The setup and results.

In all experimental setup illustrations (A-C), the control is presented on the left side, and the various treatments are on the right side. Because the number of egg clusters was low (between 0-5 clusters) we present the Bayesian posterior (see Methods) for the probability to lay a cluster. The posterior distribution is depicted by solid lines. The prior distribution (assuming random choice, with a mean of 0.5 and an STD of 0.1) is represented by dashed lines. To create these plots, eggs laid on the tested side (where the speaker was active, or hydrated plant in the initial experiment) are denoted as 1, while those on the opposite side are marked as 0. These plots thus demonstrate the probability of obtaining a 1 or 0 in each experiment. A) Drought-stressed vs. thriving plant (no playback). B1) Silence vs. drought-stressed plant playback (without a plant). B2) Deaf females in a setup with silence vs. drought-stressed plant playback (without a plant). B3) Silent plant vs. playback of drought-stressed plant. C) A box with male moth’s vs an empty box. Tomato and male clicks are presented (time signal and spectrum) in panels B and C. The horizontal black bar depicts 0.1ms.

Summary of experimental conditions including the number of repetitions, i.e. the number of times that new moths were placed in the arenas and the number of observations (each repetition was observed for approximately three consecutive nights). The total number of egg clusters and the P-values for each experiment are reported. Experiments that were replicated twice appear in two separate lines denoted for combined statistics and by #1 or #2. Experiments and observations that did not produce any egg-laying were excluded from the data set and that is why the number of observations is often the same as the number of repetitions.

Females lay eggs near acoustic playback.

A) The long arena creates an acoustic gradient, allowing us to investigate whether female moths prefer to lay their eggs in specific locations based on the sound environment. Additionally, there is sugar water in the center of the arena, which serves as the adult moth’s food. B) Egg count density (solid line) and cluster density (dashed line). Both figures display a bimodal distribution, with one peak near the speaker (-75) and another near the feeder (0). The points under the graph depict laid clusters, illustrating the relationship between the number of eggs per cluster and their spatial distribution within the arena.

Females’ movement and decision making.

A) The continuous location over time in the arena (top-view) of 4 individual moths during one trial of the drought sounds vs. silent treatment. Time is represented by color in minutes, with a red triangle indicating the playback side and red X’s marking the locations where eggs were laid. Note that we cannot be sure which of the individuals laid the eggs. B) The proportion of time moths spent in the playback side (in bins of 30 minutes) increased over time.

Male Egyptian cotton leaf moths (Spodoptera littoralis) courtship sequences recorded when we placed males in the arena (spectrogram presented).

Electro-antennograms (EAG) were used to record the electrophysiological responses of (n=9) female moth antennae (removed from the body) while exposing them to drying or hydrated tomato plant odors (n=3 in each group). To present the odors, we utilized six tomato plants of identical age, of which three were deprived of irrigation for 72 hours before the experiment. To introduce the odors to the antennae, we fashioned a tube from a leaf of each plant, through which air, carrying the scent, was blown towards the antennae using a pump. The full recording information can be found here (Shvil et al. 2023). The recordings (n=30) are presented in the left panel (Mean±SE) with dry in red and hydrated in blue. We applied a Support Vector Machine (SVM) to examine the separation between the dry and dehydrated plant recordings using 80% (24 signals) of the available data for training and a 5-fold cross validation. This procedure resulted in average accuracy of 90±14% when tested on the remaining test signals (Right panel shows a confusion matrix of the test signals of all 5 cross validations).

On the left, comparison between the egg count results (solid line) in the elongated arena and the pseudo-random distribution (dashed line) (K-S test, D = 0.3, p = 2.2 × 10⁻¹⁶). On The right, comparison between the clusters count results (solid line) pseudo-random distribution (dashed line) (K-S test, D = 0.21, p = 3.9 × 10⁻14).The speaker was placed on location −75, a feeder was placed on the center (location 0) and a resistor was placed on location 75.