scholarly journals Tiger moths and the threat of bats: decision-making based on the activity of a single sensory neuron

2009 ◽  
Vol 5 (3) ◽  
pp. 368-371 ◽  
Author(s):  
John M. Ratcliffe ◽  
James H. Fullard ◽  
Benjamin J. Arthur ◽  
Ronald R. Hoy
Keyword(s):  
Sound Production ◽  
Sufficient Information ◽  
Auditory Neuron ◽  
Predator Prey ◽  
Echolocation Calls ◽  
Tiger Moth ◽  
Prey Interaction ◽  
The Face ◽  
Tiger Moths ◽  
And Function

Echolocating bats and eared moths are a model system of predator–prey interaction within an almost exclusively auditory world. Through selective pressures from aerial-hawking bats, noctuoid moths have evolved simple ears that contain one to two auditory neurons and function to detect bat echolocation calls and initiate defensive flight behaviours. Among these moths, some chemically defended and mimetic tiger moths also produce ultrasonic clicks in response to bat echolocation calls; these defensive signals are effective warning signals and may interfere with bats' ability to process echoic information. Here, we demonstrate that the activity of a single auditory neuron (the A1 cell) provides sufficient information for the toxic dogbane tiger moth, Cycnia tenera , to decide when to initiate defensive sound production in the face of bats. Thus, despite previous suggestions to the contrary, these moths' only other auditory neuron, the less sensitive A2 cell, is not necessary for initiating sound production. However, we found a positive linear relationship between combined A1 and A2 activity and the number of clicks the dogbane tiger moth produces.

scholarly journals Anti-bat tiger moth sounds: Form and function

2010 ◽  
Vol 56 (3) ◽  
pp. 358-369 ◽  
Author(s):  
Aaron J. Corcoran ◽  
William E. Conner ◽  
Jesse R. Barber
Keyword(s):  
Duty Cycle ◽  
Sound Production ◽  
Form And Function ◽  
Low Duty Cycle ◽  
Tiger Moth ◽  
Moth Species ◽  
Tiger Moths ◽  
And Function ◽  
North And South America ◽  
North And South

Abstract The night sky is the venue of an ancient acoustic battle between echolocating bats and their insect prey. Many tiger moths (Lepidoptera: Arctiidae) answer the attack calls of bats with a barrage of high frequency clicks. Some moth species use these clicks for acoustic aposematism and mimicry, and others for sonar jamming, however, most of the work on these defensive functions has been done on individual moth species. We here analyze the diversity of structure in tiger moth sounds from 26 species collected at three locations in North and South America. A principal components analysis of the anti-bat tiger moth sounds reveals that they vary markedly along three axes: (1) frequency, (2) duty cycle (sound production per unit time) and frequency modulation, and (3) modulation cycle (clicks produced during flexion and relaxation of the sound producing tymbal) structure. Tiger moth species appear to cluster into two distinct groups: one with low duty cycle and few clicks per modulation cycle that supports an acoustic aposematism function, and a second with high duty cycle and many clicks per modulation cycle that is consistent with a sonar jamming function. This is the first evidence from a community-level analysis to support multiple functions for tiger moth sounds. We also provide evidence supporting an evolutionary history for the development of these strategies. Furthermore, cross-correlation and spectrogram correlation measurements failed to support a “phantom echo” mechanism underlying sonar jamming, and instead point towards echo interference.

Anti-bat flight activity in sound-producing versus silent moths

2008 ◽  
Vol 86 (6) ◽  
pp. 582-587 ◽  
Author(s):  
John M. Ratcliffe ◽  
Amanda R. Soutar ◽  
Katherine E. Muma ◽  
Cassandra Guignion ◽  
James H. Fullard
Keyword(s):  
Flight Time ◽  
Flight Activity ◽  
Echolocation Calls ◽  
Successful Reproduction ◽  
Tiger Moth ◽  
Moth Species ◽  
Presence And Absence ◽  
Tiger Moths ◽  
Palatable Species

The ultrasonic clicks produced by some tiger moths — all of which possess bat-detecting ears — are effective acoustic aposematic or mimetic signals, conferring protection against aerial hawking bats. Clicks are produced in response to bat echolocation calls. Palatable, silent non-tiger-moth species with bat-detecting ears fly away from distant bats and effect erratic flight maneuvers or stop flying in response to the calls of bats nearby. These flight responses are also an effective defense. We tested the hypotheses that sound-producing tiger moths (i) do not exhibit the reduction in flight time typical of silent, palatable moth species when presented with ultrasound simulating bat echolocation calls and (ii) exhibit more flight activity than silent, palatable species both in the presence and absence of ultrasound. We found that sound-producing tiger moths did not significantly reduce flight activity to bat-like sounds and that silent tiger moths and other noctuoid species did. We also found that sound-producing tiger moths flew significantly more than did silent species in both the presence and the absence of ultrasound. The benefits of acoustic aposematism may allow sound producers to spend more time aloft than silent species and thereby improve their chances of successful reproduction.

scholarly journals Survival Sounds in Insects: Diversity, Function, and Evolution

2021 ◽  
Vol 9 ◽  
Author(s):  
Melanie L. Low ◽  
Mairelys Naranjo ◽  
Jayne E. Yack
Keyword(s):  
Sound Production ◽  
Developmental Stages ◽  
Predator Prey ◽  
Evolutionary Origins ◽  
Signal Characteristics ◽  
Insect Defense ◽  
Comparative Phylogenetics ◽  
Forced Air ◽  
Intended Receiver ◽  
Tiger Moths

Insect defense sounds have been reported for centuries. Yet, aside from the well-studied anti-bat sounds of tiger moths, little is understood about the occurrence, function, and evolution of these sounds. We define a defense sound as an acoustic signal (air- or solid-borne vibration) produced in response to attack or threat of attack by a predator or parasitoid and that promotes survival. Defense sounds have been described in 12 insect orders, across different developmental stages, and between sexes. The mechanisms of defensive sound production include stridulation, percussion, tymbalation, tremulation, and forced air. Signal characteristics vary between species, and we discuss how morphology, the intended receiver, and specific functions of the sounds could explain this variation. Sounds can be directed at predators or non-predators, and proposed functions include startle, aposematism, jamming, and alarm, although experimental evidence for these hypotheses remains scant for many insects. The evolutionary origins of defense sounds in insects have not been rigorously investigated using phylogenetic methodology, but in most cases it is hypothesized that they evolved from incidental sounds associated with non-signaling behaviors such as flight or ventilatory movements. Compared to our understanding of visual defenses in insects, sonic defenses are poorly understood. We recommend that future investigations focus on testing hypotheses explaining the functions and evolution of these survival sounds using predator-prey experiments and comparative phylogenetics.

scholarly journals Characteristics of tiger moth (Erebidae: Arctiinae) anti-bat sounds can be predicted from tymbal morphology

2019 ◽  
Vol 16 (1) ◽  
Author(s):  
Nicolas J. Dowdy ◽  
William E. Conner
Keyword(s):  
Evolutionary History ◽  
Sound Production ◽  
Global Scale ◽  
Strong Positive Correlation ◽  
Acoustic Characteristics ◽  
Tiger Moth ◽  
Shared Ancestry ◽  
History Of ◽  
Tiger Moths ◽  
The Relationship

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.

scholarly journals Adaptive auditory risk assessment in the dogbane tiger moth when pursued by bats

2010 ◽  
Vol 278 (1704) ◽  
pp. 364-370 ◽  
Author(s):  
John M. Ratcliffe ◽  
James H. Fullard ◽  
Benjamin J. Arthur ◽  
Ronald R. Hoy
Keyword(s):  
Acoustic Startle ◽  
Acoustic Startle Response ◽  
Cost Benefit ◽  
Stimulus Generalization ◽  
Emission Pattern ◽  
Echolocation Calls ◽  
Risk Detection ◽  
Tiger Moth ◽  
The Face ◽  
Different Levels

Moths and butterflies flying in search of mates risk detection by numerous aerial predators; under the cover of night, the greatest threat will often be from insectivorous bats. During such encounters, the toxic dogbane tiger moth, Cycnia tenera uses the received intensity, duration and emission pattern of the bat's echolocation calls to determine when, and how many, defensive ultrasonic clicks to produce in return. These clicks, which constitute an acoustic startle response, act as warning signals against bats in flight. Using an integrated test of stimulus generalization and dishabituation, here we show that C. tenera is able to discriminate between the echolocation calls characteristic of a bat that has only just detected it versus those of a bat actively in pursuit of it. We also show that C. tenera habituates more profoundly to the former stimulus train (‘early attack’) than to the latter (‘late attack’), even though it was initially equally responsive to both stimuli. Matched sensory and behavioural data indicate that reduced responsiveness reflects habituation and is not merely attributable to sensory adaptation or motor fatigue. In search of mates in the face of bats, C. tenera 's ability to discriminate between attacking bats representing different levels of risk, and to habituate less so to those most dangerous, should function as an adaptive cost–benefit trade-off mechanism in nature.

scholarly journals Predator-prey Interaction between a Ciliated Protozoan Trochilioides recta and Filamentous Bacteria

1989 ◽  
Vol 12 (4) ◽  
pp. 239-245,231 ◽  
Author(s):  
Minako KOGA ◽  
Takeshi SEGUCHI ◽  
Tadahiro MORI ◽  
Yuhei INAMORI ◽  
Ryuichi SUDO
Keyword(s):  
Filamentous Bacteria ◽  
Ciliated Protozoan ◽  
Predator Prey ◽  
Prey Interaction
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