@article {57968, title = {Characteristics of tiger moth (Erebidae: Arctiinae) anti-bat sounds can be predicted from tymbal morphology}, journal = {Frontiers in Zoology}, volume = {16}, year = {2019}, month = {Jan-12-2019}, abstract = {

Background: Acoustic signals are used by many animals to transmit information. Variation in the acoustic characteristics of these signals often covaries with morphology and can relay information about an individual\’s fitness, sex, species, and/or other characteristics important for both mating and defense. Tiger moths (Lepidoptera: Erebidae: Arctiinae) use modified cuticular plates called \“tymbal organs\” to produce ultrasonic clicks which can aposematically signal their toxicity, mimic the signals of other species, or, in some cases, disrupt bat echolocation. The morphology of the tymbal organs and the sounds they produce vary greatly between species, but it is unclear how the variation in morphology gives rise to the variation in acoustic characteristics. This is the first study to determine how the morphological features of tymbals can predict the acoustic characteristics of the signals they produce.

Results: We show that the number of striations on the tymbal surface (historically known as \“microtymbals\”) and, to a lesser extent, the ratio of the projected surface area of the tymbal to that of the thorax have a strong, positive correlation with the number of clicks a moth produces per unit time. We also found that some clades have significantly different regression coefficients, and thus the relationship between microtymbals and click rate is also dependent on the shared ancestry of different species.

Conclusions: Our predictive model allows the click rates of moths to be estimated using preserved material (e.g., from museums) in cases where live specimens are unavailable. This has the potential to greatly accelerate our understanding of the distribution of sound production and acoustic anti-bat strategies employed by tiger moths. Such knowledge will generate new insights into the evolutionary history of tiger moth anti-predator defenses on a global scale.

}, keywords = {Anti-predator defense, bioacoustics, Collections-based research, Lepidoptera, Predictive modeling}, doi = {10.1186/s12983-019-0345-6}, url = {https://frontiersinzoology.biomedcentral.com/articles/10.1186/s12983-019-0345-6}, author = {Dowdy, Nicolas J. and Conner, William E.} } @article {48151, title = {Tympanal mechanics and neural responses in the ears of a noctuid moth}, journal = {Naturwissenschaften}, volume = {98}, year = {2011}, month = {Jan-12-2011}, pages = {1057 - 1061}, abstract = {

Ears evolved in many groups of moths to detect the echolocation calls of predatory bats. Although the neurophysiology of bat detection has been intensively studied in moths for decades, the relationship between sound-induced movement of the noctuid tympanic membrane and action potentials in the auditory sensory cells (A1 and A2) has received little attention. Using laser Doppler vibrometry, we measured the velocity and displacement of the tympanum in response to pure tone pulses for moths that were intact or prepared for neural recording. When recording from the auditory nerve, the displacement of the tympanum at the neural threshold remained constant across frequencies, whereas velocity varied with frequency. This suggests that the key biophysical parameter for triggering action potentials in the sensory cells of noctuid moths is tympanum displacement, not velocity. The validity of studies on the neurophysiology of moth hearing rests on the assumption that the dissection and recording procedures do not affect the biomechanics of the ear. There were no consistent differences in tympanal velocity or displacement when moths were intact or prepared for neural recordings for sound levels close to neural threshold, indicating that this and other neurophysiological studies provide good estimates of what intact moths hear at threshold.

}, keywords = {auditory threshold, Lepidoptera, moth auditory biomechanics, neurophysiology}, issn = {0028-1042}, doi = {10.1007/s00114-011-0851-7}, url = {http://link.springer.com/10.1007/s00114-011-0851-7}, author = {ter Hofstede, Hannah M. and Goerlitz, Holger R. and Fernando Montealegre-Zapata and Daniel Robert} }