A novel insight into the cost–benefit model for the evolution of botanical carnivory

Background The cost–benefit model for the evolution of botanical carnivory provides a conceptual framework for interpreting a wide range of comparative and experimental studies on carnivorous plants. This model assumes that the modified leaves called traps represent a significant cost for the plant, and this cost is outweighed by the benefits from increased nutrient uptake from prey, in terms of enhancing the rate of photosynthesis per unit leaf mass or area (A_N) in the microsites inhabited by carnivorous plants.Scope This review summarizes results from the classical interpretation of the cost–benefit model for evolution of botanical carnivory and highlights the costs and benefits of active trapping mechanisms, including water pumping, electrical signalling and accumulation of jasmonates. Novel alternative sequestration strategies (utilization of leaf litter and faeces) in carnivorous plants are also discussed in the context of the cost–benefit model.Conclusions Traps of carnivorous plants have lower A_N than leaves, and the leaves have higher A_N after feeding. Prey digestion, water pumping and electrical signalling represent a significant carbon cost (as an increased rate of respiration, R_D) for carnivorous plants. On the other hand, jasmonate accumulation during the digestive period and reprogramming of gene expression from growth and photosynthesis to prey digestion optimizes enzyme production in comparison with constitutive secretion. This inducibility may have evolved as a cost-saving strategy beneficial for carnivorous plants. The similarities between plant defence mechanisms and botanical carnivory are highlighted.     

The role a botanical institute can play in the conservation of the terrestrial biodiversity in a developing country

The need to integratein situ conservation into the planning process is outlined, and the importance of vegetation survey to determine conservation priorities and to identify areas suitable forin situ conservation is stressed. A case is presented, drawing on experience gained in Zimbabwe, of how a botanical institute can become an integral part of biological conservation. The institute should consist of a herbarium, a botanical garden, a gene bank and a vegetation survey unit. The function of each section, how they interlink, and how they can be integrated are discussed.     

Biodegradation of organophosphorus insecticides by two organophosphorus hydrolase genes (opdA and opdE) from isolated Leuconostoc mesenteroides WCP307 of kimchi origin

This study is aimed to reveal the molecular incidence of organophosphorus insecticides degradation during the fermentation of Korean food yeulmu-mulkimchi. To this end, two opdA and opdE which consist of 930 and 894 bp that encode 309 and 297 amino acids, respectively, were cloned from the Leuconostoc mesenteroides WCP307 strain that was isolated from chlorpyrifos (CP) impregnated kimchi. The Escherichia coli that harbored the opdA and opdE genes depleted a CP concentration of 72% and 83%, respectively, in an M9 medium after 6 days. The OpdA and OpdE enzymes molecular weights were estimated to be approximately 35 and 33 kDa and showed optimal activities at 30 °C with a pH of 7.0 and 6.0, respectively. However, the mutated OpdA (Ser128 → Ala128) and OpdE (Ser129 → Ala129) enzymes had no activities on OP insecticides and ρ-nitrophenyl butyrate substrates. In addition, the OpdA and OpdE enzymes showed profound catalytic activities against cadusafos, comnaphos, diazinon, dyfonate, ethoprophos, fenamiphos, methylparathion, and parathion insecticides. Therefore, it is assumed that OpdA and OpdE enzymes detoxified the pesticides contaminated kimchi composition like Chinese cabbages during fermentation. Furthermore, the OpdA and OpdE enzymes augmented the diversity of new LAB-opd enzymes group in nature.     

The repellent effect of two pyrethroid insecticides on the honey bee*

ABSTRACT. . An improved model for the repellent effect of pyrethroid insecticides on insects was developed using small colonies of honey bees, Apis mellifera L., in flight cages. Conditioning to scented feeders allowed the separation of foraging bees from a single colony into paired treatment and control groups. The repellent response was characterized as a sublethal toxic effect resulting in transitory inhibition of activity. Permethrin and cypermethrin were shown to be contact repellents to honey bees; exposure was primarily to the tarsi and abdominal venter. Repellency was fully reversible within 24 h. No permanent effects on either memory function or foraging efficiency were observed following acute exposure.     

Laboratory evaluation of desiccants and insecticidal soap applied to various substrates to control the deer tick Ixodes scapularis

Abstract. Desiccant and soap pest control products were tested against Ixodes scapularis nymphs on sod, pachysandra, landscaping stones and pinebark wood-chips in a laboratory study. High mortality (91–100%) was obtained with the silica-based desiccant Drione and Safer's insecticidal soap (SIS) treatments except for SIS treated woodchips. SIS and Drione contain 0.2 and 1% pyrethrins, respectively. SIS may be absorbed by the woodchips and not picked up by the nymphs as mortality decreased to 78%. Diatomaceous earth and Dri-die reduced nymphs by only 10–41%; neither desiccant contains insecticides. Nymphal mortality increased 15–17% after 20 or 100 ml of water was sprayed over sod plugs treated with SIS or Drione. The addition of isopropyl alcohol (ROH) to SIS increased the efficacy of SIS against nymphal I. scapularis on treated sod plugs but not on treated landscaping substrates. Drione, SIS, SIS-ROH and chlorpyrifos 50WP treated landscaping stones and pinebark woodchips resulted in 88–95% and 72–96% nymphal mortality, respectively. Unexpectedly, these substrates and treatments affected tick movement as well. Effective pest control products applied to xeric landscaping substrates present in maintained beds and borders near wooded areas could deter tick movement and provide significant levels of tick control.     

Identification of the ryanodine receptor mutation I4743M and its contribution to diamide insecticide resistance in Spodoptera exigua (Lepidoptera: Noctuidae)

Insect ryanodine receptors (RyRs) are the targets of diamide insecticides. Two point mutations G4946E and I4790M (numbering according to Plutella xylostella, PxRyR) in the transmembrane domain of the insect RyRs associated with diamide resistance have so far been identified in three lepidopteran pests, P. xylostella, Tuta absoluta and Chilo suppressalis. In this study, we identified one of the known RyR target site resistance mutations (I4790M) in a field‐collected population of Spodoptera exigua. The field‐collected WF population of S. exigua exhibited 154 fold resistance to chlorantraniliprole when compared with the susceptible WH‐S strain. Sequencing the transmembrane domains of S. exigua RyR (SeRyR) revealed that the resistant WF strain was homozygous for the I4743M mutation (corresponding to I4790M in PxRyR), whereas the G4900E allele (corresponding to G4946E of PxRyR) was not detected. The 4743M allele was introgressed into the susceptible WH‐S strain by crossing WF with WH‐S, followed by three rounds of backcrossing with WH‐S. The introgressed strain 4743M was homozygous for the mutant 4743M allele and shared about 94% of its genetic background with that of the recipient WH‐S strain. Compared with WH‐S, the near‐isogenic 4743M strain showed moderate levels of resistance to chlorantraniliprole (21 fold), cyantraniliprole (25 fold) and flubendiamide (22 fold), suggesting that the I4743M mutation confers medium levels of resistance to all three diamides. Genetic analysis showed diamide resistance in the 4743M strain was inherited as an autosomal and recessive trait. Results from this study have direct implications for the design of appropriate resistance monitoring and management practices to sustainably control S. exigua.     

三种植物源药剂对红火蚁的防治效果评估及其对本地蚂蚁群落影响

红火蚁Solenopsis invicta Buren是一种危险性入侵害虫,可对人类健康、农林业生产、公共安全和生态系统产生严重的负面影响。目前,化学农药是防治红火蚁的主要方法。然而,大多数化学农药并不适用于有机农场、水产养殖区等生态敏感区。为筛选出用于生态敏感区红火蚁防治的药剂,本文结合室内和田间试验评估了植物源杀虫剂苦参碱Matrine、鱼藤酮Rotenone和除虫菊素Pyrethrin对红火蚁的防治效果。室内试验结果表明,苦参碱、鱼藤酮和除虫菊素对红火蚁均具有较高的毒性。田间试验表明,25.00 mg/L和12.50 mg/L苦参碱、250.00 mg/L 和125 mg/L鱼藤酮、75.00 mg/L和37.50 mg/L除虫菊素灌巢处理,红火蚁蚁巢减退率分别达到100%、81.25%、87.50%、79.17%、71.73%和66.67%。然而,除25.00 mg/L苦参碱外,其他处理均导致在被灌巢的蚁巢周围短期内出现新蚁巢。灌巢处理后,处理区的蚂蚁多样性指数和均匀度指数升高,优势度指数下降。综上所述,苦参碱、鱼藤酮和除虫菊素适合灌巢处理防治红火蚁,其中0.5%苦参碱可溶性液剂能有效降低红火蚁种群数量,使得蚁巢减退率达100%,同时对本地蚂蚁群落没有负面影响,因此该商品制剂在红火蚁防治方面具有较好的开发潜力。     

高效氯氟氰菊酯微囊悬浮剂与二阶段法对红火蚁的田间防治效果评价

研究了高效氯氟氰菊酯微囊悬浮剂与二阶段法对红火蚁的田间防治效果。结果表明,0.25 g/L高效氯氟氰菊酯微囊悬浮剂施药后击倒红火蚁迅速,14 d后活动蚁巢减退率、工蚁减退率、蚁巢级别降低率、综合防治效果均达到100%。使用0.045%茚虫威饵剂搭配0.25 g/L高效氯氟氰菊酯微囊悬浮剂的二阶段法,5 d后红火蚁的活动蚁巢和工蚁数量均显著下降,14 d后活动蚁巢减退率、工蚁减退率、蚁巢级别降低率、综合防治效果均达到100%。结果表明,0.25 g/L高效氯氟氰菊酯微囊悬浮剂对红火蚁具有高效的控制作用,在实际使用时可根据防治面积的大小选择单独灌巢还是配合饵剂的二阶段法。     

Toxicity,behavior impairment,and repellence of essential oils from pepper‐rosmarin and patchouli to termites

Plant essential oils are potential sources of insecticidal compounds, but have rarely been explored for their effect on termites. In the present study, we assessed the chemical composition of essential oils of Lippia sidoides Cham. (pepper‐rosmarin; Verbenaceae) and Pogostemon cablin (Blanco) Benth. (patchouli; Lamiacaeae) and evaluated their toxicity, behavioral impairment, and repellence to termite species of the genera Amitermes and Microcerotermes (Isoptera: Termitidae: Termitinae). The main components of essential oils of L. sidoides and P. cablin were thymol (44.6%) and patchouli alcohol (36.6%), respectively. The essential oil of P. cablin was most potent against Amitermes cf. amifer Silvestri and had the lowest LD₅₀ (0.63 μg mg^?1). There was no difference in toxicity for Microcerotermes indistinctus Mathews between the essential oils of L. sidoides (LD₅₀ = 1.49 μg mg^?1) and P. cablin (LD₅₀ = 1.67 μg mg^?1). Pogostemon cablin essential oil was the most toxic to M. indistinctus (LC₅₀ = 0.32 μl ml^?1) and A. cf. amifer (LC₅₀ = 0.29 μl ml^?1). The essential oils analyzed exhibited high toxicity and repellence to the termites, in addition to reducing behavioral interactions among individuals, thus constituting potential termiticides.     

Substantial variation in leaf senescence times among 1360 temperate woody plant species: implications for phenology and ecosystem processes

Background and Aims Autumn leaf senescence marks the end of the growing season in temperate ecosystems. Its timing influences a number of ecosystem processes, including carbon, water and nutrient cycling. Climate change is altering leaf senescence phenology and, as those changes continue, it will affect individual woody plants, species and ecosystems. In contrast to spring leaf out times, however, leaf senescence times remain relatively understudied. Variation in the phenology of leaf senescence among species and locations is still poorly understood.Methods Leaf senescence phenology of 1360 deciduous plant species at six temperate botanical gardens in Asia, North America and Europe was recorded in 2012 and 2013. This large data set was used to explore ecological and phylogenetic factors associated with variation in leaf senescence.Key Results Leaf senescence dates among species varied by 3 months on average across the six locations. Plant species tended to undergo leaf senescence in the same order in the autumns of both years at each location, but the order of senescence was only weakly correlated across sites. Leaf senescence times were not related to spring leaf out times, were not evolutionarily conserved and were only minimally influenced by growth habit, wood anatomy and percentage colour change or leaf drop. These weak patterns of leaf senescence timing contrast with much stronger leaf out patterns from a previous study.Conclusions The results suggest that, in contrast to the broader temperature effects that determine leaf out times, leaf senescence times are probably determined by a larger or different suite of local environmental effects, including temperature, soil moisture, frost and wind. Determining the importance of these factors for a wide range of species represents the next challenge for understanding how climate change is affecting the end of the growing season and associated ecosystem processes.