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Classical olfactory conditioning in the oriental fruit fly, Bactrocera dorsalis.

Liu JL, Chen XY, Zeng XN - PLoS ONE (2015)

Bottom Line: Control effect may be influenced by learning, which could modify the olfactory response of the fly to this attractant.The acquisition of the proboscis extension reflex was used as the criterion for conditioning.A high conditioned response level was found in oriental fruit flies when an odor was presented in paired association with a sucrose reward but not when the odor and sucrose were presented unpaired.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Natural Pesticide and Chemical Biology of the Ministry of Education, College of Natural Resources and Environment, South China Agricultural University, Guangzhou, Guangdong, China.

ABSTRACT
The oriental fruit fly, Bactrocera dorsalis, is a serious pest of fruits and vegetables. Methyl eugenol (ME), a male attractant, is used to against this fly by mass trapping. Control effect may be influenced by learning, which could modify the olfactory response of the fly to this attractant. To collect the behavioral evidence, studies on the capability of this fly for olfactory learning are necessary. We investigated olfactory learning in male flies with a classical olfactory conditioning procedure using restrained individuals under laboratory conditions. The acquisition of the proboscis extension reflex was used as the criterion for conditioning. A high conditioned response level was found in oriental fruit flies when an odor was presented in paired association with a sucrose reward but not when the odor and sucrose were presented unpaired. We also found that the conditioning performance was influenced by the odor concentration, intertrial interval, and starvation time. A slight sensitization elicited by imbibing sucrose was observed. These results indicate that oriental fruit flies have a high capacity to form an olfactory memory as a result of classical conditioning.

No MeSH data available.


Related in: MedlinePlus

Effects of presenting the CS or US alone.Percentages of B. dorsalis that extended their proboscis in response to the CS (% response) in a CS-only group (n = 59) in 6 trials and in five US-only groups presented with the US alone on one (n = 63), two (n = 57), three (n = 64), four (n = 60), and five (n = 60) occasions. In the US-only training, proboscis extension responses of five groups were tested 10 min after fed sucrose solution 1–5 times. The trial number was feeding time plus one, such example: the proportion of proboscis extension in the group fed sucrose solution one time is shown at trial 2. The percentage of flies responding to CS before training was the spontaneous response level (SP). Differences between before and after feeding sucrose are denoted with asterisks (*p < 0.05; NS p > 0.05)
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pone.0122155.g003: Effects of presenting the CS or US alone.Percentages of B. dorsalis that extended their proboscis in response to the CS (% response) in a CS-only group (n = 59) in 6 trials and in five US-only groups presented with the US alone on one (n = 63), two (n = 57), three (n = 64), four (n = 60), and five (n = 60) occasions. In the US-only training, proboscis extension responses of five groups were tested 10 min after fed sucrose solution 1–5 times. The trial number was feeding time plus one, such example: the proportion of proboscis extension in the group fed sucrose solution one time is shown at trial 2. The percentage of flies responding to CS before training was the spontaneous response level (SP). Differences between before and after feeding sucrose are denoted with asterisks (*p < 0.05; NS p > 0.05)

Mentions: Because the olfactory and gustatory stimuli used as the CS and US, respectively, might modify the proboscis extension response to the CS by habituation, sensitization or other non-associative learning processes, the training was conducted by presenting only the CS or US alone to the flies. In the CS-only group, the frequency of proboscis extension was 12.1% in trial 1 and this value also refers to a spontaneous response level. After repeating the presentation of peppermint (5x), the percentage of proboscis extension did not increase during training, remaining at 7–12% in trials 1 to 6 (Q = 1.33, df = 4, p = 0.86; Fig 3). In US-only groups, response frequency was compared before and after fed with sucrose solution. The percentage of proboscis extension before feeding was the spontaneous response to CS. The flies responded significantly more often to peppermint compared with the spontaneous response level after conducting three US-only trials (χ2 = 10.0, df = 1, α′ = 0.005, p < 0.05), and no differences were found in the other groups conducted trials number one, two, four, and five (χ2 = 6.98, 4.36, 6.7, and 4.69, respectively, all df = 1, α′ = 0.005, p > 0.05)


Classical olfactory conditioning in the oriental fruit fly, Bactrocera dorsalis.

Liu JL, Chen XY, Zeng XN - PLoS ONE (2015)

Effects of presenting the CS or US alone.Percentages of B. dorsalis that extended their proboscis in response to the CS (% response) in a CS-only group (n = 59) in 6 trials and in five US-only groups presented with the US alone on one (n = 63), two (n = 57), three (n = 64), four (n = 60), and five (n = 60) occasions. In the US-only training, proboscis extension responses of five groups were tested 10 min after fed sucrose solution 1–5 times. The trial number was feeding time plus one, such example: the proportion of proboscis extension in the group fed sucrose solution one time is shown at trial 2. The percentage of flies responding to CS before training was the spontaneous response level (SP). Differences between before and after feeding sucrose are denoted with asterisks (*p < 0.05; NS p > 0.05)
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4383412&req=5

pone.0122155.g003: Effects of presenting the CS or US alone.Percentages of B. dorsalis that extended their proboscis in response to the CS (% response) in a CS-only group (n = 59) in 6 trials and in five US-only groups presented with the US alone on one (n = 63), two (n = 57), three (n = 64), four (n = 60), and five (n = 60) occasions. In the US-only training, proboscis extension responses of five groups were tested 10 min after fed sucrose solution 1–5 times. The trial number was feeding time plus one, such example: the proportion of proboscis extension in the group fed sucrose solution one time is shown at trial 2. The percentage of flies responding to CS before training was the spontaneous response level (SP). Differences between before and after feeding sucrose are denoted with asterisks (*p < 0.05; NS p > 0.05)
Mentions: Because the olfactory and gustatory stimuli used as the CS and US, respectively, might modify the proboscis extension response to the CS by habituation, sensitization or other non-associative learning processes, the training was conducted by presenting only the CS or US alone to the flies. In the CS-only group, the frequency of proboscis extension was 12.1% in trial 1 and this value also refers to a spontaneous response level. After repeating the presentation of peppermint (5x), the percentage of proboscis extension did not increase during training, remaining at 7–12% in trials 1 to 6 (Q = 1.33, df = 4, p = 0.86; Fig 3). In US-only groups, response frequency was compared before and after fed with sucrose solution. The percentage of proboscis extension before feeding was the spontaneous response to CS. The flies responded significantly more often to peppermint compared with the spontaneous response level after conducting three US-only trials (χ2 = 10.0, df = 1, α′ = 0.005, p < 0.05), and no differences were found in the other groups conducted trials number one, two, four, and five (χ2 = 6.98, 4.36, 6.7, and 4.69, respectively, all df = 1, α′ = 0.005, p > 0.05)

Bottom Line: Control effect may be influenced by learning, which could modify the olfactory response of the fly to this attractant.The acquisition of the proboscis extension reflex was used as the criterion for conditioning.A high conditioned response level was found in oriental fruit flies when an odor was presented in paired association with a sucrose reward but not when the odor and sucrose were presented unpaired.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Natural Pesticide and Chemical Biology of the Ministry of Education, College of Natural Resources and Environment, South China Agricultural University, Guangzhou, Guangdong, China.

ABSTRACT
The oriental fruit fly, Bactrocera dorsalis, is a serious pest of fruits and vegetables. Methyl eugenol (ME), a male attractant, is used to against this fly by mass trapping. Control effect may be influenced by learning, which could modify the olfactory response of the fly to this attractant. To collect the behavioral evidence, studies on the capability of this fly for olfactory learning are necessary. We investigated olfactory learning in male flies with a classical olfactory conditioning procedure using restrained individuals under laboratory conditions. The acquisition of the proboscis extension reflex was used as the criterion for conditioning. A high conditioned response level was found in oriental fruit flies when an odor was presented in paired association with a sucrose reward but not when the odor and sucrose were presented unpaired. We also found that the conditioning performance was influenced by the odor concentration, intertrial interval, and starvation time. A slight sensitization elicited by imbibing sucrose was observed. These results indicate that oriental fruit flies have a high capacity to form an olfactory memory as a result of classical conditioning.

No MeSH data available.


Related in: MedlinePlus