The caddisflies (Trichoptera, from Greek trichos, “hair”, and pteron, “wing”) are arthropods of the Class Insecta whose adults have wings covered with hairiness. Almost all of the species depend on the aquatic environment for their development. The majority inhabit rivers and streams of clean and well-oxygenated waters, although they can also be found in lentic, terrestrial and even marine environments. They are related to butterflies and moths (Lepidoptera), hence their resemblance to the latter. They are known, especially by fishermen, for the ability of their larvae to make a wide variety of constructions such as portable cases, fixed shelters, food collection nets and galleries, with silk and various materials.
Three rivers of a certain size (Río Guadalfeo, Río Chíllar, and Río Verde) flow part of their waters into the sea along the coast of Granada. However, the intermittency of the water flow and the quality of their waters do not make them suitable for the establishment of a stable community of Trichoptera. The fauna of aquatic invertebrates of these rivers in some upstream locations has been studied, so we can present the list of caddisfly species that inhabit a few hundred meters before the mouth of the sea.
| TRICHOPTERA COAST | Río Chíllar (124 m) | Río Guadalfeo (160 m) | Río Verde (160 m) |
| Rhyacophilidae | |||
| Rhyacophila munda | X | X | X |
| Ryacophila nevada | X | ||
| Glossosomatidae | |||
| Agapetus incertulus | X | ||
| Agapetus sp. | X | ||
| Hydroptilidae | |||
| Hydroptila sp. | X | X | X |
| Hydropsychidae | |||
| Hydropsyche brevis | X | ||
| Hydropsyche iberomaroccana | X | ||
| Hydropsyche infernalis | X | X | |
| Hydropsyche pellucidula | X | ||
| Psychomyiidae | |||
| Tinodes sp. | X | X | |
| TOTAL | 6 | 4 | 6 |
List of caddisfly species in three rivers of the Granada coast. Data from Río Verde are unpublished (Jesús Picazo and Antonino Sánchez-Ortega, leg.).
BIOLOGY OF THE GROUPS
Rhyacophilidae have larvae that predate on other aquatic insect larvae, do not build portable cases, and are inhabitants of the river's rapid-water zone. They generally live in clean and cold waters, although Rhyacophila mundais quite tolerant of warmer waters and with a certain amount of organic pollution. R. mundais widely distributed throughout the Iberian Peninsula and in North Africa. Rhyacophila nevadais a less tolerant species and an Iberian endemism.
The larvae of the Glossosomatidae can live in low and middle sections of the rivers since they prefer waters with moderate current speed. They make small dome-shaped stony cases and feed by scraping algae from the substrate. The species Agapetus incertulusis distributed throughout the central and southern Iberian Peninsula, as well as in North Africa.
Hydroptilidae are known by the name of “microtrichoptera2 because the smallest species of the order belong to this family. The larvae build and transport a case made of silk only, with algae and/or small grains of sand. They live in both slow and fast waters, feeding on periphyton, filamentous algae and/or organic particles.
The Hydropsychidae is one of the most widely distributed groups of caddisflies in the world, with many species that replace each other’s along river ecosystems. The larvae mainly develop on stony substrates with moderate to high current water flow. They filter and capture the organic material through a net that they make with silk in their shelter. The species collected in these locations are typical of medium-low stretches of rivers and tolerant to medium levels of organic pollution. Hydropsyche brevisis an Iberian-Pyrenean endemism, H. iberomaroccanais only present in the south-eastern of the Iberian Peninsula and in northern Africa, H. infernalisis also an Iberian endemism, of the central and southern peninsular, while H. pellucidulahas a wide European distribution.
Finally, Psychomyiidae larvae are found in the middle and lower reaches of rivers and streams. They build galleries with silk on stones or submerged surfaces, and cover them with grains of sand. They feed by scraping benthic algae and diatoms.
BIBLIOGRAPHY
- Jáimez-Cuéllar, P. (2004) Caracterización físico-química, macroinvertebrados acuáticos y valoración del estado ecológico de dos cuencas mediterráneas de influencia nival (Ríos Guadalfeo y Adra), según los criterios de la Directiva Marco del Agua. Tesis Doctoral. Universidad de Granada, Granada. 226 pp.
- González-Titos, A., Sáinz-Bariáin, M. & Zamora-Muñoz, C. (2018) Tricópteros (Trichoptera) del Parque Natural de las Sierras de Tejeda, Almijara y Alhama (sur de España). Boletin de la Asociacion Espanola de Entomologia 42, 13–32.
- Zamora-Muñoz, C., Sáinz-Bariáin, M. & Bonada, N. (2015) Orden trichoptera. Revista IDE@-SEA 64, 1–21.
CARMEN ZAMORA MUÑOZ