Abstract:
1. Two cossid moths, Coryphodema tristis and Chilecomadia valdiviana,
have recently become pests on Eucalyptus nitens in South Africa and Chile,
respectively. Both C. tristis and C. valdiviana have large host ranges and high levels
of similarity in their host distributions. Their infestations of E. nitens are the first
records of these moths on Myrtaceae.
2. The contemporaneous adoption of E. nitens as a novel host, despite widespread
availability of native and introduced Myrtaceae, suggests a non-random pattern of
invasion. Phylogenetic relatedness among the two species linked to cryptic invasion
of one or both moths at some time in the recent past provides a possible explanation
for this pattern. 3. To test this hypothesis, variation in mtDNA sequences for the COI gene of C.
tristis and C. valdiviana were analyzed. The COI mtDNA sequence data showed that
C. tristis and C. valdiviana are highly divergent genetically, indicating that both are
native on their respective continents with independent evolutionary trajectories.
4. The parallel host range expansions to E. nitens on different continents appear to
be unrelated events, likely driven by characteristics of the biology and / or ecology of
the host.
