Two simple tetrahydroisoquinoline alkaloid N-oxides from cacti

Tehuanine N-oxide was isolated from Pachycereus pringlei, and deglucopterocereine N-oxide was isolated from Pterocereus gaumeri. These     

胭脂虫Dactylopius coccus Costa培育方法研究

【目的】为探索胭脂虫Dactylopius coccus高产培育新方法。【方法】胭脂虫的室内培养模式有采摘茎片培育模式和种植培育模式两种。本研究在采摘茎片模式下开展了培育环境构筑、平铺培育、接种方式、蔗糖培育等培育技术的研究;在种植模式下进行了接种方式、轮放培育和寄主高度控制的培育技术研究。【结果】探索出胭脂虫在两种模式下的新培育方法。【结论】在采摘茎片培育模式下,采用松针覆土保湿效果较好;平铺培育产量较高,值得推广;悬挂培育宜采用网兜内置谷草接种方式。蔗糖对胭脂虫有明显助食作用,喷洒适当浓度的蔗糖有助于提高胭脂虫的产量。在种植模式下,宜进行轮放培育,寄主植株高度控制在100 cm之内且茎片级数在4级之内,可避免植株倒伏及断离。采用纱网撒种方式,可节约接种环节中大量人力。     

Host-plant shifts and adult survival in the cactus breeding Drosophila mojavensis

Abstract. 1. In order to gain insight into how Drosophila mojavensis Patterson and Crow (which lives on the rotting tissue of cactus) successfully shifted host plants, from an Opuntia species to columnar cactus species, over evolutionary time, specific components of columnar cactus and Optunia tussue were examined for their effects on adult longevity.
2. The availability of free sugars affects the survival of adult D.mojavensis . The addition of a sugar to columnar cactus tissue significantly increased the longevity of adults that fed on those tissues. This increase in adult longevity was equal to the longevity observed on unsupplemented Opuntia tissue, which has free sugars present.
3. Live microorganisms added to Opuntia tissue had a slight detrimental effect on adult longevity (longevity was decreased by approximately 1 week).
4. Low concentrations of atmospheric ethanol (independent of diet) increased the longevity of adult D.mojavensis to levels comparable in magnitude to that provided by the addition of free sugars to the diet.
5. This information and the apparent lack of a year-round supply of free sugars for D.mojavensis in nature suggests that the ethanol (produced by fermentation) rather than free sugars per se is the most important component of rotting cactus tissue for the survival of this species and may explain its successful host-plant shift.     

Host-related life history traits in interspecific hybrids of cactophilic Drosophila

In the genus Drosophila (Diptera: Drosophilidae), interspecific hybridization is a rare phenomenon. However, recent evidence suggests a certain degree of introgression between the cactophilic siblings Drosophila buzzatii Patterson & Wheeler and Drosophila koepferae Fontdevila & Wasserman. In this article, we analyzed larval viability and developmental time of hybrids between males of D. buzzatii and females of D. koepferae, raised in media prepared with fermenting tissues of natural host plants that these species utilize in nature as breeding sites. In all cases, developmental time and larval viability in hybrids was not significantly different from parental lines and, depending on the cross, hybrids developed faster than both parental species or than the slowest species. When data of wing length were included in a discriminant function analysis, we observed that both species can be clearly differentiated, while hybrids fell in two categories, one intermediate between parental species and the other consisting of extreme phenotypes. Thus, our results point out that hybrid fitness, as measured by developmental time and viability, is not lower than in the parental species.     

Prospects for biological control of cactus weeds in Namibia

Australia and South Africa have a long history of sharing successful biocontrol agents for cactus weeds but other countries, such as Namibia, could also benefit. There are four biological control agents that are widely utilised in South Africa and/or Australia for the control of 10 invasive alien Cactaceae in Namibia.