Mechanisms contributing to the competitive success of the invasive fruit fly Bactrocera invadens over the indigenous mango fruit fly, Ceratitis cosyra: the role of temperature and resource pre-emption

We investigated the influence of temperature and infestation sequence on interspecific competition between two fruit flies: an invasive ( Bactrocera invadens Drew, Tsuruta & White, ( B ) and a native ( Ceratitis cosyra Walker , C ) (both Diptera: Tephritidae) species. Mango fruits [ Mangifera indica L. (Anacardiaceae)] were co-infested with larvae at different constant temperatures (15, 20, 25, and 30 °C) and relative humidity of 50 ± 8%, using different infestation sequences at each temperature ( BC together; BC/CB 1, 2, and 3 days apart). There were significant effects of competition in most experimental treatments, resulting in reduced larval survival, pupal mass, and adult emergence for both species. At most of the infestation/temperature combinations, C. cosyra was clearly the inferior competitor. The only exception was at 20 °C when the outcome depended on the sequence of infestation: no C . cosyra survived when the sequence was BC , but more C . cosyra than B . invadens survived when it was CB . At 15 °C, all C. cosyra larvae died, while the development of B. invadens was prolonged and adult emergence reduced. We conclude that resource pre-emption and fluctuations in temperature in mango agroecosystems help to explain observed shifts in dominance between B. invadens and C. cosyra on mango in many parts of Africa. The small window of competitive superiority for C. cosyra at 20 °C and CB infestation sequence, together with other factors such as fecundity and alternative hosts, may allow for co-existence in some environments.     

Micropropagation of Searsia dentata

A method for in vitro regeneration of Searsia dentata from nodal and shoot tip explants derived from mature trees is outlined. Nodal explants produced multiple shoots from the axis when cultured on Murashige and Skoog (MS) medium containing 3% sucrose supplemented with 0, 5, 7.5, 10, or 12.5 μM N ⁶-benzyladenine (BA). An average of 5.3 shoots was obtained from nodal explants on 10 μM BA. For shoot tip explants, however, supplementation of α-naphthaleneacetic acid (NAA) with BA favored a caulogenic response. A maximum of 6.1 shoots were produced per shoot tip explant on MS containing 7.5 μM BA plus 5.0 μM NAA. The in vitro-regenerated shoots produced roots when transferred to full-strength MS medium containing 3% sucrose and 10 μM indole-3-butyric acid (IBA). The developed plantlets were transferred initially to a mist house. After an initial acclimatization period of 3–4 mo, plantlets were shifted to the greenhouse where they thrived for 9 mo. The standardized protocol for mass propagation of S. dentata should eliminate the dependence on natural stands of plants for traditional medicinal purposes, and will also serve as a means of conservation as the species is heavily overexploited.     

Phylogenetic relationships of three genera in Anacardiaceae: Bonetiella, Pseudosmodingium, and Smodingium

Phylogenetic analyses were conducted to determine the relationships between and characterize the morphological variation among three genera of Anacardiaceae:Bonetiella, Pseudosmodingium, andSmodingium. The first two genera are endemic to Mexico and the third to South Africa.Bonetiella andSmodingium are monotypic.Pseudosmodingium has eight species, six extant and two fossil, and all were included in the analyses. Fifty-six anatomical characters for leaves, wood, and fruit, as well as morphological characters, were considered. Our results indicate thatSmodingium is not closely related toPseudosmodingium andBonetiella, and that these last two genera are sister taxa.Pseudosmodingium is a monophyletic group and the two fossil species are related to species from the same geographical area of central Mexico where they were found. Fruit anatomical characters were significant at the generic level, while leaf anatomical characters were important at the species level inPseudosmodingium.

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Resumen  En este trabajo se llevaron a cabo análisis filogenéticos para determinar las relaciones filogenéticas así como caracterizar la variación morfológica de tres géneros de Anacardiaceae:Bonetiella, Pseudosmodingium ySmodingium. Los dos primeros son endémicos a México y el terceroo a Sudáfrica.Bonetiella ySmodingium son monotípicos.Pseudosmodingium incluye ocho especies, dos fósiles y el resto vivientes, y todas fueron consideradas en los análisis. Se consideraron 56 caracteres tanto anatómicos como morfológicos de hojas, madera y frutos. Nuestros resultados indican queSmodingium no está cercanamente relacionado aPseudosmodingium yBonetiella, y que estos dos últimos géneros son taxa hermanos.Pseudosmodingium es un grupo monofilético y las dos especies fósiles están relacionadas a especies que crecen en las mismas áreas geográficas del centro de México, donde fueron descubiertas. Los caracteres anatómicos del fruto fueron significativos a nivel genérico, mientras que los de hoja fueron importantes a nivel de especies enPseudosmodingium.

     

Antimicrobial and cyclooxygenase enzyme inhibitory activities of Sclerocarya birrea and Harpephyllum caffrum (Anacardiaceae) plant extracts

The growing demand of medicinal plants is posing a major threat to biodiversity conservation. Sclerocarya birrea and Harpephyllum caffrum (Anacardiaceae) are traditionally used to treat numerous ailments increasing their susceptibility to overexploitation. The aim of the study was to evaluate the medicinal efficacy of renewable aerial parts of the plants using in vitro assays, thus providing a conservation measure by plant part substitution. Plant samples were sequentially extracted with petroleum ether, dichloromethane and 80% ethanol, sonicated on ice and concentrated under vacuum. Antimicrobial activities were determined by the minimum inhibition concentration (MIC) using the micro-dilution assay. The ability of extracts to inhibit COX-1 and COX-2 enzymes was used to evaluate anti-inflammatory activity. Ethanolic extracts of S. birrea and H. caffrum exhibited high antibacterial activity (MIC < 1.0 mg/ml). S. birrea twig extract was the most active with a total activity of 1609.1 ml/g against Bacillus subtilis and an MIC of 0.098 mg/ml. Petroleum ether and dichloromethane extracts exhibited high COX-1 (90.7–99.8%) and COX-2 (69–92.6%) enzyme inhibition at a concentration of 250 μg/ml. The extracts of S. birrea and H. caffrum exhibited high antimicrobial and anti-inflammatory properties. Based on these results, plant part substitution can be a practical conservation strategy for the two species.     

Defoliating broad-nosed weevil,Plectrophoroides lutra; not suitable for biological control of Brazilian pepper (Schinus terebinthifolius)

Adults of the weevil Plectrophoroides lutra were evaluated for biological control of Schinus terebinthifolius. No-choice tests conducted on North American and other valued plants indicated the adults fed on all species offered. Thus, it is unlikely that P. lutra will be developed as a biological control for S. terebinthifolius.     

Influence of host-plant quality on the performance of <Emphasis Type="Italic">Episimus unguiculus</Emphasis>, a candidate biological control agent of Brazilian peppertree in Florida

Brazilian peppertree, Schinus terebinthifolius Raddi (Sapindales: Anacardiaceae), introduced from South America, invades a variety of habitats in Florida (e.g. disturbed sites, coastal mangrove forests). The objective of this study was to evaluate the effect of host-plant quality on the performance of Episimus unguiculus Clarke (=E. utilis Zimmerman) (Lepidoptera: Tortricidae), a potential biocontrol agent of Brazilian peppertree. Experiments were conducted in the laboratory using Brazilian peppertrees exposed either to different salinity levels (0, 6, 12 parts per thousand), or to different nutrient levels (low, medium, high). Higher survival (55%) and faster development (32 day) to adulthood was observed on plants grown in fresh-water environments (0 ppt) compared to low (6 ppt) or high-salinity environments (12 ppt). In addition, higher survival (40%), faster development (34 day) and higher fertility (88% eggs hatched) occurred in high-nutrient treatments. Based on these results, field releases should be conducted in favorable habitats (e.g., low salinity, high fertility soils) to maximize the possibility of establishment and population growth of E. unguiculus in Florida. Handling Editor: John Scott.     

漆树科植物漆酚的多样性及演化关系研究

漆酚是漆树科植物独有的化学成分,具有良好的抗氧化、抗肿瘤、抗病毒等生物活性,极具药物和工业生产开发价值。该研究通过对国内外有关漆树科各类群有关漆酚数据的搜集和整理,开展漆树科漆酚的多样性与分布情况的综合统计;同时在利用核基因ETS和叶绿体基因rps16和trnL-F重建漆树科系统发育树的基础上,探讨漆酚在漆树科及各属间的起源和演化关系。结果表明:(1)漆树科漆酚具有较高的多样性,在其苯环和-R链上都有很大的变异。(2)发现漆酚仅存在于Anacardioideae亚科中,是该亚科的一个重要界定特征。(3)基于漆酚苯环结构和-R链特征的祖先性状重建分析表明,漆树科的漆酚是由邻苯二酚向间苯二酚演化,而漆酚-R链的十五烃(烯)基则是向十七烃(烯)基平行演化。