Chemically-Mediated Attraction of Three Parasitoid Species to Mealybug-Infested Cassava Leaves

Bertschy, Catherine; Turlings, Ted C. J.; Bellotti, Anthony C.; Dorn, Silvia

doi:10.2307/3495771

Cited by 46 publications

(45 citation statements)

References 19 publications

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“…A choice was considered to have been made if a female entered either arm and then crossed a score line drawn 3 cm from the intersection of the tube. By contrast, a choice was considered to have not been made if the female remained in the common arm of the Y-tube throughout the observation period (Bertschy et al 1997). …”

Section: Methodsmentioning

confidence: 99%

Season-Long Volatile Emissions from Peach and Pear Trees In Situ, Overlapping Profiles, and Olfactory Attraction of an Oligophagous Fruit Moth in the Laboratory

2013

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Insect herbivores that have more than one generation per year and reproduce on different host plants are confronted with substantial seasonal variation in the volatile blends emitted by their hosts. One way to deal with such variation is to respond to a specific set of compounds common to all host plants. The oriental fruit moth Cydia (=Grapholita) molesta is a highly damaging invasive pest. The stone fruit peach (Prunus persica) is its primary host, whereas pome fruits such as pear (Pyrus communis) are considered secondary hosts. In some parts of their geographic range, moth populations switch from stone to pome fruit orchards during the growing season. Here, we tested whether this temporal switch is facilitated by female responses to plant volatiles. We collected volatiles from peach and pear trees in situ and characterized their seasonal dynamics by gas chromatography-mass spectrometry. We also assessed the effects of the natural volatile blends released by the two plant species on female attraction by using Y-tube olfactometry. Finally, we related variations in volatile emissions to female olfactory responses. Our results indicate that the seasonal host switch from peach to pear is facilitated by the changing olfactory effect of the natural volatile blends being emitted. Peach volatiles were only attractive early and mid season, whereas pear volatiles were attractive from mid to late season. Blends from the various attractive stages shared a common set of five aldehydes, which are suggested to play an essential role in female attraction to host plants. Particular attention should be given to these aldehydes when designing candidate attractants for oriental fruit moth females.

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Section: Methodsmentioning

confidence: 99%

Season-Long Volatile Emissions from Peach and Pear Trees In Situ, Overlapping Profiles, and Olfactory Attraction of an Oligophagous Fruit Moth in the Laboratory

2013

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“…We found differences between the three wasp species in their attraction to odours of healthy and mealybug-infested cassava plants, with Aenasius vexans showing the strongest attraction to infested plants and a better ability to distinguish infested from healthy plants (Bertschy et al, 1997). A. vexans appears to be the most specialised of the three parasitoid species and may offer advantages especially when released in pure cassava stands (Dorn, 1996).…”

Section: Introductionmentioning

confidence: 99%

Host stage preference and sex allocation in Aenasius vexans, an encyrtid parasitoid of the cassava mealybug

Bertschy

Turlings

Bellotti

et al. 2000

Entomologia Exp Applicata

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The solitary endoparasitoid Aenasius vexans Kerrich (Hymenoptera: Encyrtidae) is used for augmentative releases against the cassava mealybug, Phenacoccus herreni Cox & Williams (Sternorrhyncha: Pseudococcidae), an important pest on cassava in South America. In light of the need for large numbers of high quality females, experiments were conducted on host stage suitability and sex allocation. In choice and no-choice experiments, individual female wasps were offered second and third instar, as well as adult, hosts. During the first five days after emergence, the wasps showed a steady increase in the number of hosts they successfully parasitised per day, but the respective secondary sex ratio for each instar remained constant. Parasitism was highest for third instar hosts in no-choice tests, while in choice tests parasitism was highest in both third instars and adults. The later the developmental stage of the host at oviposition, the faster the parasitoids developed and emerged, and for each host stage, the development time of males was shorter than for females. The sex ratio of the wasps emerging from hosts that were parasitised as second instars was strongly male-biased, while the apparently preferred later stages yielded significantly more females than males. Female and male A. vexans emerging from hosts parasitised at the third instar were significantly larger than for the other stages. This may explain the preference for the third instar as well as the female-biased sex ratio, as size is usually positively correlated with higher fitness, especially in females. The results suggest that third instar hosts are the most suitable for rearing high numbers of large females.

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“…A female was considered to have made a choice if it entered either arm and crossed a score line drawn 3cm from the intersection of the tube. By contrast, a female was considered not having made a choice if it remained in the common arm of the Y-tube by the end of the observation period (Bertschy et al, 1997). A new pair of septa was used for each individual female tested, and the position of the chambers containing the septa, as well as the position of the two arms of the olfactometer, was systematically changed after testing 3-4 moths in order to avoid positional bias.…”

Section: Behavioral Effects Of Changing Ratios Of Mixture Constituentsmentioning

confidence: 99%

“…Results of behavioral bioassays were analyzed for preference (percentage of adults that made a choice between an odor or the solvent) and responsiveness (proportion of adults that made a choice) (Bertschy et al, 1997). First, chi-square tests were carried out to test the null hypothesis of no preference for a particular odor/mixture.…”

Section: Behavioral Effects Of Changing Ratios Of Mixture Constituentsmentioning

confidence: 99%

Behavioral and neurophysiological responses of an insect to changing ratios of constituents in host plant-derived volatile mixtures

Najar-Rodríguez

Galizia

Stierle

et al. 2010

Journal of Experimental Biology

108

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There was an error published in J. Exp. Biol. 213,[3388][3389][3390][3391][3392][3393][3394][3395][3396][3397] In the text of this paper, the proportions of two compounds in the plant-derived volatile mixture tested, i.e. (E)-2-hexenal and benzaldehyde, were inadvertently exchanged.In the second paragraph of the 'Chemicals and mixtures' section on p. 3389, it is stated that the mixture mimicking bioactive peach shoot volatiles was composed of (Z)-3-hexenyl acetate, (Z)-3-hexen-1-ol, (E)-2-hexenal, benzaldehyde and benzonitrile, at ratios of 69.74:14.62:13.24:2.25:0.15 vol./vol., respectively. The proportions of the compounds in the mixture should read: 69.74:14.62:2.25:13.24:0.15 vol./vol.The authors apologize for this error but confirm that the correct proportions of compounds were used throughout the study and therefore results and conclusions remain unaffected.

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Chemically-Mediated Attraction of Three Parasitoid Species to Mealybug-Infested Cassava Leaves

Cited by 46 publications

References 19 publications

Season-Long Volatile Emissions from Peach and Pear Trees In Situ, Overlapping Profiles, and Olfactory Attraction of an Oligophagous Fruit Moth in the Laboratory

Season-Long Volatile Emissions from Peach and Pear Trees In Situ, Overlapping Profiles, and Olfactory Attraction of an Oligophagous Fruit Moth in the Laboratory

Host stage preference and sex allocation in Aenasius vexans, an encyrtid parasitoid of the cassava mealybug

Behavioral and neurophysiological responses of an insect to changing ratios of constituents in host plant-derived volatile mixtures

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