Attraction of Gymnosoma rotundatum (Diptera: Tachinidae) to different amounts of Plautia stali (Hemiptera: Pentatomidae) aggregation pheromone and the effect of different pheromone dispensers

The attractiveness of different amounts of the synthetic aggregation pheromone, methyl (E,E,Z)-2,4,6-decatrienoate, of the brown-winged stink bug, Plautia stali (Hemiptera: Pentatomidae) was tested on its parasitoid, Gymnosoma rotundatum (Diptera: Tachinidae), using different types of dispensers in the field. Both sexes of G. rotundatum were attracted to the aggregation pheromone. Pheromones in rubber septum and poly-tube dispensers attracted significantly more G. rotundatum than those in PE-vial dispensers. There were no differences in the attraction of females or males when using 7 to 60 mg pheromone. However, the trap baited with 50 mg pheromone attracted significantly more G. rotundatum of both sexes than the control trap. Further research is necessary to develop an effective pheromone trap that can attract and kill P. stali and can attract G. rotundatum to increase parasitism of the host stink bugs in the field.     

Spatial and temporal influences of conifer planted forests on the orchard pest Plautia stali (Hemiptera: Pentatomidae)

Land use changes have generally been considered a local matter, but they are becoming an issue of much wider concern as changes in the use of non-agricultural lands occasionally generate nationwide agricultural pest problems. Plautia stali Scott is a serious pest in orchards, and the widespread distribution of this pest is likely associated with the expansion of planted coniferous forests in Japan. An experiment was conducted on 29 study sites in diverse areas of planted coniferous forest in central Japan, and the abundance of P. stali was monitored over four seasons for 3 years. Results revealed that the optimum radius required to cause an effect on the area surrounding the conifer planted forest was up to 4 km—specifically, 2,000, 400, 1,500, and 200 m in April, June, August, and October, respectively. Positive correlations were observed between conifer planted forests and the collected numbers of P. stali in April, June, and August. These temporal scales provide a direct evaluation of the landscape effects of a conifer planted forest on population dynamics, and this information will contribute to the development and improvement of area-wide P. stali management.     

Developmental response of the brown-winged green bug, Plautia stali (Heteroptera: Pentatomidae), to food shortage

To study developmental response of the brown-winged green bug, Plautia stali Scott, to food shortage we reared nymphs under restricted feeding conditions produced by shortening the feeding period after molt or withholding food from second to fifth instars. For second instars, molting rates were significantly reduced as the feeding period was shortened. Shortening the feeding periods for third to fifth instars also reduced molting rates, but less so; some nymphs were able to complete their developments even if no food was given to any of the instars. Compared with controls for which feeding was not restricted, nymphs that successfully reached the next instar had reduced postmolt body size as a result of restricted feeding for all instars except the fifth (2-day feeding for second instar, and 1-day feeding for third and fourth instars), whereas instar duration was unchanged or only slightly prolonged for all instars. These results suggest that only nymphs with nutritional accumulation over a specific threshold in each instar can progress to the next instar, and that, particularly for second to fourth instars, nymphs develop on schedule without prolonging instar durations to compensate for reduced growth under conditions of food shortage.     

Response of a parasitoid fly, Gymnosoma rotundatum (Linnaeus) (Diptera: Tachinidae) to the aggregation pheromone of Plautia stali Scott (Hemiptera: Pentatomidae) and its parasitism of hosts under field conditions

We studied the attraction of a tachinid fly, Gymnosoma rotundatum (Linnaeus) to the male-produced aggregation pheromone of the brown-winged green bug, Plautia stali Scott, its parasitism on the bug, and its seasonal occurrence in the field. The tachinid fly was continuously attracted to the aggregation pheromone from spring to autumn and utilized the bugs as hosts. Our field experiment to clarify the effect of the pheromone on parasitism demonstrated that parasitism occurred only in female bugs baited with synthetic aggregation pheromone and did not occur in females without the pheromone. The parasitoid flies therefore appeared to use the bug’s pheromone as a host-finding kairomone. The pheromone attracted not only female flies but also males. Male flies may increase their chance of encountering pheromone-attracted females by waiting near pheromone sources. The tachinid develops multiple generations in active hosts from spring to autumn and overwinters in dormant hosts. Thus, G. rotundatum seems to be highly adapted to using P. stali as its host, and it is a potentially important biological control agent of P. stali populations in the field.     

Spatio-temporal Distribution of Beskia aelops (Walker) (Diptera: Tachinidae) and its Potential for the Biocontrol of Oebalus poecilus (Dallas) (Hemiptera: Pentatomidae)

Oebalus poecilus is the most serious insect pest of rice in many South American countries. Presently, control of O. poecilus is wholly by the application of monocrotophos and most farmers use insecticides. Tachinid parasitoids are possible components in an IPM programme and their spatio-temporal dynamics were investigated for the first time over four crop seasons.     

Possible use of synthetic aggregation pheromones to control stinkbug Plautia stali in kaki persimmon orchards

• 1 The brown‐winged green stinkbug Plautia stali Scott (Hemiptera: Pentatomidae) is the most serious pest of all noxious stinkbugs in various orchards in Japan. An area‐wide integrated pest management programme using the species‐specific aggregation pheromone is desirable to control P. stali because nonspecific insecticides may kill arthropod natural enemies and induce the resurgence of other endemic pests.
• 2 The traditional mass‐trapping method is not expected to be effective as a result of huge migrations from cypress forests. Therefore, we chose an ‘attract‐and‐kill’ strategy of intensively installing poisonous eggplants with a synthetic aggregation pheromone lure as enclosures for the target orchards.
• 3 We found no overall control effect of the installation of poisonous eggplants, although regional differences were observed, which might originate from topological configurations or the distance from the source population in cypress forests.
• 4 The poisonous eggplants with an aggregation‐pheromone lure, however, changed the spatial distribution of fruit damage, appearing to induce the majority of the damage within a 100‐m range of the poisonous eggplants. Some damage, although at a low level, was found in regions 100–200 m away from the poisonous eggplants.
• 5 We postulate that such low‐damage regions were created because the majority of the bugs dispersed from the centre of the orchards to the areas with poisonous eggplants. The present study, in which the spatial scale of the damage spillover was estimated at approximately 150 m, has important implications for future strategies of attract‐and‐kill and possibly push–pull.

     

Density dependence and regulation in the systemNezara viridula (L.) (Hemiptera: Pentatomidae), host andTrichopoda giacomellii (Blanchard) (Diptera: Tachinidae), parasitoid

Summary The system formed byN. viridula and its almost specific parasitoidT. giacomellii has been studied in the Buenos Aires province, Argentina for 26 generations of the former and 20 generations of the latter. An intensive study over 9 host generations and key factor analysis made possible the identification and quantification of different mortality factors. The main factors determining the fluctuations in total generation mortality were: egg mortality due mainly to parasitism byT. basalis; nymphal predation on 1^st, 2^nd and 3^rd instar nymphs and migration; and adult mortality and reduction on potential natality due to parasitism byT. giacomellii. Adult mortality and reduction of potential natality, due to parasitism byT. giacomellii, was density dependent. This factor is capable of maintaining the simulations generated by a simple model based on key factor analysis, within the range of observed densities. These results suggest that parasitism byT. giacomellii can regulate the population, even in a small area of 450 m².     

Susceptibility of pest Nezara viridula (Heteroptera: Pentatomidae) and parasitoid Trichopoda pennipes (Diptera: Tachinidae) to selected insecticides

Susceptibility of the southern green stink bug, Nezara viridula (L.) (Heteroptera: Pentatomidae), and its endoparasitoid Trichopoda pennipes (F.) (Diptera: Tachinidae) to acetamiprid, cyfluthrin, dicrotophos, indoxacarb, oxamyl, and thiamethoxam was compared in residual and oral toxicity tests. In the residual toxicity test, cyfluthrin, dicrotophos, and oxamyl were highly toxic to N. viridula. Thiamethoxam was moderately toxic to these insects. Each of the four insecticides was highly toxic to T. pennipes after prolonged tarsal contact with dried residues of these chemicals. In the oral toxicity test, where N. viridula fed on food covered with insecticide residues, none of the insecticides were toxic to adults of this stink bug, but acetamiprid, dicrotophos, and thiamethoxam were moderately toxic to the nymphs. In the oral toxicity test, where N. viridula fed on a gel-food containing insecticides, cyfluthrin, dicrotophos, oxamyl, and thiamethoxam were highly toxic to this stink bug. In an oral toxicity test using contaminated sugar water, all of the insecticides were highly toxic to T. pennipes. Because insecticides were as toxic, or more toxic, to T. pennipes than to N. viridula, it is extremely important to conserve this parasitoid by applying these insecticides for control of southern green stink bugs only when the pest reaches economic threshold.     

Contribution to the tachinid fauna of southwestern Turkey (Diptera: Tachinidae)

Faunistic records for 139 tachinid species from southwestern Turkey (Mu?la province and adjacent Ayd?n, Burdur, Denizli and Antalya provinces) are given. Another 17 species of the study area are known only from published records. The known fauna of Tachinidae of southwestern Turkey thus comprises 156 species. Zoogeographic analysis of the study area revealed that tachinids belong to 29 chorological categories, divided into two supergroups: 122 species (78.2%) are more eurybiontic, and also distributed in northern parts of the Palaearctic region (19 chorological categories belong here), whereas 34 species (21.8%) are distinctly thermophilic, and have a southern type of distribution (10 chorological categories are distinguished). Altogether, 52 species (33.3%) are recorded for the first time from Turkey.     

Symbiont of the stink bug Plautia stali synthesizes rough-type lipopolysaccharide

The structures and biosynthesis of lipopolysaccharide (LPS), a major component of the outer membrane of Gram-negative bacteria, have been studied extensively in cultured bacteria such as Escherichia coli. In contrast, little is known about the structures and biosynthesis of the LPS of unculturable bacteria, including insect symbionts, many of which are Gram-negative bacteria. A brown-winged green bug, Plautia stali, is known to harbor a single species of gamma-proteobacterium in the posterior mid-gut caeca. To characterize the features of its LPS, we analyzed the genome sequence of the symbiont, and identified the putative genes involved in LPS synthesis. Genes involved in the synthesis of lipid A and the core oligosaccharide were found in the genome, but waaL, which encodes the O-antigen ligase, was not. Furthermore, we characterized the LPS of this symbiont using SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and Toll-like receptor 4 (TLR4) stimulation assays. Consistent with the genomic analysis, the SDS-PAGE analysis suggested that the symbiont had rough-type LPS, which lacked the O-antigen. The TLR4 stimulation assay demonstrated that LPS purified from the symbionts activated NF-κB-dependent reporter expression, indicating the existence of a bioactive lipid A portion in the LPS. These results suggest that the P. stali symbiont produces rough-type LPS.     

Field trials of aggregation pheromones for the stink bugs Chlorochroa uhleri and Chlorochroa sayi (Hemiptera: Pentatomidae)

In field trials, adult Chlorochroa uhleri (St?l) (Heteroptera: Pentatomidae) of both sexes were caught in significant numbers in cylindrical screen traps baited with gray rubber septum lures loaded with the main component of the male-produced pheromone, methyl (E)-6-2,3-dihydrofarnesoate. Addition of the two possible minor components of the pheromone, methyl (E)-5-2,6,10-trimethyl-5,9-undecadienoate and methyl (2E,6E)-farnesoate, did not affect attraction. Combining the pheromone with different concentrations of volatiles mimicking the odors of a known host plant, alfalfa (Medicago sativa L.), had no significant effect on attraction of adult bugs, whereas combining the pheromone with the pheromones of two sympatric stink bug species, Chlorochroa sayi (St?l) and Euschistus conspersus Uhler, decreased trap captures, suggesting interference between the pheromones. Small numbers of Chlorochroa ligata (Say) adults also were attracted, but numbers caught were too low to allow statistical comparisons between lure blends. In field trials with C. sayi, all three of the male-specific pheromone compounds [methyl geranate, methyl citronellate, and methyl (E) -6-2,3-dihydrofarnesoate] were required for optimal attraction. As with C. uhleri, adults of both sexes were attracted to pheromone lures in approximately equal numbers. Because of the decreased volatility (=release rate) of methyl (E)-6-2,3-dihydrofarnesoate in comparison with the other two, lower molecular weight pheromone components, lures needed to be loaded with a disproportionately high amount of methyl (E)-6-2,3-dihydrofarnesoate to obtain the best trap catch. There was no indication that the pheromone components of C. uhleri or E. conspersus interfered with the attractiveness of the C. sayi pheromone in lures containing a blend of all three pheromones.     

The genus Campylocheta (Diptera: Tachinidae) from Japan

Seven new species of Campylocheta are described and illustrated from Japan: abdominalis from Hokkaido, Honshu and Kyushu, flaviceps from Honshu and Tsushima, grisea from Kyushu, argenticeps from Honshu, bisetosa from Hokkaido and Honshu, hirticeps from Hokkaido, Honshu and Tsushima, and suwai from Hokkaido. Campylocheta dentifera Richter and C. umbrinervis Mesnil are redescribed and a key to nine Japanese species is provided.     

Phenology simulation model of Scotinophara lurida (Hemiptera: Pentatomidae)

A phenology simulation model was developed for Scotinophara lurida (Burmeister). The components for the model were a degree-day immigration flight model of overwintered adults, temperature-dependent developmental models of each stage, survival rates of each stage, and an adult oviposition model. A degree-day model for immigration flight of overwintered adults was developed with blacklight trap catch data by a Weibull function. Laboratory experiments using seven constant temperature regimens were conducted to determine the effect of temperature on the development of immature stages. Developmental rates of each immature stage fit well to a linear model. Distribution of developmental time for each immature stage was successfully modeled against physiological age by a Weibull function. To determine the temperature effect on longevity, fecundity, and survival of female adults, laboratory and greenhouse experiments were conducted. The adult developmental rate (1/median longevity) was described by a linear model. The oviposition model was developed incorporating the three components of average total fecundity, cumulative oviposition rate function, and survival rate function. The simulation model predicted the time of peak occurrences of life stages of S. lurida well.     

中国蝽科新记录属种（半翅目：异翅亚目）

报道中国蝽科(Heteroptera: Pentatomidae)3个中国新记录属:库蝽属 Cuspicona Dallas、赫蝽属Hermolaus Distant、昂角蝽属 Oncinoproctus Breddin,以及6个新记录种:绿库蝽 Cuspicona antica Vollenhoven、赫蝽 Hermolaus typicus Distant、笑曼蝽 Menida atkinsoni Distant、昂角蝽 Oncinoproctus griseolus Breddin、斑卷蝽 Paterculus aberrans Distant 和短线鳖蝽 Rolstoniellus malacanicus (Yang)。并给出各种的虫体背腹面照片和生殖节结构图。除绿库蝽的观察标本保存在中国科学院动物所(IZCAS)以外,其余研究观察标本保存在南开大学昆虫研究所标本馆(NKUM)。