Orientation of Hippodamia variegata (Coleoptera: Coccinellidae) to healthy and Beauveria bassiana-infected Aphis fabae (Hemiptera: Aphididae) in an olfactometer system

Authors: MARJAN SEIEDY, SAMIRA HEYDARI, MAHDI TORK

Abstract: Determination of attractive and avoidance behavior of Hippodamia variegata (Goeze) (Coleoptera: Coccinellidae) is very important in the concomitant use of Beauveria bassiana for control of Aphis fabae (Hemiptera: Aphididae). We investigated the olfactory response of the predatory insect H. variegata when receiving odors pertaining to Aphis fabae infected by B. bassiana EUT116 at 0-, 24-, 48-, and 72-h intervals in a Y-tube olfactometer set-up. Behavioral assays were conducted to assess the ability of adult H. variegata to avoid A. fabae infected with B. bassiana conidia on plants. In these experiments, H. variegata exhibited significant attraction towards the control when the predator alternative option was B. bassiana with 24-h intervals (P = 0.04) and 48- and 72-h intervals (P < 0.01 in both cases). We suggest that under laboratory conditions H. variegata could detect and avoid B. bassiana conidia; thus, B. bassiana would be a negligible threat to this predator.

Keywords: Olfactory responses, Beauveria bassiana, Aphis fabae, Aphididae, Hippodamia variegata, Coccinellidae

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