Caddisflies

Trichoptera.

Caddisflies populate all types of freshwater habitats in Latin America, both in running waters (springs, streams, waterfalls, seeps, rivers) and standing waters (lakes, ponds, marshes, pools). Some Phylloicus develop in the leaf axils of bromeliads. A few Atanato-lica move out to the moist margins of seeps and are virtually terrestrial (Holzenthal 1988).

The immatures are somewhat similar to lepidopterous larvae but with the abdominal prolegs restricted to the terminal segment and bearing anal claws. All types produce silk and are free-living, make fixed retreats, or construct portable cases for themselves. The retreat makers use silk for fabricating shelters and food-trapping nets. The case makers use silk as a matrix to bind together the material composing their cases, such as leaf fragments, twigs, and sand grains. Some cases are constructed entirely of silk. Although some case types are very characteristic, usually of genera, others, such as the common tapering, cylindrical, sand grain case, are made by a number of species in a variety of genera and families. Larvae of the lepto-cerid genus Triplectides will pick up and use empty cases of other caddisflies or make their own by tunneling a small stick. Most cases are tubular, but others may have the form of a snail shell (Helicopsyche) or may be somewhat flattened, four sided, or purselike (Hydroptilidae). Dense masses of the long, tusk-shaped cases of Atanatolica and Grumichella (Leptoceridae) and Gru-micha (Sericostomatidae) are often seen clinging to rock faces in waterfalls. These cases are made entirely of silk or have fine sand incorporated in their walls (Holzenthal 1988, Müller 1880).

The part of the larva protected by the case is generally weakly sclerotized in case makers. The free-living types are well pigmented and thick skinned throughout.

Among still water species, the larval food consists primarily of algae, fungi, and decaying organic matter and occasionally living plant tissue. Some free-living larvae, especially those in fast water, are preda-ceous on other aquatic invertebrates.

Adult caddisflies are mothlike, with body and wings clothed in short, easily detached, hairlike scales. At rest, they hold their fore wings rooflike over the body at a steep angle. The antennae are usually very long and filamentous. This stage lives near the larval habitats, and the diurnal species are often seen resting on rocks and vegetation by the water's edge. Many of the nocturnal species are attracted to artificial light.

The order is well studied generally, but very little ecological or natural history information is available specifically on Neotropical representatives (Flint 1977, 1981; Bueno-Soria and Santiago Fragoso 1982). McElravy and others (1981, 1982) compared the diversity of species at a nonseasonal site in Panama to that of Nearctic streams and found it not significantly higher but with relatively less variation over long time periods.

The order's taxonomy in the region is likewise very incomplete. According to Flint (pers. comm.), there are probably between 3,000 and 4,000 species, although only about 1,200 to 1,500 are now described (Fischer 1960-1973). Flint (1983) also provides a key to the South American families that is of general use for all of Latin America. Through the lowlands, the most common species are found in the families Leptoceridae (e.g., the black-and-white speckled Nectopsyche; fig. 6.5d, e) and Hydropsychidae (e.g., pale green Leptonema albovirens; fig. 6.5a, b). In Patagonian habitats, there are many Limnephilidae (especially Dicosmoecinae). The dominant free-living, actively predatory, Holarctic genus, Rhyacophila, is absent and replaced by the Hydrobiosidae (e.g., Atopsyche callosa; fig. 6.5c). The family Anamolo-psychidae is restricted to the far southern regions, as are the Helicophidae, Kokiri-idae, Philorheithridae, Stenopsychidae, Ta-simiidae, and a number of genera in other families (e.g., Leptoceridae: Hudsonema, Notalina; Holzenthal 1986a, 19866). All show a distinct relationship to taxa in Australia and New Zealand. Lepidostoma-tidae are present in montane areas of Mexico and Central America but absent from South America.

In parts of Brazil, the larval cases (called curubixá or grumixá) are admired by the Indians as artworks of nature and used to adorn clothing and the body. Some watercourses are even given these names because of the common occurrence of caddis flies in them (Ihering 1968: 328).

References

Bueno-Soria, J., and S. Santiago Fragoso. 1982. Trichoptera. In S. H. Hurlbert and A. Villalobos Figueroa, eds., Aquatic biota of Mexico, Central America and the West Indies. San Diego State Univ., San Diego. Pp. 398-400.

Flint, Jr., O. S. 1977. Trichoptera. In S. H. Hurlbert, ed., Biota acuática de sudamérica austral. San Diego State Univ., San Diego. Pp. 249-253.

Flint, Jr., O. S. 1981. Trichoptera. In S. H. Hurlbert, G. Rodriguez, and N. Dias dos

Figure 6.5 CADDISFLIES. (a) Hydropsychid caddisfly (Leptonema sp., Hydropsychidae) larva, (b) Hydropsychid caddisfly (Leptonema albovirens). (c) Hydrobiosid caddisfly (Atopsyche callosa, Hydrobiosidae) larva, (d) Leptocerid caddisfly (Nectopsyche sp., Leptoceridae), larva in case, (e) Leptocerid caddisfly (Nectopsyche punctata).

Figure 6.5 CADDISFLIES. (a) Hydropsychid caddisfly (Leptonema sp., Hydropsychidae) larva, (b) Hydropsychid caddisfly (Leptonema albovirens). (c) Hydrobiosid caddisfly (Atopsyche callosa, Hydrobiosidae) larva, (d) Leptocerid caddisfly (Nectopsyche sp., Leptoceridae), larva in case, (e) Leptocerid caddisfly (Nectopsyche punctata).

Santos, eds., Aquatic biota of tropical South America. Pt. 1. Arthropoda. San Diego State Univ., San Diego. Pp. 221-226.

Flint, Jr., O. S. 1983. Studies of Neotropical caddisflies. XXXIII. New species from austral South America (Trichoptera). Smithsonian Contrib. Zool. 377: 1-100.

Fischer, F. C. J. 1960-1973. Trichopterorum catalogus. 15 vols. Nederlandsche Entomol. Ver., Amsterdam.

Holzenthal, R. W. 1986a. Studies in Neotropical Leptoceridae (Trichoptera). VI. Immature states of Hudsonema flaminii (Naväs) and the evolution and historical biogeography of Hudsonemini (Triplectidinae). Entomol. Soc. Wash. Proc. 88: 268-279.

Holzenthal, R. W. 19866. The Neotropical species of Notalina, a southern group of long-horned caddisflies (Trichoptera: Leptoceridae). Syst. Entomol. 11: 61—73.

Holzenthal, R. W. 1988. Studies in Neo tropical Leptoceridae (Trichoptera). VIII. The genera Atanatolica Mosely and Grumi-chella Müller (Triplectidinae: Grumichellini. Amer. Entomol. Soc. Trans. 114: 71-128.

Ihering, R. von. 1968. Dicionário dos animais do Brasil. Ed. Univ. Brasilia, Säo Paulo.

McElravv, E. P., V. H. Resh, H. Wolda, and O. S. Flint, Jr. 1981. Diversity of adult Trichoptera in a "non-seasonal" tropical environment. 3d Int. Symp. Trichoptera, Ser. Entomol., Proc. 20: 149-156.

McElravy, E. P., H. Wolda, and V. H. Resh. 1982. Seasonality and annual variability of caddisfly adults (Trichoptera) in a "non-seasonal" tropical environment. Arch. Hydro-biol. 94: 302-317.

Müller, F. 1880. Sobre as casas construidas pelas larvas de insetos Trichoptera da Provincia de Santa Catharina. Mus. Nac. Rio de Janeiro Arch. 3: 99-134, 210-214, pis. 8-11.

0 0

Post a comment