Saturday, October 6, 2012

EPT Species List for Central Virginia: Caddisfly Photos, Part I.

In the photo above -- an unidentified common netspinner found last year in Missoula, Montana.

Entomologists divide caddisflies (Trichoptera) into three different groups: Spicipalpia, Annulipalpia, and Integripalpia.  These names refer to the nature of the terminal apex of the maxillary palps on the adults: spica = pointed; annulus = ringed; integra = entire/complete (see Glenn Wiggins, Caddisflies: The Underwater Architects, pp. 12, 107, 123, and 151).  With a focus on the lives of the larvae, Wiggins argues that the Integripalpia caddis are the "portable case-makers": the Annulipalpia caddis are the "fixed-retreat-makers" (which make nets for collecting their food): and the Spicipalpia caddis are "closed-cocoon-makers," making special cocoons for pupation.  (Wiggins, Caddisflies, pp. 12-28)
In terms of the caddis larvae that we see in our streams, the Spicipalpia group is comprised of the "free-living caddisflies" (Rhyacophilidae), the so-called "saddle case-makers" (Glossosomatidae), and the so-called "purse-makers," or "micro caddisflies" (Hydroptilidae).  He argues that Glossosomatids and Hydroptilids are not true case-makers.  (For his argument, see, especially, pp. 28-28 and 65-71.)

I will present my photos of caddisfly larvae, by species, in three different entries: 1) the Spicipalpia
families and two of the Annulipalpia families -- the fingernets (Philopotamidae) and the trumpetnet makers (Polycentropodidae);  2) the third Annulipalpia family -- the common netspinners (Hydropsychidae); and 3) Integripalpia -- i.e. all of the case-maker families.

III. Trichopera: Spicipalpia

 Rhyacophilidae (free-living caddisflies)

1. Rhyacophila carolina.  Size: not given by Beaty; Season: Winter into Spring.

2. Rhyacophila fuscula.  Size: large; Season: Fall, Winter, Spring

early instar -- head pattern not fully developed
cocoon: larva in pupation

3. Rhyacophila nigrita. Size: not given by Beaty; Season: Winter and Spring.

4. Rhyacophila glaberrima.  Size: 12 mm??; Season: Winter.

5. Rhyacophila ledra/fenestra.  Size: 14 mm; Season: Winter and Spring.

6. Rhyacophila sp. (banksi complex?)

Glossosomatidae (Saddle-case makers)

1. Glossosoma nigrior.  Size: 4-5 mm; Season: Winter and Spring.

dorsal view of case
ventral view of case revealing larva stretched over its "saddle"
dorsal view of case: larva crawling
larva emerging from case
larva outside of case: note "stubby" prolegs

Hydroptilidae ("purse-makers," micro caddisflies)

1. Hydroptila (?).  Size: up to 5 mm; Season: Summer.  (Note: I've never seen one larger than 2mm.)

microscope photos of preserved specimen
larva next to grain of rice

III. Trichopera: Annulipalpia (in part)

Philopotamidae (fingernet caddisflies)

1. Chimarra.  Size: up to 12.5 mm; Season: Late Summer into Early Winter.

2. Dolophilodes distincta.  Size: 11-12 mm; Season: Fall and Winter.

pupa in cocoon: note that cocoon is covered by a "dome" of pebbles

3. Wormaldia.  Size: up to 14.5 mm; Season: Winter and Spring.

Polycentropodidae (Trumpetnet caddisflies)

1. Polycentropus.  Size: up to 25 mm; Season: Spring and Summer.

No comments:

Post a Comment