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1.
Abstract. Water-soluble extracts of a host crucifer (Brassica oleracea L.) and non-host crucifer (Erysimum cheiranthoides L.) and isolated pure cardenolides and glucosinolates were tested on Pieris rapae L. (Lepidoptera: Pieridae) butterflies in oviposition assays and by electrophysiological recordings from the contact-chemoreceptor sensilla of the prothoracic tarsi. Ten different glucosinolates stimulated oviposition to varying degree when put on non-host plant leaves. The most active compounds were glucobrassiein and gluconasturtiin (methylindole and phenylethyl aglycone), whereas glucocapparin, sinalbin. glucotropaeolin, sinigrin and glucoalyssinin had intermediate activity. Glucocheirolin, glucoerucin and glucoiberin (sulphur-containing aglycone) were significantly less active. Of eight cardenolides applied to host-plant leaves (100 μg each), four glycosides deterred oviposition strongly (erysimoside, erychroside, cymarin and K-strophanthin-β). Erycordin, helveticoside, digitoxin and strophanthidin had little or no deterrent activity. Sensilla located laterally on the prothoracic tarsi of female butterflies contained one receptor cell sensitive to sucrose. None of the tested extracts or pure compounds stimulated any cell in these sensilla. In contrast, the cells in the medial sensilla showed little or no sensitivity to sucrose. One cell was found to be sensitive to cardenolide glycosides. The threshold for one of the most active compounds, erychroside, was about 0.1 μg/ml (1.5 times 10-7 M). Two receptor cells, characterized by spikes of differing amplitude, were sensitive to glucosinolates. One of these, with larger amplitude spikes, seemed to be the same as the cell sensitive to cardenolides. The threshold for the most active glucosinolates, glucobrassicin and gluconasturtiin was estimated to be below 0.1 mg/ml (2 times 10-4 M). The neural activity of both classes of compounds, cardenolides and glucosinolates, was significantly correlated with their behavioural activity as deterrents or stimulants.  相似文献   

2.
The occurrence of salt‐, sugar‐sensitive neurones and a mechanoreceptor neurone in the antennal hair‐like gustatory sensilla of the click beetle Agriotes obscurus L. (Coleoptera, Elateridae) is demonstrated using the electrophysiological sensillum tip‐recording technique. The stimulating effect of 13 water soluble sugars at 100 mm is tested on the neurones of these sensilla. Sucrose and fructose are the two most stimulating sugars for the sugar‐sensitive neurone, evoking almost 30 spikes s?1 at 100 mm . The stimulating effect of arabinose, glucose, mannose, maltose and raffinose is three‐ to five‐fold lower, in the range 5.9–9.6 spikes s?1. The remaining six sugars, xylose, galactose, rhamnose, cellobiose, trehalose and lactose, have very low (<1 spikes s?1) or no ability to stimulate the sugar‐sensitive neurone. Concentration/response curves of the sugar‐sensitive neurone to sucrose, fructose and glucose at 0.01–100 mm overlap to a large extent in hibernating, cold reactivated and reproductively‐active beetles. A remarkable 9–50% decrease in the number of spikes evoked by 100 mm fructose and 10–100 mm sucrose occurs, however, in reproductively‐active beetles in June compared with beetles at the beginning of hibernation in October. These findings show that A. obscurus is capable of sensing a wide range sugars via their antennal gustatory sensilla.  相似文献   

3.
Abstract.  The longevity and nutrient levels of Pseudacteon tricuspis provided with 1  m solutions of five naturally occurring sugars, fructose, glucose, sucrose, trehalose and melezitose, are compared. All but melezitose, result in significant increases in the longevity of P. tricuspis in comparison with sugar-starved flies (flies provided with water only). Sugar-starved female and male P. tricuspis have an average longevity of 3.3 and 4.1 days, respectively. Provision of free water in addition to sugar solution is necessary for optimum longevity by female and male flies. Longevity is increased by 2.4–2.6-fold by the two monosaccharides, fructose and glucose, and by 2.6–2.8-fold by the disaccharides, sucrose and trehalose. Phorid flies provided with the trisaccharide sugar, melezitose, had a marginal increase in lifespan (approximately 1 day), but this is not significantly different from the longevity of sugar-starved flies. Significantly greater levels of total sugars are detected in P. tricuspis fed the disaccharide sugars (sucrose, trehalose) or the monosaccharide sugars (fructose, glucose), compared with flies provided with melezitose (trisaccharide), or to sugar-starved flies. Fructose is not detected in sugar-starved flies, or in flies fed glucose or trehalose. However, high levels of fructose are detected in flies fed sucrose or fructose, whereas levels of fructose in melezitose-fed flies are intermediate. In general, significantly greater glycogen levels are detected in P. tricuspis fed sucrose, glucose, trehalose or fructose, compared with melezitose-fed or sugar-starved flies. Levels of total sugars and glycogen in sugar-fed flies are positively correlated with wing length, possibly indicating a higher accumulation of storage sugars by larger flies. These results are discussed in relation to the nutritional ecology of the phorid fly.  相似文献   

4.
The activity in the gustatory nerve from the anterior part of the tongue, the chorda tympani proper nerve, has been recorded during stimulation of the tongue of a New World monkey, Saguinus midas tamarin. A series of 0.3 M sugars and 0.07 M NaCl, 0.07 M sucrose, 0.004 M acetic acid and 0.00005 M quinine hydrochloride were used as taste stimuli. The concentrations of the last four stimuli were the same as those earlier found to be the lowest concentrations at which this monkey in behavioural experiments discriminates between them and water. The records showed that these threshold concentrations all elicited a neural response. Further, the neural activities during stimulation with the series of 0.3 M sugars were recorded. Using the amplitudes of the responses as a measure, the order between them was found to be fructose greater than glucose greater than lactose greater than arabinose greater than sucrose = galactose greater than raffinose. This order was discussed and related with the order found in behavioural experiments. With both methods, fructose seemed to be the strongest stimulus, but then the order among the sugars differed.  相似文献   

5.
The ovipositor of Spodoptera littoralis has many sensilla, which implies a distinct sensory function of this organ in the assessment of the egg laying substrates and placement of eggs. The ovipositor is composed of two papillae densely packed with sensilla. Scanning electron microscopy showed that there are four categories of sensilla chaetica (s. chaetica), characterized based on differences in distribution, length and morphology, distributed on each papilla: Type I with 69 ± 2.9 sensilla on each papilla (length: 29–163 μm) distributed at the base; Type II with 19 ± 1.8 sensilla (length: 287–446 μm) distributed medially; Type III with 120 ± 7.8 sensilla (length: 62–156 μm) distributed distally; and Type IV 8 ± 0.9 sensilla (length: 72–91 μm) scattered between Type III sensilla. The structure of s. chaetica Types I–III suggests a mechanosensory function, whereas electrophysiological analysis of s. chaetica Type IV showed responses from four gustatory neurons and one mechanosensory neuron. Of the chemoreceptive neurons, one responded to salt, one to the secondary compound caffeine, one to sugars, mainly sucrose and fructose, and lastly one potentially to water. Behavioral studies are needed to verify the role of these sensilla during choice of oviposition site.  相似文献   

6.
Using conventional electrophysiological methods, the galeal sensilla chaetica of the honey bee, Apis mellifera, responded linearly to the log of solute concentrations of sucrose, glucose, fructose, NaCl, KCl, and LiCl but not to CaCl2 or MgCl2, which failed to give consistent responses. These sensillae had much higher firing rates for sugar than salt solutions; their relative responses to lower concentrations being NaCl < KCl < LiCl ? fructose < glucose ? sucrose. At higher concentrations NaCl < LiCl < KCl ? glucose < fructose ? sucrose. Four different spike types were seen. The first type had the highest amplitude and resulted from sugar stimulation. The second type had a lower height and occurred in the first 30 sec of salt stimulation. A third type with the lowest height appeared with those of the second type after prolonged stimulation with KCl. A fourth type with a high amplitude resulted from mechanical stimulation. The sensilla adapted to sugar solutions linearly to the logarithm of time and non-linearly to the log of salt concentrations. Glucose-fructose mixed-sugar solution effected synergism of response while sucrose solutions caused inhibition when mixed with glucose and/or fructose. Responses of the sensilla to mechanical stimulation showed phasic-tonic characteristics. None of the sensilla tested responded to water.  相似文献   

7.
A two-choice bioassay was developed to evaluate the role of host-plant berry compounds on the oviposition site acceptance of the generalist moth Lobesia botrana (Denis & Shiffermüller). A key feature was the lining of the bioassay arena with felt which focused oviposition on the test substrates. Initial experiments comparing substrates with different physical features indicated that smooth textures and spherical shapes with interstices favour oviposition. Artificial oviposition substrates were thus constructed with glass spheres in order to test the behavioural activity of grapevine berry extracts. Only polar extracts obtained by soaking berries in methanol or water stimulated oviposition (more eggs were laid on the extract-treated substrate than on the control substrate), whereas more apolar ones obtained with chloroform or hexane had no significant effect. The prior removal of epicuticular waxes from grape berries before extraction did not enhance the stimulatory activity of the methanol extract. The oviposition response to this extract was dose-dependent. It is concluded that polar compounds present on grape berries act as oviposition stimulants for L. botrana.  相似文献   

8.
Before oviposition, a Lygus rugulipennis (Poppius) (Heteroptera: Miridae) female explores the substrate with her mouthparts, performing ‘probing’ behaviour which eventually leads to a choice of oviposition site. In this study, morphological and behavioural observations were carried out in order to define the mechanisms through which female bugs recognise suitable oviposition sites. The morphological study was conducted using electron‐microscopy techniques, while the behavioural experiments aimed at the temporary (using ZnSO4) or permanent (i.e., cauterization of the rostrum and ablation of both stylets and labium) inactivation of sensory structures located in the labium tip and in the stylets, which are probably involved in oviposition site selection. The tip of the labium of L. rugulipennis females is characterised by the presence of 11–12 uniporous gustatory sensilla which are innervated by 3–6 sensory neurones. One aporous mechanoreceptor is located ventrally on both areas of the labium tip. Other aporous mechanosensilla are found more proximally on the labium. ZnSO4 labium tip treatment did not affect oviposition site selection, while stylet amputations, as well as rostrum cauterisations, resulted in almost complete oviposition failure. Labium tip‐ablated females oviposited similarly to control females. These results suggest that the sensory neurones associated with the stylets are involved in the location of the oviposition site. Uniporous gustatory sensilla on the labium tip are not involved in the final steps of the oviposition behaviour. However, they seem to play a role in assessing the suitability of the substrate as a food source.  相似文献   

9.
We were interested in determining the feeding response of the Caribbean fruit fly, Anastrepha suspensa Loew (Diptera: Tephritidae), to various sugar concentrations to develop an improved bait for adults. We compared the consumption of 0.01-1.00 M concentrations of glucose, fructose, raffinose, and sucrose in no-choice tests for 24-h- and 6-d-old male and female flies. Sucrose was the most consumed sugar or within the most consumed group of sugars at 0.02-0.20 M concentrations. There were no differences in consumption among sugars at 0.01, 0.40, and 1.00 M. Consumption generally increased with increasing sugar concentration except that sucrose consumption peaked at 0.20 M. Twenty-four-hour females consumed less fructose than other sugars; 24-h males consumed more sucrose than fructose or raffinose, with an intermediate response to glucose. Females in the 6-d group consumed more sucrose than the other three sugars, whereas 6-d males exhibited no difference in consumption among sugars. In choice tests, flies consumed more sugar solution than water, but the difference between 0.20 M fructose and water was not significant for 24-h males or 24-h females. In choice tests between 0.20 M fructose and 0.20 M sucrose, both 24-h and 6-d females showed a preference for fructose. Males of both age classes showed no preference. These results indicate that the responses of flies to different sugars can vary by sugar, gender, and age.  相似文献   

10.
Abstract .Female 2-day-old Neobellieria (= Sarcophaga ) bullata (Parker) (Diptera: Sarcophagidae) were exposed to different concentrations of sucrose, glucose and fructose in a single-choice potometer, and the volume ingested in the first hour was measured. Nerve spike activity in response to the same sugars was recorded from medium labellar taste hairs of similar flies by tip-recording. Two classes of chemosensory cells responded to sucrose, glucose and fructose. Cell 1 showed an increasing spike activity with sugar concentration, whereas cell 2 did not; cell 1 was identified as the 'sugar cell'.
For both spike activity in cell 1 and feeding, sucrose was the most stimulatory sugar. The dose–response curves for glucose and fructose crossed over at about 200 m m . At higher concentrations, glucose was more stimulatory for both cell 1 and for feeding, and at lower concentrations, fructose. The pattern of spike activity supports a separate location on the sensory cells of receptors for pyranose and fructose forms of sugar. The strong correlation between volume ingested and spike activity indicates that sugar feeding is controlled by sensory input from the 'sugar' cells of labellar chemosensilla. Moreover, the results suggest that the flies do not distinguish between these sugars except by apparent 'sweetness'.  相似文献   

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