| 1. |
- Azeem, Muhammad, et al.
(författare)
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Chemical composition and repellent activity of native plants essential against dengue mosquito, Aedes aegypti
- 2019
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Ingår i: Industrial crops and products (Print). - : Elsevier BV. - 0926-6690 .- 1872-633X. ; 140
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Tidskriftsartikel (refereegranskat)abstract
- Aedes aegypti L. (Diptera: Culicidae) mosquito is an important vector of chikungunya, dengue and yellow fever. Plant based essential oils may serve as good alternatives to commercially available mosquito repellent, DEET. Steam distillation was used for the extraction of essential oils from fresh collected aerial parts of plants viz Chenopodium ambrosioides, Conyza sumatrensis, Erigeron canadensis, Eucalyptus camaldulensis, Mentha spicata, Parthenium hysterophorus, and Tagetes minuta. The essential oils were tested for mosquito repellent activity against laboratory reared female Ae. aegypti by human bait technique. Identification of chemical constituents of essential oils was carried out by gas chromatography-mass spectrometry (GC-MS). The essential oil of M. spicata, E. canadensis, P. hysterophorus, C. sumatrensis, T. minuta, C. ambrosioides, and E. camaldulensis exhibited 100%, 80%, 63.9%, 51.4%, 50.2%, 39.7%, and 13.7% mosquito repellent activity respectively, at the tested dose of 30 mu g/cm(2). The most abundant constituents of M. spicata, E. canadensis, P. hysterophorus, C. sumatrensis and T. minuta essential oils were piperitenone oxide (47.1%), limonene (41.3%), germacrene D (36.6%), cis-lachnophyllum ester (33.3%) and dihydrotagetone (20.9%) respectively. M. spicata essential oil completely inhibited the attractiveness of human hands toward female mosquitoes for more than 45 min thus showed bioactivity comparable to that of commercially used mosquito repellent, DEET. This study suggests that the dilute solution of M. spicata essential oil could be used as potent mosquito repellent against Ae. aegypti alternative to commercially available synthetic mosquito repellents.
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| 2. |
- Binyameen, Muhammad, et al.
(författare)
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Eugenol, a Plant Volatile, Synergizes the Effect of the Thrips Attractant, Ethyl Iso-Nicotinate
- 2018
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Ingår i: Environmental Entomology. - : Oxford University Press (OUP). - 0046-225X .- 1938-2936. ; 47, s. 1560-1564
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Tidskriftsartikel (refereegranskat)abstract
- The onion thrips, Thrips tabaci Lindeman (Thysanoptera: Thripidae), is a polyphagous pest that causes serious damage to agricultural crops, vegetables, and ornamental plants worldwide. Farmers rely on the extensive usage of synthetic chemical insecticides to control T. tabaci. There is a dire need to develop alternative control strategies to overcome the problems posed by chemical insecticides. Efficient traps would allow sensitive monitoring and possibly mass trapping. A field experiment was conducted to evaluate the potential of three plant compounds with known release rates (ranging from 6-30 mg/d); eugenol (Eug), 1, 8-cineole (eucalyptol), and linalool in all possible combinations with a thrips attractant, ethyl iso-nicotinate (EI). A combination of EI with Eug increased the effect of EI by attracting 100% more thrips (effect size, 1.95) as compared to the control of EI alone. Catches in remaining treatments were lower and or not significantly different from EI alone. The results from our study could be used to develop improved volatile blends to be used for monitoring traps. Our data suggests that these traps could be effective even at very low populations.
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| 3. |
- Kromann, Sophie, et al.
(författare)
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Concurrent modulation of neuronal and behavioural olfactory responses to sex and host plant cues in a male moth
- 2015
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Ingår i: Proceedings of the Royal Society B: Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 282
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Tidskriftsartikel (refereegranskat)abstract
- Mating has profound effects on animal physiology and behaviour, not only in females but also in males, which we show here for olfactory responses. In cotton leafworm moths, Spodoptera littoralis, odour-mediated attraction to sex pheromone and plant volatiles are modulated after mating, producing a behavioural response that matches the physiological condition of the male insect. Unmated males are attracted by upwind flight to sex pheromone released by calling females, as well as to volatiles of lilac flowers and green leaves of the host plant cotton, signalling adult food and mating sites, respectively. Mating temporarily abolishes male attraction to females and host plant odour, but does not diminish attraction to flowers. This behavioural modulation is correlated with a response modulation in the olfactory system, as shown by electro-physiological recordings from antennae and by functional imaging of the antennal lobe, using natural odours and synthetic compounds. An effect of mating on the olfactory responses to pheromone and cotton plant volatiles but not to lilac flowers indicates the presence of functionally independent neural circuits within the olfactory system. Our results indicate that these circuits interconnect and weigh perception of social and habitat odour signals to generate appropriate behavioural responses according to mating state.
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| 4. |
- Schiebe, Christian, et al.
(författare)
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Styrene, (+)-trans-(1R,4S,5S)-4-Thujanol and Oxygenated Monoterpenes Related to Host Stress Elicit Strong Electrophysiological Responses in the Bark Beetle Ips typographus
- 2019
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Ingår i: Journal of Chemical Ecology. - : Springer. - 0098-0331 .- 1573-1561. ; 45:5-6, s. 474-489
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Tidskriftsartikel (refereegranskat)abstract
- Bark beetles kill apparently vigorous conifers during epidemics by means of pheromone-mediated aggregation. During non-endemic conditions the beetles are limited to use trees with poor defense, like wind-thrown. To find olfactory cues that help beetles to distinguish between trees with strong or weak defense, we collected volatiles from the bark surface of healthy felled or standing Picea abies trees. Furthermore, living trees were treated with methyl jasmonate in order to induce defense responses. Volatiles were analyzed by combined gas chromatography and electroantennographic detection (GC-EAD) on Ips typographus antennae. Compounds eliciting antennal responses were characterized by single sensillum recording for identification of specific olfactory sensory neurons (OSN). Release of monoterpene hydrocarbons decreased, while oxygenated compounds increased, from spring to early summer in felled trees. In both beetle sexes particular strong EAD activity was elicited by trace amounts of terpene alcohols and ketones. 4-Thujanol gave a very strong response and the absolute configuration of the tested natural product was assigned to be (+)-trans-(1R,4S,5S)-thujanol by stereoselective synthesis and enantioselective gas chromatography. One type of OSN responded to all ketones and five other OSN were characterized by the type of compounds that elicited responses. Three new OSN classes were found. Of the eight EAD-active compounds found in methyl jasmonate-treated bark, the known anti-attractant 1,8-cineole was the one most strongly induced. Our data support the hypothesis that highly active oxygenated host volatiles could serve as positive or negative cues for host selection in I. typographus and in other bark beetles.
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| 5. |
- Walker, William, et al.
(författare)
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Effects of different animal manures on attraction and reproductive behaviors of common house fly, Musca domestica L
- 2016
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Ingår i: Parasitology Research. - : Springer Science and Business Media LLC. - 0932-0113 .- 1432-1955. ; 115, s. 3585-3598
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Tidskriftsartikel (refereegranskat)abstract
- Insects rely mainly on their well-developed and highly sophisticated olfactory system to discriminate volatile cues released from host and nonhost substances, mates, oviposition substrates, and food sources. Onset of first mating, mating duration, and onset of first oviposition, oviposition period, fecundity (number of eggs laid by a female), and longevity of freshly emerged Musca domestica L. (Diptera: Muscidae) adults were observed in the presence of different animal manures: cow, horse, donkey, poultry, and an artificial diet. The M. domestica adults exposed to horse manure showed a delay in onset of first mating and first oviposition, prolonged mating duration, and reduced fecundity compared to the artificial diet (control). Likewise, the fecundity was reduced in the presence of donkey manure as compared to artificial diet. The onset of first mating was delayed and duration of first mating was shortened in the presence of cow manure as compared to artificial diet and no oviposition was observed throughout the duration of the experiment. However, the reproductive behaviors and all fitness measures in adults exposed to poultry manure were similar or even better, compared to the artificial diet. Surprisingly, in a free-choice attraction assay, the highest numbers of adult flies were attracted toward the cow manure as compared to all other manures as well as the artificial diet. However, the numbers of flies captured in all other types of manures were not different than the artificial diet (control). Furthermore, chemical analysis of headspace samples of manures revealed qualitative differences in odor (volatile) profiles of all manures and artificial diet, indicating that behavioral differences could be due to the differences in the volatile chemistry of the adult ovipositional substrates and larval growth mediums. This study may contribute toward both understanding the linkage between ecological adaptations and host selection mechanisms and the development of pest management strategies against this serious pest of medical and veterinary importance.
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| 6. |
- Walker, William, et al.
(författare)
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Functional evolution of Lepidoptera olfactory receptors revealed by deorphanization of a moth repertoire
- 2017
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Insects detect their hosts or mates primarily through olfaction, and olfactory receptors (ORs) are at the core of odorant detection. Each species has evolved a unique repertoire of ORs whose functional properties are expected to meet its ecological needs, though little is known about the molecular basis of olfaction outside Diptera. Here we report a pioneer functional analysis of a large array of ORs in a lepidopteran, the herbivorous pest Spodoptera littoralis. We demonstrate that most ORs are narrowly tuned to ubiquitous plant volatiles at low, relevant odorant titres. Our phylogenetic analysis highlights a basic conservation of function within the receptor repertoire of Lepidoptera, across the expansive evolutionary radiation of different major clades. Our study provides a reference for further studies of olfactory mechanisms in Lepidoptera, a historically crucial insect order in olfactory research.
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