John C. Morse

In another contribution to the systematics of Indian caddisflies, six species of genus Cheumatopsyche are reported for the first time from the geographic limits of India. Ch. maculipennis (Ulmer 1930), Ch. hippolyte Malicky 1997, Ch. cocles Malicky & Chantaramongkol 1997, all from Tamil Nadu; Ch. costalis (Banks 1913) from Odisha; Ch. schmidiana Oláh, Flint & Johnson 2007 from Karnataka; and Ch. chinensis (Martynov 1930) from Arunachal Pradesh are re-illustrated, redescribed, and recorded for the first time from India. Additionally, Ch. criseyde Malicky & Chantaramongkol 1997 from Tamil Nadu is re-illustrated and redescribed based on freshly collected specimens. With these additions the genus is represented by 64 species in India.

A total of 1,510 caddisfly species representing 28 families and 155 genera are reported from the 63 states and provinces of Canada and the United States of America (USA). These species have been described over a period of nearly 270 years, with the most prolific period occurring during the 1930–1940s. The families Hydroptilidae (307), Limnephilidae (255), and Hydropsychidae (159) contain the most species, whereas six families contain less than five species each. Canada and the USA host 644 and 1,487 species, respectively. The states and provinces with the greatest species richness are Tennessee (384), Virginia (383), and Alabama (378), and those with the least are Rhode Island (27), Prince Edward Island (23), and Nunavut (15). Differences in state species assemblages largely followed a geographic pattern, with a non-metric multidimensional scaling ordination suggesting six regions of caddisfly diversity corresponding to the central, far north, northeastern, northwestern, southeastern, and southwestern portions of the study area. Caddisfly species richness was highest in the southeastern region, despite being the smallest region of the six, and lowest in the far north. Species rarefaction predicted 129–181 species remain to be discovered within the two countries, while multiple linear regression modeling using common environmental variables suggested 17 states and provinces with at least 50 species remaining to be found in each.

In land-scarce Singapore, where fresh water is a critical resource, Trichoptera communities can serve as a biomonitoring tool, yet are poorly known. This study seeks to address this gap by establishing a preliminary understanding of trichopteran diversity and distribution in Singapore’s freshwater streams. From October 2023–January 2024, 11 stream sites across forested nature reserves ( N = 5), buffer parks ( N = 4), and urban areas ( N = 2) were surveyed for trichopteran larvae. Only eight sites (four in forest streams, four in buffer streams) yielded Trichoptera, totalling 107 larval specimens comprising six families (Calamoceratidae, Ecnomidae, Hydropsychidae, Leptoceridae, Odontoceridae, and Polycentropodidae). Leptoceridae were most abundant, Ecnomidae were the rarest, and Hydropsychidae were the most widely distributed. In this study, Trichoptera were absent from the urban streams, which had greater depth and total dissolved solids, but similar Trichoptera assemblages and environmental parameters were recorded in both forest and buffer streams. Although differences between the latter two stream types were not statistically significant, buffer streams had the highest abundance and taxonomic richness. Comparison with past literature also reveals differences in recorded Trichoptera diversity, thus, this study presents an updated record for Trichoptera in Singapore’s streams. These findings further add to a baseline for future biomonitoring, research, and informing long-term freshwater conservation efforts in Singapore.

Recent phylogenomic studies have concluded that the ancestor of order Trichoptera and suborder Integripalpia probably had a larva that was “free living,” without a portable case or fixed retreat. Phylogenies inferred from those investigations regarding hypotheses for other probable functional traits of larvae and pupae of the Trichoptera ancestor and its immediate descendants were considered, especially with reference to the extant amphiesmenopteran sister lineage Lepidoptera. To test our hypotheses an Ancestral Character State Reconstruction by Parsimony Analysis was performed to explore functional traits for five habitat and behavioral traits. Like the larva of Micropterigidae, the basal lineage of Lepidoptera, the ancestral caddisfly larva was not only “free living” but also was a shredding herbivore of bryophytes. Like that larva, it may have been often submerged, perhaps as a semi-aquatic sprawler in madicolous or hygropetric habitats, but it could also have been a clinger in lotic-erosional habitats. Also, the characteristics of the pupal cocoon are not clear; it may have been closed and permeable like that of Micropterigidae, or it was closed and semipermeable like that of Hydroptilidae, or it was open in a long-dome shelter like that of the Annulipalpia ancestor.

In land-scarce Singapore where fresh water is a critical resource, Trichoptera communities can serve as a biomonitoring tool yet are poorly known. This study seeks to address this gap by establishing a preliminary understanding of trichopteran diversity and distribution in Singapore’s freshwater streams. From October 2023–January 2024, 11 stream sites across forested nature reserves (n = 5), buffer parks (n = 4), and urban areas (n = 2) were surveyed for trichopteran larvae. Only eight sites (four in forest streams, four in buffer streams) yielded Trichoptera, totalling 107 larval specimens comprising six families (Calamoceratidae, Ecnomidae, Hydropsychidae, Leptoceridae, Odontoceridae, and Polycentropodidae). Leptoceridae were most abundant, while Ecnomidae was the rarest, and Hydropsychidae were the most widely distributed. In this study, Trichoptera were absent from the urban streams, which had greater depth and total dissolved solids, but similar Trichoptera assemblages and environmental parameters were recorded in both forest and buffer streams. Although differences between the latter two stream types were not statistically significant, buffer streams had the highest abundance and taxonomic richness. Comparison with past literature also reveals differences in recorded Trichoptera diversity, thus this study presents an updated record for Trichoptera in Singapore’s streams. These findings further add to a baseline for future biomonitoring, research, and informing long-term freshwater conservation efforts in Singapore.

Caddisflies (Trichoptera) are among the most diverse groups of freshwater animals with more than 16 000 described species. They play a fundamental role in freshwater ecology and environmental engineering in streams, rivers and lakes. Because of this, they are frequently used as indicator organisms in biomonitoring programmes. Despite their importance, key questions concerning the evolutionary history of caddisflies, such as the timing and origin of larval case making, remain unanswered owing to the lack of a well-resolved phylogeny. Here, we estimated a phylogenetic tree using a combination of transcriptomes and targeted enrichment data for 207 species, representing 48 of 52 extant families and 174 genera. We calibrated and dated the tree with 33 carefully selected fossils. The first caddisflies originated approximately 295 million years ago in the Permian, and major suborders began to diversify in the Triassic. Furthermore, we show that portable case making evolved in three separate lineages, and shifts in diversification occurred in concert with key evolutionary innovations beyond case making.

We describe a new species of the genus Calamoceras which currently has only two species: Calamoceras illiesi Malicky & Kumanski 1974 and Calamoceras marsupus Brauer 1865. We also discuss its ecology by analyzing some biophysical parameters. The larva and the adult of this new species, Calamoceras riffensis sp. nov. have been found by specialists from the Rif region in northwestern Morocco since 1998. All the specimens collected differ from the two known species by conspicuous morphological differences.

Based on a recalibrated BEAST diversification time analysis, we provide a revised chronology for the evolution of major lineages of Trichoptera. Fossil evidence indicates that caddisflies evolved at least by the Norian of Late Triassic (median age 222.6 Ma), compared with our estimate of at least 201.3 Ma. The ancestors of suborders Annulipalpia and Integripalpia also evolved as early as the Norian. Fossil evidence indicates that the ancestor of subterorder Phryganides lived at least by the Aalenian of Middle Jurassic (median age 173.6 Ma), compared with our estimate of at least 174.1 Ma.

Phragmosis, or the use of specially modified body parts and associated behaviors to block an opening as defense against predators, is a commonly observed phenomenon in certain ants and termites that block entrances of their subterranean nests with large, flat heads. It has been reported in some beetles and other insects and even in some frogs. Common features of phragmosis in caddisfly larvae include a hard and usually flat body surface, with or without stout spines, and the behavior of fitting that body surface tightly in the opening of its case. A different defensive strategy occurs in snails and case-making larvae of camptosomate leaf beetles (Chrysomelidae: Cryptocephalinae and Lamprosomatinae) that protect themselves from predators by securing the openings of their shells or cases firmly against the substrate, a behavior we call “cathaptosis.” Common features of cathaptosis in caddisfly larvae include a case with its vulnerable opening oriented parallel with the substrate and accompanied by behavior that grips the substrate, fixing the case opening firmly against it when threatened. We suggest that these defensive strategies have evolved multiple times in Trichoptera, especially in case-making larvae. We demonstrate some examples and provide tentative lists of caddisflies whose larvae may have evolved these defensive strategies.