Lethal and repellent effects of transfluthrin and metofluthrin used in portable blowers for personal protection against Ochlerotatus togoi and Aedes albopictus (Diptera: Culicidae)

The lethal efficacy of three vaporizing insecticides – 0.6% transfluthrin and 0.6% metofluthrin in portable battery‐powered blowers and 2.5% bioallethrin in electric mats – was assessed in unventilated and ventilated screened room conditions against Ochlerotatus togoi (Theobald) females. The mosquitoes were highly susceptible to transfluthrin and metofluthrin. Mean mortality rates of mosquitoes exposed to transfluthrin and metofluthrin in portable blowers ranged from 95 to 100% at a distance of 10 cm from mosquito cages in both room conditions; this was a >2.4‐fold greater mortality rate than for mosquitoes exposed to bioallethrin in electric mats under the same conditions (mean 40%). The three insecticides showed a decrease in mortality rate at a distance of 70 cm: rates were <5.0, 32.5, 85.0 and 90.0% for 10, 30, 60, and 120 min after exposure, respectively, for the same exposure periods in a closed room. In semi‐field repellent tests with human volunteers, 0.6% concentrations of transfluthrin and metofluthrin provided mean biting protection of 76.1 and 59.9% on legs, 68.5 and 52.1% on arms, 63.4 and 63.1% on the chest, and 87.1 and 52.9% on the face, respectively. In field tests, 0.6% transfluthrin effectively repelled Armigeres subalbatus and Aedes albopictus, with mean biting protection of 85.4 and 89.3% on exposed legs and arms, respectively, of the human volunteers. Metofluthrin at 0.6% also effectively repelled Ar. subalbatus, with mean biting protection levels of 71.8 and 73.5% on the legs and arms, respectively. There was no significant difference of repellent activity between the two vaporizing insecticides in the field.     

General biology of Ostrinia palustralis memnialis (Walker), a potential biological control agent of Rumex spp. in Korea

Ostrinia palustralis memnialis is an oligophagous insect that feeds on the species of the genus Rumex. Continuous rearing of O. palustralis memnialis was carried out from 2004 to 2005, and its general biology was studied. The preliminary host specificity test showed a promising result for O. palustralis memnialis as a potential biological control agent for Rumex spp.     

Management of Fruit Flies (Diptera: Tephritidae) of the Most Perishable Fruits

We investigated to minimize the dependency on the use of chemicals and thus develop safe and environmental friendly control program for the most perishable fruits i.e., apple,‘ber’, guava and mango. Our findings on the composition of fruit fly species reveal that Bactrocera dorsalis was dominant on apple (33.96% existence), Corpomya incompleta on‘ber’(51.91% existence) and Bactrocera zonata on guava (49.62% existence) and mango (74.66% existence). The correlation between population and infestation percentage was non‐significant in apple orchards, whereas positive and highly significant in between population and infestation, as well as on the cumulative basis in‘ber’, guava and mango orchards during 1998‐1999. Hoeing, baiting and methyl eugenol were statistically equal resulting about 77% decrease in infestation. The maximum control of 91.68% was observed where all four‐control operations including Dipterex® were integrated together. Weather factors, when computed together, had maximum effect on population fluctuation and infestation with rainfall contributing the major role. For guava fruits, the months of August (14.06A individuals/trap/day) and September (13.81A individuals/trap/day) were important, resulting in maximum infestation percentage of 10.76 to 14.74%, respectively.     

Four New Species of Symphypleona (Collembola) from Korea

ABSTRACT Four new species of Symphypleona, Ptenothrix plumiseta, Deuterosminthurus serratus, Sminthurus annulatus, Smithurinus distinctus , are described from Korea. Especially two genera, Deuterosminthurus and Sminthurinus are new record to Korea. Korean Collembola Symphypleona add up to 18 species, 11 genera in 6 family.     

Vulnerability of alpine stream biodiversity to shrinking glaciers and snowpacks

Climate change poses a considerable threat to the biodiversity of high latitude and altitude ecosystems, with alpine regions across the world already showing responses to warming. However, despite probable hydrological change as alpine glaciers and snowpacks shrink, links between alpine stream biota and reduced meltwater input are virtually unknown. Using data from the French Pyrénées, we demonstrate that taxonomic richness and total abundance of stream macroinvertebrates increase significantly as meltwater (snow melt and glacier melt) contributions to river flow decrease. Macroinvertebrate species showed a gradation of optimum meltwater conditions at which they persist. For example: Habroleptoides berthelemyi (Ephemeroptera), Perla grandis (Plecoptera) and Rhithrogena spp. (Ephemeroptera) increased in abundance when meltwater contributions to streamflow decrease, whereas in contrast, Rhyacophila angelieri (Trichoptera) and Diamesa latitarsis spp. (Diptera) decreased in abundance. Changes in alpine stream macroinvertebrate community composition as meltwater contributions decline were associated with lower suspended sediment concentration, and higher water temperature, electrical conductivity and pH. Our results suggest α diversity (at a site) of streams presently fed by meltwaters will increase with future meltwater reductions. However, β diversity (between‐sites) will be reduced as snow melt and glacier melt decrease because the habitat heterogeneity associated with spatiotemporal variability of water source contributions will become lower as meltwater contributions decline. Extinction of some endemic alpine aquatic species (such as the Pyrenean caddis fly R. angelieri) is predicted with reduced meltwater inputs, leading to decreases in γ diversity (region). Our identification of significant links between meltwater production and stream macroinvertebrate biodiversity has wider implications for the conservation of alpine river ecosystems under scenarios of climate change induced glacier and snowpack loss.     

Cold hardiness in the black rice bug, Scotinophara lurida

Abstract.  The mechanisms and strategies for winter survival of the black rice bug Scotinophara lurida are investigated along with the relationship between cold hardiness and diapause. The ability of S. lurida to survive subzero temperatures varies depending on developmental stage, temperature and exposure duration. Mean supercooling point (SCP) varies from –7.6 to –10.7 °C with developmental stage, but is not significantly different between stages examined. The SCP also varies with season, being lowest in January and increasing rapidly in February and remaining almost at the same level (–7.3 to 9.6 °C) until April The osmolality of haemolymph of field-collected S. lurida adults rises dramatically from 53.9 mOsm kg⁻¹ in August to 75.3 mOsm kg⁻¹ in December, and then declines linearly to 57.0 mOsm kg⁻¹ in May. Field-collected S. lurida adults show a peak glucose content in October, glycerol content in November and trehalose content in December. Only trehalose content decreases after the application of the juvenile hormone analogue, fenoxycarb, suggesting that trehalose is a cryoprotectant during diapause. These various physiological and biochemical traits related to cold tolerance in S. lurida may be, at least in part, under the control of juvenile hormone through the reproductive diapause programme.