Jessica A' Goldstein, University of Delaware, Department of Entomology and Wildlife Ecology

1
A morphological revision of the tiger moth genus
Syntomeida Harris. (Lepidoptera Noctuoidea
Arctiidae Arctiinae Euchromiini).
Jessica A. Goldstein, University of Delaware,
Department of Entomology and Wildlife
Ecology Rebecca B. Simmons, University of North
Dakota, Department of Biology
Abstract Members of the family Arctiidae
possess many intriguing life history traits,
including the use of ultrasonic signals or
pheromones for communication during courtship.
Most arctiid genera exhibit either one or the
other of these types of signals however, both of
these signals can be found in the same genus,
Syntomeida Harris, making it an especially useful
model for studying the evolution of these traits.
The monophyly of Syntomeida has been uncertain
historically. Here we present results supporting
a new tree splitting Syntomeida into three
different genera. Sixty-six Syntomeida and
twenty-four outgroup specimens were dissected and
their morphologies were examined. Twenty-three
morphological characters provided the data matrix
and a branch and bound search was performed.
These results suggest that Syntomeida is not a
real genus containing members of the genus
Phoenicoprocta and a yet novel genus. This study
shows how genitalia characteristics can be
effective at distinguishing relationships at the
species level. Also our data suggest that the
use of ultrasound during courtship of arctiid
moths evolved more than once.
Syntomeida appears to be made up of three
separate lineages
1. Core Syntomeida
S. syntomoides, S. ipomoeae, S. melanthus, S.
vulcana, and S. austera All use chemical signals
(pheromones) to locate a mate. They have tymbal
organs, but do not use them during mating
(Sanderford, pers. comm.)
2. Phoenicoprocta relatives
S. hampsonii and S. joda Use pheromones, but have
more striations on their tymbal organs than the
previous species (pers. obs.). The presence of
these striations suggests that they might use
these tymbal organs in courtship, but no studies
have examined this possibility.
Figure 1. Observed phylogenetic tree of
genus Syntomeida and outgroups used in study.
The asterix () are branches supported 100 by
taxon jackknifing and the numbers are decay
indices above 1.
3. Empyreuma relatives
Shared Characters
S. epilais Appears to have lost the ability to
produce male mating pheromones and documented S.
epilais courtship using tymbal organs (Sanderford
Conner, 1990).
Superfamily Noctuoidea
- tympanal organs in all 50,000 species - hear
ultrasound, which they use to avoid bats
Family Arctiidae
Materials and Methods. - Dissected 20 species
from 10 genera - The ingroup was made up of the 8
species from Syntomeida - The outgroup was made
up of 12 species from 9 genera - We used 23
characters 17 of which were genitalia
characters - We used MacClade 4.06 (Maddison
Maddison 2000) and PAUP (Swofford 2000)
- Transformation series analysis (TSA) was
performed resulting in 2 trees with a length of
87 steps
- sequester noxious secondary plant
compounds - many wasp mimics - metathoracic
tymbal organs produce ultrasound that disrupts
bat echolocation
Genus Syntomeida Harris.
Figure 2. Possible evolution of acoustic signals
during mating if this character evolved twice in
this clade.

• 8 species of diurnal wasp mimics from
• Nearctics and Neotropics
• genus established based on locality and
  external
• characteristics
• S. syntomoides (Boisduval)
• S. ipomoeae (Harris)
• S. melanthus (Cramer) S. vulcana (Druce)
• S. austera (Dognin) S. hampsonii (Barnes)
• S. joda (Druce) S. epilais (Walker)

Results. There is especially strong support for
moving S. hampsonii and S. joda to Phoenicoprocta
with a decay index value of 9 (Figure 1). The
decay index does offer further support that S.
hampsonii and S. joda are each others closest
relatives by grouping them together with a decay
index value of 3. Syntomeida epilais is also
separated from the rest of the clade Syntomeida
(S. syntomoides, S. ipomoeae, S. melanthus, S.
vulcana, and S. austera). The genus Empyreuma is
supported, but S. epilais is not included in it,
as we had expected. The grouping of the two
Empyreuma species E. anassa and E. pugione
without S. epilais is strongly supported by the
decay index and has a decay value of 5. The
genus Syntomeida, as we hypothesized, was also
supported by a decay index of 2 as well as the
taxon jackknifing. The K-H test (Kashino
Hasegawa, 1989) found that our tree is
significantly better than the 1000 random trees
as well as the traditional tree and our
hypothesized tree (plt0.05 for each comparison).
Pheromone Mating (Core Syntomeida and
Phoenicoprocta relatives) - Female perches and
releases long range pheromone - Male senses
pheromone and flies upwind - Male finds female
and releases short range pheromone - Female
accepts male and copulation occurs Acoustic
Mating (S. epilais) - Female perches and calls
to male - Male hears calls and begins calling
back meanwhile flying towards the female - Male
finds female and continues to call Female
accepts male and copulation occurs
Discussion. We had originally hypothesized S.
epilais would be found to be closely related to
the genus Empyreuma and therefore the use of
acoustic signals during mating evolved once
(Figure 2). This assertion was not supported by
our analysis. Behavioral studies need to be done
on the taxa nested in the same clade as S.
epilais Macrocneme, Histaea, Empyreuma, Dycladia
and Chrysoscale to see whether or not these
species also use their tymbal organs in mating
(Figure 3). The behaviors between S. epilais
and Empyreuma are not homologous. In S. epilais,
both males and females call to each other. In
Empyreuma, only males produce sound during
courtship. Hence the use of sound in courtship
evolved two different ways. This observation is
logical because the structures needed to produce
these sounds were already present in all tiger
moths. The use of these structures in courtship
instead of defense probably involved only a
simple behavioral change. Our tree supported
the other preliminary observations that S. joda
and S. hampsonii would be assimilated into the
genus Phoenicoprocta, which was clear from their
similar morphology. This group has well
developed tymbal organs with many striations,
which may mean that, like S. epilais, they also
use their tymbal organs for courtship. A system
where moths use both pheromones and acoustic
signals during courtship has not been seen, but
it would be interesting to observe the courtship
behavior of these two species. At the very least
it suggests that members of this genus have
relatively advanced defenses against bat
predation.
Figure 3. Possible evolution of acoustic signals
during mating if this character evolved once in
this clade.
image adapted from www.nysaes.cornell.edu/ent/scaf
folds/1995/scaffolds_0717
Works cited. Barnes, W. 1904. New species of
North American Lepidoptera. The Canadian
Entomologist 36165. Boisduval, J. A. 1836.
Glaucopsis syntomoides. Spec. Gen. Lepid. 1 pl.
16, (fig. 4.) Bremmer, K. 1994. Branch support
and tree stability. Cladistics
10295-304. Cramer, J. 1779. Sphinx melanthus.
Papillons Exot. 3 pl. 248 C. Dognin, P.. 1902.
Syntomeida austera. Ann. Soc. Entomol. Belg.
46228. Druce, H. 1889. Mr. H. Druce on new
Species of Lepidoptera. Annals Mag. Nat. Hist.
483. Druce, H. 1897. Supplement. Biol.
Centr.-Amer., Lepidoptera Heterocera
2332-333. Harris, T. W. 1839. Catalogue of
North American Sphinges. American Journal of
Science 36316-317. Kashino, H. and M.
Hasegawa. 1989. Evaluation of the maximum
likelihood estimate of the evolutionary tree
topologies from DNA sequence data, and the
branching order in Hominoidea. Journal of
Molecular Evolution 29170-179. Maddison, D. R.
and W. P. Maddison. 2000. Macclade Analysis of
phylogeny and character evolution, version 4.06.
Sinauer Associates, Sunderland,
Massachusets. Mickevich, M. F. 1982.
Transformation series analysis. Systematic
Zoology 31461-478. Sanderford, M. V. and W. E.
Conner. 1990. Courtship sounds of the polka-dot
wasp moth, Syntomeida epilais. Naturwissenschaften
77345-347. Swofford, D. L. 2000. PAUP
Phylogenetic Analysis Using Parsimony (And Other
Methods), version 4.0b10. Sinauer Associates,
Sunderland, Massachusetts. Walker, F. 1854. List
of the specimens of lepidopterous insects in the
collection of the British Museum.1223-229.
Objectives. 1. Does taxonomy reflects phylogeny
and, accordingly, is the genus Syntomeida
monophyletic? 2. If Syntomeida is not
monophyletic, how are these species
related? 3. How did the use of acoustic signals
during courtship evolve in Euchrominii?
Future Directions. Now that the relationships of
the genus Syntomeida have been deduced, future
research should focus on the systematic placement
of S. epilais, using molecular and
morphological characters. Once the sister genus
of S. epilais have been found, then studies
examining the evolution of intraspecific
communication in arctiids and the extent of this
communication can be conducted.
Aknowledgements. Specimens USNM, CMNH, BMNH,
LACM Advice Jordan Price (SMCM), Julian Dohanue
(LACM), Bill Conner (WFU)