Testing semiochemicals from aphid, plant and conspecific： attraction of Harmonia axyridis

Harmonia axyridis Pallas （Coleoptera： Coccinellidae） is an invasive specie affecting the dynamics and composition of several guilds. Nowadays, no biological control method is available to reduce the populations of this harmful coccinellid. Attractants and semiochemicals seem to be the best alternative but only few studies have tested the impact of semiochemicals on this Asian lady beetle. In this work, through wind- tunnel experiments, semiochemicals from aphids （Z,E-nepetalactone, [E]-β-farnesene, a-pinene and β-pinene）, from coccinellids （[-]-β-earyophyllene） and from the nettle Urtica dioica L. were evaluated as potential attractants. The nettle volatile compounds （[Z]-3- hexenol and [E]-2-hexenal） were extracted using a Clevenger Apparatus and identified by headspace gas chromatography-mass spectroscopy. In the wind-tunnel experiments, the main components of the aphid alarm pheromone as well as a component of the aphid sexual pheromone strongly attracted both sexes of the Asian lady beetle while （-）-β- caryophyllene only attracted few individuals and had no impact on the males. The nettle extract as well as the （Z）-3-hexenol oriented both males and females to the odor source. The （E）-2-hexenal was shown to have no effect on females even if this green leaf volatile attracted males. Because Z,E-nepetalactone was identified as the most efficient attractant in the wind-tunnel experiments, this volatile was also tested in a potato field where H. axyridis has been showed to respond to this semiochemical. This study highlighted that Z,E-nepetalactone orientated the Asian lady beetle H. axyridis under natural condi- tions, indicating that this volatile compound could certainly help for an efficient biological control approach against this invasive specie.

Influence of Garlic Intercropping or Active Emitted Volatiles in Releasers on Aphid and Related Beneficial in Wheat Fields in China

In order to develop biological control of aphids by a ＂push-pull＂ approach, intercropping using repellent emitting plants was developed in different crop and associated plant models. Garlic is one of the potential plant that could be inserted in crops to decrease the pest occurrence in neighboring crop plots. In this study, field works were conducted in wheat fields in Langfang Experimental Station, Hebei Province in China from October 2009 to July 2010 during wheat developmental season. The effect of wheat intercropping with garlic but also the volatiles emission on the incidence of the English grain aphid, Sitobion avenae Fabricius （Homoptera： Aphididae） was assessed. Natural beneficial occurrence and global yields in two winter wheat varieties that were susceptible or resistant to cereal aphid were also determined comparing to control plots without the use of garlic plant intercrop nor semiochemical releaser in the fields. S. avenae was found to be lower in garlic oil blend treatment （GOB）, diallyl disulfide treatment （DD） and wheat-garlic intercropping treatment （WGI） when compared to the control plots for both two varieties （P〈0.01）. Both intercropping and application of volatile chemicals emitted by garlic could improve the population densities of natural enemies of cereal aphid, including ladybeetles and mummified aphids. Ladybeetle population density in WGI, GOB and mummified aphids densities in WGI, DD were significantly higher than those in control fields for both two varieties （P〈0.05）. There were significant interactions between cultivars and treatments to the population densities of S. avenae. The 1 000-grain weight and yield of wheat were also increased compared to the control. Due to their potential alternatives as a biological control agent against cereal aphid, garlic intercropping and related emitted volatiles are expected to contribute to the further improvement of integrated pest management systems and to potentially reduce the amount of traditional synthetic pesticides applied in wheat fields.

The Integrated Pest Management, Biotechnology andthe Challenges That Biotechnology Is Likely to Face

The paper discusses the advantages of biotechnology, the challenges it will face, the global food demands as worldpopulation grows and the need for the balance between biotechnology and traditional technology to enhance food production.Genetically modified crops have a number of advantages than conventional crops, so have caused a good number of farmers acrossthe world to embrace biotechnology. The projected rise in the world population by 2050 to be at 9.7 billion and by 2100 atapproximately 11 billion has led to adoption of biotechnology in an attempt to meet the global food requirements. The foreseeablechallenges will be the sustainahility of genetically modified crops against insects＇ resistance and the safety of these geneticallymodified crops. We are at a stage in human development, where we need a balanced approach to solving this world challenge ofhunger and malnourishment, a safe sustainable approach using the best of the conventional crop technology and the best ofbiotechnology to achieve sustainable intensification of crop productivity on the 1.5 billion ha of cropland globally.

Physiological Reasons for Attractiveness of Female Breast

In this article the possibilities of functioning of breast as an attractant to male and leading to a long lasting relation in many cases are discussed. The three mechanisms discussed are on the basis of visual stimuli, pheromone and other chemicals like sebum.

Trichoderma metabolites trigger aggregation behavior in Formosan subterranean termites (Coptotermes formosanus)

Our previous studies have shown that some Trichoderma fungi trigger aggregation behavior in Formosan subterranean termites,Coptotermes formosanus Shiraki.However,the mechanisms underlying the induction of termite aggregation by Trichoderma fungi remain unclear.Here,we found that the aqueous or acetone extract of Trichoderma asperellum Samuels,Lieckfeldt&Nirenberg and Trichoderma virens Pers.ex Fries isolated from the gut or cuticle of C.formosanus elicited significant termite aggregation in 2-choice tests.We then screened 9 Trichoderma metabolites(3-acetoxy-2-butanone,phenol,3-ethoxypropionic acid,ethyl 2,4-dioxovalerate,diglycolic acid,d-valine,styrene,3-aminopyridine,and hexyl acetoacetate)that triggered termite aggregation.Among them,phenol(1000μg/mL),3-ethoxypropionic acid(10μg/mL),ethyl 2,4-dioxovalerate(1000μg/mL),and diglycolic acid(1000μg/mL)showed the strongest activities,triggering termite aggregation throughout the 24-h period.As T.asperellum and T.virens produce different metabolites that trigger aggregation behavior in termites,the mechanisms underlying the interaction between subterranean termites and Trichoderma fungi likely vary.Future studies are needed to test whether these chemicals can attract termites and increase bait consumption.

Chemical and behavioral analysis of the cuticular hydrocarbons from Asian citrus psyllid, Diaphorina citri

Huanglongbing （HLB） is the most destructive disease of citrus worldwide. The Asian citrus psyllid, Diaphorina citri Kuwayama （Hemiptera： Psyllidae）, is the vector of the phloem-inhabiting bacterium, Candidatus Liberibacter asiaticus, which is presumed to cause HLB in Florida citrus. Laboratory and field studies were conducted to examine the behavioral responses of male and female D. cirri to their cuticular extracts. In olfactometer assays, more male D. citri were attracted to one, five, or 10 female cuticular extract equivalent units than blank controls. The results were confirmed in field studies in which clear or yellow traps baited with 10 female cuticular extract equivalent units attracted proportionately more males than clear traps baited with male cuticular extract or unbaited traps. Analyses of cuticular constituents of male and female D. citri revealed differences between the sexes in chemical composition of their cuticular extracts. Laboratory bioassays with synthetic chemicals identified from cuticular extracts indicated that dodecanoic acid attracted more males than clean air. Traps baited with dodecanoic acid did not increase total catch olD. citri as compared with blank traps at the dosages tested; however, the sex ratio ofpsyllid catch was male biased on traps baited with the highest lure loading dosage tested （10.0 mg）.

Honeydew volatile emission acts as a kairomonal message for the Asian lady beetle Harmonia axyridis （Coleoptera： Coccinellidae）

The Asian lady beetle Harmonia axyridis Pallas is considered as an invasive species in most territories where it has been introduced. Because aphid honeydew acts as an attraetant for many aphid predators and parasitoids, the objectives of this work were to collect and identify the volatile compounds released from the aphid excretory product to evaluate how these semiochemicals could affect the H. axyridis foraging behavior. Twelve volatile chemicals were identified from the Megoura viciae Buckton honeydew including four alcohols, three ketones, three aldehydes, a pyrazine and a monoterpene. The volatiles 3-methyl-l-butanol and 3-methyl-butanal were highlighted as the two most abundant semiochemicals released from the M. viciae honeydew. Vieia faba L. plants treated with crude honeydew attracted more than 80% of the tested individuals with 40% of attracted beetles located on the plant. Four volatile compounds （3-hydroxy-2-butanone, 3-methyl-butanal, 3-methyl-1-butanol and limonene） were also highlighted to attract more than 75% of the coccinellids toward the odor source and to locate about 35% of them on the plants. Limonene was the most efficient attractant since 89% of the H. axyridis responded to this odor. The use of the identified semiochemicals as well as the composition of an artificial honeydew could certainly be helpful to control the dispersal of the Asian lady beetle H. axyridis.

Is aggregated oviposition by the blow flies Lucilia sericata and Phormia regina （Diptera： Calliphoridae） really pheromone-mediated？

When female blow flies Lucilia sericata and Phormia regina （Diptera： Cal- liphoridae） oviposit in aggregations on carrion, even-aged larval offspring reportedly de- velop faster, and fewer are parasitized or preyed upon. The benefits of aggregated ovipo- sition equally affect con- and heterospecific larvae sharing a resource. The benefits imply that female blow flies engage in coordinated, pheromone-mediated oviposition behavior. Yet, repeated attempts to identify oviposition pheromones have failed invoking doubt that they exist. Simply by regurgitating and feeding on carrion, flies may produce attractive semiochemicals. If flies were to aggregate in response to feeding flies rather than oviposit- ing flies, then the semiochemical cue（s） may be associated with the salivary gland. Working with L. sericata and P.. regina and using liver as a surrogate oviposition medium, we test the hypotheses, and present data in their support, that （i） gravid or nongravid females ovipositing and/or feeding on liver enhance its attractiveness to gravid and nongravid fe- males; （ii） females respond to semiochemicals from feeding heterospecific females; （iii） females respond equally well to semiochemicals from feeding con- and heterospecific females; （iv） macerated head tissues of females applied to liver enhance its attractiveness; and （v） females in direct contact with and feeding on liver, but not when next to yet physically separated from liver, enhance attraction of flies. We conclude that oviposition site-seeking females do not respond to an oviposition pheromone. Instead, they appear to coopt semiochemicals associated with feeding flies as resource indicators, taking chances that resources are suitable for oviposition, and that ovipositing flies are present.

Language of plants: Where is the word?

Plants emit biogenic volatile organic compounds（BVOCs） causing transcriptomic, metabolomic and behavioral responses in receiver organisms. Volatiles involved in such responses are often called ＂plant language＂. Arthropods having sensitive chemoreceptors can recognize language released by plants. Insect herbivores, pollinators and natural enemies respond to composition of volatiles from plants with specialized receptors responding to different types of compounds. In contrast, the mechanism of how plants＂hear＂ volatiles has remained obscured. In a plant-plant communication, several individually emitted compounds are known to prime defense response in receiver plants with a specific manner according to the chemical structure of each volatile compound. Further, composition and ratio of volatile compounds in the plant-released plume is important in plantinsect and plant-plant interactions mediated by plant volatiles. Studies on volatile-mediated plant-plant signaling indicate that the signaling distances are rather short, usually not longer than one meter. Volatile communication from plants to insects such as pollinators could be across distances of hundreds of meters. As many of the herbivore induced VOCs have rather short atmospheric life times, we suggest that in long-distant communications with plant volatiles,reaction products in the original emitted compounds may have additional information value of the distance to emission source together with the original plant-emitted compounds.

Kairomonal effect of sex pheromone components of two lepidopteran olive pests on Trichogramma wasps

Egg parasitoids are known to use a wide range of chemicals, emitted by plants, host eggs or adults, for host selection. The effect of the sex pheromone components of the lepidopteran olive pests Prays oleae （Lepidoptera： Yponomeutidae） and Palpita unionalis （Lepidoptera： Pyralidae） was studied under laboratory conditions, on the foraging behaviour of the egg parasitoid Trichogramma oleae （Hymenoptera： Trichogrammatidae）. The re- sponse of T. oleae wasps to （Z）-7-tetradecenal and （E）-1 l-hexadecenal, major sex phero- mone components ofP. oleae and P. unionalis respectively, depended on the dose of the pheromone used in a Y-tube olfactometer bioassay. （E）-11-hexadecenal elicited maximum attraction （70%） at a dose of 1 pg, while a dose of 100 pg （Z）-7-tetradecenal attracted 80% of the tested wasps. （E）-11-hexadecenyl acetate, the second sex pheromone component of P. unionalis, and the binary blend of（E）-i 1-hexadecenyl acetate： （E）-11-hexadecenal （7：3） were not attractive at these doses. The results of this research are discussed in view that they may be considered as alternatives in the biological control of these pests.

Behavioral evidence for contextual olfactory-mediated avoidance of the ubiquitous phytopathogen Botrytis cinerea by Drosophila suzukii

Herbivorous insects may benefit from avoiding the smell produced by phytopathogens infecting plant host tissue if the infected tissue reduces insect fitness.However,in many cases the same species of phytopathogen can also infect host plant tissues that do not directly affect herbivore fitness.Thus,insects may benefit from differentiating between pathogen odors emanating from food and nonfood tissues.This is based on the hypothesis that unecessarily staying attentive to pathogen odor from nonfood tissue may incur opportunity costs associated with not responding to other important survival functions.In this study adults of Drosophila suzukii Matsumura,an invasive larval frugivore,showed reduced attraction to the odor of raspberry fruit,a food tissue,when infected with Botrytis cinerea Pers.,a ubiquitous phytopathogen,in favor of odors of uninfected raspberry fruit.Moreover,D.suzukii oviposited fewer eggs on infected raspberry fruit relative to uninfected raspberry fruit.Larval survival and adult size after eclosion were significantly reduced when reared on B.cinerea-infected raspberry relative to uninfected fruit.Interestingly,when the behavioral choice experiment was repeated using Botrytis-infected vsuninfected strawberry leaves,a nonfood tissue,in combination with fresh raspberry fruit,odor from B.cinerea-infected leaves did not reduce D.suzukii attraction to raspberries rel-ative to raspberries with uninfected leaves.These behavioral results illustrate the important role context can play in odor-mediated interactions between insects,plants and microbes.We discuss implications of our findings for developing a repellent that can be useful for the management of D.suzukii.

Abundance of volatile organic compounds in white ash phloem and emerald ash borer larval frass does not attract Tetrastichus planipennisi in a Y-tube olfactometer

Many natural enemies employ plant- and/or herbivore-derived signals for host/prey location. The larval parasitoid Tetrastichus planipennisi Yang （Hymenoptera： Eulophidae） is 1 of 3 biocontrol agents currently being released in an effort to control the emerald ash borer （EAB）, Agrilus planipennis Fairmaire （Coloeptera： Burprestidae） in North America. To enhance its efficiency, allelochemicals that attract it need to be assessed. In this study, ash phloem volatile organic compounds （VOCs） of black, green, and white ash, and EAB larval frass were compared. Foraging behavior of T. planipennisi females in response to VOCs of white ash or frass from EAB larvae feeding on white ash phloem was tested using a Y-tube olfactometer. Results indicated that the 3 ash species had similar VOC profiles. EAB larval frass generally contained greater levels of VOCs than phloem. Factor analysis indicated that the 11 VOCs could be broadly divided into 2 groups, with c^-bisabolol, fl-caryophyllene, （E）-2-hexenal, （Z）-3-hexenal, limonene, methyl benzoate, methyl indole-3-acetic acid, methyl jasmonate, methyl salicylate as the first group and the rest （i.e., methyl linoleate and methyl linolenate） as a second. Abundance of VOCs in white ash phloem tissue and frass, nevertheless, did not attract T. planipennisi females. The concealed feeding of EAB larvae might explain the selection for detectable and reliable virbrational signals, instead of undetectable and relatively unreliable VOC cues from phloem and frass, in short-range foraging by T. planipennisi. Alternatively, it is possible that T. planipennisi is not amenable to the Y-tube olfactometer assay employed.