Life History of Sialis (Megaloptera: Sialidae) in a Lentic and Lotic Ecosystem in Central Texas

We studied the life history and feeding habits of two coexisting and closely related sister species of Sialis (Sialis itasca Ross and Sialis velata Ross) from a reservoir and river in central Texas. Measurement of larval head capsules and emergence showed the two species to have 10 larval instars, a...

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Bibliographic Details
Published in:The American midland naturalist 2006-01, Vol.155 (1), p.50-62
Main Authors: LOCKLIN, JASON L, ARSUFFI, THOMAS L, BOWLES, DAVID E
Format: Article
Language:English
Subjects:
Aquatic insects
Capsules
Competition
Contents
Diet
Ecological life histories
Ecology
Environmental conditions
Insect ecology
Insect larvae
Insects
Instars
Lakes
Larvae
Larval development
Life cycles
Physical growth
Water temperature
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Summary:We studied the life history and feeding habits of two coexisting and closely related sister species of Sialis (Sialis itasca Ross and Sialis velata Ross) from a reservoir and river in central Texas. Measurement of larval head capsules and emergence showed the two species to have 10 larval instars, and the seasonal distribution of immature and adult life stages showed synchronous, seasonal, univoltine life histories with a single cohort. Life history dynamics were somewhat faster in the river, probably due to higher temperatures during the larval growth periods. Larvae exhibited a more rapid larval development rate and earlier prepupal and adult emergence patterns relative to those reported from more northern latitudes. However, a univoltine life cycle appears to represent the norm for Sialis in geographic locations where water temperatures are not limiting to growth and suggests that evolutionary/genetic constraints play a greater role in regulating life history in these insects than environmental factors. Analysis of larval diets showed prey consumed by members of both populations consisted of ostracods, oligochaetes and chironomids.
ISSN:0003-0031
1938-4238
DOI:10.1674/0003-0031(2006)155[0050:LHOSMS]2.0.CO;2