Molecular association and morphological characterisation of Himalopsyche larval types (Trichoptera, Rhyacophilidae).

Anna E Hjalmarsson,Sonja C Jähnig,Simon Vitecek,Wolfram Graf,Steffen U Pauls

doi:10.3897/zookeys.773.24319

Abstract

Himalopsyche Banks, 1940 (Trichoptera, Rhyacophilidae) is a genus of caddisflies inhabiting mountain and alpine environments in Central and East Asia and the Nearctic. Of 53 known species, only five species have been described previously in the aquatic larval stage. We perform life stage association using three strategies (GMYC, PTP, and reciprocal monophyly) based on fragments of two molecular markers: the nuclear CAD, and the mitochondrial COI gene. A total of 525 individuals from across the range of Himalopsyche (Himalayas, Hengduan Shan, Tian Shan, South East Asia, Japan, and western North America) was analysed and 32 operational taxonomic units (OTUs) in our dataset delimited. Four distinct larval types of Himalopsyche are uncovered, and these are defined as the phryganea type, japonica type, tibetana type, and gigantea type and a comparative morphological characterisation of the larval types is presented. The larval types differ in a number of traits, most prominently in their gill configuration, as well as in other features such as setal configuration of the pronotum and presence/absence of accessory hooks of the anal prolegs.

Highlights

With ~15,000 described and around 50,000 presumed species, caddisflies are one of the larger insect orders and the largest primary aquatic insect order
We included larvae collected in Japan and Thailand identified as H. japonica and H. acharai, respectively, no molecular data for these specimens were available
The results from separate runs were stable except for General Mixed Yule Coalescent method (GMYC) with c oxidase (COI). This instability did not affect larval association and we hereafter only refer to COI run 1 which delimited 48 GMYC clusters (Table 4, Suppl. material 2, 3)

Summary

Introduction

With ~15,000 described and around 50,000 presumed species, caddisflies are one of the larger insect orders and the largest primary aquatic insect order (de Moor and Ivanov 2008). Trichoptera have merolimnic life histories and the larvae have long been recognised as important ecological indicators (Resh and Unzicker 1975). They have several remarkable ecological traits, among others their diverse case-building behaviour or their ability to invade all types of aquatic habitats across the globe (except Antarctica; Holzenthal et al 2007, Wiggins 1996). While renowned for their intricate cases, larvae of some caddis families roam freely, and only build pupal retreats. This family entails the genera Himalopsyche Banks, 1940, Fansipangana Mey, 1996, Philocrena Lepneva, 1956, Phoupanpsyche Malicky, 2008, and Rhyacophila Pictet, 1834

Methods

Results

Discussion

Conclusion