The Courtship of Drosophila Melanogaster males involves a sequence of characteristic behavioral elements. Identification of the genes required for active male courtship will help our understanding of the molecular mechanisms for maintaining male courtship activity. In this study, we examined the effect of conditional suppression of the activity of Drosophila transcription factor CrebB-17A on each courtship element by analyzing courtship using an event recorder. The mean frequencies of orientation, following, and wing vibration decreased in males overexpressing the CrebB-17A repressor. The mean durations of the courtship bout and each courtship element were normal in these flies and that of courtship break was markedly lengthened. These findings show that ongoing CrebB-17A activity is required for maintaining courtship break at the wild-type level, suggesting that CrebB-17A-mediated gene expression is involved in the reinitiation of male courtship after courtship break in Drosophila.
In order to elucidate the impact of secondary parasitism on a banker plant system, aphid parasitoids on banker plants were surveyed for four years in commercial greenhouses producing eggplant and sweet pepper in Kochi Prefecture, Japan. A banker plant system using Aphidius colemani was introduced into the greenhouses in November or December for the control of pest aphids from February through May. The mean rate of secondary parasitoids to total parasitoids on the alternative host aphid (Rhopalosiphum padi) on banker plants was less than 35% in the early season. In March or April, the mean rate exceeded 40%, and was more than 70% by May or June. Three main species of secondary parasitoids, Alloxysta sp. nr victrix, Dendrocerus laticeps and Syrphophagus sp., occurred throughout the season. In addition, Asaphes suspensus and Pachynouron aphidis occurred later in the season. In greenhouses where the banker plant system of aphid control failed, the increase of secondary parasitism on banker plants was sharper than in greenhouses with successful aphid control. In March and April, the higher rates of secondary parasitism on banker plants had a significant influence on the failure of aphid control.
A series of 3-oxygenated derivatives of α-ionone and α-ionol have been characterized as highly specific male lures for the solanaceous fruit fly Bactrocera latifrons (Hendel). In order to optimize the activity, we tested several analogous compounds derived from the three known attractants, 3-oxo-α-ionone, 3-oxo-α-ionol, and 3-hydroxy-α-ionone. 3-Oxo-7,8-dihydro-α-ionone and 3-oxo-7,8-dihydro-α-ionol were found to be potent attractants as well as feeding stimulants for the males in an indoor bioassay. While trans-3-hydroxy-α-ionone showed moderate attractant and feeding stimulant activity, the corresponding cis-isomer was weakly active, indicating the importance of the stereochemistry at the C-3 position. Synthetic trans-3-acetoxy-α-ionone exhibited lower activity than the corresponding 3-hydroxy derivative. B. latifrons males fed actively on 3-oxo-7,8-dihydro-α-ionone, transformed it to 3-oxo-7,8-dihydro-α-ionol, and sequestered this compound in a substantial quantity in the rectal glands. Males that fed on 3-oxo-7,8-dihydro-α-ionol incorporated the compound mostly unchanged in the rectal gland. In both cases, the rectal content was approximately 1 μg/gland at 6 h post-feeding on the chemicals, respectively. Selective accumulation of these 3-oxygenated α-ionone/α-ionol analogs suggests their possible role as a male sex pheromone.
The population density and dispersal of adult Chinese white pine beetle in Qinling Mountains, Shaanxi, China, were estimated by mark-release-recapture at the peak period of its diffusion in 2008 and 2009. Before this study, laboratory trials implemented using a self-regulating crisper and flight mill system showed that marking the beetles with spray paint had no effect on its survival and flight behavior. Our results showed that the female recapture rate (infested success rate) was 23.7%, 24.9%, 20.3%, 28.4% and 27.5%, respectively, in five released plots and positively correlated with crown density. The attacking sequence of the beetles was from south and west to north and east in every host tree. Meanwhile, the distance was not the foremost factor in the natural process of beetles selectively attacking Pinus armandi Franch. After all beetles had been simultaneously released in the center of both Plots D and E, the attack time ranged from 1 to 9 d and 10 d, respectively, with peak appearing in 3–6 d, and the dispersal distances varied from 0 to 32 m and 34 m, with the distribution being leptokurtic, with most observations around the mean mark-release-recapture distance of 17.4 m and 17.3 m.
The Nilaparvata lugens (Stål) is a major rice pest in Asia. Nitenpyram is a novel neonicotinoid insecticide developed by Takeda Chemical Industry Co., Ltd. The effects of sublethal concentration (LC30) of this insecticide on life-table parameters and wing formation of N. lugens were studied in the laboratory. The results showed that nitenpyram could reduce the fecundity of N. lugens to a great extent and demonstrated further activity against this pest in addition to direct toxicity. The fecundity (eggs per female) of N. lugens treated with a sublethal concentration of nitenpyram was 75.4% of the control in macropterous cohorts, and 69.8% in brachypterous cohorts. A sublethal concentration of nitenpyram showed the significant induction of macropterous adults in both macropterous and brachypterous cohorts, which are important in the control of N. lugens, particularly in the prediction of emigrating populations in newly colonized areas.
The paper wasp Polistes chinensis antennalis is characterized by a high incidence of worker oviposition, even in the presence of their original queen. To analyze the fine-scale genetic structure within colonies, we isolated nine novel microsatellite loci for this species, for which 13 microsatellite loci were reported. No linkage disequilibrium was detected among all 22 loci. The primer pairs described here are useful in analyzing the colony and population genetic structures of this species.
Borage (Borago officinalis L.) is anticipated as a banker plant in strawberry greenhouses to adopt integrated aphid management, because borage has a stimulatory influence on parasitoid wasps attacking aphids. However, before actually using borage, we had to answer the following question: will borage become a hotbed for spider mites? To investigate this, host plant suitability and acceptance by 18 tetranychid mite species were tested on borage and strawberry leaves. The mites were two Panonychus species, two Eotetranychus species and 14 Tetranychus species, including the green and red forms of T. urticae that were counted as separate species. Borage appeared an unsuitable host, because females of all 18 mite species did not lay eggs, females of most species could not survive for more than 5 days, and larvae of all 18 mite species did not develop to nymphal stages on borage. Conversely, strawberry was a suitable host for 13 of the 18 spider mite species: females laid eggs and about 90% of larvae successfully reached adulthood. Thus, these13 species have the potential to become pests of strawberry. Offering female spider mites the choice between interconnected borage and strawberry leaf discs, (1) most females moved from borage to strawberry except for the two Panonychus species and E. asiaticus, and (2) few females moved from strawberry to either borage or strawberry. Consequently, it is highly unlikely that borage will become a hotbed for any of the spider mite species.
The host plants and seasonal occurrence of larvae and pupae of Omphisa anastomosalis were examined on Kume Island through the extensive collection of convolvulaceous host candidates from 2001 to 2010. The frequency of infestation was highest on Ipomoea indica (5.8 insects per 100 m of vine) followed by sweet potato (2.1 insects). Other Ipomoea spp. were infested rarely or not at all (<0.6 insects). On I. indica, infestation frequency was negatively correlated with air temperature, with a large peak from January to February. The pupal ratio among the total population showed two clear peaks in June and October, and was zero or nearly zero in August and from December to April. These results suppose that at least two generations occur within a year, and may suggest a delay of larval development due to low temperatures in winter and the inhibition of pupation by high temperatures or other unknown factor(s) in summer. Further, the infestation frequency of I. indica decreased from April to July, while it increased or did not change in the sweetpotato field during this period.
Two mirid bugs, Stenotus rubrovittatus (Matsumura) and Trigonotylus caelestialium (Kirkaldy) (Heteroptera: Miridae), are sympatric pests that infest rice in many regions of Japan. Three components, hexyl butyrate, (E)-4-oxohex-2-enal and (E)-hex-2-en-1-yl butyrate, in S. rubrovittatus and three other components, hexyl hexanoate, (E)-hex-2-en-1-yl hexanoate and octyl butyrate, in T. caelestialium, were identified as sex attractant pheromone components in these species. The synthetic pheromone lures for S. rubrovittatus do not attract T. caelestialium and vice versa. The attractiveness of the combination of two separate lures for the two mirid bugs within one trap (combination lures) and the attractiveness of a mixed lure, in which all six synthetic-pheromone components of both species were loaded onto a single septum, were compared with that of separate lures for each species in field experiments. Both the combination lures and the mixed lure were as attractive to males of both mirid bugs as the separate lures for each species in fields with gramineous plants. In paddy fields, the mixed lure was also as attractive to males of both species of mirid bugs as the separate lures for each species. These results suggest that the mixed lure and the combination lures could be useful as simultaneous monitoring tools for two sympatric major rice pests using a single trap.
The green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae), is an important insect pest of a canola crop Brassica napus L., in Ardabil, Iran. Host plant resistance is an essential component of the integrated management of M. persicae. In field experiments, the population density of M. persicae was higher on Zarfam and lower on Ebonite, Elite, Okapi, RGS003, and Opera among the 19 canola cultivars during 2008 and 2009. In a free-choice situation, the numbers of attracted aphids per plant was lowest on Opera (1.2). In the life table study, aphids reared on Opera had the shortest adult longevity (8.3 days), lowest numbers of progeny per female (15.4) and the lowest survival rate (62.5%) compared to the other five cultivars. The intrinsic rate of the natural increase (rm) and population growth rate (λ) were lowest on Opera and highest on Zarfam. The generation time (T) was shortest on Opera (11.7 d) and longest on RGS003 (13.1 d), whereas the doubling time (DT) was longest on Opera (3.58 d) and shortest on Zarfam (2.26 d). Our results clearly suggest that Opera was the highest resistant host among the tested cultivars and has the potential to be used in the integrated management of M. persicae.
Two antimicrobial peptide cDNA clones, abaecin (named AcjAba) and defensin (named AcjDef2) were isolated from the Japanese honeybee, Apis cerana japonica, using rapid amplification of cDNA end (RACE) methods. Deduced amino acid sequences of AcjAba and AcjDef2 in A. c. japonica showed high identity with those in the European honeybee, Apis mellifera (97.1%, and 93.0%, respectively). In the mature peptide region, only one amino acid residue (Val) of A. mellifera abaecin was replaced with (Ile) of A. c. japonica abaecin. Quantitative real-time RT-PCR was carried out to investigate the expression profiles of AcjAba and AcjDef2 after inoculation with Paenibacillus larvae, the causative agent of American foulbrood. The transcription of AcjAba and AcjDef2 was not significantly up-regulated in response to exposure to P. larvae. As social insects, honeybees have evolved behavioral traits during their evolutionary history to reduce threats from invading pathogens. The relationship between the defensive behaviors and innate immune systems of Japanese honeybees is discussed.
Aphid parasitoids are often observed to gather around borages (Borago officinalis) used as banker plants in strawberry greenhouse. The attraction of Aphidius colemani as a model aphid parasitoid was observed in response to borage. An aphid generalist parasitoid, A. colemani, shows a preference based on their experience after hatching from mummies of the host-plant volatiles on which their host aphids are reared. A. colemani colonies reared on three host plant-aphid systems (borage/green peach aphid; Japanese radish/green peach aphid; barley/oat bird cherry aphid). A 4-arm olfactometer was used to test the preference of female A. colemani for several plants (infested Japanese radish; infested barley; infested, uninfested and mechanically-damaged borage). Females from each group showed a preference for the plant on which their hosts had been reared and also infested borage regardless of the host plant/aphid system. These results suggested that volatiles from aphid-infested borage attract A. colemani.
The effects of sucrose on the survival and oviposition of predacious insects Stethorus japonicus, Oligota kashmirica benefica, and Scolothrips takahashii, under no-prey conditions, were investigated. In all three predacious insect species, adult females fed on sucrose under no-prey conditions survived significantly longer than those on only water. In addition, in S. japonicus and O. kashmirica benefica, females fed sucrose under no-prey conditions recommenced oviposition significantly earlier and required fewer spider mite (Tetranychus urticae) eggs to recommence after re-feeding on T. urticae eggs than those on only water. On the other hand, in S. takahashii, even females supplied only with water under no-prey conditions recommenced oviposition immediately after re-feeding on T. urticae eggs. Thus, sucrose had no significant effects on the recommencement of oviposition. These results suggested that sucrose was effective to maintain the populations of these predacious insect species even under no-prey conditions.
Larvae of the polyphagous moth, Helicoverpa armigera (Lepidoptera: Noctuidae), were observed feeding intensively on disc florets of Cosmos bipinnatus Cav. (Asteraceae) in fields in western Japan during autumn. We compared larval feeding preference and performance, such as the survival rate, developmental period and pupal weight between disc florets and ray florets of C. bipinnatus in the laboratory. Larvae showed a strong preference for disc florets of C. bipinnatus. Larvae reared on disc florets showed a higher survival rate, and developed more quickly into heavier pupae than larvae reared on ray florets, suggesting that either disc florets provide the required nutrients or that ray florets contain secondary metabolites that negatively affect larval development. Although the mechanisms that elicit larval preference to disc florets remain unknown, our study demonstrated that disc florets alone generated improved growth of H. armigera larvae and might be an important food source in late autumn when larvae are preparing for overwintering.
A single distinct EAG-active compound was found in the extract of virgin females of the sweetpotato vine borer moth, Omphisa anastomosalis (Guenée) (Lepidoptera: Crambidae), and was identified as (10E,14E)-10,14-hexadecadienal (E10E14-16:Ald) at ca. 20 ng/female. Minor related compounds were also identified as hexadecanal (16:Ald), (10E)-10-hexadecenal (E10-16:Ald) and (14E)-14-hexadecenal (E14-16:Ald) at 3.1%, 3.0% and 0.7% amounts relative to the EAG-active component, respectively. In the field, more male moths were captured with traps baited with high amounts of E10E14-16:Ald, which confirmed that this compound is a sex pheromone component. The attractiveness was, however, significantly inferior to that of virgin females. The attractiveness did not increase when minor related compounds were added to the compound. Nevertheless, synthetic E10E14-16:Ald should be useful for monitoring field populations of O. anastomosalis.
A short excursion was made to the western part of Mauritania to investigate increasing populations of the desert locust, Schistocerca gregaria, in October 2009. The size of locust populations observed ranged from <1 to >20 individuals per 25 m2. Adults from low- and high-density populations were similar in morphometric ratios of F/C and E/F (F, hind femur length; C, maximum head width; E, fore wing length) and the ratios were similar to those reported for solitarious forms. However, locusts from high-density populations were mostly yellow, while those from low-density populations were brown or whitish. The former were observed ovipositing in groups. These observations, together with the fact that some of the females from high-density populations had ovarian eggs significantly larger than those found in females from low-density populations, suggested that gregarization might have occurred after adult emergence. Aggregations of nymphs were observed at many sites, and nymphs with black patterns typically observed in transient and gregarious populations were found together with those with solitarious body coloration, i.e. green or brown. A prompt action of locust control by National Locust Control Center was likely to have contributed to prevent further upsurges in the locust populations in the following seasons.