How Do Vibrational Signals Differ When Red Milkweed Beetles Interact during Contests and Copulation?
Mentor 1
Rafael Rodriguez Sevilla
Start Date
28-4-2023 12:00 AM
Description
Vibrational communication is ecologically important to insects. Substrate-borne vibrations are commonly used by herbivorous insects to communicate species-specific information during contests and copulations. The herbivorous red milkweed beetle (Coleoptera: Cerambycidae) lives, breeds, and fights on the common milkweed plant. In this polygamous beetle species, males engage in male-male competition to access and, ultimately, copulate with females. They communicate by producing vibrational signals composed of both low-frequency hums and high-frequency pulses in both mating and fighting contexts. Here, we hypothesize that these vibrational signals communicate different information based on the behavioral contexts. We placed male beetles into three behavioral scenarios: male-male (contests), male-female (copulations), or male-female-male (copulations then contests). We captured behaviors using cameras set up around the milkweed plant and a laser vibrometer focused on the plant to detect the vibrational signals that the beetles produced. We compared the vibrational duration, relative intensity, pulse rate, and other frequency parameters produced by males in both contests and copulatory situations. We found that the duration of the signals, relative intensity, and the pulse rate differed between the two contexts while other frequency parameters did not differ. Our data supports our hypothesis and indicates that these signals are used to communicate context-specific information with conspecifics. These results suggest that males use vibrations to communicate aggression and dominance in fighting whereas, during mating, the males communicate male readiness-to-mate to females which may induce and maintain copulatory behaviors.
How Do Vibrational Signals Differ When Red Milkweed Beetles Interact during Contests and Copulation?
Vibrational communication is ecologically important to insects. Substrate-borne vibrations are commonly used by herbivorous insects to communicate species-specific information during contests and copulations. The herbivorous red milkweed beetle (Coleoptera: Cerambycidae) lives, breeds, and fights on the common milkweed plant. In this polygamous beetle species, males engage in male-male competition to access and, ultimately, copulate with females. They communicate by producing vibrational signals composed of both low-frequency hums and high-frequency pulses in both mating and fighting contexts. Here, we hypothesize that these vibrational signals communicate different information based on the behavioral contexts. We placed male beetles into three behavioral scenarios: male-male (contests), male-female (copulations), or male-female-male (copulations then contests). We captured behaviors using cameras set up around the milkweed plant and a laser vibrometer focused on the plant to detect the vibrational signals that the beetles produced. We compared the vibrational duration, relative intensity, pulse rate, and other frequency parameters produced by males in both contests and copulatory situations. We found that the duration of the signals, relative intensity, and the pulse rate differed between the two contexts while other frequency parameters did not differ. Our data supports our hypothesis and indicates that these signals are used to communicate context-specific information with conspecifics. These results suggest that males use vibrations to communicate aggression and dominance in fighting whereas, during mating, the males communicate male readiness-to-mate to females which may induce and maintain copulatory behaviors.
