Two new species of the genus Dactyloscirus (Acari: Prostigmata: Bdelloidea: Cunaxidae) from Sumatra, Indonesia, with a key to known species.

Two new species of predatory cunaxid mites belonging to the genus Dactyloscirus are described: Dactyloscirus sumatranus Corpuz-Raros and Naredo sp. n. and D. ladangjagung Corpuz-Raros and Lit sp. n. Both inhabit soil in corn fields in Sumatra Island, Indonesia. Dactyloscirus. sumatranus closely resembles D. dolichosetosus Den Heyer, 1979, but differs in having the basal half of chelicera strongly inflated, about four times thicker than in the distal half (vs. slender and gradually tapered), hysterosomal setae f1 and h1 at least twice as long as the anterior pairs c1-e1 (vs. only slightly longer), and famulus of tarsus I only ¾ the length of the closely associated asl (vs. longer). Dactyloscirus ladangjagung resembles D. hoffmannae Swift, 1996, but differs by the number of setae on some leg segments, namely, basifemora (5-5-3-2 vs. 5-5-3-1 sts) and tibiae (5-5-5-4 vs. 4-5-4-2 sts), and in having setae g4 the longest of genital setae (vs. setae g3). An updated key to 30 known Dactyloscirus species is provided.

Isovitexin-2'-O-beta-[6-O-E-p-coumaroylglucopyranoside] from UV-B irradiated leaves of rice, Oryza sativa L. inhibits fertility of Helicoverpa armigera.

UV-B irradiated rice leaves (Oryza sativa L.) contained four closely related flavonoids, with either an isoorientin or isovitexin aglycone. These flavonoids have previously been purified and characterized, and were added to artificial diets of the African bollworm (Helicoverpa armigera Hübner) at 0.1x concentration found in irradiated rice leaves. Consumption of different diets had relatively small effects on laval, pupal and adult duration, weight and survival, indicating the insects lived near normal life cycles on all diets. However, one of the compounds, flavonoid IIa, isovitexin-2''-O-beta-[6-O-E-p-coumaroylglucopyranoside], dramatically reduced the number of fertile eggs laid to 7% of control insects (P<0.001) when added to insect diets at 18 nmol gFW(-1) (14 ppm). A similar antifertility effect was observed when only the male partner consumed diet containing flavonoid IIa, indicating that the reduced fertility may be male specific. In contrast, the fecundity and fertility of insects eating diets containing the closely related flavonoids, isoorientin-2''-O-beta-[6-O-E-p-coumaroylglucopyranoside] or isoorientin-2''-O-beta-[6-O-E-p-feruloylglucopyranoside], were not significantly different to control diets.

Effects of crude and partially purified extracts from UV-B-irradiated rice leaves on Helicoverpa armigera (Hübner).

The effect of crude and partially purified extracts from ultraviolet-B (UV-B)-irradiated rice (Oryza sativa L.) leaves on the growth and development of corn earworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), was investigated. Fifty muL droplets of a liquid diet containing different concentrations of the crude and partially purified extracts were fed to H. armigera neonates to determine possible short-term toxicity effects. A choice test using a solid artificial diet was also performed to determine larval feeding preferences and antifeedant effects. To study effects on the life history of the insect, different concentrations of the crude and partially purified extracts were also incorporated in the artificial diet and fed to individually confined neonates of H. armigera. The neonates were reared up to the adult stage. Results showed that crude and partially purified extracts of UV-B-irradiated rice leaves demonstrated antifeedant, growth-inhibitory and antibiotic properties against H. armigera. At high concentrations, the extract initially stimulated larval feeding; however, there were subsequent negative effects on pupal and adult traits, thereby reducing the reproductive potential of adults. These partially purified extracts appeared to have an antifertility effect because adults laid fewer eggs and, of those eggs laid, viability was lower. These results suggest that the accumulated flavonoids or other phenolics in UV-B-irradiated leaves, extracted from UV-B-resistant rice cultivar 'M202,' affected the growth, development and reproduction of H. armigera, a polyphagous insect pest.