A Comparative survey of proboscis and tymbal morphology in Tiger moths (lepidoptera: erebidae: arctiini)
File(s)
Date
2016-08-23Author
Coy, Stacey L.
Advisor(s)
Zaspel, Jennifer
Metadata
Show full item recordAbstract
Arctiini (tiger moths) include some of the most brightly colored,
charismatic moths in the order Lepidoptera. Bright coloration and sound
production in tiger moths can serve as defense mechanisms to warn predators of
their unpalatability. In some arctiines, atypical adult feeding behaviors have
been documented, including obtaining secondary plant compounds for chemical
protection rather than nutrition, a.k.a. pharmacophagy. Tiger moth species have
also been recorded warning bat predators of their distastefulness by producing
sound with specialized structures. Other tiger moths are palatable, and use
sound to jam bat sonar, thereby evading predation.
Previous morphological work has demonstrated an association between
some adult feeding behaviors and uniquely specialized proboscis sensory
structures. Whether adult pharmacophagous tiger moths have specialized
structures for pharmacophagy was previously unknown. I hypothesized there is
a connection between the number of proboscis sensory structures, adult
pharmacophagy and phylogeny in arctiines. My results demonstrate that
individuals known to sequester pyrrolizidine alkaloids (PA’s) as adults have
more proboscis sensilla on average than those that do not sequester PA’s as
adult, but are PA feeders as larvae.
Some tiger moths have developed a secondary organ, the tymbal, for
defense through ultrasonic sound. Little morphological work has been done to
examine tymbal microstructure; however, some evidence suggests variation in
tymbal size between tiger moth species. I predicted there is a correlation
between the surface area of the tymbal and specific defensive behaviors (e.g.,
acoustic aposematism vs. jamming). Results from my morphological surveys
provided new character states for comparative evolution analyses within a
phylogenetic framework. Further, this work has predictive power providing
valuable insight into unknown species behaviors, and can inform future studies
in chemical ecology and behavior.
Subject
Lepidoptera
Moths
Tiger moths
Permanent Link
http://digital.library.wisc.edu/1793/75219Description
A Thesis Submitted In Partial Fulfillment of the Requirements For the Degree of Master of Science - Biology