Show simple item record

dc.contributor.authorSandberg, John B.
dc.date.accessioned2020-10-21T20:15:18Z
dc.date.available2020-10-21T20:15:18Z
dc.date.issued1996-08
dc.identifier.urihttp://digital.library.wisc.edu/1793/80662
dc.description.abstractThree stonefly species (Plecoptera: Perlodidae) were studied in two central Wisconsin trout streams from January 1992 to June 1994. Nymphal growth data suggested each had a (slow) univoltine life cycle. All had eggs that were ovoid in shape and round in cross section. Isoperla lata Frison first instar nymphs hatched in mid June and required approximately 11 months before completing development. Growth rate was nearly exponential from June to January (maximum average size attained in February) and then declined until emergence. There were approximately 11-17 instars. Females were, on average, larger than males throughout the growth period. Nymphs were primarily carnivorous throughout development and fed on Chironomidae, Ephemeroptera, and Plecoptera. Adults exhibited a 6-18 day synchronous emergence beginning in mid to late April when stream temperature was approximately 14°C. Longevity was 2-25 (x = 18.2 ± 4.51) days for males and 7-39 (x = 21.7 ± 5.35) days for females. Mean fecundity of dissected females was 322 ± 121 eggs. Ova measured approximately 363 μm in length and exhibited a synchronous short term hatch which lasted approximately 40-46 days ( x = 43 ± 3). Isoperla cotta Ricker nymphal development was observed for seven months and growth rate was continuous from December to June. Maximum average size was attained before emergence in early June. On average, males were slightly larger than females until late April when females grew larger. Nymphs were carnivorous and fed primarily on Chironomidae. Adults exhibited a 15-20 day synchronous emergence beginning in late May to early June when stream temperature was approximately 15°C. Longevity was 6-8 (x =7.17±0.68) days for males and 1-10(x =6.61 ±2.2) days for females. Ova measured 262 μm in length and only one dissected female contained 161 mature eggs. Isoperla slossonae (Banks) nymphs were observed for 10 months and growth rate was nearly exponential from September to April (maximum average size was attained in April) and then declined until emergence. Females, on average, were larger than males throughout the growth period. Nymphs primarily fed on Chironomidae, diatoms and algae. Adults exhibited a 19-29 day synchronous emergence beginning in late April to early May when stream temperature was approximately 12°C. Longevity was 1-23 (x = 12.74 ± 5.81) days for males and 2-28 (x = 17.36 ± 4.78) days for females. Mean fecundity of dissected females was 390 ± 127 eggs. Ova measured 265 μm in length.en_US
dc.description.sponsorshipCentral Wisconsin Chapter of Trout Unlimited, the Natural Resource Management Division at Fort McCoy, WI, and the Biology and Water Resources Departments at the College of Natural Resources, University of Wisconsin-Stevens Point.en_US
dc.language.isoen_USen_US
dc.publisherUniversity of Wisconsin-Stevens Point, College of Natural Resourcesen_US
dc.titleLife Cycles of Isoperla Lata Frison, I. Slossonae (Banks), and I. Cotta Ricker (Plecoptera: Perloididae) in two Central Wisconsin Streamsen_US
dc.typeThesisen_US


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record