at the rate of 5 t ha-1 combined with N fertilizer recorded superior total dry matter (TDM) and maximum uptake of all nutrients in both soils. Total dry matter accumulation and nutrient uptake had positive correlation, while soil pH showed negative correlation with TDM and uptake of all nutrients. Based on experimental findings, S0 at the rate of 5 t ha-1 combined with N fertilizer is suitable for growth of maize in both soils. Collectively, the results indicate that Al Zaid soil is more favorable due to higher nutrient uptake and growth of maize than Al Semaih soil.Key words: Elemental sulfur, nutrient uptake, maize, sandy calcareous soil

Study on wing fanning as a signal of sexual response and courtship behavior of Bactrocera papayae

A series of experiments was carried out at the Institute of Biological Sciences, University of Malaya to identify wing fanning as an attraction or signal of sexual response and courtship behavior of Bactrocera papayae. Sexual natures such as signal or attraction and courtship behavior were determined through males and females with modified wings and sensory receptors, respectively. Wing fanning was effective to attract female towards male (42 to 48%) and vice versa (22 to 25%). Sexual attractiveness and signaling by males varied with light intensity. Females were attracted more at 18:20 to 18:55 by frequent wing fanning by males and sharply declined after sunset. Least attraction (10%) was observed by females toward males with modified wings compared to males with non modified wings. Similarly, males were less attracted by females with modified sensory receptors. Significantly, weaker sexual response was found when both the aristae and antennae were removed. Mating rate (12 to 14%) was reduced significantly by males wing removal and clipping (>50%) and wing bases waxed. Modified females mated less than non-modified ones due to the preventive measure of the pheromone receptor. Olfactory signals appear to be more important than acoustic signals in determining whether a female would mate or not. Pheromone along with acoustic receptor modification played a key factor in the success of mating. Acoustic and olfactory signals appear less important when eliminated singly, but combined elimination of olfactory and acoustic signal reduces the mating of females by a greater magnitude

Toxicity of imidacloprid gel bait against laboratory strain of Periplaneta americana (L.) (Dictyoptera : Blattidae) and Blattella germanica (L.)(Dictyoptera : Blattellidae)

The efficacy of a 2.15% imidacloprid gel bait against laboratory strain Periplaneta americana and Blattella germanica was evaluated under laboratory conditions. The susceptibility trend of both species towards imidacloprid was: adult male < adult female < nymphs. All stages of both species were dead within 10 days in primary poisoning testing. Periplaneta americana adult male (LT50 = 0.47 h; LT95 = 5.24 h) died fastest, while nymphs of B. germanica took the longest time to reach 95% mortality (LT95 = 43.84 h). In indirect exposure via secondary poisoning, only adult males of P. americana (LT50 = 100.63 h) and B. germanica (LT50 = 54.66 h) obtained 50% mortality before the testing ended. No complete mortalities were achieved in any stages of both species within 10 days of secondary poisoning testing. Therefore, imidacloprid gel bait used in this study was able to cause complete mortalities within less than 2 days of 10-day primary poisoning testing but less effective in the 10-day secondary poisoning testing

Review of Malaysian black flies (Diptera: Simuliidae): note on new record on Simulium kalimantanense from Sabah

Black flies are the two-winged, small-bodied (3mm to 6mm) and blood-sucking insects of medical and veterinary importance. Female of certain species play a role as a vector of several disease agents including, Onchocerca volvulus, causative agent of human onchocerciasis. Despite their medical significance, the biodiversity of black flies in the Borneo part of Malaysia as well as other Southeast Asian countries (except Thailand, Vietnam and Indonesia) are unknown. Our recent visit to the Kangkawat Reserve within the Imbak Canyon Conservation Area (ICCA) has successfully discovered one new record from Malaysia, Simulium kalimantanense of the S. banauense species-group and one from Sabah, Simulium sarawakense of the S. epistum species-group. Based on these current findings, the total number of species and species-group of black flies inhabiting Malaysia has increased to 96 and 22 respectively

The Influence of 1-Triacontanol on the Growth, Flowering, and Quality of Potted Bougainvillea

Selected physiological and biochemical parameters were monitored at the vegetative and reproductive growth stages in potted Bougainvillea plants treated with five different concentrations of TRIA. Advanced flowering, flower bud number, and blooming rate increased significantly with 0.5 and 1.0 mg/L TRIA treatments. Similarly, photosynthetic rate, pigment content, quantum yield, and stomatal conductance increased significantly with 2.5, 1.0, and 5.0 mg/L TRIA treatments. Higher levels of N, P, and K, as well as increased total soluble solids (TSS) and higher sugar and protein contents, were recorded in treated plants. Furthermore, 46% more flowers, a 1.5-fold increase in bract weight, increased longevity, and 40% less leaf abscission were recorded following 2.5 mg/L TRIA treatment. Phenol and flavonoid contents, sucrose phosphate synthase (SPS), and antioxidant activities were also markedly increased with 2.5 and 1.0 mg/L TRIA treatments. However, ethylene production was significantly lower in the treated plants. Positive correlations were observed between leaf TSS and flowering time and flower number, between leaf sugar content and bract weight, and between net photosynthesis and bract growth and dry matter production. It can be concluded that the foliar spray of TRIA stimulates growth, enhances flowering, and improves the quality of potted Bougainvillea plants

Temephos resistance in field Aedes (Stegomyia) albopictus (Skuse) from Selangor, Malaysia

Larvae of Aedes albopictus obtained from dengue endemic areas in Selangor, Malaysia were evaluated for their susceptibility to operational dosage of temephos (1 mg/L). Larval bioassays were carried out in accordance to modified WHO standard methods. Biochemical microassay of enzymes in Ae. albopictus was conducted to detect the emergence of insecticide resistance and to define the mechanisms involved in temephos resistance. The 50% mortality lethal time (LT50) for Ae. albopictus tested against temephos ranged between 58.65 to 112.50 minutes, with resistance ratio ranging from 0.75 – 1.45. This study addressed the fluctuation of time-related susceptibility status of Ae. albopictus towards insecticide. Significant difference on the weekly enzyme levels of non-specific esterase’s, mixed function oxidases and glutathione S-transferases was detected (p 0.05). Only glutathione Stransferases displayed high level of activity, indicating that Ae. albopictus may be resistant to other groups of insecticide. The insensitive acetylcholinesterase was detected in some field collected Ae. albopictus populations, indicating the possibility of emergence of carbamate or other organophosphate resistance in the field populations. Continuous resistance monitoring should be conducted regularly to confirm the efficacy of insecticides for dengue control

Influence of elemental sulfur on nutrient uptake, yield and quality of cucumber grown in sandy calcareous soil

Abstract This study was carried out to investigate the effect of elemental sulfur (S 0 ) and sulfur oxidizing bacteria (Paracoccus versutus) on nutrient uptake, yield and quality of cucumber grown in sandy calcareous soils. Both elemental sulfur powder (S 0 P) and pellets of sulfur powder-Tiger 90 (S 0 T) were applied at rates of 0, 1, 5 and 10 t/ha at Al Hamraneya. On the contrary, S 0 P was used at rates of 0, 1, 5 and 10 t/ha combined with or without Paracoccus versutus (Pv) at Al Kuwaitat, United Arab Emirates (UAE). Higher concentrations of N, P, S, Mn and Zn in leaves and yield of cucumber at both locations were obtained with application of S 0 at rates of 5 and 10 t/ha. Total soluble sugar (TSS) content and vitamin C was higher with the application of S 0 at rates of 5 and 10 t/ha. Application of Pv individually or with varying levels of S 0 P had no positive effect on nutrients uptake, yield and quality of cucumber. A positive correlation was observed between shelf life and vitamin C. At Al Hamraneya S 0 P performed better than S 0 T. The results reveal that application of S 0 P at the rate of 5 t/ha in sandy calcareous soils can enhance the nutrients uptake ability, increase yield and superior quality of cucumber at both locations in UAE