象虫金小蜂中国新记录

本文首次报道了象虫金小蜂在中国的分布,并用图文简要地描述其特征.该蜂是四纹豆象、米象、谷象、玉米象、烟草甲和药材甲等重要贮藏物害虫的天敌.     

Behaviour of males in relation to the female sex pheromone in the parasitoid wasp, Anisopteromalus calandrae (Hymenoptera: Pteromalidae)

Male sexual behaviour in Anisopteromalus calandrae was observed and experimentally analyzed. The female secretes a sex pheromone which releases the wing vibration of males. The female sex pheromone, and not the visual stimulus, is essential for the recognition by males of the nearby presence of a female. This pheromone which is secreted from glands situated in abdomen of the female, is already released since pupal stage, but the male is attracted most effectively by the female still under the reed of the beans. Copulation takes place immediately after the female comes out of the bean.

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Résumé Le comportement sexuel mâle chez Anisopteromalus calandrae a été observé et expérimentalement analysé. La femelle émet la phéromone sexuelle qui déclenche la vibration des ailes chez le mâle. La phéromone sexuelle, et non le stimulus visuel, est essentielle pour que le mâle reconnaisse la présence voisine d'une femelle. Cette phéromone, sécrétée par des glandes situées dans l'abdomen de la femelle, est émise dès le stade nymphal, et le mâle est effectivement attiré par les femelles encore incluses dans le pois. L'accouplement a lieu aussitôt que la femelle sort dehors.

     

Differential mRNA expression levels and gene sequences of a putative carboxylesterase-like enzyme from two strains of the parasitoid Anisopteromalus calandrae (Hymenoptera: Pteromalidae).

Carboxylesterase-like enzyme cDNAs have been cloned and sequenced from malathion-resistant and susceptible strains of the parasitoid Anisopteromalus calandrae (Howard) (Hymenoptera: Pteromalidae). The cDNAs consist of 1963 nucleotides including a 35 bp untranslated 5'-end, a 1596 bp open reading frame, and a 332 bp untranslated 3'-end. The open reading frame encodes 532 amino acid residues. The predicted protein sequence from these cDNAs includes 2 potential N-glycosylation sites, a carboxylesterase type-B serine active site FGGDSENVTIFGESAG, and conserved residues Ser187, Glu317, and His432 to function as the catalytic triad. The predicted carboxylesterase-like enzyme sequence is most similar to that of the carboxylesterase from the peach-potato aphid, Myzus persicae with 45% sequence identity. Alignment of the parasitoid carboxylesterase-like enzyme cDNAs revealed that there are two nucleotide differences in the open reading frame between the parasitoid strains, including a silent mutation and a point mutation that presumably causes a gene product difference. A nucleotide thymine at position 658 in the susceptible strain cDNA is replaced by a guanine in the resistant strain cDNA. This substitution leads to an amino acid change from tryptophan (Trp220) in the susceptible strain to glycine (Gly220) in the resistant strain. This substitution is genetically linked to resistance but it is not known how or if this amino acid substitution affects detoxification of malathion. Northern blot analyses demonstrated that expression level of the carboxylesterase-like enzyme mRNA in adult A. calandrae is approximately 30-fold higher in the resistant strain relative to that in the susceptible strain. Southern analysis indicated that Pst I or Eco RI restriction sites are different in the two strains. Both a modified gene structure and an increase in expression of carboxylesterase may be responsible for the high level of resistance found in this beneficial wasp.     

Suitability of five mealybug species (Hemiptera,Pseudococcidae) as hosts for the solitary parasitoid Anagyrus sp. nr. pseudococci (Girault) (Hymenoptera: Encyrtidae)

Anagyrus sp. nr. pseudococci is an endoparasitoid which has been used as a biological control agent of mealybug pests. In this study, we compared the suitability of five mealybugs species with different phylogenetic relationships and geographical origins as hosts of this parasitoid. The selected mealybugs were: (1) a Mediterranean-native species, Planococcus ficus, sharing a long co-evolutionary history with the parasitoid; (2) three exotic species, the Afrotropical Planococcus citri, the Australasian Pseudococcus calceolariae and the Neotropical Pseudococcus viburni, with a recent history; and (3) the Neotropical Phenacoccus peruvianus, with no previous common history with the parasitoid. Host suitability was assessed based on different fitness parameters, such as body size, developmental time, emergence rate and sex ratio. The parasitoid was able to complete development in all mealybug species. Nevertheless, its emergence rate significantly varied among mealybug species, with the highest values observed in Pl. ficus and Pl. citri, intermediate values in Ps. calceolariae and the lowest ones in Ps. viburni and Ph. peruvianus. The body size of adult wasp females varied with host suitability and was positively correlated with other measures of parasitoid fitness, including the emergence rate and the sex ratio. The parasitoid developmental time differed among mealybug species but did not correlate with any other measure of fitness. A female biased sex ratio was found in the parasitoid progeny emerged from all mealybug species, except in Ps. viburni and Ph. peruvianus. There was a direct relationship between the proportion of females in the parasitoid progeny and the emergence rate.     

Host-size-dependent feeding behaviour and progeny sex ratio of Anisopteromalus calandrae (Hym., Pteromalidae)

Host-size related feeding and oviposition behaviour, and allocation of progeny sex by Anisopteromalus calandrae (Howard) were tested on Sitophilus oryzae L. The parasitoid showed a host-size-dependent partition of feeding and oviposition behaviour, preferring small hosts for feeding, but large hosts for oviposition. Neither the mutual interference nor the host density showed any effect on the behaviour of the parasitoid. Allocation of progeny sex by the female parasitoid appeared to be based more likely on absolute than on relative host size encountered. A model for the progeny sex ratio was constructed based on: (1) ovipositional preference of the parasitoid on large hosts; (2) feeding preferentially on small hosts; and (3) host-size-related regulation of progeny sex ratio. The progeny sex ratio of the parasitoid predicted by the model was in close agreement with the observed value.     

Regulation of Progeny Sex by Anisopteromalus calandrae (Hymenoptera: Pteromalidae) in Relation to Host Preference,Host Vulnerability and Host Size

Regulation of progeny sex by Anisopteromalus calandrae (Howard) in relation to host preference, host vulnerability and host size was studied with two host species, Sitophilus oryzae (L.) and Callosobruchus chinensis L. A. calandrae preferred S. oryzae to C. chinensis (preference index = 0.87). The progeny sex ratio (females/total) was significantly higher on C. chinensis, the less preferred host, than on S. oryzae regardless of the instar age of the two host species. A. calandrae could locate only a few young larvae of C. chinensis (≤third instar), which could be apparently due to the low vulnerability of the young larvae locating deeper in the adzuki bean kernels. The larval instar age of Sitophilus oryzae affect the progeny sex ratio of A. calandrae, but that of Callosobruchus chinensis did not except invulnerable ones. The progeny sex ratio of A. calandrae produced from C. chinensis, ranged from 0.66±0.05 to 0.82±0.02. The invulnerability of the young larval instar of C. chinensis and regulation of the progeny sex ratio by A. calandrae based on host size in a manner of absolute rule could explain the higher sex ratio on the young larval instar of C. chinensis, less preferred and less vulnerable host, than the old larval instar of S. oryzae, highly preferred host. The differences in host vulnerability could be another factor for A. calandrae assigning progeny sex ratio.     

多寄主型寄生蜂蝇蛹俑小蜂对新寄主的选择与适应性

【目的】明确多寄主型寄生蜂蝇蛹俑小蜂Spalangia endius对不同类型新寄主的偏好选择与适应性。【方法】选择分别以瓜实蝇Zeugodacus cucurbitae、南瓜实蝇Z.tau和家蝇Musca domestica的蛹为寄主饲养的蝇蛹俑小蜂成蜂,比较研究其对上述3种寄主中其他2种非饲养寄主的选择行为、寄生选择及适应性。【结果】与家蝇蛹相比,以瓜实蝇蛹为饲养寄主的蝇蛹俑小蜂成蜂偏好选择和寄生南瓜实蝇蛹,且在南瓜实蝇蛹上产生更多的子代;以南瓜实蝇蛹为饲养寄主的蝇蛹俑小蜂成蜂偏好选择和寄生瓜实蝇蛹,且在瓜实蝇蛹上产生更多的子代;而以家蝇蛹为饲养寄主的蝇蛹俑小蜂成蜂对瓜实蝇蛹和南瓜实蝇蛹的选择数量以及在选择和非选择试验条件下的寄生率与子代数量上并无显著差异。此外,以瓜实蝇和南瓜实蝇蛹为饲养寄主的蝇蛹俑小蜂成蜂分别更容易适应南瓜实蝇和瓜实蝇蛹。【结论】基于3种蝇的生态位关系,推测蝇蛹俑小蜂偏好选择和更容易适应与其饲养寄主有重叠生态位的新寄主。     

Quality of different aphids species as hosts for the parasitoid Aphidius ervi Haliday (Hymenoptera: Braconidae: Aphidiinae)

The suitability of Macrosiphum euphorbiae (Thomas), Aulacorthum solani (Kaltenbach) and Acyrthosiphon kondoi Shinji (Hemiptera: Aphididae) as hosts for the aphid parasitoid Aphidius ervi Haliday was evaluated by assessing host size, host preference, and host quality. Tests were carried out in an environmental chamber at 22±1oC, 70±10% RH and 12h photophase. Replicates (11) consisted of one 24h-old mated female of A. ervi without a previous oviposition experience. Female was released into a Petri dish (5 cm) with 20 2nd and 3rd instars of one of each aphid species tested on a leaf disc of the host plant onto a 1% water-agar layer. Parasitoid emergency was lower in A. kondoi (78.7%) compared to M. euphorbiae (92.2%) and A. solani (91.7%). Acyrthosiphon kondoi (0.36 mm) was the smallest host. The parasitoid showed preference (74.0% parasitism) for M. euphorbiae, the largest host (hind tibia length=0.73 mm), which in turn yielded larger A. ervi females (0.75 mm).     

Morphology and chemistry of Dufour glands in four ectoparasitoids: Cephalonomia tarsalis,C. waterstoni (Hymenoptera: Bethylidae), Anisopteromalus calandrae,and Pteromalus cerealellae (Hymenoptera: Pteromalidae)

The venom apparatus of four hymenopterous parasitoids, including two bethylids, C. tarsalis (Ashmead) and C. waterstoni (Gahan), and two pteromalids, A. calandrae (Howard) and P. cerealellae (Ashmead), were removed and the associated Dufour glands characterized with respect to their external morphology and chemistry. Dufour glands in all four species have a characteristic translucent appearance that apparently results from their lipid content. The stalked Dufour glands of C. tarsalis and C. waterstoni are pear-shaped and have overall lengths of approximately 0.2 and 0.15 mm, respectively. The thin venom glands are bifurcate and insert through a fine duct into the transparent ovoid- to pear-shaped venom reservoir in these bethylids. In A. calandrae and P. cerealellae the Dufour glands are elongated, tubular structures of ca. 0.35 and 0.8 mm in length, respectively, that constrict to a short stalk that empties into the common oviduct. The venom glands in these pteromalids are simple elongated structures that insert into the sac-like venom reservoir through a fine duct. The chemistry of the volatile contents of the Dufour gland in these four species differs considerably. C. tarsalis Dufour glands contain the same hydrocarbon components as found on the cuticle of this species (Ann. Entomol. Soc. Am. 91:101-112 (1998)), and no other chemicals. The Dufour glands of C. waterstoni also contain only hydrocarbons, most of which are the same as the cuticular hydrocarbons (Ann. Entomol. Soc. Am. 85:317-325 (1992)), but in addition the Dufour gland contains ca. 3% of a mixture of 2,17- and 2,19-dimethyl C(23). A. calandrae Dufour gland chemistry is somewhat more complex than that of either of the two bethylids, but like the bethylids, only hydrocarbons are present. The carbon number range is from C(30) to C(39) and consists of a mixture of n-alkanes (C(30)-C(38)); 3-, 5-, 7-, 9-, 11-, 12-, 13-, 14-, 15- and 17-methyl alkanes; 3,7- and 3,11-dimethyl alkanes; 5,9- and 5,17-dimethyl alkanes; 7,11-, 9,13-, 13,17-, 14,18- and 15,19-dimethyl alkanes; 3,7,11- and 3, 9,15-trimethyl alkanes; and 3,7,11,15-tetramethyl alkanes. The cuticular hydrocarbons of this species have not been previously reported, but they are the same as the Dufour gland hydrocarbons. The Dufour glands of P. cerealellae contain both hydrocarbons and two long-chain aldehydes. Most of the hydrocarbons are identical to those found on the cuticle of this species (Ann. Entomol. Soc. Am. 94:152-158 (2001)), but in addition, 5,9-dimethyl C(27), 5,13-, 5,17- and 5,19-dimethyl C(35), 12- and 14-methyl C(36), 12,16- and 13,17-dimethyl C(36), 13-methyl C(37) and 13,17-dimethyl C(37) are present. The two aldehydes detected in glands from P. cerealellae are n-tetracosanal (C(23)CHO) and n-hexacosanal (C(25)CHO).     

Flight activity in the parasitoid waspNasonia vitripennis (Hymenoptera: Pteromalidae)

Flight activity in females of the parasitoid wasp Nasonia vitripennis(Walker) was examined by measuring still-air tethered flight. There was a large amount of variation among females in flight duration. The longest single flight (with no pauses of more than 5 s) was more than 2 h long. Mating status had a significant and large effect on flight: mated females flew twice as long as virgin females. There also was a slight but significant effect of age on flight, with 3-day-old females being less likely to fly than 1-day-old females. Flight duration was not affected by prior exposure to other females, to honey, or to a low or a high host density.     

Additional notes on Anisopteromalus sp. (Hymenoptera: Pteromalidae), the sibling species of a parasitic wasp of stored‐product pests,Anisopteromalus calandrae (Howard): A new alternative host,an eye color mutant and DNA barcodes

A parasitic wasp of stored‐product pests, Anisopteromalus calandrae (Howard), is known to have a sibling species with a different chromosome number. Here, we report establishment and characterization of an eye color mutant in this sibling species. The phenotype of the mutant is red eye in adults, and crossing experiments revealed that the mutant phenotype is recessive to wild type (brown eye color). We also report DNA barcode sequences (a partial sequence of mitochondrial cytochrome‐c oxidase subunit I) of A. calandrae and the sibling species to enable accurate identification of these morphologically similar species. Analyses of our laboratory strains showed that 12.6% of the analyzed sequences (82 of 652 bp) differed between the two species. Finally, we note that the seed beetle Callosobruchus chinensis (Linné) (family Bruchidae), host of our laboratory strains of the sibling species, is a new record of alternative host at the family‐level for the wasp (known hosts: Anobiidae (natural host) and Curculionidae (alternative host)).     

The European species of Coelopisthia (Hymenoptera: Pteromalidae)

Abstract. Four species of Coelopisthia Förster are recognized from Europe, including two new species from Britain: areolata sp.n., caledonica sp.n., extenta (Walker), pachycera Masi. These species are keyed and biological data presented.     

Interaction between Acarophenax lacunatus (Cross & Krantz) (Prostigmata: Acarophenacidae) and Anisopteromalus calandrae (Howard) (Hymenoptera: Pteromalidae) on Rhyzopertha dominica (Fabricius) (Coleoptera: Bostrichidae)

The interaction between Acarophenax lacunatus (Cross & Krantz) and Anisopteromalus calandrae (Howard) may be a promising tool for the integrated pest management of stored grain insect pests. The objective of this study was to evaluate the compatibility of these two natural enemies on Rhyzopertha dominica (Fabricius). The experimental units were petri dishes (140 x 10 mm) containing 30 g of whole wheat grains (13% water content) infested with 20 adults of R. dominica. The treatments consisted of inoculation of A. lacunatus and A. calandrae, separately and associated, in eight replicates. Three inoculations of five adult females of the natural enemies were carried out in each petri dish at five, ten and fifteen days after the infestation of R. dominica. All treatments were stored during 60 days in environmental chamber at 30 +/- 1 degrees C, 60 +/- 5% relative humidity and 24 h scotophase. The smallest numbers of physogastric females of A. lacunatus and of adults of A. calandrae were obtained when the natural enemies were in association. The use of A. calandrae alone demonstrated a low instantaneous rate of increase (r(i)) of R. dominica and a high protection of the wheat grains. The association of A. calandrae with A. lacunatus led to the lowest number of immatures of R. dominica. These results demonstrate the importance of this interaction as a tool of for the integrated management of R. dominica in stored wheat grains.     

Suitability of heat- and freeze-killed oothecae of the American cockroach (Dictyoptera: Blattidae) as hosts for an oothecal parasitoid, Aprostocetus hagenowii (Hymenoptera: Eulophidae)

The objective of this study was to evaluate the suitability of heat- and freeze-killed oothecae of Periplaneta americana (L.) (Dictyoptera: Blattidae) as hosts for parasitoid Aprostocetus hagenowii (Ratzeburg) (Hymenoptera: Eulophidae). The oothecae were subjected to -20, 45, 48, 50, and 55 degrees C at different exposure times (15, 30, 45, and 60 min). The effects of heat- and freeze-killed oothecae on several biological parameters (e.g., parasitism and emergence rates, developmental times, progeny number, and sex ratio) ofA. hagenowii were determined. Embryonic development of 2-d-old oothecae was terminated by either freezing at -20 degrees C or heating at > or = 48 degrees C for > or =30 min. A. hagenowii parasitized live oothecae as well as both heat- and freeze-killed oothecae. Percentage parasitism, emergence rates, and developmental times ofA. hagenowii in both heat- and freeze-killed oothecae were not significantly different from those of the live oothecae. Both heating and freezing did not influence progeny number (male and female) and sex ratio of A. hagenowii emerged from killed oothecae.     

Influence of body size on fecundity and sperm management in the parasitoid wasp Anisopteromalus calandrae

A large body size is considered to be advantageous to the reproductive success of females as a result of several factors, such as the allocation of more resources to reproduction and the efficient management of sperm transferred by males. In the present study, the effects of female body size, female mating status and additional food availability on fecundity and the offspring sex ratio are investigated in the parasitoid wasp Anisopteromalus calandrae Howard (Hymenoptera: Pteromalidae). Because of haplodiploid sex determination, females must fertilize eggs to produce female offspring but not to produce male offspring. As predicted, female fecundity and the number of female offspring are positively correlated with body size. However, although the volume of the spermatheca increases with female body size, the amount of sperm stored in the spermatheca is relatively constant, irrespective of body size. Consequently, larger females produce a greater proportion of male offspring, especially at the end of the oviposition sequence, suggesting that larger females that possess more resources for reproduction and produce a larger number of offspring are more likely to suffer sperm depletion. The results of the present study also show that mated females have an increased fecundity compared with virgin females, although the opportunity to feed on honey along with host feeding has no impact upon fecundity or the sex ratio.     

The reproductive strategy of the gregarious parasitoid,Pteromalus puparum (Hymenoptera: Pteromalidae)

Summary Pteromalus puparum is a gregarious parasitoid of lepidopterous pupae. To determine in which phase of a host outbreak superparasitism occurs, field investigations were carried out on seasonal prevalence of the host, Papilio xuhtus, and parasitism by P. puparum in a citrus grove in Fukuoka, Japan in 1974. Host pupation occurred from May to November and the parasitoid attacked the host throughout this period. Pupal density increased rapidly after mid-August and the percentage parasitism decreased during this period. A high level of parasitism was attained after one or more parasitoid generations in mid-September. The superparasitism was observed after mid-September when the parasitoid attained extremely high density, and resulted in an increase in the proportion of males, high mortality, and a decrease in the size of the progeny.     

Assessment of frozen larvae of Callosobruchus maculatus as hosts for rearing Pteromalus cerealellae (Ashmead) (Hymenoptera: Pteromalidae)

The suitability of frozen host larvae for rearing Pteromalus cerealellae (Ashmead) (Hymenoptera: Pteromalidae), an ectoparasitoid of Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae) and other stored-product insects was investigated. The reproductive potential (number and sex ratio of progeny) of female P. cerealellae was compared on live (fresh) C. maculatus larvae (concealed within cowpea seeds) versus frozen larvae (obtained by freezing infested cowpea seeds at ?20 °C for 48 h) which were subsequently thawed and held at ambient conditions (～25 ± 1 °C, 50 ± 5% RH) for 4, 24, 48, 72, 96, and 120 h before exposure to female parasitoids. No significant differences were recorded in the numbers and sex ratios of the progeny produced by female P. cerealellae on live larvae compared to frozen host larvae that were thawed and held at ambient conditions for up to 96 h, suggesting that live and frozen larvae of C. maculatus are equally suitable for rearing P. cerealellae. However, the data showed that progeny production on frozen hosts gradually declined with thawing duration and was significantly reduced at the thawing duration of 120 h. When live and frozen host larvae were simultaneously presented together to female P. cerealellae at different exposure periods, relatively greater progeny production was recorded on live hosts than on frozen hosts at 12, 24, and 48 h of exposure. This may suggest preference of female P. cerealellae for live versus frozen host larvae. These results are discussed in relation to the life history strategy and host location behavior of P. cerealellae, and may have practical implications in the development of efficient mass rearing systems for the parasitoid.     

The reproductive strategy of the gregarious parasitoid,Pteromalus puparum (Hymenoptera: Pteromalidae)

Summary Pteromalus puparum is a gregarious parasitoid of many butterfly pupae. Adult size, mortality, and sex ratio of P. puparum, as a parasitoid of Papilio xuthus, were unit weight of the host. Effects of female size on fecundity, wing load, and longevity were also examined.The highest total weight of progeny from the host was attained when the number of eggs per gram of the host was approximately 150. Positive correlations were observed between the size of the females and their fecundity and wing load. The maximum longevity of the female kept with honey but without hosts was attained when the initial number of parasitoids per g of the host was 150.Considering the total fecundity of all female progeny, the reproductively most efficient number of eggs to be deposited per g of the host was estimated to be approximately 300. However, as shortage of food for the adult females strongly affects their fecundity, the reproductively most efficient number of eggs to be deposited per g of the host was about 70 when the adult female progeny was not provided with food.The optimal number of eggs to be deposited when the emale oviposits in the host under field conditions is discussed.     

The reproductive strategy of the gregarious parasitoid,Pteromalus puparum (Hymenoptera: Pteromalidae)

Summary Host size of Pteromalus puparum, a gregarious pupal parasitoid, shows a wide inter- and intraspecific variation. Experiments were made to study the regulation of the number and sex ratio of progeny per host by the parasitoid. The parasitoid could discriminate inter- and intraspecific size differences of the host and regulate the number of eggs according to the host size when a single female attacked the host. The sex ratio of progeny (proportion males) was about 0.1. The number of progeny laid by the female agreed with the energetically most efficient number og eggs in order to maximize total weight of progeny per host but not with the reproductively most efficient number of eggs to maximize the total fecundity of the progeny. The parasitoid laid smaller number of eggs in a half buried host, but the number was much larger than a half of those in a fully exposed host. When more than one female attacked a single host, the number and sex ratio of progeny per host increased with the number of females attacking the host, but the number of progeny per female decreased. The change of the sex ratio agreed with the prediction of the local mate competition model.