Nature Lab

Each month, we highlight research MDC uses to improve fish, forest, and wildlife management.

Species of Conservation Concern

Caddisfly Study

If you’re a fly-angler, you’ve probably tied a caddisfly pattern or two. Whether as stream-dwelling larvae or mothlike adults, caddisflies tempt hungry fish.

Caddisflies can also be viewed as animal representatives of their associated habitat systems. This means their presence, abundance, and health indicate the condition of their native places.

One caddisfly species, Glyphopsyche missouri, occurs at Maramec Spring and nowhere else on Earth. Another, Agapetus artesus, also occurs at Maramec Spring. They represent fauna of the cave and karst/springs habitat system described in the Missouri State Wildlife Action Plan.

“However,” said MDC Scientist Bill Mabee, “little is known about the distribution, life history, environmental requirements, or tolerance to environmental stress of either species.” Mabee led a team to determine if the two species, neither of which had been studied in more than a decade, still occur within their native range.

In the fall of 2017, Mabee’s team scouted Maramec Spring Branch and the Meramec River to document the species’ occurrence and characterize their aquatic habitat. They collected enough evidence to make a second visit in January of 2018.

“Our efforts reaffirmed populations of these two species persist in the Maramec Spring Branch,” Mabee said. “We also were able to start filling knowledge gaps about these species’ habitat-use during their early life stages.”

To ensure maintenance of sustainable populations, Mabee said, more detailed studies of distribution, life history, and environmental requirements of these and other cave and karst/springs habitat system species are needed.

“The more we know about these species’ needs, the better we can conserve them and the habitat elements — including stream characteristics and plant species — they depend on,” he said.

Caddisfly Study at a Glance

MDC’s Research Partners

Missouri State University, The James Foundation, U.S. Geological Survey

Management Implications

To ensure sustainable populations, more detailed studies of distribution, life history, and environmental requirements of G. missouri and other aquatic species associated with spring habitats are needed.

Objectives

• Determine if populations of either species persist in Maramec Spring Branch
• Characterize early life-stage habitat
• Obtain information on diet of G. missouri larvae

Methods

• Sampling: Collect larvae by hand and characterize habitat at collection sites
• Taxonomy: Identify larvae, case-making materials, and gut contents

Findings

• Larval cases indicated use of fine gravel, slender sticks, shells of immature aquatic snails, and bits of red algae
• G. missouri specimens dissected for dietary analysis revealed fragments of several species of algae and moss

Learn more at research.mdc.mo.gov.