Comparison of Simulium jenningsi (Diptera: Simuliidae) Larval Gut Contents across Instars
Start Date
13-11-2015 8:00 PM
End Date
13-11-2015 9:59 PM
Description
Black fly larvae (Diptera: Simuliidae) are a widely distributed and oftentimes dominant consumer in lotic ecosystems. However, detailed information on the composition of their diet across instars is lacking. Knowledge of their diet is important in order to understand their ecological significance as well as advance sustainable management efforts. For instance, differential instar susceptibility to Bacillus thuringiensis var. israelensis (Bti), the primary larvicide used to suppress pestiferous adult populations, has been identified. Further, current science suggests that larval diet, particularly diatoms, may contribute to impaired Bti effectiveness. Therefore, we examined gut diatom density, species composition, diversity, morphology, and ecological guilds across larval instars of Simulium jenningsi, the target species of management programs. Larval collections were made in conjunction with the Pennsylvania Department of Environmental Protection Black Fly Suppression Program from lotic systems primarily within the Susquehanna River basin (n= 14). We measured collected larvae and assigned them to size (instar) categories. Intact larvae were then subjected to a chemical digestion procedure yielding “cleaned” diatoms. A minimum of 300 diatom valves were identified to species and enumerated. Diatom community metrics were compared among instars and between geographic regions using ANOVA. A total of 134 diatom sp. were recovered from Simulium gut analyses. Preliminary results for community metrics will be discussed. Our work here provides a practical technique for detailed examination of Simulium larval gut contents across instars, ecological and spatial information on diatom consumption, and insight into a potentially important variable affecting Bti efficacy and population management of black flies in the commonwealth.
Type
Poster
Language
eng
Comparison of Simulium jenningsi (Diptera: Simuliidae) Larval Gut Contents across Instars
Elaine Langone Center, Terrace Room
Black fly larvae (Diptera: Simuliidae) are a widely distributed and oftentimes dominant consumer in lotic ecosystems. However, detailed information on the composition of their diet across instars is lacking. Knowledge of their diet is important in order to understand their ecological significance as well as advance sustainable management efforts. For instance, differential instar susceptibility to Bacillus thuringiensis var. israelensis (Bti), the primary larvicide used to suppress pestiferous adult populations, has been identified. Further, current science suggests that larval diet, particularly diatoms, may contribute to impaired Bti effectiveness. Therefore, we examined gut diatom density, species composition, diversity, morphology, and ecological guilds across larval instars of Simulium jenningsi, the target species of management programs. Larval collections were made in conjunction with the Pennsylvania Department of Environmental Protection Black Fly Suppression Program from lotic systems primarily within the Susquehanna River basin (n= 14). We measured collected larvae and assigned them to size (instar) categories. Intact larvae were then subjected to a chemical digestion procedure yielding “cleaned” diatoms. A minimum of 300 diatom valves were identified to species and enumerated. Diatom community metrics were compared among instars and between geographic regions using ANOVA. A total of 134 diatom sp. were recovered from Simulium gut analyses. Preliminary results for community metrics will be discussed. Our work here provides a practical technique for detailed examination of Simulium larval gut contents across instars, ecological and spatial information on diatom consumption, and insight into a potentially important variable affecting Bti efficacy and population management of black flies in the commonwealth.