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1.
We assessed the role of visual and olfactory cues on oviposition preference in the oligophagous tomato fruit fly, Neoceratitis cyanescens (Bezzi) (Diptera: Tephritidae). In a field survey, we evaluated the stage of susceptibility of field‐grown tomatoes by monitoring N. cyanescens infestations from fruit‐setting up to harvest, in relation to post‐flowering time, size, and visual properties of fruit. In two‐choice laboratory experiments, we tested the degree to which females use visual and olfactory cues to select their host plant for oviposition. In addition, we investigated the ability of flies to avoid fruit already infested by conspecific eggs or larvae, and the influence of natal host fruit on oviposition preference. Neoceratitis cyanescens females preferentially lay their eggs in small yellow‐green unripe fruit (2–3.5 cm diameter, 10–21 days post‐flowering). Damage to fruit was significantly affected by brightness and size properties. In laboratory experiments, females chose to lay their eggs in bright orange rather than yellow domes. On the sole basis of olfactory stimuli, females showed a significant preference for unripe vs. ripe host fruit, for unripe fruit vs. flowers or leaves, and for host vs. non‐host fruit (or control). However, colour interacted with odour as females dispatched their eggs equally between the yellow dome and the bright orange dome when unripe fruit of tomato was placed under the yellow dome vs. ripe fruit under the bright orange dome. When offered real ripe and unripe tomatoes, females preferred unripe tomatoes. Females significantly chose to lay eggs in non‐infested fruit when they were given the choice between these or fruit infested with larvae. In contrast, recent stings containing eggs did not deter females from laying eggs. Rather, they could have an attractive effect when deposited within <1 h. Regardless of their natal host plant, tomato or bugweed, N. cyanescens females laid significantly more eggs in a dome containing bugweed fruit. However, 15% of females originating from tomato laid eggs exclusively in the dome with tomato, against 3% of females originating from bugweed.  相似文献   

2.
Tephritidae fruit fly larvae develop entirely in the host chosen by the females. To improve the fitness of their progeny, females would benefit from rejecting previously exploited hosts. Anastrepha fraterculus and Ceratitis capitata are two species of fruit flies having similar nutritional requirements and overlapping in their distribution. Previous studies found that competition between the larvae of these species might reach high levels, suggesting that cross-recognition would be an adaptive trait. In this work, we tested the ability of A. fraterculus and C. capitata females to recognize and avoid fruits previously infested by both conspecific and heterospecific females. In laboratory behavioural arenas, females were presented with fruits that had been previously exposed to either conspecific or heterospecific females. Then, we conducted choice and non-choice assays to compare the response of A. fraterculus and C. capitata females to infested and non-infested fruits. In non-choice tests, the females from both species rejected fruits previously infested by conspecific and heterospecific individuals. However, the rejection occurred at different steps of the sequence leading to oviposition: A. fraterculus showed a lower rate of visits to infested fruits, whereas C. capitata visited both infested and non-infested fruits, but the latency to visit a fruit and the rejection frequency were higher and the duration of the visit to infested fruit was lower. In choice assays, the rejection of heterospecific infested fruit was higher than that of conspecific infested fruits, for both species. Our results suggest that, regardless of the sensory mechanism used by females, the recognition of previous infestation is bidirectional and females of both species, belonging to different genera, recognize fruit infested by heterospecifics. These responses indicate that cross-recognition, supposedly a highly beneficial trait, could be occurring in nature, thus reducing interspecific competition and contributing to the coexistence of these species.  相似文献   

3.
The egg distribution patterns ofEurytoma amygdali Enderlein (Hymenoptera, Eurytomidae), which oviposits singly in green, developing almonds, were studied in the laboratory and in the field. In the laboratory, individual females were caged with a number of almonds and the eggs deposited in each fruit were counted. In the field, eggs were censused in almonds of different varieties at regular intervals, over four seasons (1988–91). In the susceptible ‘Retsou’ variety, eggs were uniformly distributed among fruits, both in the laboratory and in the field, as long as the mean number of eggs per almond was ≤2.5. When the mean number of eggs per almond was higher the egg distributions were random. This suggests that, up to a certain level of infestation, females were able to assess egg load of fruits and oviposit in the less infested ones. The main factor enabling the females to discriminate and select the less infested almonds for oviposition is probably a host-marking pheromone. In 1990, the same patterns of egg distribution were observed in samples taken from 5 other almond varieties that are not as susceptible as Retsou and have thicker pericarp and harder endocarp. In 1991 however, when fruits developed more rapidly than in 1990, egg distributions in 3 of these 5 varieties (Truoito, Ai, and Marcona) were not uniform. Although the mean number of eggs per fruit was low (1.2–2.0), many fruits of these varieties contained no eggs. This suggests that, in some less susceptible varieties, egg distribution might also be affected by certain fruit parameters, unfavourable for oviposition, related to the pericarp thickness and endocarp hardness.  相似文献   

4.
Bactrocera dorsalis (Hendel) is a major pest of a wide variety of fruits and vegetables. This study aimed to evaluate the potency of combining edible vegetable oil application and artificial fruit provision to reduce the oviposition of B. dorsalis in chilli fruits. Experiments were conducted in laboratory using a 20‐L plastic container provided with chilli fruits and in semi field using a fruit‐bearing chilli plant caged with insect screen. The laboratory test revealed that the combination of coconut oil application and artificial fruit provision significantly reduced fruit fly visits, eggs laid and the number of infested chilli fruits no matter when the chilli fruits were without prepuncture or with prepuncture. Further study using a caged chilli plant also found that this combination had significant effects on fruit fly visits and infestation in chilli fruits. These results provide an indication that coconut oil and artificial fruit can work together to reduce fruit fly attacks on chilli fruits. Combining the use of coconut oil and artificial fruit is likely to create an integrated behavioural manipulation (push and pull) of female B. dorsalis that lead to a much lower fruit fly infestation in chilli fruits.  相似文献   

5.
Behavioural responses of Queensland fruit fly, Bactrocera tryoni (Froggatt) (Diptera: Tephritidae), females to fruit dipped in water and fruit dipped in 0.5% (vol/vol) aqueous emulsions of a mineral oil were determined and analysed. The mineral oil was an nC20–22 distillation fraction of the base oil used to produce an nC23 horticultural mineral oil. Females caged with oil‐treated fruit had significantly longer prelanding intervals than females caged with water‐dipped fruit. The latter was attacked immediately or shortly after being caged with flies whereas some oil‐dipped fruit was not attacked within 180 min. The percentage of landings that led to oviposition on water‐ and oil‐treated fruit were 58 and 13%, respectively, and the percentages ovipositing after probing were 74 and 25%, respectively. Likewise, average times spent probing were 7 vs. 31 s whereas average times spent ovipositing were 321 vs. 223 s. Females spent less than half as much time on oil‐treated fruit than on water‐treated fruit. Transition probabilities of rejection, when applied to the behaviour sequence indicated that oil‐treated fruits are about nine times less likely to be infested with B. tryoni.  相似文献   

6.
Effect of marking pheromone on clutch size in the Mediterranean fruit fly   总被引:2,自引:0,他引:2  
Abstract Using acridine orange to selectively stain eggs, we showed that wild-collected female Mediterranean fruit flies (Ceratitis capitata Wiedemann) laid fewer eggs per clutch in fruit previously infested with eggs than in uninfested fruit. This effect is apparently attributable to marking pheromone deposited by females after oviposition: clutch size on fruit infested with eggs but free of marking pheromone was not statistically different from that on uninfested fruit. Clutch size on uninfested fruit on which marking pheromone was artificially transferred was significantly lower than that on uninfested and untreated fruit. Marking pheromone had a comparable though not statistically significant effect on the clutch size of females originating from a strain maintained in the laboratory for several hundred generations.  相似文献   

7.
This study reports a model that utilizes pheromone trap catches to assess the fruit damage caused by Carposina sasakii. The model consisted of four steps: (1) obtaining influx population density using pheromone traps, (2) estimating the actual female population within a defined area using an estimated conversion rate, (3) calculating the total number of eggs using the oviposition model of C. sasakii, and (4) estimating the proportion of fruits infested with eggs (potential damaged fruits) using the relationship between mean egg density per fruit and the proportion of fruits infested with eggs. The relationship between mean egg density ([`(x)] \bar{x} ) per fruit and variance (s 2) was well described by Taylor’s power law, and its parameters were successfully incorporated into the equation that estimates the relationship between mean egg density and the proportion of fruits infested with eggs. In peach orchards, the model accurately predicted the proportion of fruits infested with eggs at the beginning of C. sasakii emergence in early season, but overestimated it in the mid-season. The fitting ability of the model outputs largely increased when the factor of oviposition behavior of C. sasakii was incorporated into the simulation processes, applying the allocation module of total eggs between peaches and apples.  相似文献   

8.
Gary P. Fitt 《Oecologia》1984,62(1):37-46
Summary When offered a choice, females of the fruit flies Dacus tryoni (Frogg.) and D. jarvisi (Tryon) strongly preferred to lay in fruits without larvae rather than fruits which already contained larvae. Fruits which contained even low densities of larvae, including newly hatched ones, received many fewer eggs than control fruits. This preference was not influenced by the species of larvae present in the fruits nor by the distance to uninfested fruits. Discrimination occurred when fruits with and without larvae were close together (10 cm apart) and also when they were separated by distances of about one metre. Laboratory assays suggested that the flies detect chemical changes in the fruit associated with the decomposition which accompanies larval feeding, but they do not seem to detect the larvae Perse. This behaviour may be significant when these two species utilise the same host since the species which is able to infest fruits first will reduce the availability of hosts for the other species. In contrast to many other Tephritids (e.g. Rhagoletis, Anastrepha and Ceratitis) female Dacus don't discriminate against fruits which contain eggs nor do they deposit a pheromone to deter oviposition by females that subsequently visit the fruit. An hypothesis is proposed to explain the absence of oviposition-deterring pheromones in Dacus, and their presence in many other species of Tephritidae, on the basis of differences in life history and population structure.  相似文献   

9.
Transgenic cotton that produces insecticidal crystal protein Cry1Ac of Bacillus thuringiensis (Bt) has been effective in controlling pink bollworm, Pectinophora gossypiella (Saunders). We compared responses to bolls of Bt cotton and non-Bt cotton by adult females and neonates from susceptible and Cry1Ac-resistant strains of pink bollworm. In choice tests on caged cotton plants in the greenhouse, neither susceptible nor resistant females laid fewer eggs on Bt cotton bolls than on non-Bt cotton bolls, indicating that the Bt toxin did not deter oviposition. Multiple regression revealed that the number of eggs laid per boll was negatively associated with boll age and positively associated with boll diameter. Females also laid more eggs per boll on plants with more bolls. The distribution of eggs among bolls of Bt cotton and non-Bt cotton was clumped, indicating that boll quality rather than avoidance of previously laid eggs was a primary factor in oviposition preference. Parallel to the results from oviposition experiments, in laboratory no-choice tests with 10 neonates per boll, the number of entrance holes per boll did not differ between Bt cotton and non-Bt cotton for susceptible and resistant neonates. Also, like females, neonates preferred younger bolls and larger bolls. Thus, acceptance of bolls by females for oviposition and by neonates for mining was affected by boll age and diameter, but not by Bt toxin in bolls. The lack of discrimination between Bt and non-Bt cotton bolls by pink bollworm from susceptible and resistant strains indicates that oviposition and mining initiation are independent of susceptibility to Cry1Ac.  相似文献   

10.
Insects ensure the survival of their offspring by depositing their eggs in suitable environments. Even generalist egg-laying insects often show preferences for specific host plants. The cocoa pod borer (CPB), Conopomorpha cramerella (Snellen) (Lepidoptera: Gracillariidae), successfully infests and reproduces on relatively few host plants, but has a major economic impact only on cocoa, Theobroma cacao L. (Malvaceae). Choice tests were performed in the laboratory to compare the frequency of insect visits, the duration of the visits, and the number of eggs laid on the fruits for each combination of host plants tested – that is, cocoa clones or fruits of rambutan (Nephelium lappaceum L.), Fijian longan (Pometia pinnata JR Forst & G Forst, both Sapindaceae), and langsat (Lansium domesticum Corrêa, Malvaceae). Our laboratory study showed that, when given the choice, CPB significantly favored cocoa pods over other host fruits (rambutan, langsat, or Fijian longan). Females also deposited more eggs on unripe fruits than on ripe fruits of similar size. The preference to lay eggs on specific cocoa clones in the bioassays did not reflect the level of the clone resistance to CPB damage reported from the field. Consequently, oviposition preference of female CPB does not seem to be the main factor explaining field resistance of some cocoa clones to CPB infestation.  相似文献   

11.
In laboratory and field experiments, stimuli were tested that might affect oviposition decisions by female peach twig borer moths, Anarsia lineatella Zeller (Lepidoptera: Gelechiidae). When given a choice between immature green peach fruits, green mature peach fruits and soft-ripe peach fruits, the latter received the fewest eggs. Fuzzy halves of peach fruits received ten times more eggs then shaved hairless halves. Volatiles from both almond and peach shoots induced more oviposition by females than by control stimuli. Similarly, volatiles from immature green peach fruits, mature green or mature hard-ripe peach fruits induced more oviposition than their respective control stimuli. In a choice experiment, volatiles from immature peach fruit stimulated three times more oviposition than those from soft-ripe peach fruit. Discrimination against mature soft-ripe peach fruits as potential oviposition sites may lie in the phenology of A. lineatella and host peach fruits. Larval development to the pupal stage takes 15–27 days. Therefore, any eggs laid on a ripe fruit 14 days before it falls from the tree will not likely develop into adult insects because developing larvae will only reach third or fourth instar before the fruit is decomposed, and only first and second instar larvae can overwinter.  相似文献   

12.
  • 1 The oviposition behaviour of white‐spotted sawyer beetle Monochamus scutellatus (Say) (Coleoptera: Cerambycidae) females was studied under laboratory and field conditions.
  • 2 Females walked over the bark surface and stopped to palpate it with their labial and maxillary palpi. Once a potential oviposition site was located, the female excavated a scar in the bark with her mandibles, deposited an egg and brown plug in the scar and inserted her mandibles again into the scar prior to leaving the area.
  • 3 Female M. scutellatus preferred to lay eggs on bolts containing no eggs (control) to those containing eggs from other females, but did not show this preference when provided with control bolts and those containing their own eggs. When females were provided with bolts containing their own eggs and bolts containing eggs from other females, they laid more eggs on bolts containing their own eggs. Females laid more eggs on control bolts than on bolts containing their own larvae or larvae from other females.
  • 4 The brown plug in the oviposition scar may provide a protective barrier to the egg, a chemical message that the site is occupied, or both.
  相似文献   

13.
The role of chemical stimuli in host selection and oviposition of Sesamia nonagrioides (Lef) was studied in the laboratory using eight corn hybrids. Female oviposition preference was evaluated on plants of the eight hybrids, their extracts in pentane and methanol, and volatiles collected by steam distillation in ether. Results from two-choice bioassays indicate various degrees of female preference to the hybrids. Four hybrids received more eggs than control plants, whereas the remainder received fewer eggs. Relatively similar results were obtained when filter paper sticks baited with pentane and steam distillation extracts were evaluated. Methanol extracts from all eight hybrids received fewer eggs than the methanol controls. Results showed that pentane and steam distillation extracts contain chemicals that elicit female oviposition response, while methanol extracts may contain chemicals that deter or repel females to oviposition.  相似文献   

14.
We compared the host-searching and oviposition behaviors of two Neotropical figitid parasitoids (Hymenoptera) that exploit the same resource: ripe fruit infested by fruit fly larvae (Tephritidae) that have fallen to the ground. Sexually mature Aganaspis pelleranoi (Brèthes) and Odontosema anastrephae Borgmeier females were exposed individually, under no choice conditions, to four types of fruit: 1) Clean, intact guavas, Psidium guajava L. (no fruit fly larvae, no perforations); 2) clean, with artificial perforations; 3) artificially infested (with larvae), no perforations; 4) infested with artificial perforations. A behavioral transition matrix and sequence diagram of the following behaviors was constructed: walking on fruit, detection of larvae via the antennae, tarsi or aculeus, fruit perforation and penetration, and oviposition. Overall, we found that infested fruit (intact and with artificial perforations) elicited the most activity in the females of both species and that A. pelleranoi females exhibited a significantly more diverse behavioral repertoire (i.e., more transitions) and were significantly more active than O. anastrephae females. Females of both species penetrated the fruit in search of larvae by biting through the epi- and mesocarp, but O. anastrephae remained inside for significantly longer periods (up to eight hours). A. pelleranoi females used both their antennae and tarsi to detect larvae but the use of these structures varied depending on context: in infested fruit tarsi were used preferentially (usually while standing still) while in uninfested fruit, antennae were mainly used (usually while walking). In the case of O. anastrephae females the reverse pattern was usually observed with antennae most commonly used to detect larvae in infested fruit. We discuss our findings in light of their evolutionary, ecological and practical implications.  相似文献   

15.
Larvae of Ostrinia nubilalis (Hübner) cause significant damage to maize ears and reduce market value of fresh sweet corn. Females rely on volatile cues to locate and oviposit preferentially on maize plants. In addition, oviposition behavior of females is influenced by soil management practices as they usually lay more eggs on maize plants grown on conventional soil than on organic soils that harbor rich microbial diversity. Since some plant growth‐promoting rhizobacteria (PGPR) are known to mediate plant health via suppression of soil pathogens and enhanced uptake of nutrients; we hypothesized that inoculation of maize seeds with PGPR will alter emission of maize volatile and reduce the attractiveness of plants to ovipositing O. nubilalis. Plants treated with the single PGPR strain Bacillus pumilus INR‐7, two PGPR mixtures (Blend‐8 or Blend‐9) or untreated plants were presented to O. nubilalis females in oviposition choice bioassays. Headspace volatile organic compounds (VOCs) from the plants were analyzed by gas chromatography–mass spectrometry (GC–MS). Ostrinia nubilalis laid significantly fewer eggs on PGPR‐treated plants compared to untreated plants. In two‐choice oviposition experiments, significantly higher numbers of eggs were laid on untreated plants compared to PGPR‐treated plants. PGPR‐treated plants emitted fewer VOCs than untreated plants which, in part, explains the relatively fewer eggs on PGPR‐treated plants. These results indicate that selected PGPR treatments can alter maize plant volatiles with important ramifications for plant‐insect interactions. The implication of this finding is discussed in the context of integrated management of soil health to improve crop resistance to biotic stressors.  相似文献   

16.
Abstract 1. When offered a choice, female diamondback moths (Plutella xylostella) oviposited more eggs on plants with non‐parasitised conspecific larvae than on plants with parasitised larvae. 2. The leaf area consumed by parasitised larvae was significantly lower than that by non‐parasitised larvae. However, this quantitative difference in larval damage did not explain the female’s ability to discriminate between plants with parasitised and non‐parasitised larvae, as females showed an equal oviposition preference for plants infested by higher or lower densities of non‐parasitised larvae. 3. Pupal weight and duration of the larval stage of P. xylostella were independent of whether larvae were reared on plants that were previously infested by either non‐parasitised or parasitised larvae. 4. The larval parasitoid Cotesia vestalis did not distinguish between plants infested by non‐parasitised larvae and plants infested by larvae that had already been parasitised by conspecific wasps. 5. Based on these data, it can be concluded that the moth oviposition preference for plants infested by non‐parasitised conspecifics relative to plants infested by parasitised conspecifics was not explained by plant quality or by the attractiveness of plants towards wasps. It is hypothesised that one of the reasons for this preference is avoidance of plants where a relatively high risk of parasitism is expected due to the emergence of parasitoids from the parasitised host larvae.  相似文献   

17.
We investigated how the distribution pattern of eggs and larval on the host plant, Turritus glabra, was influenced by the oviposition behavior of the pierid butterfly Anthocharis scolymus. Females searched for the host plants visually and they frequently approached taller host plants with sparse surrounding vegetation. After encountering host plants, oviposition behavior of females was independent of host plant characteristics such as height, density, and type of surrounding vegetation. A female laid eggs singly on a host plants. Most females appeared to lay their eggs regardless of the presense of eggs on the host plant. Consequently egg and larva tended to be abundant on conspicuous host plants as measured by height or relative isolation from other plants. However, overcrowding of eggs on an individual host decreased the survival rate of larvae.  相似文献   

18.
To determine the effect of larval frass of Monochamus alternatus on oviposition preference of the female adults, three tests were performed in the laboratory. Individual females were provided with a frass-coated, Pinus densiflora bolt and an untreated bolt simultaneously and were allowed to oviposit for 24 h. They deposited a significantly smaller number of eggs on frass-coated bolts. The females supplied with frass-coated bolts deposited no eggs on them, indicating that the larval frass deterred the females from oviposition. When individual females were provided simultaneously with a pine bolt applied with a methanol extract of larval frass and another bolt applied with methanol alone, they deposited a significantly smaller number of eggs on frass extract-applied bolts for 24 h. These results suggest the presence of a putative oviposition deterrent in larval frass of M. alternatus. Each test was replicated 19-20 times using different females.  相似文献   

19.
Chad J. Huth  Olle Pellmyr 《Oecologia》1999,119(4):593-599
Insect larvae such as those of yucca moths that feed on small, patchily distributed food items often face an elevated risk of intraspecific competition or cannibalism. For this reason, ovipositing females may assess a potential oviposition site for prior conspecific eggs or larvae before deciding whether to oviposit. Selective abortion of yucca flowers with high egg numbers prevents competition among larvae of the yucca moth Tegeticula yuccasella, but the same mechanism should select for female detection of and fewer ovipositions in flowers that already contain eggs. Female yucca moths presented with either virgin or previously visited flowers laid significantly fewer eggs in the latter flowers and pollinated them less often. A significant negative association was found between number of previous oviposition attempts in a flower and number of additional attempts by a female, suggesting a quantitative assessment of prior egg load, but the correlation coefficient was low. Factors contributing to this low correlation may include variation in signal quality, poor detection capability, uncertainty contributed by a variable oviposition attempt to egg ratio, and a variable response criterion based on recent female experience and physiological status. Females rationed their pollen by pollinating at decreasing frequency during a bout within a flower, and by depositing smaller pollen loads during later pollinations within a flower. Females ovipositing into a previously visited flower pollinated as frequently as would a first female for a given oviposition attempt within a flower, i.e., the probability of pollination after the nth oviposition was independent of whether it was performed by a first or a later moth. Experimental presentation of virgin flowers marked with a homogenate from female abdomens induced the same oviposition and pollination behavior as seen on previously visited flowers, suggesting the presence of a host-marking pheromone. Given that all eggs within a selectively aborted flower die, there may be selection among some yucca moths for providing a strong signal of floral egg status to conspecific females. Received: 1 December 1998 / Accepted: 7 February 1999  相似文献   

20.
Water extract of fresh frass of Spodoptera littoralis larval instars (L1–3, L4, L5 and L6) fed on Castor oil leaves was prepared by soaking at concentration (20?g frass/50?ml distiled water) followed by steering before filtration. Oviposition deterrent activity of the extract to S. littoralis and A. ipsilon adult females was evaluated as the mean number of laid eggs in treatments in comparison with control under laboratory conditions. Total amount of phenols and flavonoids in larval frass was determined. Extraction of L6 frass obtained complete oviposition deterrent to S. littoralis adult moths and the minimum number of laid eggs by A. ipsilon adult females (11.8?eggs/female) in comparison with control (1026.0 and 848.2?eggs/female respectively). Maximum number of laid eggs by S. littoralis females was 361.0/f at treatment with L1–3 frass extract and 748.0/adult female of A. ipsilon at treatment with L4 frass extract. Low amount of phenols and/or flavonoids in frass extract of L6 increased the oviposition deterrent effect while high amount of them as obtained in L4 frass extract (3.504 and 1.610%, respectively) decreased the effect at both of tested insects.  相似文献   

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