A morphological revision of the tiger moth genus Syntomeida Harris.
(Lepidoptera: Noctuoidea: Arctiidae: Arctiinae: Euchromiini).
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
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.
Euchromia sperchia
Syntomeida hampsonii
Syntomeida joda
Chrysoscale prinicipalis
Dycladia correbioides
Empyreuma anassa
Syntomeida epilais
Chrysoscale ignitia
Histaea prosperina
Empyreuma pugione
*
5
2. Phoenicoprocta relatives
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
Macrocneme cyanea
All use chemical signals (pheromones) to locate a mate. They have
tymbal organs, but do not use them during mating (Sanderford,
pers. comm.)
evolution of these traits. The monophyly of Syntomeida has been uncertain historically. Here we
Agyrtidia uranophila
in the same genus, Syntomeida Harris, making it an especially useful model for studying the
Syntomeida melanthus
Eurota hermoine
S. syntomoides, S. ipomoeae, S. melanthus, S. vulcana, and S.
austera
exhibit either one or the other of these types of signals; however, both of these signals can be found
Syntomeida austera
use of ultrasonic signals or pheromones for communication during courtship. Most arctiid genera
Syntomeida ipomoeae
Members of the family Arctiidae possess many intriguing life history traits, including the
Syntomeida appears to be made up of three separate lineages:
1. Core Syntomeida:
Syntomeida vulcana
Abstract:
Syntomeida syntomoides
Rebecca B. Simmons, University of North Dakota, Department of Biology
Phoenicoprocta chrysorrhoea
Eurota picta
Jessica A. Goldstein, University of Delaware, Department of Entomology and Wildlife Ecology
*
3
3
2
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.
3. Empyreuma relatives
Shared Characters:
*
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.
2
9
2
*
2 trees
87 steps
*
2
CI = 0.62
*
RI = 0.71
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
Objectives.
1.
2.
3.
Does taxonomy reflects phylogeny and, accordingly, is the genus
Syntomeida monophyletic?
If Syntomeida is not monophyletic, how are these species related?
How did the use of acoustic signals during courtship evolve in
Euchrominii?
Aknowledgements. Specimens: USNM, CMNH, BMNH, LACM
Advice: Jordan Price (SMCM), Julian Dohanue (LACM), Bill Conner (WFU)
Euchromia sperchia
Phoenicoprocta chrysorrhoea
Eurota picta
Syntomeida hampsonii
Syntomeida joda
Dycladia correbioides
Chrysoscale prinicipalis
Empyreuma anassa
Empyreuma pugione
Syntomeida epilais
Chrysoscale ignitia
Histaea prosperina
Macrocneme cyanea
Agyrtidia uranophila
Syntomeida melanthus
Eurota hermoine
Syntomeida austera
Syntomeida ipomoeae
2
*
Figure 2. Possible
evolution of acoustic
signals during mating if
this character evolved
twice in this clade.
2 trees
87 steps
5
*
3
Euchromia sperchia
Phoenicoprocta chrysorrhoea
Eurota picta
RI = 0.71
Syntomeida hampsonii
*
Chrysoscale prinicipalis
Syntomeida joda
CI = 0.62
Empyreuma anassa
Dycladia correbioides
*
2
*
3
2
Discussion.
image adapted from www.nysaes.cornell.edu/ent/scaffolds/1995/scaffolds_0717
9
Empyreuma pugione
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
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 other’s 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 (p<0.05 for each comparison).
2
Syntomeida epilais
-
Results.
*
Chrysoscale ignitia
Histaea prosperina
-
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)
*
2
Macrocneme cyanea
-
3
3
Agyrtidia uranophila
Genus Syntomeida Harris.
*
5
Syntomeida melanthus
Eurota hermoine
sequester noxious secondary plant compounds
many wasp mimics
metathoracic tymbal organs produce ultrasound
that disrupts bat echolocation
Syntomeida austera
-
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
Syntomeida ipomoeae
Family Arctiidae
Syntomeida syntomoides
tympanal organs in all ~50,000 species
hear ultrasound, which they use to avoid bats
-
Syntomeida vulcana
Appears to have lost the ability to produce male mating
pheromones and documented S. epilais courtship using tymbal
organs (Sanderford & Conner, 1990).
Syntomeida vulcana
Superfamily Noctuoidea
Syntomeida syntomoides
S. epilais
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.
*
2
9
2
*
Figure 3. Possible
evolution of acoustic
signals during mating if
this character evolved
once in this clade.
2 trees
87 steps
*
2
CI = 0.62
*
RI = 0.71
Works cited.
Barnes, W. 1904. New species of North American Lepidoptera. The Canadian Entomologist 36:165.
Boisduval, J. A. 1836. Glaucopsis syntomoides. Spec. Gen. Lepid. 1: pl. 16, (fig. 4.)
Bremmer, K. 1994. Branch support and tree stability. Cladistics 10:295-304.
Cramer, J. 1779. Sphinx melanthus. Papillons Exot. 3: pl. 248 C.
Dognin, P.. 1902. Syntomeida austera. Ann. Soc. Entomol. Belg. 46:228.
Druce, H. 1889. Mr. H. Druce on new Species of Lepidoptera. Annals Mag. Nat. Hist. 4:83.
Druce, H. 1897. Supplement. Biol. Centr.-Amer., Lepidoptera Heterocera 2:332-333.
Harris, T. W. 1839. Catalogue of North American Sphinges. American Journal of Science 36:316-317.
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 29:170-179.
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 31:461-478.
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.
Sanderford, M. V. and W. E. Conner. 1990. Courtship sounds of the polka-dot wasp moth, Syntomeida
epilais. Naturwissenschaften 77:345-347.
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.1:223-229.