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Phylogenetic test of speciation by host shift in leaf cone moths ( Caloptilia ) feeding on maples ( Acer )

View Article: PubMed Central - PubMed

ABSTRACT

The traditional explanation for the exceptional diversity of herbivorous insects emphasizes host shift as the major driver of speciation. However, phylogenetic studies have often demonstrated widespread host plant conservatism by insect herbivores, calling into question the prevalence of speciation by host shift to distantly related plants. A limitation of previous phylogenetic studies is that host plants were defined at the family or genus level; thus, it was unclear whether host shifts predominate at a finer taxonomic scale. The lack of a statistical approach to test the hypothesis of host‐shift‐driven speciation also hindered studies at the species level. Here, we analyze the radiation of leaf cone moths (Caloptilia) associated with maples (Acer) using a newly developed, phylogeny‐based method that tests the role of host shift in speciation. This method has the advantage of not requiring complete taxon sampling from an entire radiation. Based on 254 host plant records for 14 Caloptilia species collected at 73 sites in Japan, we show that major dietary changes are more concentrated toward the root of the phylogeny, with host shift playing a minor role in recent speciation. We suggest that there may be other roles for host shift in promoting herbivorous insect diversification rather than facilitating speciation per se.

No MeSH data available.


Sampling localities of Caloptilia moths collected from Acer trees in Japan. Sampling information for each species shown in Figure S2.
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ece32266-fig-0001: Sampling localities of Caloptilia moths collected from Acer trees in Japan. Sampling information for each species shown in Figure S2.

Mentions: We sampled Caloptilia moths that use Acer trees at 73 sites covering a wide geographic range in Japan (Figs. 1, S2) during May–October of 2011–2015. Moths were sampled by searching for larvae in leaf rolls (fourth or fifth instar) or pupae on maple leaves. In total, 254 specimens were obtained, used to delimit species and to establish the host range for each species. Delimitation of species was based on sequences of the mitochondrial cytochrome oxidase subunit I (COI) gene; major divergences in COI sequences clearly corresponded with differences in wing pattern and genital morphology. Species were morphologically identified following Kumata (1982). To further determine whether the Caloptilia species feeding on maples resulted from a single radiation, we additionally sampled 44 Caloptilia species that use nonmaple hosts and six species in closely related genera (Gracillaria, Calybites, and Eucalybites; for details, see Table S1) and reconstructed a species‐level phylogeny of Caloptilia. For the species‐level phylogeny, one representative specimen of each Caloptilia species feeding on maple was included in the analysis. All moth specimens were kept in ethanol prior to DNA extraction.


Phylogenetic test of speciation by host shift in leaf cone moths ( Caloptilia ) feeding on maples ( Acer )
Sampling localities of Caloptilia moths collected from Acer trees in Japan. Sampling information for each species shown in Figure S2.
© Copyright Policy - creativeCommonsBy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4979720&req=5

ece32266-fig-0001: Sampling localities of Caloptilia moths collected from Acer trees in Japan. Sampling information for each species shown in Figure S2.
Mentions: We sampled Caloptilia moths that use Acer trees at 73 sites covering a wide geographic range in Japan (Figs. 1, S2) during May–October of 2011–2015. Moths were sampled by searching for larvae in leaf rolls (fourth or fifth instar) or pupae on maple leaves. In total, 254 specimens were obtained, used to delimit species and to establish the host range for each species. Delimitation of species was based on sequences of the mitochondrial cytochrome oxidase subunit I (COI) gene; major divergences in COI sequences clearly corresponded with differences in wing pattern and genital morphology. Species were morphologically identified following Kumata (1982). To further determine whether the Caloptilia species feeding on maples resulted from a single radiation, we additionally sampled 44 Caloptilia species that use nonmaple hosts and six species in closely related genera (Gracillaria, Calybites, and Eucalybites; for details, see Table S1) and reconstructed a species‐level phylogeny of Caloptilia. For the species‐level phylogeny, one representative specimen of each Caloptilia species feeding on maple was included in the analysis. All moth specimens were kept in ethanol prior to DNA extraction.

View Article: PubMed Central - PubMed

ABSTRACT

The traditional explanation for the exceptional diversity of herbivorous insects emphasizes host shift as the major driver of speciation. However, phylogenetic studies have often demonstrated widespread host plant conservatism by insect herbivores, calling into question the prevalence of speciation by host shift to distantly related plants. A limitation of previous phylogenetic studies is that host plants were defined at the family or genus level; thus, it was unclear whether host shifts predominate at a finer taxonomic scale. The lack of a statistical approach to test the hypothesis of host‐shift‐driven speciation also hindered studies at the species level. Here, we analyze the radiation of leaf cone moths (Caloptilia) associated with maples (Acer) using a newly developed, phylogeny‐based method that tests the role of host shift in speciation. This method has the advantage of not requiring complete taxon sampling from an entire radiation. Based on 254 host plant records for 14 Caloptilia species collected at 73 sites in Japan, we show that major dietary changes are more concentrated toward the root of the phylogeny, with host shift playing a minor role in recent speciation. We suggest that there may be other roles for host shift in promoting herbivorous insect diversification rather than facilitating speciation per se.

No MeSH data available.