Hygroreception in Olfactometer Studies

MARTÍNEZ, ANDRÉS SANTIAGO; HARDIE, JIM

PHYSIOLOGICAL ENTOMOLOGY (PRINT)

Año: 2009 vol. 34 p. 211 - 216

0307-6962

In olfactometric studies, a technique used to measure insect behaviouralbias towards airborne chemicals, many of the factors that could affect the bioassayoutcome other than the volatiles themselves are carefully controlled (e.g. lightingconditions, temperature, spatial position, physiological state of the insects, time ofday when the bioassay is performed) but one factor, namely humidity, is overlookedfrequently when studying responses to plant volatiles. Many insect species respondpositively and negatively to changes in humidity and, during bioassays, differencesarising from odour choices with different water vapour release rates might haveconfounding effects versus the original intent of the behavioural study. The presentstudy aims to assess the effect of different substrates on the water vapour content ofair in an olfactometer-like set-up. The results show that airflow humidity is affectedby the odour source used in the olfactometer air flow. In addition, the response ofthe aphid parasitoid Aphidius colemani Viereck (Hymenoptera: Aphidiidae) is studiedtowards different humidities and plant material in an olfactometer. The presentstudy suggests that humidity needs to be controlled in olfactometric studies.