Tomato variety affects larval survival but not female preference of the generalist moth Trichoplusia ni

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In herbivorous insects, the choice that females make for a suitable host plant is crucial for survival ofits offspring because the neonate larvae are generally not capable of moving great distances. The preference-performance hypothesis states that herbivore females will choose to oviposit on hosts onwhich their offspring will have better performance. In this study, we investigated whether Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae) females are able to discriminate among a weedy race, a landrace, and a commercial cultivar of tomato plants, Solanum lycopersicum L. (Solanaceae), and how their choice affects the offspring performance. Additionally, we identified the volatile compounds and recorded the density of glandular trichomes of the tomato plants. Females did not show a preference for any of the three types of tomato plants. Females oviposited more on the adaxial surface ofleaves of commercial cultivar plants than on (any surface of) leaves of weedy-race plants. The relative abundance of volatiles varied quantitatively among the three types of tomato plants. Commercial cultivar plants released a higher abundance of volatiles than weedy race and landrace plants. Weedy-raceplants had a higher density of glandular trichomes types I and VI than the commercial cultivar. More neonate larvae died if fed on the weedy race and landrace plants than when reared on commercial cultivar plants. Results suggested that the higher mortality of T. ni larvae may be related to a higher density of glandular trichomes on landrace and weedy-race plants than on commercial cultivar plants, although other constitutive and induced defenses may be involved. Our results do not support the preference-performance hypothesis. eng

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