Figure 4.

Examples of circadian clock-controlled interactions between Lepidoptera and plants. (A) The interplay between Manduca sexta and Petunia axillaris circadian clocks. Petunia axillaris flower scent production displays a circadian oscillation with a peak during the night (green clock). When M. sexta and P. axillaris clocks are synchronized (in phase), moths show higher levels of flower visits regarding moths with a circadian clock shifted by 12h compared to the plant clock (out of phase; Fenske et al., 2018). Manduca sexta circadian clocks are indicated in red. Solid and dashed red lines represent the higher and lower number of flower visits, respectively. (B) Trichoplusia ni caterpillars feeding on Arabidopsis thaliana. Arabidopsis thaliana jasmonate-mediated defenses show a circadian oscillation, which peaks during the day (green clock). When T. ni and A. thaliana clocks are synchronized (in phase), caterpillars feed less and, in turn, grow less rapidly compared to caterpillars with an internal clock shifted by 12h compared to the plant clock (out of phase; Goodspeed et al., 2012). Trichoplusia ni circadian clocks are indicated in red. (C) Schematic representations of the daily oscillations in locomotor and feeding activities (blue line) and expression of detoxification genes (red line) in Spodoptera litura caterpillars. In light/dark (LD) conditions, midguts and fat bodies show a 24h rhythmic transcription of detoxification genes with a peak during the daytime, when larvae are inactive, do not feed, and show a digestion activity at the highest levels (Zhang et al., 2021; see text for explanation).