An Integrative Study on Asphondylia spp. (Diptera: Cecidomyiidae), Causing Flower Galls on Lamiaceae, with Description, Phenology, and Associated Fungi of Two New Species

Umberto Bernardo,Francesco Nugnes,Adriano Stinca,Rosario Nicoletti,Gennaro Viggiani,Simona Gargiulo,Andrea Becchimanzi

doi:10.3390/insects12110958

Abstract

Simple SummaryCurrent knowledge of some species of Asphondylia (Diptera: Cecidomyiidae) is very scarce, such as those causing flower galls on Lamiaceae. Their role in natural and agricultural ecosystems remains to be investigated. Hitherto, the description of new species of this genus was mostly based on morphological variations of both the adult and the young instars. However, these variations are frequently limited and unreliable for species discrimination, and need the essential support of molecular data. Interesting aspects that are widely unexplored of this group of Asphondylia are their biological traits and the association with parasitoids and fungi. This paper provides an integrated description of two species of Asphondylia infesting flowers of Clinopodium vulgare and Micromeria graeca, and also provides data on host range and symbiosis with associated fungi.An integrative study on some species of Asphondylia was carried out. Two species of gall midges from Italy, Asphondylia rivelloi sp. nov. and Asphondylia micromeriae sp. nov. (Diptera: Cecidomyiidae), causing flower galls respectively on Clinopodium vulgare and Micromeria graeca (Lamiaceae), are described and illustrated. The characteristics of each developmental stage and induced galls are described, which allowed the discrimination of these new species in the complex of Asphondylia developing on Lamiaceae plants. Molecular data based on sequencing both nuclear (ITS2 and 28S-D2) and mitochondrial (COI) genes are also provided in support of this discrimination. Phylogeny based on nuclear markers is consistent with the new species, whereas COI phylogeny suggests introgression occurring between the two species. However, these species can also be easily identified using a morphological approach. Phenology of host plants and gall midges are described, and some peculiar characteristics allow the complete and confident discrimination and revision of the treated species. Gall-associated fungi were identified as Botryosphaeria dothidea, Alternaria spp., and Cladosporium spp.

Highlights

Gall midges (Cecidomyiidae) are one of the largest and most diverse families of Diptera, with about 6600 described species worldwide
The specimens of Asphondylia collected from C. vulgare and M. graeca showed some morphological, molecular, and bio-ecological traits that allow distinguishing them from the allied species known on Lamiaceae
The first clade grouped samples of A. hornigi and A. serpylli without any distinction related to the host plant

Summary

Introduction

Gall midges (Cecidomyiidae) are one of the largest and most diverse families of Diptera, with about 6600 described species worldwide. Among the six subfamilies belonging to this family, the subfamily Cecidomyiinae is the largest and most diverse, and includes fungivorous, herbivorous, and predatory species. The genus Asphondylia Loew (Diptera: Cecidomyiidae) belongs to the Asphondyliini tribe, subtribe Asphondyiliina, the latter of which is a monophyletic group including about 300 species of gall makers [1,3]. Among the 20 Asphondylia species recorded on Lamiaceae plants, 18 are from the Palaearctic region [3,4]. A study project on the Asphondylia species, causing flower galls on Lamiaceae, started in 2014 and several papers have been published on this topic [4,5,6,7]

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