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1.
We previously discovered that (2,4,4‐trimethyl‐2‐cyclohexenyl)‐methyl butyrate (cyclolavandulyl butyrate, CLB) is an attractant for the mealybug‐parasitic wasp Anagyrus sawadai Ishii (Hymenoptera: Encyrtidae: Anagyrini). This wasp is not likely to parasitize the Japanese mealybug, Planococcus kraunhiae (Kuwana) (Hemiptera: Pseudococcidae), under natural conditions. In this study, we showed that this ‘non‐natural’ enemy wasp can parasitize P. kraunhiae in the presence of CLB in field experiments. Laboratory‐reared mealybugs placed on persimmon trees with CLB‐impregnated rubber septa were parasitized significantly more often by endoparasitic wasps than those on non‐treatment trees (18.1–40.3 vs. 0–6.3%). Anagyrus sawadai accounted for 20% of the wasps that emerged from mealybugs placed on CLB‐treated trees. Moreover, CLB attracted another minor parasitoid, Leptomastix dactylopii Howard (Hymenoptera: Encyrtidae: Anagyrini), which also parasitized more P. kraunhiae in the presence of CLB. All wasps that emerged from the mealybugs on control trees were Anagyrus fujikona Tachikawa, a major parasitoid of P. kraunhiae around the test location. These results demonstrated that CLB can recruit an indigenous, but ‘non‐natural’ enemy that does not typically attack P. kraunhiae under natural conditions, as well as a minor natural enemy, for biological control of this mealybug species.  相似文献   

2.
Fig wasps (Chalcidoidea, Agaonidae, Agaoninae) are the exclusive pollinators of fig trees (Ficus spp., Moraceae). Fig development on the African fig tree, F. burtt-davyi, is normally synchronised on individual trees, but not between trees. Consequently the females of each generation of the pollinating species (Elisabethiella baijnathi) have to disperse to other trees to find ‘receptive’ figs which are suitable for oviposition. This paper examines this aspect of fig - fig wasp biology. The flight speed of insects is closely linked to their size, and directional flight is difficult for small insects, such as fig wasps, in all but the lightest of winds. We investigated the movements of fig wasps between trees using sticky traps placed around fig trees or near cotton bags containing figs. Away from the trees, the densities of flying wasps at different heights was also determined. When the wasps disperse from their natal figs they take off near-vertically. They are unable to exert directional control once they enter the air column and are subsequently blown downwind. Near receptive host trees the wasps appear to lose height and then fly upwind at speeds of around 25 cm/sec.  相似文献   

3.
We studied the distribution and spread of the invasive social wasp Vespula germanica in Argentina, focusing on the contribution of queen dispersal to territorial expansion. Vespula germanica is native to Eurasia and has invaded several regions of the world, including Southern Argentina. Flight potential of field‐collected queens was measured using flight mills. Also, by means of an extensive survey we estimated the rate of spread by analysing the relationship between years since arrival and distance from the introduction locality. The mean distance flown by wasp queens in flight mills was 404.7 ± 140.8 m (mean ± SE, n = 59), while the rate of spread of V. germanica was estimated at 37.2 ± 2.1 km year?1 (mean ± SE, n = 67), although faster towards the south. The observed spread rate of V. germanica wasps in Argentina confirms the invasive potential shown by several Hymenoptera species worldwide. Still, a stratified geographical expansion pattern does not match observed queen dispersal abilities, suggesting that human‐aided transport of hibernating queens is the central driver of the current distribution of these wasps. We suggest that despite several life‐history traits known for social insects that contribute to successful invasion, wasp spread must still rely strongly on human mediated pathways. This observation sheds light on those factors that are crucial for managing invasions of this and related pestiferous wasps.  相似文献   

4.
The effects of thelytoky-inducing Wolbachia ( &#102 -proteobacteria) on Trichogramma cordubensis and T. deion (Hymenoptera, Trichogrammatidae) were studied in laboratory and greenhouse conditions. One infected (thelytokous, all female) line of each wasp species was compared with its conspecific uninfected (arrhenotokous, sexual) counterpart for several fecundity and dispersal traits. Arrhenotokous lines had a higher fecundity than their thelytokous counterparts, which suggests that Wolbachia negatively affect the fecundity of Trichogramma females. The arrhenotokous females dispersed more in the laboratory than their thelytokous counterparts. In the greenhouse, the opposite effect or no difference between lines was found, indicating that the laboratory set-up used to measure dispersal is not useful to predict relative dispersal of the females in the greenhouse. Calculations show that by releasing 100 adult wasps of both lines, thus including arrhenotokous males in the sexual line, more eggs are parasitized by the thelytokous wasps. Therefore, in spite of their lower individual female fecundity, thelytokous lines have a better potential for biological control than their arrhenotokous counterparts.  相似文献   

5.
Several hymenopteran parasitoids are infected with parthenogenesis‐inducing (PI) Wolbachia. Infected wasps produce daughters instead of sons from unfertilized eggs. Thus far, little is known about the direct effects of PI Wolbachia on their host's fitness. Here, we report reduced competitive ability due to Wolbachia infection in a minute parasitoid wasp, Trichogramma kaykai Pinto and Stouthamer (Hymenoptera: Trichogrammatidae). Immature survival of infected individuals in a host parasitized by a single infected female, laying a normal clutch of eggs, was lower than those parasitized by a single uninfected individual. When the offspring of infected and uninfected females shared the same host, the infected immatures had significantly lower survival rates than their uninfected counterparts. The survival rate of infected immatures was higher when they competed with other infected immatures from a different infected parent than in competition with uninfected immatures of conspecific wasps. Thus, the host Trichogramma can suffer a substantial reduction in fitness when it is infected with the PI Wolbachia. We discuss why such a reduction is to be expected when populations of infected and uninfected individuals co‐occur, and how the reduced competitive ability of PI Wolbachia influences the spread of the bacteria in the field.  相似文献   

6.
The pine wood nematode (Bursaphelenchus xylophilus), which causes the symptoms of pine wilt disease, is recognized worldwide as a major forest pest. It was introduced into Portugal in 1999. It is transmitted between trees almost exclusively by longhorn beetles of the genus Monochamus, including, in particular, M. galloprovincialis (Coleoptera: Cerambycidae) in maritime pine forests. Accurate estimates of the flight capacity of this insect vector are required if we are to understand and predict the spread of pine wilt disease in Europe. Using computer‐linked flight mills, we evaluated the distance flown, the flight probability and speed of M. galloprovincialis throughout adulthood and investigated the effects of age, sex and body weight on these flight performances, which are proxies for dispersal capacity. The within‐population variability of flight performance in M. galloprovincialis was high, with a mean distance of 16 km flown over the lifetime of the beetle. Age and body weight had a significant positive effect on flight capacity, but there was no difference in performance between males and females. These findings have important implications for managing the spread of the pine wood nematode in European forests.  相似文献   

7.
Most mutualisms are exploited by parasites, which must strike an evolutionary balance between virulence and long‐term persistence. Fig‐associated nematodes, living inside figs and dispersed by fig wasps, are thought to be exploiters of the fig–fig wasp mutualism. The life history of nematodes is synchronized with the fig development and adapted to particular developmental characteristics of figs. We expect host breeding systems (monoecious vs. gynodioecious figs) and seasonality to be central to this adaptation. However, the details of the adaptation are largely unknown. Here, we conducted the first field surveys on the prevalence of nematodes from monoecious Ficus microcarpa L.f. (Moraceae), gynodioecious Ficus hispida L.f., and their pollinating fig wasps in two seasons and two developmental stages of figs in Xishuangbanna, China. We followed this up by quantifying the effects of nematodes on fitness‐related traits on fig wasps (e.g., egg loads, pollen grains, and longevity) and fig trees (seed production) in gynodioecious F. hispida. The magnitude of nematode infection was compared between pre‐ and post‐dispersal pollinators to quantify the probability of nematodes being transported to new hosts. Our results showed that Ficophagus microcarpus (Nematoda: Aphelenchoididae) was the only nematode in F. microcarpa. In F. hispida, Martininema guangzhouensis (Nematoda: Aphelenchoididae) was the dominant nematode species, whereas Ficophagus centerae was rare. For both species of Ficus, rainy season and inter‐floral figs had higher rates of nematode infection than the dry‐hot season and receptive figs. Nematodes did not affect the number of pollen grains or egg loads of female wasps. We did not detect a correlation between seed production and nematode infection. However, carrying nematodes reduced the lifespan and dispersal ability of pollinator wasps, indicating higher rates of post‐emergence mortality in infected fig wasps. Severely infected fig wasps were likely ‘filtered out’, preventing the overexploitation of figs by wasps and stabilizing the interaction over evolutionary time.  相似文献   

8.
Sirex noctilio F. (Hymenoptera: Siricidae) is a woodwasp of pine trees that has recently invaded and established in North American forests. Although S. noctilio has had a limited impact in North America to date, there is some concern that it could have a significant impact on pine plantations, especially in the southeastern U.S.A. Moreover, there are few data on the flight capacity of male S. noctilio. We found no association between parasitism by D. siricidicola and whether or not S. noctilio initiated flight on the flight mill. Male wasps that were parasitized by nematodes were heavier than non-parasitized males, but there was no significant difference in mass between parasitized and non-parasitized females. We also examined the flight capacity of male and female S. noctilio in relation to nematode parasitism, body mass, temperature (for only males), and diel period. Body mass, temperature, and diel period affected flight in S. noctilio such that wasps were generally observed to fly faster, farther, and more frequently if they were heavier, flying at warmer temperatures, and flying during the photoperiod. The fact that nematode-parasitized male wasps were found to fly farther than the non-parasitized males is consistent with the hypothesis that nematode parasitism does not negatively affect the flight capacity of S. noctilio.  相似文献   

9.
Control of the invasive wasp, Sirex noctilio Fabricius using the parasitic nematode Deladenus siricidicola Bedding is a well known example of a successful classical biological control program. Despite its wide-scale success, this control method has recently had poor success in the summer rainfall areas of South Africa. Data from previous studies showed variation in nematode parasitism from inoculated trees (inoculation success) between different tree sections and among inoculation times. They also pointed to moisture content of the wood or virulence of the nematode as the most likely underlying factors influencing variations in inoculation success. The results from our study showed that the highest levels of parasitism was obtained from early inoculations and from the bottom sections of trees, where moisture content of the wood was highest, supporting the hypothesis that moisture content influences parasitism. However, even when moisture content was adequate, average inoculation success remained below 25% and was often 0%, suggesting that there are other barriers to inoculation success. Different sources from which the nematodes were produced did not influence inoculation success, indicating that nematode virulence is most likely not the cause of the low success. Another interesting finding was that parasitized wasps were larger than unparasitized wasps. Background parasitism was present despite the poor success with past inoculations, but the data also suggest that the natural build-up of this population could be constrained by the same factors that influence inoculations.  相似文献   

10.
《Biological Control》2000,17(2):155-163
Studies were conducted on the combined use of the eulophid parasitoid wasp Diglyphus begini Ashmead and the entomopathogenic nematode Steinernema carpocapsae (Weiser) for control of the leafminer Liriomyza trifolii (Burgess) on chrysanthemums. Several factors indicated that these two agents were suitable for combined use: adult D. begini were not susceptible to nematode infection, leafminer larvae parasitized by the wasp were less susceptible to nematode infection, adult wasps detected and tended to avoid ovipositing on nematode-infected leafminer larvae, nematode-infected larvae served as host-feeding sources for the adult wasps, and nematodes showed equal orientation toward paralyzed/parasitized leafminer larvae and healthy leafminer larvae. However, interspecific interference and intraguild predation (IGP) between the agents were found. Infection of D. begini larval stages by nematodes was seen in petri dishes and in intact leaf mines. The presence of nematodes in mines with wasp eggs decreased the chance of wasp survival to adulthood. IGP may be minimized through proper timing of natural enemy releases.  相似文献   

11.
Various physiological effects of Wolbachia infection have been reported in invertebrates, but the impact of this infection on behavior and the consequences of these behavioral modifications on fitness have rarely been studied. Here, we investigate the effect of Wolbachia infection on the estimation of host nutritive resource quality in a parasitoid wasp. We compare decision‐making in uninfected and Wolbachia‐infected strains of Trichogramma brassicae Bezdenko (Hymenoptera: Trichogrammatidae) on patches containing either fresh or old host eggs. For both strains, fresh eggs were better hosts than older eggs, but the difference was smaller for the infected strain than for the uninfected strain. Oviposition behavior of uninfected wasps followed the predictions of optimal foraging theory. They behaved differently toward high‐ vs. low‐quality hosts, with more hosts visited and more ovipositions, fewer high‐quality hosts used for feeding or superparasitism, and a sex ratio that was more biased toward females in patches containing high‐quality hosts than in patches containing low‐quality ones. Uninfected wasps also displayed shorter acceptance and rejection times in high‐quality hosts than in hosts of lower quality. In contrast, infected wasps were less efficient in evaluating the nutritive quality of the host (fresh vs. old eggs) and had a reduced ability to discriminate between unparasitized and parasitized hosts. Furthermore, they needed more energy and therefore engaged in host feeding more often. This study highlights possible decision‐making manipulation by Wolbachia, and we discuss its consequences for Wolbachia fitness.  相似文献   

12.
Although the timing of oögenesis appears to be a major life‐history organizer in the parasitoid Hymenoptera, relatively little is known about how this trait correlates with population dispersal by flight in these wasps. Pre‐oviposition flight behaviours of 1‐day‐old female wasps in a vertical flight chamber are measured to test correlations between these traits and with reproductive timing. The focus of the present study is on two genera of whitefly parasitoids (Encarsia and Eretmocerus) that differ in reproductive timing when feeding on a shared host (Bemisia tabaci). The two Eretmocerus species engage in vertical flight within 3 min of release far more frequently than the three Encarsia species. Because the former typically possess a more time‐limited reproductive strategy than the latter, this lends support for a positive interspecific association between early‐life reproduction and early‐life flight incidence. Within species, however, egg load does not correlate with flight propensity for any of the tested species. Furthermore, in Eretmocerus eremicus, the relationship between effective flight distance (i.e. the product of vertical climb rate and flight duration) and egg load appears to be labile rather than fixed because different trials show evidence for either negative or positive correlations between these variables. The source of this context dependence may be variation in either biotic (e.g. longevity) or abiotic (e.g. temperature and relative humidity) factors.  相似文献   

13.
Understanding the factors that affect animal dispersal behavior is important from both fundamental and applied perspectives. Dispersal can have clear evolutionary and ecological consequences, but for nonnative insect pests, dispersal capacity can also help to explain invasion success. Vespula germanica is a social wasp that, in the last century, has successfully invaded several regions of the world, showing one of the highest spread rates reported for a nonnative insect. In contrast with nonsocial wasps, in social species, queens are responsible for population redistribution and spread, as workers are sterile. For V. germanica, it has been observed that queen flight is limited to 2 distinct periods: early autumn, when new queens leave the nest to mate and find sheltered places in which to hibernate, and spring when new colonies are founded. Our aim was to study the flight behavior of V. germanica queens by focusing on the different periods in which dispersal occurs, characterizing as well the potential contribution of queen flight (i.e., distance) to the observed geographical spread. Our results suggest that the distances flown by nonoverwintered queens is greater than that flown by overwintered individuals, suggesting that the main queen dispersal events would occur before queens enter hibernation. This could relate to a behavioral trait of the queens to avoid the inbreeding with related drones. Additionally, given the short distances flown and remarkable geographical spread observed, we provide evidence showing that queen dispersal by flight is likely to contribute proportionately less to population spread than human‐aided factors.  相似文献   

14.
Ficus burtt-davyi, like most other fig species (Ficus, Moraceae), is exclusively pollinated by its own unique species of fig wasp, in this caseElisabethiella baijnathi (Chalcidoidea, Agaonidae). Because fig crop development on any one tree is usually synchronised, the small and short-lived female wasps have to migrate and find other trees bearing figs which are at suitable stage of development for oviposition. However, the likelihood of successful location and subsequent arrival at a new host tree is dependent on distance and the effect of environmental factors such as wind and temperature. This study examines the relationship between ambient temperatures and the timing of fig wasps emergence from their natal figs and the commencement of their dispersal flight. The behaviour of the wasps arriving at figs which were ready to be pollinated was also examined. The female wasps did not appear to distinguish between the figs and other parts of the tree when in flight. However, after landing on the tree their search for figs was more directed as they visited more figs than leaves. Short-range recognition of figs appears to be by contact chemo-reception, but the wasps showed a preference for entering figs which did not already contain a female wasp.  相似文献   

15.
High parasitism by a native parasitoid, Phasgonophora sulcata Westwood (Hymenoptera: Chalcididae), has been reported on emerald ash borer (hereafter EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), in North America. Use of this parasitoid in an augmentative biological control program has been proposed to slow the spread of EAB, yet information is lacking on key aspects of this parasitoid’s dispersal. We document the flight capacity and walking activity of P. sulcata, its potential fecundity, and describe how age, body size, temperature, and time of day affect these parameters. Wasp flight capacity, measured using flight mills, increased with temperature and decreased with age. Unexpectedly, age and body size did not affect wasp walking activity, and we saw no relationship between walking activity and flight capacity. Older wasps had lower potential fecundity than younger wasps. These results suggest that P. sulcata should be released as pupae near EAB-infested ash trees to improve efficacy and potential biological control success.  相似文献   

16.
Abstract

The nematode (Pheromermis spp.) is a potential biocontrol agent for wasps (Vespula spp.) in countries where invasive populations of wasps cause serious economic, social, and conservation problems. Using a simulation model previously developed for hornets, which belong to a genus with a similar biology to Vespula, we investigated the possibility of using nematodes as a biological control agent. The model wasp colony was exposed to different simulated levels of nematode infection during colony development, and the final number of wasp sexuals produced recorded. The model predicted that early and high levels of wasp infection had the greatest effect on reducing sexual production. However, even colonies with high (80%) levels of infection were still able to produce some sexuals, indicating that wasp colonies are resilient to infections. The model identified several key areas needing further research, including the effects of nematodes on the behaviour and physiology of wasps, of lengthening the infective period, and of increasing infection levels in both the wasps and intermediate transport hosts.  相似文献   

17.
徐睿  张媛  彭艳琼  杨大荣 《生态学报》2016,36(4):1134-1140
榕树及其专一性传粉榕小蜂组成了动植物界最为经典的协同进化关系,传粉榕小蜂演化出欺骗性是非常罕见的。在雌雄同株的高榕隐头果内,共存着一种传粉榕小蜂Eupristina altissima和一种欺骗性的小蜂Eupristina sp.,两种小蜂在雌花期进入隐头果内繁殖,但有不同的繁殖特点。对比研究了两种小蜂从成虫羽化到产卵和传粉这个阶段的雌蜂个体大小、孕卵量及繁殖差异,结果表明:羽化期两种雌蜂的平均个体小,经飞行小个体的雌蜂易死亡,大个体雌蜂到达接受树,但通过苞片通道,一些个体较大的传粉榕小蜂被夹死导致进入果腔的雌蜂相对小,而欺骗性小蜂易通过苞片以至进入果腔的雌蜂个体较大。两种未产卵雌蜂均表现为个体大者孕卵量较多,但两种雌蜂的平均孕卵量没有差异。即使有充足雌花资源产卵,两种雌蜂均未产完所有卵,产卵后两种雌蜂卵巢中的卵量均显著减少,遗留下的卵量两种小蜂间没有差异。传粉榕小蜂只有部分个体传完所携带花粉,并表现为传粉越成功的雌蜂,产卵越多。存在种内竞争时,两种小蜂的产卵量均减少,传粉榕小蜂的传粉效率也降低。在种间竞争背景下,欺骗性小蜂产卵更成功,传粉榕小蜂的产卵和传粉量均受到极大抑制。研究结果说明雌花期隐头果内传粉榕小蜂只适量利用雌花资源产卵繁殖后代,更有效地传粉繁殖榕树种子,这可能是维持榕-蜂互惠系统稳定共存的重要机制之一;欺骗者稳定存在需降低与传粉者的直接竞争,而欺骗者和传粉者分散在不同果内,甚至是不同的树上繁殖是理想的繁殖策略。  相似文献   

18.
Some polysphinctine parasitoid wasps can alter the web building behavior of their host spiders. In this paper, we describe and illustrate a new species Eruga unilabiana sp. nov. and report for the first time, to the best of our knowledge, the interaction between this parasitic wasp and the linyphiid spider Dubiaranea sp. We investigated the wasp's host selection, development, and manipulation of host behavior. We found that most of the parasitized spiders were intermediate‐sized adult females that probably provide sufficient resources for parasitoid larvae and are less vulnerable for parasitoid females than larger host individuals at attack. The cocoon web of Dubiaranea sp. consists of a complex three‐dimensional tangle structure with several non‐stick radial lines that converge at the cocoon. In addition, E. unilabiana individuals construct their cocoons horizontally, which differ from cocoons of the majority of polysphinctine wasps. This study provides important information and discussion to further understand the evolution of parasitoid wasp–spider interactions.  相似文献   

19.
The wood‐boring wasp, Sirex noctilio, is a global invasive pest that infects and kills pine trees by inoculating spores of a symbiotic fungus (Amylostereum areolatum) at oviposition. Wasp larvae depend on fungal growth to feed, while the fungus relies on female wasps to initially condition the pine tree by inoculating a phytotoxic venom and for dispersal. Wasp larvae use the fungus as an external gut for the digestion of lignocellulosic compounds resulting in a strong correlation between fungal growth inside the wood and wasp fitness. This study explores the hypothesis that female wasps will use fungal volatiles as a synomone in the process of locating suitable oviposition areas (i.e. trees). Using a Y‐tube olfactometer, adult female wasp behaviour was assessed towards fungal and pine tree volatiles (i.e. positive control). Our results are the first to demonstrate attraction of female S. noctilio towards volatiles of their fungal symbiont. Furthermore, the positive response towards these volatiles seems to be stronger than the response to a known attractant (i.e. pine volatiles). These results could be an important contribution to improving baits for monitoring and control purposes. Further work is needed, mainly oriented towards the identification of the volatiles that trigger the observed attraction response and their possible synergistic effects with tree volatiles.  相似文献   

20.
The number of mature eggs carried by a female parasitoid at any given moment (egg load) is a fitness‐related parameter affecting reproductive potential and impacting upon host population dynamics. Microplitis rufiventris Kokujev (Hymenoptera: Braconidae) is a solitary koinobiont endoparasitoid wasp of several noctuid pests, including Spodoptera littoralis. The number of mature eggs carried by females at emergence is approximately 50. The rate of egg maturation is strongly affected both by feeding status and access to host larvae. In early adult life, egg maturation rates are lower for 6–72 h in fed wasps compared with food‐deprived wasps. When given access to hosts, honey‐fed wasps live for approximately 9 days with high lifetime fecundity (226 eggs). By contrast to early adult life, the total realized fecundity is positively affected by feeding status, where water‐fed and starved females have 140 and 107 eggs, respectively. Egg resorption is most pronounced in the later life of females. The results suggest, in addition to confirming the effect of honey‐feeding on total fecundity, that fecundity of starved wasps includes rapid egg maturation early in life, which potentially could improve the performance of the parasitoid as a biological control agent.  相似文献   

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