中红侧沟茧蜂寄生粘虫的生物学特性(英文)

报道了中红侧沟茧蜂寄生粘虫时的某些生物学特性。雌蜂的每次产卵动作约有３．１％的比率产出两粒卵,４．６％的比率没有卵产出。寄主龄期与寄生率呈负相关关系,雌蜂在寄主体内产两粒卵能提高寄生率。寄主龄期同后代寄生蜂的性比没有相关性,不是影响性比的主要因素。文中讨论了影响中红侧沟茧蜂性比的可能因素,并认为二龄粘虫是大规模繁殖该寄生蜂的最好寄主。     

Host Stage Selection and Sex Allocation by Gyranusoidea tebygi (Hymenoptera: Encyrtidae), a Parasitoid of the Mango Mealybug, Rastrococcus invadens (Homoptera: Pseudococcidae)

Host stage selection and sex allocation by Gyranusoidea tebygi Noyes (Hym,, Encyrtidae) were studied in choice and no-choice experiments in the laboratory. The parasitoid reproduced on first, second, and third instars of the mango mealybug, Rastrococcus invadens Williams (Hem., Pseudococcidae), and it avoided hosts that were already parasitized. Host feeding was occasionally observed. Sex ratios of the offspring produced by individual wasps were highly biased in favor of females, whereas the sex ratio of groups of wasps foraging under crowded conditions varied from male biased in smaller hosts to female biased in larger hosts. Females had longer developmental times than males, developed faster in larger mealybugs than in smaller ones, and were always larger than males emerging from the same host instar. Their size increased with the instar of the host at oviposition. About 90% of all ovipositions in second and third instar nymphs resulted from an attack with multiple stings, starting with a sting in the head of the host for the most part. The function of these head stings is either to assess quality of the host or to subdue hosts prior to oviposition. Encounter rates, number of attacks, and number of stings during one attack increased, while ovipositions decreased with host instar. Time investment per oviposition and time spent preening increased with increasing host age because older hosts defended themselves more vigorously than younger ones. Thus, while fitness of the parasitoid increased with host size, fitness returns per time decreased. The implications of this host selection behavior for the biological control of the mango mealybug are discussed.     

Reproductive performance of Nesolynx thymus (Hymenoptera: Eulophidae), in relation to age of Musca domestica (Diptera: Muscidae)

An investigation was undertaken to record the influence of host age on the reproductive performance of Nesolynx thymus (Hymenoptera:Eulophidae). This is an indigenous, gregarious, ecto-pupal parasitoid of certain dipteran insects, including the tachinid fly, Exorista bombycis (Louis) which is a well-known endo-larval parasitoid of the silkworm, Bombyx mori. Each gravid N. thymus female was allowed to parasitise 1–4-day-old puparia of Musca domestica L. for 2 days at a parasitoid–host ratio of 1:20. The parasitised host puparia were observed for progeny recovery, sex ratio, female longevity and fitness (adult size). In addition, reproductive performance of the parasitoid progeny was assessed by allowing its females to parasitise for 2 days, 3-day-old puparia of E. bombycis at a parasitoid–host ratio of 1:4. There was a significant negative correlation between host age and parasitisation rate, parasitoid developmental duration, sex ratio and female longevity while the correlation was positive between host age and parasitoid recovery per host puparium. Similarly, negative correlation was observed between host age and morphometric parameters (body length, head width and wing span of male and female and length and width of female abdomen) of the progeny adults. Host age did not have any impact on the reproductive performance of progeny adults when allowed to parasitise puparia of E. bombycis.     

Effects of parasitization or injection of parasitoid-derived factors from the endoparasitic wasp Glyptapanteles porthetriae (Hym., Braconidae) on the development of the larval host, Lymantria dispar (Lep., Lymantriidae)

Second instar larvae of Lymantria dispar were parasitized or injected with parasitoid-derived factors such as venom, calyx fluid or parasitoid eggs from Glyptapanteles porthetriae . Growth and development of the host larvae were affected in all different groups compared to control larvae of the same age, injected with Ringer solution. The greatest impact on host growth and on the duration of the 3rd instar was caused by injecting parasitoid eggs. Treated larvae showed melanized capsules or nodules in the hemocoel. While the wasp age had no effect on parasitization efficiency or on the percentage of melanized particles in the hemocoel, significantly more encapsulations were found in larvae parasitized by old wasps as opposed to young wasps. Superparasitization (double or quadruple oviposition) increased the parasitization efficiency markedly. While none of the control larvae showed melanized particles, in the groups of single and superparasitized (2× and 4×) hosts a high percentage of melanized particles (capsules and nodules) occurred.     

Sex Allocation by a Parasitoid Wasp (Hymenoptera: Ichneumonidae) to Different Host Species: A Question for the Mechanism of Host Size Estimation

Sex allocation by the polyphagous solitary pupal parasitoid wasp Pimpla luctuosa Smith to a small host species, Galleria mellonella (L.), and a large host species, Mamestra brassicae L., was investigated to test whether female wasps responded to hosts of different sizes across different host species. In the experiments, both host species were presented to each test female wasp. Primary and secondary sex ratio experiments revealed that female wasps laid more female eggs in larger pupae of each host species, indicating that female wasps recognized size differences within host species. The wasp sex ratio (male ratio) from M. brassicae, however, was much higher than that expected on the basis of the sex ratio curve from different-sized G. mellonella. Larger hosts of each host species yielded larger wasps, indicating that the host size estimation by female wasps across different host species was incomplete or was not simple. These results suggested that P. luctuosa evaluated host size not only by physical measures such as dimension but also by other unknown measures. A possible explanation for the adaptiveness of different sex ratio responses by Pimpla luctuosa to different host species was discussed.     

The effect of host instar on the size and sex ratio of the endoparasitoidDacnusa sibirica

Older instars of the leafminer hostChromatomyia syngenesiae Hardy (Diptera: Agromyzidae) at parasitization resulted in larger female adults of the larval-pupal endoparasitoidDacnusa sibirica Telenga (Hymenoptera: Braconidae). The sex ratio in the parasitoid offspring became increasingly female biased and development period decreased with increasing age of the host at parasitization. Older host instars were therefore considered to produce a fitter parasitoid.     

Influence of aphid size,age and behaviour on host choice by the parasitoid wasp Ephedrus californicus: a test of host-size models

Summary When host quality varies, parasitoid wasps are expected to oviposit selectively in high-quality hosts. We tested the assumption underlying host-size models that, for solitary species of wasps, quality is based on host size. Using Ephedrus californicus, a solitary endoparasitoid of the pea aphid, we evaluated the influence of aphid size (= mass), age and defensive behaviours on host selection. Experienced parasitoid females were given a choice among three classes of 5-day-old apterous nymphs: small aphids that had been starved daily for 4 h (S4) and 6 h (S6) respectively, and large aphids permitted to feed (F) normally. Wasps attacked more, and laid more eggs in, small than large aphids (S6>S4>F). This rank-order for attack did not change when females could choose among aphids of the same size that differed in age; however, wasps oviposited in all attacked aphids with equal probability. Host size did not influence parasitoid attack rates when aphids were anaesthetized so that they could not escape or defend themselves. As predicted by host-size models, wasp size increased with host size (F>S4; S6), but large wasps required longer to complete development than their smaller counterparts (S4E. californicus reflects a trade-off between maximization of fitness gains per egg and the economics of search-time allocation. Because large aphids are more likely to escape parasitization, a wasp must balance her potential gain in fitness by ovipositinng in a high-quality (large) aphid against her potential cost in terms of lost opportunity time if the attack fails.     

SEX-RATIO MANIPULATION IN RESPONSE TO HOST SIZE BY THE PARASITOID WASP SPALANGIA CAMERONI: A LABORATORY STUDY

The prediction of Charnov et al.'s (1981) host-size model that there should be a negative relationship between host size and wasp sex ratio (proportion sons) was supported for Spalangia cameroni, a solitary parasitoid wasp. The relationship was shown to be a result of offspring sex manipulation by females in response to host size rather than a result of differential mortality of the sexes. A major assumption of the host-size model is that host size has a greater effect on the ultimate reproductive success of emerging female wasps than of males. This assumption was not supported. Host size had a positive effect on the size of both male and female S. cameroni. However, neither host size nor wasp size affected longevity, production of offspring by females, or ability of males to compete for mates. Host size may differentially affect the reproductive success of female and male wasps through effects on other aspects of reproductive success. Tests of the assumptions of offspring sex-ratio manipulation hypotheses are scarce but critical, not only for parasitoid wasps, but also for other organisms.     

Determination of the optimal parasitoid‐to‐host ratio for efficient mass‐rearing of the parasitoid,Sclerodermus pupariae (Hymenoptera: Bethylidae)

Sclerodermus pupariae Yang et Yao (Hymenoptera: Bethylidae) is used as a potential biocontrol agent for several buprestid and cerambycid larvae. This study aimed to enhance the efficiency of mass‐rearing of this parasitoid by investigating the fitness gain of this bethylid wasp, including the proportion of successful parasitism and development, brood size, sex ratio, proportion of winged female offspring, body size and longevity of female offspring, under eight different maternal parasitoid density treatments using Thyestilla gebleri Faldermann as host in the laboratory. The results indicated that the foundress densities did not affect the parasitism or emergence rate of this parasitoid. Brood size of the parasitoids increased significantly when the number of maternal wasps ranged from one to four. However, further increases in foundress number did not affect the parasitoid brood size. The sex ratios of S. pupariae were always female‐biased. The proportions of male in the progeny colonies were <10% throughout all experimental treatments. The percentage of winged female progeny was not significantly influenced by the density of adult maternal parasitoids. Body sizes of parasitoids significantly declined with increasing maternal parasitoid densities. Although the parasitoid body size reduced when maternal wasp number was higher, it could be compromised by the relatively higher number of female offspring produced. Further, more than 70% of the parasitoids remained alive when they were stored at 12°C for four months throughout the experiments. These findings suggest that exposure of four female wasps to a single host larva would result in the highest fitness of S. pupariae. Our findings might provide a new approach to enhance the efficiency of mass‐rearing of this bethylid wasp.     

Host specificity of the egg pupal parasitoid Fopius arisanus (Hymenoptera: Braconidae) in La Reunion

Fopius arisanus is a polyphagous parasitoid of Tephritidae, which has been recently introduced to La Réunion Island as part of a classical biological control programme. We carried out laboratory experiments to assess the host specificity of this parasitoid, initially reared on Bactrocera zonata, and then offered for parasitization the eight local tephritid pest species. Naive or experienced parasitoid females were given tephritid eggs in no choice tests. Fopius arisanus females parasitize all fly species but parasitism varies with host species. No adult wasps emerge from Bactrocera cucurbitae and the survival of this species is only slightly affected by parasitism. Dissections show that the late instars of this fly may eliminate the parasitoid by encapsulation. When developing on Ceratitis capitata, Ceratitis rosa, Dacus ciliatus, Dacus demmerezi, and Neoceratitis cyanescens, parasitoid survival rate ranges from 10 to 25%. Bactrocera zonata and Ceratitis catoirii are the best hosts, yielding parasitoid survival rates of more than 70% with no premature mortality. The egg-larval mortality of C. capitata, C. rosa, D. ciliatus, and N. cyanescens, and the pupal mortality of D. demmerezi, are significantly increased by parasitism. The size of emerging adults is affected by host species and is correlated to pupal weight. Bactrocera zonata would be a favorable host to support routine colonization of F. arisanus for mass production of this parasitoid.     

Biology of Cotesia ( = Apanteles) telengai (Hymenoptera: Braconidae) on its natural host Agrotis segetum (Lepidoptera: Noctuidae)

The host suitability of Agrotis segetum Denis & Schiff., A. ipsilon Hufn., Spodoptera littoralis Boisd, S. exigua Hub., Mythimna loreyi Duponchel and Mamestra oleracea L. for the gregarious braconid Cotesia ( = Apanteles) telengai Tobias was determined under laboratory conditions. The parasitoid only completed its development in larvae of A. segetum. The percentage of successfully parasitized larvae and the mean duration of C. telengai egg‐larval period were inversely related to the age of the host or host instar at parasitization. The mean number of parasitoids which emerged per parasitized larva was positively correlated with the larval age. The sex ratio was consistently high (ca. eight males to one female), independent of the host instar parasitized, as compared to 1:1 as observed frequently in field populations of this wasp. The females of C. telengai were active and produced offspring at temperatures of 15, 20, 25 and 30° C. However, the mean percentage of parasitized larvae increased from 13.1 to 72% and the mean progeny per parasitoid female increased from 14.7 to 129.4 parasitoids, both significant, when the experimental temperature was raised from 15 to 30°C, while their mean development time decreased from 75.5 to 19.2 days. At 25°C, the virgin and mated females continued oviposition until days 16 and 17, with a lifetime total of progeny of 397.6 (SD ±224.7) and 611.1 (SD± 128.8) parasitoids respectively, reaching a maximum of 64.3 and 99.2 on day 2 respectively.     

Host-size-dependent sex ratio in a parasitoid wasp

Charnov's host-size model explains parasitoid host-size-dependent sex ratio as an adaptive consequence when there is a differential effect of host size on the offspring fitness of parasitoid males versus females. This article tests the predictions and the assumptions of the host-size model. The parasitoid wasp Pimpla nipponica Uchida (Hymenoptera: Ichneumonidae) laid more female eggs in larger or fresher host pupae when choice among hosts of different sizes or ages was allowed. Then, whether an asymmetrical effect of host size and age on the fitness of females versus males existed in P. nipponica was examined. Larger or fresher host pupae yielded larger wasps. Larger females lived longer, whereas male size did not influence male longevity. Large males mated successfully with relatively large females but failed with small females, whereas small males could mate successfully either with small or with large females. Thus, small-male advantages were found, and this held true even under male–male competition. Ovariole and egg numbers at any one time did not differ among females of different sizes. Larger females attained higher oviposition success and spent less time and energy for oviposition in hosts. Larger females produced more eggs from a single host meal. Taken together, females gained more, and males lost more, by being large. Host size and age thus asymmetrically affected the fitness of offspring males versus females through the relationships between host size or hast age and wasp size, which means the basic assumption of the host-size model was satisfied. Therefore, sex ratio control by P. nipponica in response to host size and age is adaptive. Received: November 13, 1998 / Accepted: January 18, 1999     

Sex ratio manipulation by the parasitoid waspSpalangia cameroni in response to host age: A test of the host-size model

Summary A sex ratio response to host resources as measured by external host dimensions has been demonstrated in many parasitoid wasps, includingSpalangia cameroni. The responses generally are in the direction predicted by sex ratio theory, specifically the host-size models. Here I show that femaleS. cameroni also respond to differences in resource availability not associated with changes in external host dimensions, and this response is in the direction predicted by host-size models. When given old and young hosts simultaneously, femaleS. cameroni oviposit a greater proportion of sons in old than in young host pupae, at least for 0-day old versus 3-day old hosts. Old hosts weigh less than young hosts but are not significantly different in external width. Thus it appears that the offspring sex ratio response may result from mothers detecting physical or chemical changes within the host which are associated with host age. No evidence is found that the manipulation in response to host age has been selected for via an effect of host age on wasp size; there was no significant effect of host age on either male of female wasp size. A second prediction of the host-size models is also supported by this study: when each female is presented with only a single host age, rather than two host ages simultaneously, host age has no effect on offspring sex ratio.     

Effects of host age and host availability on developmental period,adult size,sex ratio,longevity and fecundity inLariophagus distinguendus Förster (Hymenoptera: Pteromalidae)

The effects of host age on parasitoid reproductive capacity are studied using the pteromalid parasitoid Lariophagus distinguendusFörster and its bruchid hosts, Callosobruchus chinensis (L.) and C. maculatus (F.). A series of experiments were performed to investigate relationships between age and size of host parasitized and the developmental period of pre-imaginal progeny, sex ratio, female size, longevity, fecundity and oviposition rate. There was no effect of host size on preimaginal parasitoid developmental period. Sex ratio varied from less than 5% females from young (small) hosts to 60% females from mature (large) hosts. Adult size, female longevity, fecundity, and oviposition rate were also positively related to host age. Females provided mature hosts lived longer than those provided either young hosts or no hosts, possibly because of an increased ability to host-feed from the larger hosts. The implications of these findings to parasitoid population reproductive capacity and host-parasitoid synchrony are discussed.     

Effect of exposure time on mass‐rearing production of the olive fruit fly parasitoid,Psyttalia lounsburyi (Hymenoptera: Braconidae)

Classical biological control programmes rely on mass production of high‐quality beneficial insects for subsequent releases into the field. Psyttalia lounsburyi (Silvestri) (Hymenoptera: Braconidae) is a koinobiont larval–pupal endoparasitoid of tephritid flies that is being reared to support a classical biological control programme for olive fruit fly in California. The mass‐rearing system for a P. lounsburyi colony, initiated with insects originally collected in Kenya, was evaluated with the goal of increasing production, while at the same time reducing time requirements for rearing in a quarantine facility. We tested the effect of exposure time of a factitious host Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), on parasitization, adult production, superparasitism, and sex ratio of P. lounsburyi and survival of the host. Parasitization rates were highest (31%) at 3‐ and 4‐hr exposure times, while adult production (i.e., emergence of wasp progeny) was highest (16%) at the 2‐hr exposure time. Superparasitism over the course of the study was 1.5% and did not appear to be a factor affecting parasitoid production. The sex ratio of wasp progeny was male‐biased and did not vary significantly over different exposure times. The rate of stings on host larvae increased with exposure time and was consistent with decreases in pupal eclosion from larvae and emergence rate of adult flies. When compared to current rearing procedures, the 2‐hr exposure time resulted in an overall 2.8‐fold increase in P. lounsburyi production when standardized for time.     

Refrigeration of Riptortus clavatus (Hemiptera: Alydidae) eggs for the parasitization by Gryon japonicum (Hymenoptera: Scelionidae)

Gryon japonicum (Ashmead) (Hymenoptera: Scelionidae) is a solitary egg parasitoid of Riptortus clavatus (Thunberg) (Hemiptera: Alydidae) one of the most important pests in soybean in Korean and Japan. Refrigeration of R. clavatus eggs for up to 120 days was evaluated as a method of mass production of G. japonicum. The refrigeration reduced the eclosion of eggs, thus no nymph emerged after 30 days of egg refrigeration. Increased duration of host acceptance behaviors by G. japonicum and some detrimental effects on parasitism rate, developmental time, longevity, and adult size of the parasitoid were found in refrigerated host eggs. However, all the biological parameters of G. japonicum were unaffected by the refrigeration of up to 30 days. Gryon japonicum parasitized 16 and 14 host eggs daily that were refrigerated for 15 and 30 days, respectively, which did not differ from parasitization of fresh host eggs. Furthermore, refrigeration of host eggs did not reduce the reproduction of the emerged adult parasitoids and emergence and sex ratio of their progeny. Gryon japonicum also parasitized 14 and 13 refrigerated host eggs per day kept at 26.3°C and 78.7% RH for 2 and 4 days of post-refrigeration without significant reduction, respectively. These results show that refrigeration of R. clavatus eggs can be a good method for mass rearing of the parasitoid, and the host eggs killed by cold storage can be supplemented in the field to boost field parasitism.     

Improvements in rearing method for Hyposoter didymator (Hymenoptera: Ichneumonidae), considering sex allocation and sex determination theories used for Hymenoptera

An improved rearing method for the larval endoparasitoid Hyposoter didymator was developed in the laboratory considering the single locus complementary sex determination (sl-CSD) theory as well as other factors affecting sex ratio: (1) use of the preferred host of the parasitoid in nature; (2) appropriate host size (large enough to favor female development); (3) appropriate parasitoid age (experienced in parasitization); (4) implication of all genotypes on offspring production (unselected parasitizing couples); and (5) genetic variability (regular infusion of wild stock). Firstly, to corroborate the sl-CSD theory, a small rearing was sib-mated in seven generations until males accounted for more than 90%. Secondly, a new parasitoid rearing method was developed using a single large population and two inbred lines (as reservoirs of alleles) to maintain allelic diversity according to the Cook’s Model. The quality of insects obtained with this method was evaluated by measuring the percentages of parasitized hosts and adult emergence and the sex ratio of the progeny during 42 generations. Parasitized host percentages were >80% and an average of 40% of females were obtained in practically all generations. Low percentages (<2%) of dead immature stages were recorded, and life span of adults was 32 ± 1.3 and 18 ± 2.2 d for females and males, respectively. The advantages of this rearing method compared to others previously developed for this parasitoid and its application to others hymenopteran parasitoid are discussed.     

Reproductive performance of <Emphasis Type="Italic">Nesolynx thymus</Emphasis> (Hymenoptera: Eulophidae) as influenced by host (<Emphasis Type="Italic">Musca domestica</Emphasis>) size

An investigation was conducted to understand the influence of host size on the reproductive performance of Nesolynx thymus, an ecto-pupal parasitoid of the uzi fly, Exorista bombycis, inflicting 10–20% loss to silkworm crops in the southern silk producing states of India. Two day-old adults of N. thymus were allowed to parasitize pupae of M. domestica, categorized into big and small at a parasitoid-host ratio of 1:20. After parasitoid adult eclosion, data on parasitization rate, developmental duration, male, female and total adult recovery per pupa and per female, sex ratio, adult size and adult longevity were recorded. The performance of first generation adults as influenced by host size was also recorded by allowing the first generation adults to parasitize three day-old pupae of E. bombycis. The parameters female and total progeny production per female, sex ratio, longevity, body length and wing span of males, females, head width of male, and abdomen length of female increased significantly with host size. No impact of host size was observed on performance of first generation adults.     

Reproductive biology of the microtype tachinid fly Zenillia dolosa (Meigen) (Diptera: Tachinidae)

Reproductive biology including mating, adult longevity, fecundity and development of the tachinid fly Zenillia dolosa was investigated for optimizing rearing procedures using Mythimna separata as a host in the laboratory. Females lay microtype eggs containing a first instar larva on food plants of the host and then the eggs must be ingested by the host for parasitization. Mating success was 58.5% with mating duration of 80.7 min. Mating was most successful when day 0–1 females were kept with day 2–4 male flies. Female body size was positively correlated with its fecundity but not with longevity. However, females that survived longer produced more eggs during their lifetime. Parasitoids successfully developed in 4th to 6th instar host larvae. Host instars at the time of parasitoid egg ingestion significantly influenced development time of the immature parasitoid, but did not affect body size of the emerging parasitoid. We suggest that pairing newly emerged females with day 2–4 males should result in higher mating success and using the last instar hosts for parasitization should minimize development time of the parasitoid for rearing.     

Interspecific competition between the braconid endoparasitoids Glyptapanteles porthetriae and Glyptapanteles liparidis in Lymantria dispar larvae

The effect of interspecific competition between the solitary endoparasitoid Glyptapanteles porthetriae Muesebeck (Hymenoptera: Braconidae) and the gregarious Glyptapanteles liparidis Bouché (Hymenoptera: Braconidae), was investigated in larvae of Lymantria dispar L. (Lepidoptera: Lymantriidae). Host larvae were parasitized by both wasp species simultaneously in premolt to the 2^nd or the 3^rd host instar or in an additional approach with a 4‐day delay in parasitization by the second wasp species. Host acceptance experiments revealed that both wasp species do not discriminate between unparasitized host larvae and larvae parasitized previously by the same or the other species. In more than 90% female wasps parasitized the larva they encountered first. During the period of endoparasitic development, larvae of the competing parasitoid species never attacked the egg stage of the other species. When host larvae were parasitized simultaneously by both wasp species, the rate of successful development of both species depended on the age of the host larva at the time of its parasitization; G. liparidis emerged successfully from 44% of host larvae parasitized during the premolt to 2^nd instar, G. porthetriae from 28%, and in 20% of the hosts both parasitoid species were able to develop in one gypsy moth larva. However, when host larvae were parasitized simultaneously during premolt to the 3^rd instar, G. liparidis was successful in 90% of the hosts, compared to 8% from which only G. porthetriae emerged. In the experiments with delayed oviposition, generally the species that oviposited first succeeded in completing its larval development. Larvae of the species ovipositing with four days delay were frequently attacked and killed by larvae of the first parasitizing species or suffered reduced growth. As the secondary parasitoid species, G. porthetriae‐larvae were never able to complete their development, whereas G. liparidis developed successfully in at least 12,5% of the multiparasitized host larvae. Thus, multiparasitism of gypsy moth larvae by both Glyptapanteles species corresponds to the contest type; however, G. porthetriae is only able to develop successfully as the primary parasitoid of young host larvae.