Lepidoptera

Introduction

Moths and butterflies. A very large order of some 112,000 species worldwide, over 11,000 species occur in North America north of Mexico. Only secondarily aquatic, very few species are truly aquatic, most are associated with aquatic and semiaquatic vegetation, mostly polypneustic. Use silk extensively, some make cases. Endopterygota, holometabolous.

Recognition

Larvae without wingpads, thoracic legs well developed, abdominal prolegs present with crochets. Pupae are obtect with 2 pair of wings, above or below water. Adults with 2 pairs of membranous wings covered with overlapping scales, mouthparts a coiled sucking tube.

Life Cycle

The eggs hatch to the first instar larvae, which often lacks the gills of older instars. There are generally 4 to 6 larval instars. May be univoltine of multivoltine. Pupation normally occurs in the habitat of the larvae. Adults mate and lay the eggs in the habitat of the larvae.

Trophic Roles

Most members of the order are plant feeders (shredders- herbivores). Many of the semiaquatic species feed directly on aquatic vascular plants, which is very rare in primary aquatic groups. Some scrap algae from rocks.

Communities

Very simple with seldom more than couple species found in any water body. Many populations are heavily parasitized.

Economic Importance

Terrestrial species include many important plant pests. Some aquatic species may be useful in controlling aquatic plants.

Collecting

Larvae of the lotic scrapers may be taken in normal benthic samples. Plant feeders must be picked from or cut out of the plant material by hand. Some leaf and stem mining species leave holes and feces exposed on the floating leaves. Adults are generally attracted to lights.

Rearing

The pupae can be easily reared until the adults emerge, by keeping them alive in a cool place. Getting the larvae to pupae can be more difficult.

Preservation

Larvae are best fixed in Kahle's fluid and transferred to 70% ethanol after a few days. Adults must be collected dry, killed in a killing jar and pinned or pointed with the wings spread. Double mounts with minutens are usually necessary.

Taxonomy

The more fully aquatic species are poorly known. Numerous nomenclatural changes complicate use of the older literature. A specialists' group.

Family Pyralidae- a very large family, contains the most fully aquatic species. Three main ecological groups: lentic case building shredders, lotic scrapers, and leaf or stem miners.

Montana Species list

  • Family Pyralidae
    • Petrophila spp.

Updated on 23 NOV 1995 D.L. Gustafson
AIM home page
dlg@rivers.oscs.montana.edu