Exploration of Substrate Vibrations as Communication Signals in a Webspinner from Ecuador (Embioptera: Clothodidae)
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Embiopterans are among the least known of all insect orders, and yet their behavior is worthy of investigation for many reasons. They spin silk produced in glands in their front tarsi and live in groups, usually mothers with their young and sometimes in large colonies with many reproductive females sharing the silk. We discovered a large embiid (Clothodidae) in an Ecuadorian rain forest living under camouflaged silk sheets spun onto the bark of trees. Observations in previous studies of a related Trinidadian clothodid revealed that individuals shake and lunge their bodies in response to intruders of their silk domicile. We took the opportunity afforded by the discovery of the large clothodids to rear them in the laboratory and to investigate their communication behavior. We used piezoelectric film to detect substrate vibrations generated by adult females as elicited by a variety of intruders (an artificial stimulus, conspecific female or male, or a female of different species of webspinners). The residents produced three signals distinguishable by behavioral action, frequency (hertz), pulses per bout, and amplitude at peak frequency. We designated these as lift silk, shake, and snapback. Shakes varied the most in amplitude and frequency in response to the different intruders, and therefore, we propose that shakes may transmit the most information as individuals contact each other. This is the first report to characterize spectral qualities and contexts of substrate vibrations in an embiopteran.
KeywordsEmbiid silk sound analysis subsocial behavior
We thank RB Cocroft for advice during early stages of this project, S de la Torre for supporting this work in her research laboratory at USFQ, EC Rooks for assistance in field work, and ES Ross for identifying the clothodid and for providing assistance with locating Ecuadorian populations of webspinners. An official research permit (#018-IC-FAU-DNBAPVS/MA) was obtained by JSE from the Ecuadorian government to collect the insects. We thank D Romo and GB Cruz of USFQ for assisting us with the permitting procedures and logistics in Ecuador. We acknowledge grants awarded to JSE from the National Science Foundation USA (#DEB 0515865) and Santa Clara University (#DPROVO52).
Electronic supplementary material
The online version of this article (doi: 10.1007/s13744-012-0034-z) contains supplementary material, which is available to authorized users.
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