黄钩尺蛾在四个茶树无性系品种上的生长和存活(英文)

在实验室条件下, 对食叶害虫黄钩尺蛾Hyposidra infixaria Walker在4个茶树Camellia sinensis无性系品种（TV1, TV9, TV25和Teen ali 17）上的生长和存活进行了研究, 以确定其最适合寄生的茶树无性系品种。结果表明： 在TV25上的黄钩尺蛾幼虫期 (15.78 d)比在TV1 (18.14 d), TV9 (18.00 d)和Teen ali 17 (17.00 d)上显著缩短。黄钩尺蛾按幼期龄数分为5龄型和6龄型两类。6龄型幼虫在TV25上的发生率显著高于其在其他3个无性系品种上的发生率。在TV25上黄钩尺蛾幼虫和蛹的体重也显著高于在其他3个无性系品种上的。同样地, 以TV25为食的黄钩尺蛾未成熟阶段的存活率显著高于其以其他3个无性系品种为食的存活率。基于生长参数和存活率, 我们发现TV25是黄钩尺蛾最适合寄生的茶树无性系品种。     

Developmental Role of Juvenile Hormone Metabolism in Lepidoptera

SYNOPSIS. Lepidopteran juvenile hormone (JH) esterase appearsto have a functional role in the regulation of embryogenesis,larval growth and development, and adult reproduction. In preovipositionaland newly laid eggs of the tobacco hornworm, Manduca sexta,JH esterase activity was elevated presumably to metabolize maternalJHs, and then declined after blastoderm formation. Also, a singlepeak in hemolymph JH esterase activity was found prior to ecdysisin the second through the fourth instar of M. sexta, the functionof which is unclear. However, in the last instar, elevated hemolymphJH esterase activity was noted prior to wandering and againprior to ecdysis to scavenge the last traces of JH necessaryfor normal development. The hemolymph JH esterase is likelyof multiple tissue origin for the prewandering peak with thefat body excluded as a source for the prepupal peak; an inhibitoryfactor from the brain and JH regulate JH esterase biosynthesis.In adult cabbage loopers, Trichoplusia ni, elevated hemolymphJH esterase activity appeared to be important in reducing theJH titer and preventing egg maturation. Structure/activity datawith trifluoromethylketones were incorporated into the designof a novel, JH esterase inhibitor, the sulfone and hydrate ofoctylthio-1,1,1- trifluoropropan-2-one, with selective and persistent,in vivo inhibitory activity. The topical application of thiscompound to last instar larvae and virgin adults of T. ni producedjuvenizing effects (delayed pupation and induced egg maturation/oviposition,respectively) providing direct evidence of a functional rolefor JH esterase in lepidopteran development.     

Salinity-induced enhancement of L-myo-inositol 1-phosphate synthase in rice (Oryza sativa L.)

The salt-tolerant varieties of rice (Oryza sativa L.) exhibit enhanced activity of the chloroplast form of L-myo-inositol 1-phosphate synthase (EC 5.5.4.1) under NaCl treatment either during the seedling stage or in fully grown plants during field growth. The salt-induced enhancement was noticeable only in chloroplasts from light-grown plants. The effects of these treatments on the cytosolic inositol synthase activity were less pronounced. While the effect of salt on the activity of the two forms was marginal in the salt-sensitive varieties during seedling growth, salinity affected the chloroplast inositol synthase activity adversely in these varieties during growth of the plants under field conditions. The salt-enhanced activities of inositol synthase(s) in the highly salt-tolerant varieties studied were found to be comparable to that observed in Porteresia coarctata, a halophytic wild rice species. The implications of these findings, which suggest a role of the inositol pathway in osmoregulation, are discussed.     

Relative abundance and species composition of some dung beetles (Coleoptera: Scarabaeinae) in Bangladesh

1. The occurrence and community structure of dung beetle species (Coleoptera: Scarabaeinae) in the faecal deposits of man and some domestic vertebrates varied according to dung type, seasonal conditions and soil type. 2. Of the twenty-four species belonging to six genera, Onthophagus was the prevalent genus and O. ramosellus the most abundant species. 3. Cattle dung was the dominant food type.     

Spacing and sucker management in the commercial plantain production in the rainforest belt of Nigeria

Maintaining one, two or three suckers per rootstock in plantain (Musa spp.) populations of 2000, 1600 and 1333 per hectare were evaluated for sustained yield in the orchard for three harvest cycles. The yield per plantain for the plant crop was not significantly affected by either population density or the number of suckers maintained. However, the total yield significantly increased with the increased plantain population per hectare. The yield per plantain decreased in the first and subsequent ratoon crop harvests as the original plantain population per hectare doubled or tripled when two or three suckers were maintained respectively per rootstock. Although the total yield per hectare was significantly higher when two or three suckers were maintained per rootstock, the individual bunch weight and the fingers significantly decreased to an unacceptable size to the consumers. Establishment of orchards at 1600 plantains per hectare with two suckers maintained per rootstock in subsequent cycles produced consistently good quality marketable fingers and sustained high yield.