Wavelength-Specific Behavior of the Western Flower Thrips (Frankliniella occidentalis): Evidence for a Blue-Green Chromatic Mechanism

Abstract

<jats:p>The western flower thrips (Frankliniella occidentalis) is a serious pest in horticulture, feeding on leaf tissue and floral resources. Blue and yellow sticky traps are commonly used for monitoring and control in greenhouses. The mechanisms underlying the color preferences are largely unknown. The use of light-emitting diodes (LEDs) is a promising approach to increase the attractiveness of visual traps and to study the color choice behavior in insects. The color preferences of F. occidentalis were systematically investigated in a series of choice experiments with several LEDs from the ultraviolet (UV) and visible spectral range. Blue LEDs were most attractive, followed by green, while only a moderate attractiveness of UV was observed. Blue and green were identified as two separate attractive ranges. When light from blue and green LEDs was mixed, the attractiveness decreased compared to its single components. In conclusion, F. occidentalis exhibits two different wavelength specific behaviors towards blue and green. Compelling indications are provided that these behaviors are controlled by two photoreceptors maximally sensitive in the blue and green range with an inhibitory chromatic interaction between both. Since the known UV sensitive photoreceptor could be confirmed, a trichromatic photoreceptor setup is suggested for F. occidentalis. For advanced plant protection strategies, the results offer several opportunities to optimize monitoring or even develop mass trapping devices.</jats:p>

Haze of glue determines preference of western flower thrips (Frankliniella occidentalis) for yellow or blue traps

“…Although the B:Y ratios changes only slightly between Stikem and D41 on yellow plates (see results: 2%) it has been shown that small changes in composition can lead to major shifts in behaviour 30 . The recently published “blue-green opponency” of western flower thrips 29 is a colour opponency that may play a role even though our thrips strain responds in general better to yellow, which is considered a bright supernatural green to insects. While Stukenberg et al 29 showed that blue and green LEDs were attractive, addition of green LED to blue LED decreased attraction compared to its single components.…”

“…The recently published “blue-green opponency” of western flower thrips 29 is a colour opponency that may play a role even though our thrips strain responds in general better to yellow, which is considered a bright supernatural green to insects. While Stukenberg et al 29 showed that blue and green LEDs were attractive, addition of green LED to blue LED decreased attraction compared to its single components. We measured increased reflection of blue and green on yellow sticky plates with Stikem and decreased reflection of green on blue plates with Stikem compared to D41 (Fig.…”

“…honey bees, bumble bees and other insects, including several herbivores like F. occidentalis 29 where addition of green to blue and vice versa reduces attraction and for whitefly where small amounts of blue reduces attraction to green 30 . This opponency mechanism suggests that the output of several photoreceptors cause an antagonistic neural interaction 29 , 31 – 33 . This may explain differential colour preference found.…”

The role of plant physiology and cultivar of chrysanthemum in the resistance against Western flower thrips

“…The behavior of thrips to green flowers might also be explained by this 'settling behavior' of insects. Western flower thrips might not only respond to the flower colors, but most likely also respond to the vegetative, and thus, corresponding green parts of a plant (Stukenberg et al, 2020).…”

“…It is not clear whether Western flower thrips show a preference for a certain shape or color of flowers. Most studies investigating the influence of color use only colored traps (Otieno et al, 2018;Stukenberg et al, 2020).…”