The evolutionary history ofTrichoptera (Insecta): A case of successful adaptation to life in freshwater

Abstract

The insect order Trichoptera (caddisflies) forms the second most species‐rich monophyletic group of animals in freshwater. So far, several attempts have been made to elucidate its evolutionary history with both morphological and molecular data. However, none have attempted to analyse the time frame for its diversification. The order is divided into three suborders – Annulipalpia, Integripalpia and ‘Spicipalpia’. Historically, the most problematic taxon to place within the order is ‘Spicipalpia’, whose larvae do not build traditional cases or filtering nets like the majority of the caddisflies. They have previously been proposed to be the sister group of all other Trichoptera or more advanced within the order, with equivocal monophyly and with different interordinal placements among various studies. In order to resolve the evolutionary history of the caddisflies as well as timing their diversification, we utilized fragments of three nuclear (carbamoylphosphate synthethase, isocitrate dehydrogenase and RNA polymerase II) and one mitochondrial (cytochrome oxidase I) protein coding genes, with 16 fossil trichopteran taxa used for time calibration. The ‘spicipalpian’ families are recovered as ancestral to all other caddisflies, though paraphyletic. We recover stable relationships among most families and superfamilies, resolving many previously unrecognized phylogenetic affinities amongst extant families. The origin of Trichoptera is estimated to be around 234 Ma, i.e. Middle – Late Triassic.

Diversity and distribution of the Caddisflies (Insecta: Trichoptera) of Ecuador

“…The members of this order are considered to be biological indicators of good to excellent water quality and are highly sensitive to human disturbance to running waters worldwide (Chang et al, 2014). Currently, there are about 15,000 species described, making Trichoptera the second most diverse monophyletic group of aquatic animals, surpassed only by the clade Diptera: Culicomorpha/Psychodomorpha (Malm, Johanson & Wahlberg, 2013). In Trichoptera, The Neotropical region is the 3rd most species rich in the world with 2100 species recorded as of 2008 after the Oriental and Palearctic regions (De Moor & Ivanov, 2008).…”

Revised classification and evolution of leucotrichiine microcaddisflies (Trichoptera: Hydroptilidae) based on morphological and molecular data

“…Microcaddisflies belong to Hydroptilidae, the most diverse caddisfly family, which currently contains over 2000 species in about 70 genera distributed on every habitable continent (Holzenthal et al ., ). Traditionally, they are included in the suborder Spicipalpia, the closed‐cocoon‐making caddisflies, a group of five families generally regarded as nonmonophyletic (Wiggins, ; Holzenthal et al ., ; Malm et al ., ). Based on molecular and morphological data, Kjer et al .…”

The First Mitochondrial Genome for Caddisfly (Insecta: Trichoptera) with Phylogenetic Implications

“…Almost 14,300 extant caddisfly species, placed in 49 families and 688 genera, have been described 2 forming the seventh largest order of all insects and second largest extant monophyletic animal group in freshwater 3. It has been estimated that the world fauna may contain as many as 50,000 species 4 and is distributed in all zoogeographical regions and sub-regions with the exception of the Antarctic 5.…”