蜜蜂寄生螨—狄斯瓦螨的研究进展

狄斯瓦螨Varroa destructor是对世界养蜂业危害最大的蜜蜂寄生虫,严重危害蜜蜂封盖幼虫、蛹和成蜂,并携带和传播蜜蜂病毒,造成蜂群生产力严重下降乃至全群毁灭。狄斯瓦螨的有效防治措施的研发有赖于对其研究进展的了解,本文综述了以下3方面的研究概况:1)狄斯瓦螨的繁殖特性;2)对蜜蜂的危害;3)主要防治方法。以期为蜂螨相关的研究和应用奠定基础。     

Potential mechanism for detection by Apis mellifera of the parasitic mite Varroa destructor inside sealed brood cells

Abstract The parasitic mite Varroa destructor Anderson & Trueman is a major pest of the honeybee Apis mellifera L. throughout the world. Chemical agents currently used for mite control leave contaminating residues and promote pesticide resistance. As an alternative means of control, it would be useful to identify natural substances enabling bees to detect Varroa inside brood cells. These substances could then be used to trigger mite hygienic behaviour by bees.
In this study several techniques were used to screen substances that might allow detection of infested brood cells by bees. Gas chromatography-mass spectrometry analysis was performed on substances extracted in dichloromethane from the contents of brood cells. Solid phase microextraction and solid injection were performed on substances obtained from living and dead Varroa, respectively. Electroantennography was performed to assess the sensitivity of olfactory receptors in bee antennae to some of these substances.
Principal component analysis based on proportions of cuticular substances allowed discrimination between bees and other cell contents. Foundress Varroa exhibited the greatest dissimilarity to healthy pupae that were used as controls. Immature Varroa and faecal material were intermediate. High molecular weight compounds, mainly dimethylalkanes, were proportionally the most characteristic components of foundress Varroa . This finding suggests that these compounds would be the most apt to induce uncapping of cells infested by Varroa . Solid-phase microextraction and solid injection demonstrated the presence of aliphatic acids, esters, and one alcohol, eicosenol, in Varroa . Electroantennographic recordings showed that mite-resistant bees were more responsive to some acids and one ester. We speculate that these compounds may be involved in recognition of living Varroa by honeybees.     

First Philippine record of the parasitoid,Comperiella sp. (Hymenoptera: Encyrtidae): a potential biocontrol agent against Aspidiotus rigidus (Hemiptera: Diaspididae)

The encyrtid genus Comperiella Howard has so far not been reported in the Philippines, where there is currently an outbreak of the coconut scale insect Aspidiotus rigidus Reyne particularly in the southern parts of the island of Luzon and in some areas in Mindanao. Among Comperiella species, only C. unifasciata Ishii has been reported as a parasitoid of A. rigidus. We report not only new sightings of this parasitoid genus in the Philippines from surveys conducted in parts of the provinces of Laguna and Batangas, but also the discovery of a possibly new species that, like C. unifasciata, has been found to parasitize A. rigidus at a high rate. These findings have presented a potential of biological control against the coconut scale insect problem that has threatened the coconut industry in the country.     

蜜蜂幼虫血淋巴游离氨基酸和微量元素含量的差异对其抗螨特性的影响

重新界定的外寄生螨类---狄斯瓦螨Varroa destructor(Anderson and Trueman),严重危害全世界的西方蜜蜂Apis mellifera。但是对其原始寄主东方蜜蜂Apis cerana不构成可见的危害。在西方蜜蜂群中,狄斯瓦螨在雄蜂房和工蜂房都能进行繁殖。在其亚洲的原始寄主东方蜜蜂群中,它们可以寄生于雄蜂和工蜂,但在工蜂房中不育。蜜蜂的血淋巴是狄斯瓦螨生存和繁殖需要摄取的惟一食物来源,推测血淋巴中的某种物质含量会影响狄斯瓦螨的繁殖。对中华蜜蜂Apis ceranaFabricius和意大利蜜蜂ApismelliferaL.工蜂和雄蜂封盖幼虫血淋巴中游离氨基酸和与营养有关的微量元素含量进行了比较,发现其存在明显差异,并推测这些差异与东方蜜蜂抗螨能力强有关。     

The efficacy of Dryacide, an inert dust, against two species of Astigmatid mites, Glycyphagus destructor and Acarus siro, at nine temperature and moisture content combinations on stored grain

Dryacide, an inert silicaceous dust, was tested for efficacy on wheat after 14 and 28 days exposure against the mites Acarus siro and Glycyphagus destructor at doses of 1, 3 and 5 g kg–1, moisture contents (MCs) of 14.5, 15.5 and 16.5% and temperatures of 10, 17.5 and 25°C. After 28 days at 10°C, all doses were effective against A. siro with the exception of the lowest dose at the highest MC, but against G. destructor complete control only occurred at 3 g kg–1 and 14.5% MC and at 5 g kg–1 and 14.5 and 15.5% MC. After 28 days at 17.5°C, the dust was fully effective against A. siro at 3 and 5 g kg–1 but only at 14.5% MC. Glycyphagus destructor was only completely controlled after 28 days at 5 g kg–1 and 14.5% MC. After 14 days at 25°C, A. siro was completely controlled at 3 and 5 g kg1 and 14.5% MC as was G. destructor after 28 days. Neither species appeared to ingest the dust but considerable quantities adhered to their cuticles. The high mortalities observed under the range of experimental conditions, particularly the lowest temperature, suggest that a dose of 3 g kg–1 may be effective as a replacement for organo-phosphorous (OP) pesticide surface treatments in an integrated storage strategy based on grain cooling. © Rapid Science Ltd. 1998     

蜜蜂巢房大小影响狄斯瓦螨的繁殖行为

在具有相同类型幼虫的雄蜂和工蜂巢房中,人工接入狄斯瓦螨Varroa destructorAnderson&Trueman,比较巢房大小不同,对于螨繁殖的影响。结果显示:狄斯瓦螨在具有工蜂幼虫的工蜂房(WW)中的繁殖率为94.4%,而在具有工蜂幼虫的雄蜂房(WD)中繁殖率只有27.7%,差异极显著。在具有工蜂幼虫的工蜂房中,每只雌螨产出后代的平均数为3.35±1.56只;在具有工蜂幼虫的雄蜂房中每只雌螨产出后代的平均数为0.49±0.93只,差异极显著。表明:在具有相同类型幼虫存在的情况下,狄斯瓦螨喜欢较小的巢房,狄斯瓦螨在较小巢房中的繁殖能力明显高于较大的巢房。     

Leaf growth signals the onset of effective plant resistance against Hessian fly larvae

For plant resistance that is induced rather than constitutive, the precise timing of a sequence of events must be considered (i.e., initial detection of the insect by the plant's surveillance systems, up-regulation of signaling and defense pathways, achievement of effective levels of defense, and finally down-regulation of signaling and defense). Here, we provide a timeline for the interaction between resistant wheat ( Triticum aestivum L.) (Poaceae) and the Hessian fly, Mayetiola destructor (Say) (Diptera: Cecidomyiidae). To create this timeline, we measured the daily growth of the third, fourth, and fifth leaves of susceptible and resistant plants. Because each leaf had a different spatial relationship to the site of larval attack (i.e., the sheath epidermal cells of the third leaf) and a different pattern of growth relative to the 3–5 days that larvae attacked resistant plants, we learned different things from each leaf. The third leaf shows how quickly responses of susceptible and resistant plants diverge (i.e., 36–60 h after initial larval attack). The fourth leaf shows that, for both susceptible and resistant plants, negative effects of larval attack extend beyond the third leaf. These negative effects are more severe for susceptible plants, but even in resistant plants continue for several days after larvae have died. The fifth leaf is interesting because it shows how rapidly the resistant plant recovers from larval attack. Thus, 204–348 h after initial attack, a time when the fourth leaf of resistant plants is showing reduced growth and the fifth leaf of susceptible plants is showing zero growth, the fifth leaf of resistant plants shows a small increase in growth. Grasses with resistance gene-mediated resistance may have a two-fold strategy, using resistance mechanisms to stop Hessian fly larvae from further attack and tolerance mechanisms to protect resources for future plant growth.     

Patterns in Varroa destructor depend on bee host abundance,availability of natural resources,and climate in Mediterranean apiaries

1. Varroa destructor Linnaeus (Acari: Varroidae) is one of the greatest threats to apiculture. This study examines the role of host density, natural resource availability for bees, the management and climate in driving spatial and annual variability in the abundance of Varroa, and the occurrence of colony losses, recorded in apiaries across a Mediterranean island over a 2‐year period, using a hierarchical generalised linear model framework. 2. The seasonal abundance of Varroa showed a bimodal pattern with two peaks, the first one being in spring and larger than the second one located in summer/autumn. In contrast, bee colony losses were mainly concentrated in autumn/winter. 3. The abundance patterns of Varroa were best explained by models combining host, climate, and resource availability. A key novel finding was that low availability of natural flowering resources leads to high levels of infestation of Varroa, highlighting the importance of preserving natural resources around apiaries for the maintenance of pollination services in the landscape. Varroa abundance was also found to increase as bee density increased, probably as a result of the greater brood availability. Moreover, Varroa abundance increased as temperatures decrease and decreases as relative humidity increases, which is consistent with previous studies. Anti‐varroa treatments were only found to impact Varroa levels in the second 6 months of the year. Organic treatments outperformed synthetic treatments. 4. Empirical research on optimal seasonal timing and combinations of treatments, as well as impacts of climate and resource availability on natural dynamics of bees and Varroa in different climate zones, is urgently required.     

Development of a 44K SNP assay focussing on the analysis of a varroa-specific defence behaviour in honey bees (Apis mellifera carnica)

Honey bees are exposed to a number of damaging pathogens and parasites. The most destructive among them, affecting mainly the brood, is Varroa destructor. A promising approach to prevent its spread is to breed for Varroa-tolerant honey bees. A trait that has been shown to provide significant resistance against the Varroa mite is hygienic behaviour, a behavioural response of honey bee workers to brood diseases in general. This study reports the development of a 44K SNP assay, specifically designed for the analysis of hygienic behaviour of individual worker bees (Apis mellifera carnica) directed against V. destructor. Initially, 70,000 SNPs chosen from a large set of SNPs published by the Honey Bee Genome Project were validated for their suitability in the analysis of the Varroa resistance trait 'uncapping of Varroa-infested brood'. This was achieved by genotyping of pooled DNA samples of trait bearers and two trait-negative controls using next-generation sequencing. Approximately 36,000 of these validated SNPs and another 8000 SNPs not validated in this study were selected for the construction of a SNP assay. This assay will be employed in following experiments to analyse individualized DNA samples in order to identify quantitative trait loci (QTL) involved in the control of the investigated trait and to evaluate and possibly confirm QTL found in other studies. However, this assay is not just suitable to study Varroa tolerance, it is as well applicable to analyse any other trait in honey bees. In addition, because of its high density, this assay provides access into genomic selection with respect to several traits considered in honey bee breeding. It will become publicly available via AROS Applied Biotechnology AS, Aarhus, Denmark, before the end of the year 2011.