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991.
We developed a predator–prey activity with eighth-grade students in which they used wolf spiders (Lycosa carolinensis), house crickets (Acheta domestica), and abiotic factors to address how (1) adaptations in predators and prey shape their interaction and (2) abiotic factors modify the interaction between predators and prey. We tested student understanding with pre- and postquizzes, written observations, and interpretations of graphical results.  相似文献   
992.
The potential of an in vitro technique to study root‐knot nematode infection on banana roots was investigated. Regenerated banana plants were placed horizontally on Gamborg B5 (GB5)‐medium and incubated under a light‐dark regime of 16h‐8h. Temperature fluctuated between 24 and 33 °C. Banana roots were inoculated with Meloidogyne incognita race 1 coming from roots of a transgenic tomato (Lycopersicon esculentum cv. Moneymaker) grown on GB5‐medium at 28 °C in complete darkness. Root‐knots appeared on primary and secondary banana roots two to seven days after nematode inoculation. After 28 days, egg masses protruded through the cortex and two days later juveniles hatched and reinfected banana roots. This method holds promise for dynamic studies of banana root infection with root‐knot nematodes.  相似文献   
993.
Twelve isolates of Lasiodiplodia theobromae were collected from 12 different commercial banana cultivars belonging to various banana growing regions of Tamil Nadu, India. The results revealed that most of the L. theobromae isolates exhibited significant differences in morphology, colour and spore size. However, all 12 isolates took 3–4 days invariably to cover the 90 mm Petri plates. Among the 12 isolates, the isolates LT3a from Robusta and LT10c from dwarf Cavendish produced abundant pycnidia. These isolates were also analysed through Random amplified polymorphic DNA (RAPD) markers for genetic diversity. Polymerase chain reaction amplification of total genomic DNA of the 12 isolates of L. theobromae with 14 random primers generated numerous polymorphisms among the isolates, while many of the intense bands were shared among majority of the isolates. Cluster analysis also indicated a high degree of genetic variability within L. theobromae isolates from different banana cultivars. The 12 isolates were separated into three clusters namely A, B and C. The maximum similarity index of 80% was recorded between the isolates LT7d from Karpuravalli and LT10c from dwarf Cavendish. The least similarity index of 29.41% was recorded with the isolates LT1f isolated from Poovan and LT5a isolated from Virupakshi. Within the species of L. theobromae the genetic variability was high and it underlines and validates existence of significant intra-specific diversity in isolates of L. theobromae infecting different banana cultivars.  相似文献   
994.
How aphid alarm pheromone can control aphids: a review   总被引:1,自引:0,他引:1  
Aphids are the major pests of arable crops, mostly in temperate regions. They are monophagous as well as polyphagous. They inflict damage in brassica, potato, cotton, vegetable and fruit crops. They damage their host plant directly by feeding upon their phloem sap, or indirectly by transmitting pathogens to them. Their life cycle can be autoecious as well as heteroecious. Aphids use semiochemicals for various purposes, in gathering information from their environment and for communication among themselves. They protect themselves from predators and parasitoids by escape response which is arbitrated by use of alarm pheromone signalling. When alarm pheromone, (E)-ß-farnesene, is released, nearby aphids exhibit a variety of behaviours like moving away, running, dropping off the plant and even attacking the predator. Previous studies of integrated pest management strategies have been aimed at the usage of alarm pheromone. However, scientists require complete knowledge of aphid ecology as well as aphid interaction with its natural enemies to establish efficient and viable biological control. This review presents analysis of the existing aphid pest management methodologies and effectiveness of alarm pheromone on aphids and their natural enemies.  相似文献   
995.
Date palm is one of the most important products in Iran. Kerman province is one of the most important producers of this crop. Major areas of date palm cultivation in the province involve Bam, Jiroft and Shahdad. Date palm acreage of Shahdad is over 3500 hectares. Date palm varieties in Shahdad are Ghasb, Shamsaee and Bazmani. Ghasb date palm is most important in Shahdad that is classified as dry product. Date Palm trees have many pests such as the horned beetle dates, spider mite, leafhopper and moths; and according to the studies done in 2008–2009, Ephestia figulilella is the most important pest on fruit dates in Shadad, sometimes 90% of product is contaminated by this pest. This pest has four to five generations per year and overwintered as all of stages in storage and larvae in garden.  相似文献   
996.
The postembryonic development of the female reproductive system in the pycnogonid Propallene longiceps is examined. The germ cells can be detected first in the later stage of the 3rd instar and become a paired gonad covered with gonadal epithelium in the next instar. The larval gonad changes its shape: paired at the 4th instar, reversed U-shaped at the fifth, unpaired at the sixth, and paired again at the seventh. Oocytes can be distinguished, and the extension of the ovary into the walking legs begins at the 7th instar. Growing oocytes protrude outward from the ovary on cellular stalks in the pedal part. The trunk ovary becomes U-shaped, and the oviducts and genital pores start forming at the 8th instar. The disappearance of trunk ovary begins at the 9th instar, and is complete at the next adult stage. The connection between the pedal ovarian lumen and the genital pores via the oviducts is complete in the adult, and the female reproductive system becomes segmentally arranged. This study confirms that the segmental arrangement of adult female reproductive system in P. longiceps, which is unique among recently described arthropods, is a secondary state in pycnogonids attained by reducing the trunk part of ovary.  相似文献   
997.
The present work shows predatory behaviour of the social orb-weaver spider, Geratonephila burmanica n. gen., n. sp. (Araneae: Nephilidae) against a parasitic wasp, Cascoscelio incassus n. gen., n. sp. (Hymenoptera: Platygastridae) in Early Cretaceous Burmese amber. An adult male and juvenile of G. burmanica in the same web provide the first fossil evidence of sociality in spiders. The spider is characterised by a pedipalp with a hemispherical tegulum, a subtegulum curved at 180°and an apical spiralled embolas-conductor bent approximately 45°at midpoint. The male wasp is characterised by an ocellar tubercle, 12-segmented antennae with a feeble five-segmented clava, thick sensilla trichodea curvata with rounded ends on the claval antennomeres, a short uncus, a short post-marginal vein and a nebulose radial sector (Rs) vein extending from the uncus to the costal margin of the forewing. This is the first fossil evidence of spider sociality and a fossil spider attacking prey trapped in its web.  相似文献   
998.
This study investigated the use of two anesthetic agents, isoflurane and carbon dioxide, in Chilean rose tarantulas (Grammostola rosea). We compared the onset, duration of anesthesia, and recovery time with both gases, and made observations regarding the effects of the anesthetic protocols. Subjectively, episodes for the isoflurane animals were uneventful. The spiders were calm throughout and did not respond adversely to gas exposure. Conversely, animals anesthetized with carbon dioxide experienced violent inductions and recoveries; the tarantulas appeared agitated when the carbon dioxide flow began. Seizure‐like activity and defecation would frequently be noted prior to induction with carbon dioxide. Neither isoflurane nor carbon dioxide seemed to have any clinically apparent short‐ or long‐term impact. The animals were all normal for at least 1‐year postexperiment. Future studies should focus on defining the impact, if any, that these anesthetic agents have on the health of invertebrate species. Zoo Biol. 32:101‐103, 2013. © 2012 Wiley Periodicals, Inc.  相似文献   
999.
Laboratory tests were conducted in Italy to evaluate the acceptance and suitability of the alien butterfly Cacyreus marshalli Butler as host for three indigenous parasitoids, Trichogramma brassicae (Bezdenko), Exorista larvarum (L.) and Brachymeria tibialis (Walker). Only E. larvarum and B. tibialis showed potential to adapt to C. marshalli. Their contribution to biological control appeared to be especially related to host mortality due to incomplete parasitoid development.  相似文献   
1000.
三峡水库周期性水淹结束后,消落带植物积极恢复生长的能力有利于其生存和定居,因此,探究影响植物恢复生长的关键生理生态机制对于消落带生态治理具有重要意义。采用野外采样、对比测定的手段,研究了生长于三峡水库消落带的狗牙根和牛鞭草根系在冬季水淹结束后清除活性氧(ROS)的关键酶活力恢复动态。结果表明:与对照相比,经历水淹的植物恢复初期发生明显氧化胁迫,超氧化歧化酶(SOD)、抗坏血酸过氧化物酶(APX)均维持了水淹诱导增加的活力水平。两个物种的过氧化氢酶(CAT)在水淹中活力均较低;出露之后后狗牙根CAT趋向于对照水平,牛鞭草CAT活力迅速上升但未到显著水平。水淹结束后24 d各个酶活力均回复到对照水平,表明氧化胁迫已基本消失。消落带位点植物不同酶活力之间表现出显著的相关关系,这可能是植株维持ROS代谢内稳态的表现。  相似文献   
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