Statistical Inference for Olfactometer Data

Ricard, Ingrid; Davison, A. C.

doi:10.1111/j.1467-9876.2007.00588.x

Cited by 18 publications

(20 citation statements)

References 15 publications

(14 reference statements)

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“…The entity computing a repetition in the statistical analysis corresponds to the response of a group of nematodes released, which was shown to follow a multinomial distribution (50). Because the data did not conform to simple variance assumptions implied in using the multinomial distribution, we used quasi-likelihood functions to compensate for the overdispersion of nematodes within the olfactometer (51).…”

Section: E␤c Emission Screensmentioning

confidence: 99%

Restoring a maize root signal that attracts insect-killing nematodes to control a major pest

Degenhardt

Hiltpold

Köllner

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

303

265

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Fig. 2.Transformants releasing E␤C suffered less damage than control lines when EPNs were present. (A) Root damage measured on plants that had received neither WCR eggs nor nematodes was minimal, and there was no difference between transformed and nontransformed plants (n ϭ 5, P ϭ 0.87). (B) Root damage on plants that received only WCR eggs, but no nematodes, was substantial. Again, no significant difference was found between the transformed and nontransformed plants (n ϭ 5, P ϭ 0.18). (C) In plots that received WCR eggs and H. megidis, roots from transformed plants (pooled) had significantly less damage than roots from control lines (n ϭ 30, P ϭ 0.007). Approximately one-quarter of the transformed plants were found not to emit E␤C. Removing these plants from the statistical analysis did not significantly affect the results. The letters above the bars indicate significant differences within a graph. Error bars indicate standard errors.

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Section: E␤c Emission Screensmentioning

confidence: 99%

Restoring a maize root signal that attracts insect-killing nematodes to control a major pest

Degenhardt

Hiltpold

Köllner

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

303

265

View full text Add to dashboard Cite

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“…The adequacy of the model was assessed through likelihood ratio statistics and examination of residuals in the software package R (R Foundation of Statistical Software, version 2.4.0; www. r-project.org) Ricard and Davison, 2007). We tested treatment effects (i.e., odor sources) for naive and experienced wasps individually.…”

Section: Bioassaysmentioning

confidence: 99%

A Maize (E)-β-Caryophyllene Synthase Implicated in Indirect Defense Responses against Herbivores Is Not Expressed in Most American Maize Varieties

et al. 2008

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The sesquiterpene (E)-b-caryophyllene is emitted by maize (Zea mays) leaves in response to attack by lepidopteran larvae like Spodoptera littoralis and released from roots after damage by larvae of the coleopteran Diabrotica virgifera virgifera. We identified a maize terpene synthase, Terpene Synthase 23 (TPS23), that produces (E)-b-caryophyllene from farnesyl diphosphate. The expression of TPS23 is controlled at the transcript level and induced independently by D. v. virgifera damage in roots and S. littoralis damage in leaves. We demonstrate that (E)-b-caryophyllene can attract natural enemies of both herbivores: entomopathogenic nematodes below ground and parasitic wasps, after an initial learning experience, above ground. The biochemical properties of TPS23 are similar to those of (E)-b-caryophyllene synthases from dicotyledons but are the result of repeated evolution. The sequence of TPS23 is maintained by positive selection in maize and its closest wild relatives, teosinte (Zea sp) species. The gene encoding TPS23 is active in teosinte species and European maize lines, but decreased transcription in most North American lines resulted in the loss of (E)-b-caryophyllene production. We argue that the (E)-b-caryophyllene defense signal was lost during breeding of the North American lines and that its restoration might help to increase the resistance of these lines against agronomically important pests.

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“…We also took into account the significant overdispersion of the data previously observed (Davison 2003;Tamò et al 2006) by using a stochastic version of the model. Our model also considered the censored nature of our data since not all the wasps made a choice during the 30 min (Ricard and Davison 2007).…”

Section: Statisticsmentioning

confidence: 99%

Effects of Rewarding and Unrewarding Experiences on the Response to Host-induced Plant Odors of the Generalist Parasitoid Cotesia marginiventris (Hymenoptera: Braconidae)

et al. 2010

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Associative learning is known to modify foraging behavior in numerous parasitic wasps. This is in agreement with optimal foraging theory, which predicts that the wasps will adapt their responses to specific cues in accordance with the rewards they receive while perceiving these cues. Indeed, the generalist parasitoid Cotesia marginiventris shows increased attraction to a specific plant odor after perceiving this odor during contact with hosts. This positive associative learning is common among many parasitoids, but little is known about the effects of unrewarding host searching events on the attractiveness of odors. To study this, preferences of female C. marginiventris for herbivore-induced odors of three plant species were tested in a six-arm olfactometer after the wasps perceived one of these odors either i) without contacting any caterpillars, ii) while contacting the host caterpillar Spodoptera littoralis, or iii) while contacting the non-host caterpillar Pieris rapae. The results confirm the effects of positive associative learning, but showed no changes in innate responses to the host-induced odors after "negative" experiences. Hence, a positive association is made during an encounter with hosts, but unsuccessful host-foraging experiences do not necessarily lead to avoidance learning in this generalist parasitoid.

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Statistical Inference for Olfactometer Data

Cited by 18 publications

References 15 publications

Restoring a maize root signal that attracts insect-killing nematodes to control a major pest

Restoring a maize root signal that attracts insect-killing nematodes to control a major pest

A Maize (E)-β-Caryophyllene Synthase Implicated in Indirect Defense Responses against Herbivores Is Not Expressed in Most American Maize Varieties

Effects of Rewarding and Unrewarding Experiences on the Response to Host-induced Plant Odors of the Generalist Parasitoid Cotesia marginiventris (Hymenoptera: Braconidae)

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