Vietnam, a Hotspot for Chromosomal Diversity and Cryptic Species in Black Flies (Diptera: Simuliidae)

Abstract

The increasing attention on Vietnam as a biodiversity hotspot prompted an investigation of the potential for cryptic diversity in black flies, a group well known elsewhere for its high frequency of isomorphic species. We analyzed the banding structure of the larval polytene chromosomes in the Simulium tuberosum species group to probe for diversity beyond the morphological level. Among 272 larvae, 88 different chromosomal rearrangements, primarily paracentric inversions, were discovered in addition to 25 already known in the basic sequences of the group in Asia. Chromosomal diversity in Vietnam far exceeds that known for the group in Thailand, with only about 5% of the rearrangements shared between the two countries. Fifteen cytoforms and nine morphoforms were revealed among six nominal species in Vietnam. Chromosomal evidence, combined with available molecular and morphological evidence, conservatively suggests that at least five of the cytoforms are valid species, two of which require formal names. The total chromosomal rearrangements and species (15) now known from the group in Vietnam far exceed those of any other area of comparable size in the world, supporting the country’s status as a biodiversity hotspot. Phylogenetic inference based on uniquely shared, derived chromosomal rearrangements supports the clustering of cytoforms into two primary lineages, the Simulium tani complex and the Southeast Asian Simulium tuberosum subgroup. Some of these taxa could be threatened by habitat destruction, given their restricted geographical distributions and the expanding human population of Vietnam.

Ecological and geographical speciation in Lucilia bufonivora: The evolution of amphibian obligate parasitism

“…Thus, geographical isolation of L. bufonivora and rapid mtDNA evolution rates appear to be facilitating on-going cryptic speciation. This phenomenon is relatively common within Diptera, as reported in geographically isolated populations of gall midges, tephritid flies, flesh flies and black flies (Hall et al, 2009; Tadeo et al, 2015; Adler et al, 2016; Duque-Gamboa et al, 2018). The status of L. bufonivora in Canada as a distinct species, however, remains to be resolved, and will also require detailed morphological examination of specimens from both Eastern and Western hemispheres.…”

Chromosomal and Molecular Diversity in the Simulium ornatum Group (Diptera: Simuliidae) in the Western Tian Shan Range of Central Asia

“…Images of diagnostic sequences were made with a Jenoptik ProgRes ® SpeedXT Core 5 digital camera (JENOPTIK Optical Systems, Huntsville, AL, USA) on a BH-2 Olympus microscope (Olympus Corporation, Center Valley, PA, USA) and chromosomal maps were prepared with Adobe ® PhotoShop ® Elements 8 (Adobe Systems Incorporated, San Jose, CA, USA). Chromosomal mapping procedures and terminology follow those of Adler et al [ 9 , 16 ]. All rearrangements were mapped.…”

First record of the subfamily Oxytorinae (Insecta, Hymenoptera, Ichneumonidae) from the Oriental Region, with descriptions of two new species from Vietnam

“…Field courses took place in two national parks: Bach Ma National Park in central Vietnam (June 2018) and Cuc Phuong National Park in northern Vietnam (April-May 2019). The Bach Ma National Park demarcates the border between north and south Vietnam ranging from lowland to high mountains, with Bach Ma being considered as a biodiversity hotspot ( Adler et al 2016 , Kunich 2003 , Ngoc et al 2016 , Tobias 2014 ). The Cuc Phuong National Park in northern Vietnam is located at the junction between the temperate tropical and the subtropical regions.…”