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1.
Sensitivity of the cabbage butterfly,Pieris rapae L. to feeding deterrents was compared for larvae reared on different food sources under laboratory conditions. Since cabbage-reared larvae normally reject nasturtium,Tropaeolum majus L., the effects of previous exposure to allelochemicals on larval acceptance or rejection of this plant were also examined. When compared with cabbage-reared larvae, nasturtium-reared larvae were less sensitive to feeding deterrents including cymarin, erysimoside and 2-O-β-d-glucosyl cucurbitacin E. Nasturtium-reared larvae were insensitive to chlorogenic acid, which was deterrent to cabbage-reared larvae. Feeding by larvae reared on a wheat germ diet was not deterred by these compounds. The results indicate that dietary experience can extensively affect larval sensitivity to feeding deterrents and that cross habituation of larvae to deterrents occurs in response to certain chemical constituents of nasturtium and wheat germ diet. Digitoxin, however, proved to be an exception. Larvae reared on either nasturtium or wheat germ diet were as sensitive to digitoxin as those reared on cabbage. Previous results have shown that rejectionof nasturtium by cabbage-reared larvae is due to the presence of strong feeding deterrents in this plant. However, more than 50% of 2nd instar larvae reared from neonate on cabbage leaves treated with strophanthidin, cymarin, erysimoside, digitoxigenin and digitoxin accepted nasturtium as a food source. 2-O-β-d-glucosyl cucurbitacin E, 2-O-β-d-glucosyl cucurbitacin I and rutin were also active in causing larvae to feed on nasturtium. Thus dietary exposure to unrelated plant chemicals can profoundly affect insect acceptance of a plant that contains feeding deterrents.  相似文献   

2.
A unique group of immunoglobulin-binding proteins (IGBPs), produced by ixodid male ticks during the latter half of their prolonged feeding period, improves the feeding performance of co-feeding females. As a follow-up to this observation, we investigated whether male tick feeding also affects the feeding of other developmental stages. Immature stages of Rhipicephalus sanguineus (Latreeille) and Amblyomma americanum (L.) were fed on rabbits in the presence or absence of conspecific males. The mean weight of larvae and nymphs of both species that fed around males and detached from the host on the first day of dropping was significantly higher than when the immature ticks fed on rabbits in the absence of males. However, larvae of both species and nymphs of R. sanguineus that fed slower and detached on the second day of dropping did not show significant differences in weight. A similar pattern was observed for A. americanum nymphs although, unlike R. sanguineus, the presence of males also influenced the feeding performance of the nymphs that fed slowly and detached on the second day of drop-off. The improved feeding performance demonstrated by immature ticks in the presence of males may be due to immunomodulatory saliva proteins, such as immunoglobulin-binding proteins (IGBPs) that are introduced into the co-feeding site. The results are considered in relation to the distribution of ixodid tick species on their natural hosts.  相似文献   

3.
I investigated the activity budget and diet of Yakushima macaques (Macaca fuscata yakui,)in warm temperate broad- leaved forest of Yakushima, Japan. Both time spent feeding and time spent moving varied considerably between half- months. However, total time spent in active behaviors— feeding time plus moving time— was stable. The composition of the diet also showed considerable variation between half- months. The macaques fed mainly on fruits, seeds,mature leaves, fallen seeds, flowers, and young leaves, each of which accounted for more than 30% of feeding time in at least 1 half- month. They also ate insects and fungi, but each of them comprised ≤ 25 and ≤ 8% of feeding time in any half- month, respectively. Time spent feeding on mature leaves, young leaves, flowers, or fallen seeds is positively correlated with total time feeding and is negatively correlated with time moving. In contrast, time feeding on fruits, seeds, insects or fungi is negatively correlated with time feeding and is positively correlated with time moving. Foraging on foods that have a low energy content, a high density, and a relatively even distribution— mature leaves— or that need much manipulation to be processed— flowers and fallen seeds— increased feeding time, while foraging on foods for which monkeys must search intensively in the forest— fruits, seeds, insects, and fungi— led to increased moving time. I examined foraging strategies of Yakushima macaques in terms of moving costs and the quality of food items. Regarding time feeding on fruits, which have more energy and may need less manipulation than other foods, as a benefit, and moving time as a cost, they seemed to employ a strategy that balanced the costs and benefits of foraging.  相似文献   

4.
Competitive interactions in arthropod predators are well-known, but positive interactions have received less attention. The two-spotted stinkbugPerillus bioculatus often feeds gregariously on leaf beetle larvae and caterpillar prey. Consequences of prey sharing amongP. bioculatus conspecifics of dissimilar size (instar) was studied using Colorado potato beetle (CPB) prey. Rearing second-instar (N2) nymphs ofP. bioculatus with an N5 conspecific facilitated early feeding on L4 CPB larvae (a difficult prey to handle by N2 nymphs but not by N5’s), thus increasing survival and accelerating development. One in every 20 cases ofP. bioculatus foraging in the field was accounted for by pairs or small groups of mostly feeding individuals. CPB egg masses and L4’s represented a disproportionate number of cases of aggregated feeding byP. bioculatus, compared to feeding singly. Small CPB larvae decreased in the diet of aggregated stinkbugs compared to L4 larvae and egg masses, suggesting that sharing these prey may be favorable or unavoidable. In a field test measuring residence/survival of N2’s limited to L4 prey, the N2’s rate of residence/survival increased significantly when large nymphs acting as food providers were also present. The function of communal feeding inP. bioculatus is discussed, as well as the potential for greater impact on prey density that may be expected from tolerance to opportunistic feeding by conspecifics in slightly gregarious predators.  相似文献   

5.
The clinical picture produced by the feeding of larvae of Ornithodoros aff. puertoricensis on laboratory mice, was studied using different larval infestation protocols that included 30, 40 or 50 larvae per mouse and control uninfested groups. Clinical effects appeared around 72 h of larval feeding, having a first stage characterized by hyperaemia in both nasal and ocular mucosa, followed by respiratory symptoms (96–120 h) and nervous incoordination (120–144 h). No one mouse evidenced paralysis, and nervous symptoms were never observed in animals infested with only 30 larvae. High mortality (commonly up to 70%) was observed in mice with respiratory symptoms, while 100% of animals in the nervous phase died between 168 and 192 h after the beginning of larval feeding. When some infested mice were treated with a solution of Amitraz the larvae were killed and reversion of symptoms was observed. These effects are ascribed to the presence of a toxin in the saliva of the feeding larvae.  相似文献   

6.
Avermectin at 1 ppm was slightly toxic by contact to the different immature stages of the predacious miteAmblyseius gossipi El-Badry. When immatures ofA. gossipi ingested treated prey on clean leaf discs, the toxicity increased and the resulted ΦΦ oviposited at a significantly lower rate. In contrast, dicofol at 250 ppm was extremely toxic by contact and caused a significant mortality to the immatures when it was ingested. Female mortality increased and fecundity decreased as the time of feeding treated prey increased from 24 h to 192 h. In case of dicofol a permanent depression in reproduction was recorded after feeding treated prey for 144 h. Females ofA. gossipi suffered a depression in reproduction when fed on prey formerly kept on plant leaves treated with avermectin. This depression was reported, only, after 192 h of feeding on prey previously reared on leaves treated with dicofol.   相似文献   

7.
We evaluated tritrophic level interactions among fungal endophytes (Acremonium spp.) of fescue grasses (Festuca spp.), the root-feeding Japanese beetlePopillia japonica Newman larvae, and the entomopathogenic nematodeHeterorhabditis bacteriophora Poinar. Third-instarP. japonica larvae were introduced into pots containing endophyteinfected or endophyte-free plants of tall fescueFestuca arundinacea Schreber (cultivars Kentucky 31 and Georgia Jesup Improved) and the Chewings fescueFestuca rubra commutata Guad. (cultivars F-93 and Jamestown II). After two weeks, the surviving larvae were recovered, and their susceptibility to nematodes was evaluated in sand columns. Endophytes enhanced the rate of nematode-induced mortality in all cultivars except Georgia Jesup Improved, and increased the proportion of dead larvae with nematodes in all cultivars except Jamestown II. Endophytes in the cultivar Kentucky 31 were associated with improved nematode establishment in the larvae. No effect on nematode reproduction was found. Since endophytes produce biologically active alkaloids, we tested the effects of an ergot alkaloid, ergotamine tartrate, on the feeding behavior and weight ofP. japonica larvae in agar medium. The alkaloid caused feeding deterrence, and reduced the consumption of medium by the larvae, resulting in weight loss. These larvae were more susceptible toH. bacteriophora than the untreated larvae. Unfed ‘starved’ larvae were more susceptible to nematodes than those fed on untreated agar. Our results support the hypothesis that endophyte-induced starvation ofP. japonica would reduce larval vigor, and render them more susceptible to entomopathogenic nematodes.  相似文献   

8.
Biological data of three generations of Amblyomma tigrinum in the laboratory are reported and the suitability of different host species for immature ticks are compared. Grouping the three generations, infestations by both the larval and nymphal stages were performed on chickens (Gallus gallus), wistar rats (Rattus norvegicus), rabbits (Oryctolagus cuniculus),wild mice (Calomys callosus), dogs (Canis familiaris) and opossums (Didelphis albiventris). Only dogs were used for infestations by adult ticks. Tick developmental periods were observed in an incubator at 27°C and RH 90%. The proportion of engorged larvae recovered from chickens (21.7% of the exposed larvae) was significantly larger (p<0.001) than those from the five mammal species used in the infestations (maximum of 3.1%). A significant larger (p<0.01) proportion of engorged larvae successfully molted after being fed on chickens than on mammal hosts. The proportion of engorged nymphs recovered from chickens (28.8% of the exposed nymphs) was significantly larger (p<0.001) than those from mammal hosts (range: 0–2.1%). Larvae showed similar feeding periods on exposure to different host species, except for those larvae fed on C. callosus, which showed significantly longer (p<0.001) feeding periods. Engorged larvae detachment peaked on the 5th feeding day, followed by the 6th day, on all hosts except for C. callosus. Larval premolt periods were similar for engorged ticks exposed to different host species, except for larvae fed on dogs, which showed significantly longer (p<0.001) premolt periods. Host detachment of engorged nymphs peaked on the 6th feeding day on chickens. Although nymphal detachment on rats peaked on the 8th day, only 15 nymphs were recovered from this host species. In a sample of 144 F3 nymphs fed on chickens no significant difference (p>0.10) was found between the feeding or premolt periods of 82 males and 62 females, but female nymphs were significantly heavier (p<0.005) than male nymphs. Sixteen engorged females (61.5% of the exposed ticks) were recovered after being fed on dogs, and all these females laid viable eggs. Chickens, the only avian host, were the most suitable host when compared with the five mammal species. Dogs were demonstrated to be a suitable host for adults of A. tigrinum, which is consistent with, several reports of adult A. tigrinum ticks parasitizing dogs in different areas of South America. Our results reinforce that in these same areas avian species are the major hosts for immature stages of this tick species. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

9.
I studied gray woolly monkeys (Lagothrix lagotricha cana)in an undisturbed central Amazonian terra firme forest, near the headwaters of the Urucu river, Tefé, Amazonas, Brazil (5°50’S, 65°16’W). I report the diet and feeding ecology of a group of 39–41 individuals, based on systematic feeding observations obtained during 11 months. Woolly monkeys are primarily frugivorous; mature fruits and young seeds account for 83 and 7% of 3298 feeding records, respectively. On a seasonal basis, however, they relied heavily on young foliage (16%), seed-pod exudates (6%), and flowers (3%), particularly during the greatest annual period of ripe fruit scarcity, as determined by a phenological survey. Animals represent only 0.1% of their year-round diet, and they spent little time capturing arthropods and other prey items. Although at least 225 plant species, belonging to 116 genera and 48 families, are in their diet, the three top-ranking families (Moraceae, Sapotaceae, and Leguminosae) account for 43% of their food species and 63% of the time they spent feeding on a year-round basis. I compare the feeding ecology and diet of L. 1. canain the Urucu and other taxa of Lagothrixin upper Amazonia — the last large-bodied Neotropical primates to be studied — to those of other ateline genera: Atelesand Brachyteles. An erratum to this article is available at .  相似文献   

10.
鳞翅目昆虫的寄主选择主要是成虫的任务,但幼虫也可以精细调节取食部位。低龄幼虫记忆一些与食物伴随的化学信息能够提高适合度。当幼虫被迫离开寄主植物后,最好是搜索与此前取食过的寄主气味相似的植物,以便节省寄主转移的生理代谢成本。棉铃虫幼虫嗜食作物花器,因此推测花香挥发物可以代表幼虫食物的典型化学信息。采用人工饲料为无条件刺激,在条件化训练开始时,使初孵幼虫取食时暴露在7种花香挥发物下,随后7 d逐日测试低龄幼虫学习表现。结果发现,在7次测试中,苯乙醛选择频次有3次显著多于对照,芳樟醇条件化组在2次测定中处理被选频次显著或极显著多于对照,苯乙醇条件化组仅1次对处理选择频次显著多于对照,其他4种挥发物无论训练时间长短均不能造成嗅觉偏好性的改变,说明棉铃虫在取食过程中是选择性采集食物关键化学信息。然而,无经历组无论训练时间如何均不对苯乙醛表现出嗅觉偏好性,证实气味偏好性的改变并非生理性成熟所致。总之,和同种的成虫以及若虫期比较活泼的其他种类相比,棉铃虫低龄幼虫嗅觉联系性学习表现较差,并且嗅觉偏好性变化与条件化训练时长没有明确关系,结合棉铃虫的生态学习性讨论了可能的原因。  相似文献   

11.
The osteological development of elements forming the oral cavity was examined in early stage larvae of the grouper,Epinephelus coioides, from hatching to 242.5 hours after hatching. By the time of initial mouth opening, at 54 hours after hatching, the fundamental elements, composed of the trabecula, some components of the lower branchial and hyoid arches, the quadrate and symplectic-hyomandibular cartilages, maxilla and Meckel's cartilage, had appeared. No further elements were observed until 165 hours after initial mouth opening, except some components in the lower branchial arch and head region. The appearance of new elements and initial ossification of existing cartilage occurred thereafter, but all elements related to feeding either had not appeared or had not started ossifying until 188.5 hours after initial mouth opening. Based on the morphology and developmental modes of these elements, the feeding mode of grouper larvae was considered to be “sucking/grasping.” However, the appearance and ossification of elements occurred slowly, with no transitional phase from sucking to grasping modes of feeding being observed during the study; such delayed development of the feeding-related bony elements was considered to be a cause of the difficulty in rearing early stage grouper larvae.  相似文献   

12.
The MHV-68 (designed as Murid herpesvirus 4 (MuHV 4) strain 68) isolated from two rodents, Myodes glareolus and Apodemus flavicollis, is considered as a natural pathogen of free-living murid rodents. Recently, the detection of MHV antibodies in the blood of animals living in the same biotope as MHV-infected mice has suggested that ticks may have a role in the transmission of this pathogen. Ixodes ricinus is one the most abundant tick species in Europe known to transmit multiple pathogens causing human and animal diseases. In this study, nymphs and larvae feeding on 116 individuals of a temperate lizard species—the green lizard Lacerta viridis captured in the Slovak Karst National Park, were examined for MHV-68. The specific sequence of virion glycoprotein 150 was amplified in DNA individually isolated from I. ricinus ticks using single-copy sensitive nested polymerase chain reaction. MHV-68 was detected in ten of 649 nymphs and in five of 150 larvae, respectively. We found that 9.6% of green lizards fed at least one MHV-68-infected immature tick. Occurrence of MHV-68 within all ticks tested was 1.8%. This study is first to show that immature I. ricinus ticks feeding on free-living lizards in a Central European region could be infected with gammaherpesvirus (MHV-68), naturally infecting free-living murid rodents. Our results provide evidence supporting the hypothesis that ticks may play a mediating role in circulation of MHV-68 in nature.  相似文献   

13.
Laboratory rearing of spruce budworm, Choristoneura fumiferana, in conjunction with field rearing indicated that the feeding behaviour of the larvae, which is affected by the insect population density, significantly influenced the impact of balsam fir, Abies balsamea, staminate flowering on spruce budworm biology. At low budworm density, the production of pollen in the midcrown of host trees reduced the insect development time by 5 days without affecting pupal weight, fecundity and survival. However, at high budworm density, the small amount of current-year foliage produced by flowering branches forced old larvae (sixth instar) either to feed on 1-year-old foliage (backfeeding) or to move from the midcrown to the lower crown section where staminate flowers are absent and more current-year foliage is available. When old larvae fed on old foliage, they exhibited reduced pupal weight and fecundity without losing the advange in development time that they obtained from feeding on pollen during their early stages of development. On the other hand, when old larvae moved to the lower crown section, they avoided the negative effects of backfeeding but lost the advantage in development time that was gained from feeding on pollen. Results from this study indicated that the production of staminate flowers by balsam fir trees could have opposite effects on spruce budworm population dynamics depending upon the insect population density when flowering occurs.  相似文献   

14.
15.
The functional response of 3rd instarChrysopa carnea (Stephens) larvae feeding on 4 densities ofHeliothis virescens (F.) eggs was determined on caged cotton (Gossypium hirsutum L.).C. carnea larvae had a mean search rate of 1.08×10−5 ha/predator-day or 0.11 row-m/predator-day.   相似文献   

16.
M. Campos  R. Gonzalez 《BioControl》1990,35(3):411-420
The rearing ofRaphitelus maculatus Walker, which oviposits through the bark onto beetle larvae has been carry out under standard laboratory conditions of 22 ± 2°C, 60% R.H. and photoperiod 16L∶8D. The host (Phloeotribus scarabaeoides Bernard) has been reared by cutting fresh branches of living olive tree on which they overwinter as adults. The effect of several rearing conditions (feeding conditions) on longevity and fecundity has been tested. The time of parasitoid and host development as well as the periods of emergence from the infested cut branches has been determined. It has been noted that both longevity and fecundity are influenced by the feeding conditions, reaching toca. double value when parasitoids were fully fed. Under standard rearing conditionsR. maculatus completes its life cycle in 17–18 days depending on sex, whereasP. scarabaeoides takes about 48 days. Finally 3 emergence periods has been observed from which the 1st is the most important and the 3rd is always the less significantly one, provided that the emerging brood cannot oviposits easier than the parents due to a decrease on host larvae proportion as well as on parasitoid fecundity.   相似文献   

17.
Biological activities of the salannin type of limonoids isolated fromAzadirachta indica A. Juss were assessed using the gram pod borerHelicoverpa armigera (Hubner) and the tobacco armywormSpodoptera litura (Fabricius) (Lepidoptera: Noctuidae). Inhibition of larval growth was concomitant with reduced feeding by neonate and third instar larvae. All three compounds exhibited strong antifeedant activity in a choice leaf disc bioassay with 2.0, 2.3 and 2.8 (μ/cm2 of 3-O-acetyl salannol, salannol and salannin, respectively deterring feeding by 50% inS. litura larvae. In nutritional assays, all three comounds reduced growth and consumption when fed to larvae without any effect on efficiency of conversion of ingested food (ECI), suggesting antifeedant activity alone. No toxicity was observed nor was there any significant affect on nutritional indices following topical application, further suggesting specific action as feeding deterrents. When relative growth rates were plotted against relative consumption rates, growth efficiency of theH. armigera fed diet containing 3-O-acetyl salannol, salannol or salannin did not differ from that of starved control larvae (used as calibration curve), further confirming the specific antifeedant action of salannin type of limonoids. Where the three compounds were co-administered, no enhancement in activity was observed. Non-azadirachtin limonoids having structural similarities and explicitly similar modes of action, like feeding deterrence in the present case, have no potentiating effect in any combination.  相似文献   

18.
Rohlfs M 《Oecologia》2008,155(1):161-168
Although still underrepresented in ecological research, competitive interactions between distantly related organisms (so-called “interkingdom competition”) are expected to be widespread in various ecosystems, with yet unknown consequences for, e.g. trophic interactions. In the model host–parasitoid system Drosophila melanogaster–Asobara tabida, toxic filamentous fungi have been shown to be serious competitors that critically affect the density-dependent survival of host Drosophila larvae. This study investigates the extent to which the competing mould Aspergillus niger affects key properties of the well-studied Drosophila–parasitoid system and how the host–parasitoid interaction influences the microbial competitor. In contrast to slightly positive density-dependent host mortality under mould-free conditions, competing A. niger mediated a strong Allee effect for parasitised larvae, i.e. mortality decreased with increasing larval density. It was found that the common toxic fungal metabolite kojic acid is not responsible for higher death rates in parasitised larvae. Single parasitised Drosophila larvae were less harmful to fungal reproduction than unparasitised larvae, but this effect vanished with an increase in larval density. As predicted from the negative effect of fungi on host survival and thus on parasitoid fitness at low larval densities, A. tabida females spent less time foraging in fungus-infested patches. Interestingly, even though high host larval densities increased host survival, parasitoids still reduced their search efforts in fungus-infested patches, indicating a benefit for host larvae from feeding in the presence of noxious mould. Thus, this experimental study provides evidence of the potentially important role of interkingdom competition in determining trophic interactions in saprophagous animal communities and the dynamics of both host–parasitoid and microbial populations.  相似文献   

19.
Laboratory experiments were conducted to evaluate the behavior of Helicoverpa armigera (Hübner) and Spodoptera litura (Fabricius) larvae on meridic diet with different concentrations of Bt spray formulation Delfin or isolated Cry1Ac protein or the foliage and bolls from transgenic cotton, Bollgard hybrid RCH-317 Bt. Both insect species selectively fed on nontreated diet compared with the diet treated with Delfin. While H. armigera exhibited concentration response with Cry1Ac, this protein did not affect S. litura larvae. In general Helicoverpa selected diet with low concentrations (EC20 and EC50 levels) of Cry1Ac compared with higher concentrations of Cry1Ac. In order to develop appropriate management strategies, a thorough understanding of the behavioral mechanisms leading to the responses of insects to the proteins in transgenic varieties is required. Thus, based on results of the insects fed individually on the leaf discs or bolls from transgenic cotton plants alone or under choice situation with meridic diet revealed that H. armigera larvae preferred meridic diet to transgenic leaves or bolls expressing Cry1Ac protein. H. armigera larvae preferred meridic diet to plant material; more than 70% larvae were seen on the meridic diet, and average larval weight gain was in the range of 121.7–130.5 mg. However, in case of S. litura the larvae showed no significant discrimination between meridic diet and the leaf discs. In fact more than 60% larvae preferred leaf discs for feeding, though Cry1Ac expression in leaf discs was in the range of 0.9–2.18 μg/g. Thus differences in behavioral response could potentially impact the level of efficacy of crop cultivars that have been genetically engineered to produce these proteins.  相似文献   

20.
Despite its circum-tropical distribution, we report, for the first time in Italy and Sicily, the presence of Megalorhipida leucodactyla (Fabricius 1974), a species recorded only once before in Europe. Several adults, pupae and larvae of different instars were found on Boerhavia repens L. ssp. viscosa (Choisy) Maire (Nyctaginaceae), recorded for the first time in Italy (Sicily) in 1967. We provide both an update of Boerhavia repens ssp. viscosa’s distribution in Sicily and the results of our vegetational survey, based upon the phytosociological method by Braun-Blanquet Sigmatist School, on Boerhavia repens ssp. viscosa in Palermo city’s urban areas. This plant, naturalised especially in Palermo city, appears to have become an invasive plant, increasingly spreading in larger areas, by even replacing the native flora in urban ecosystems. This study also provides the results of laboratory bioethological observations on some specimen of both adults and larvae (the latter while feeding on Boerhavia repens ssp. viscosa’s fruits). Finally, using bibliographic data, we drew a map of the distribution of both Megalorhipida leucodactyla and Boerhavia repens ssp. viscosa in the Mediterranean basin.  相似文献   

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