Leaf gall polymorphism and molecular phylogeny of a new Bruggmanniella species (Diptera: Cecidomyiidae: Asphondyliini) associated with Litsea acuminata (Lauraceae) in Taiwan, with ecological comparisons and a species description

• Published in: Entomological science 2020-03, Vol.23 (1), p.10-22
• Main Authors: Lin, Sheng‐Feng, Tokuda, Makoto, Yang, Man‐Miao
• Format: Article
• Language: English
• Subjects: Asphondyliina; Cecidomyiidae; COI; Ecological studies; Entomology; Gall; gall inducer; gall polymorphism; Galling; Galls; Geographical distribution; Lauraceae; Leaves; Litsea; Morphometry; Phenotypes; Phylogeny; Polymorphism; Species; systematics; Taxonomy
• ISSN: 1343-8786; 1479-8298
• DOI: 10.1111/ens.12391

Two types of cecidomyiid leaf galls, cup‐shaped and umbrella‐shaped, occur on Litsea acuminata (Lauraceae) in Taiwan. Based on the concept of gall shapes as “extended phenotypes” of gall inducers, these two types could be induced by different gall midge species. However, galls with intermediate shapes between the two types were recently discovered, which implies that possible genetic exchanges occur between the gall inducers of both types. To clarify the taxonomic status of gall midges responsible for the two types of galls on L. acuminata, we undertook taxonomic, molecular phylogenetic and ecological studies. Our findings show that the two gall types are induced by the same Bruggmanniella species and the species is new to science. We describe the species forming this range of galls as Bruggmanniella litseae sp. n., and compare their geographical distribution, galling position and morphometry. Based on our results, a possible evolutionary scenario of B. litseae sp. n. is discussed. Our molecular and morphological findings show that Bruggmanniell litseae sp. n. is responsible for polymorphic leaf gall on Litsea acuminata. The geographical distribution, galling position, and morphometry of different gall types are compared and discussed for possible evolutionary scenario.