Showing papers in "Applied Entomology and Zoology in 1988"

Cold Resistance in Four Species of Beetles Overwintering in the Soil, with Notes on the Overwintering Strategies of Some Soil Insects

Abstract: such studies compiled by SeMME (1982), for instance, a total of 123 species overwintering in a supercooling condition was cited, in which 82 species overwintered aboveground, 33 on the ground surface, whereas only 8 underground, Obviously insects everwintering in the soil must be more numerous than shown by this list, though the precise ratio is at present unavailable. For a full understanding ofstrategies in insect overwintering, therefore, accumulation ofknowledge on soil overwintering species is essential, together with elucidatlon of the mechanisms of their cold resistance, This paper reports cold resistance of fbur species of beetles overwintering in soil at

Relationship between Wing-Form Response to Nymphal Density and Black Colouration of Adult Body in the Brown Planthopper, Nilaparvata lugens (Homoptera:Delphacidae)

Abstract: During successive selection for adults with a special wing form from a population oz the brown planthopper, IViloparvata l gens, a negative corrclation was found between the propertion of brachypters and the grade of black pigmentation in thc adults: population including more blackish individuals tendedi to exhibit a lower ratio ofbrachypters. The selection for blackish macropters finally generated a population producing predominantly rnacropters, whilc the selection for yellowish brown brachypters produced a population exhibiting totally brachypters, over broad ranges of nymphal densities in both sexes, Two populations from Malaysia and the Philippines were quite similar to this brachypter producing population in their wing-form responses to density. All of 14 populatiens cellected in Saga and Nagasaki Prefectures during 1986 and 1987 were highly macropterous and their body colours were

Histological and SEM Observations on the Invasion and Succeeding Growth of Entomogenous Nematode, Steinernema feltiae (str. DD-136), in Spodoptera litura (Lepidoptera : Noctuidae) Larvae

Abstract: succeeding growth ofSteinemema.fettiae (DD-136) in SPodoPtera literra l rvae. At an early time (3 hr) after inoculation, the infective juveniles were not always observed on the mouth or anus of a still active insect. Nematode invasion occurred as promptly as in 1 hr after inoculation with ca. 1,OOOjuveniles and then increased with time. Twelve to 24 hr after inoculation, more nematodes were obseTved in hemocoel than in alimentary canal, cspecially in the hernocoel lying beneath the deeply invaginated intersegmental membrancs, Generally, the most developed nematodes were in the insect head, Nematodes grew rapidly from 24 to 36 hr after inoculation, accompanied by the drastic disintegration ofinsect tissues in which they often ernbedded themselves. SEM observations clearly revealed a nematode Iiving on and in a larva and also a nematode feeding on rather Iarge pieces of various insect tissues.