Anti-bat tiger moth sounds: Form and function

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.

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

Biology Letters ◽

10.1098/rsbl.2009.0079 ◽

2009 ◽

Vol 5 (3) ◽

pp. 368-371 ◽

Cited By ~ 17

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.

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

Canadian Journal of Zoology ◽

10.1139/z08-024 ◽

2008 ◽

Vol 86 (6) ◽

pp. 582-587 ◽

Cited By ~ 5

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.

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A REVIEW OF TIGER MOTHS (LEPIDOPTERA: EREBIDAE: ARCTIINAE: ARCTIINI) FROM FLORES ISLAND, LESSER SUNDA ARCHIPELAGO, WITH DESCRIPTION OF A NEW SPECIES AND NEW SUBSPECIES

Ecologica Montenegrina ◽

10.37828/em.2018.16.1 ◽

2018 ◽

Vol 16 ◽

pp. 1-15 ◽

Cited By ~ 1

Author(s):

Ivan N. Bolotov ◽

Alexander V. Kondakov ◽

Vitaly M. Spitsyn

Keyword(s):

New Species ◽

Current Knowledge ◽

The Body ◽

Moderate Level ◽

New Subspecies ◽

Tiger Moth ◽

Local Endemic ◽

Moth Species ◽

Tiger Moths ◽

A New Species

The Wallacean Region is considered a unique evolutionary hotspot, but the current knowledge of lepidopteran faunas on certain islands is very far from being complete. Here we present a preliminary checklist of the Arctiini fauna of the Flores Island based on available collection materials and a review of the body of literature. In total, for the island fauna we list 22 tiger moth species, with eight newly recorded species. Among novel records, local endemic Spilarctia mikeli Bolotov, Kondakov & Spitsyn sp. nov. and Aloa cardinalis danau Bolotov, Kondakov & Spitsyn ssp. nov. were discovered. Additionally, several taxa with broad ranges such as Amerila astreus, Creatonotos gangis, Euchromia horsfieldi, Lemyra maculifascia, Nyctemera distincta and Utetheisa pulchelloides were new for the island fauna. In general, 15 taxa are prospective endemic Wallacean elements, among which seven taxa are unknown outside the Flores Island: Orhantarctia cymbalophoroides, Lemyra everetti, L. floresina, Aethalida owadai floresiensis, Nyctemera scalarium regalis, Spilarctia mikeli sp. nov. and Aloa cardinalis danau ssp. nov. Our findings reveal that the tiger moth fauna of the Flores Island has rather moderate level of endemism, with only 32% of putative endemic taxa.

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

Frontiers in Zoology ◽

10.1186/s12983-019-0345-6 ◽

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.

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Extreme duty cycles in the acoustic signals of tiger moths: Sexual and natural selection operating in parallel

Integrative Organismal Biology ◽

10.1093/iob/obaa046 ◽

2021 ◽

Author(s):

Yohami Fernández ◽

Nicolas J Dowdy ◽

William E Conner

Keyword(s):

Natural Selection ◽

Mate Choice ◽

Acoustic Communication ◽

Duty Cycle ◽

Sound Production ◽

Acoustic Signals ◽

High Duty Cycle ◽

Duty Cycles ◽

Tiger Moths

Abstract Sound production in tiger moths (Erebidae: Arctiinae) plays a role in natural selection. Some species use tymbal sounds as jamming signals avoiding bat predation. High duty cycle signals have the greatest efficacy in this regard. Tiger moth sounds can also be used for intraspecific communication. Little is known about the role of sound in the mating behavior of jamming species or the signal preferences underlying mate choice. We recorded sound production during the courtship of two high duty cycle arctiines, Bertholdia trigona and Carales arizonensis. We characterized variation in their acoustic signals, measured female preference for male signals that vary in duty cycle, and performed female choice experiments to determine the effect of male duty cycle on the acceptance of male mates. Although both species produced sound during courtship, the role of acoustic communication appears different between the species. Bertholdia trigona was acoustically active in all intraspecific interactions. Females preferred and ultimately mated with males that produced higher duty cycles. Muted males were never chosen. In C. arizonensis however, sound emissions were limited during courtship and in some successful matings no sound was detected. Muted and clicking males were equally successful in female mate-choice experiments, indicating that acoustic communication is not essential for mating in C. arizonensis. Our results suggest that in B. trigona natural and sexual selection may work in parallel, to favor higher duty cycle clicking.

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Scanning tunneling microscopy (STM) of DNA and RNA

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100152148 ◽

1989 ◽

Vol 47 ◽

pp. 34-35

Author(s):

Patricia G. Arscott ◽

Gil Lee ◽

Victor A. Bloomfield ◽

D. Fennell Evans

Keyword(s):

Molecular Structures ◽

Inorganic Materials ◽

Resolving Power ◽

Scanning Tunneling ◽

Tunneling Microscopy ◽

Form And Function ◽

Dna And Rna ◽

Calf Thymus ◽

And Function ◽

The Relationship

STM is one of the most promising techniques available for visualizing the fine details of biomolecular structure. It has been used to map the surface topography of inorganic materials in atomic dimensions, and thus has the resolving power not only to determine the conformation of small molecules but to distinguish site-specific features within a molecule. That level of detail is of critical importance in understanding the relationship between form and function in biological systems. The size, shape, and accessibility of molecular structures can be determined much more accurately by STM than by electron microscopy since no staining, shadowing or labeling with heavy metals is required, and there is no exposure to damaging radiation by electrons. Crystallography and most other physical techniques do not give information about individual molecules.We have obtained striking images of DNA and RNA, using calf thymus DNA and two synthetic polynucleotides, poly(dG-me5dC)·poly(dG-me5dC) and poly(rA)·poly(rU).

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