CIRCADIAN CHANGES IN FEEDING ACTIVITY AND DIET OF HYDROPSYCHE SAXONICA MCLACHLAN, 1884
| Authors | |
|---|---|
| Year of publication | 2005 |
| Type | Article in Proceedings |
| Conference | Symposium RIVER BOTTOM VI, Book of abstracts |
| MU Faculty or unit | |
| Citation | |
| Field | Zoology |
| Keywords | Hydropsyche saxonica; instars; circadian changes; feeding activity; diet |
| Description | Circadian changes in feeding activity and diet of IV and V instar larvae of Hydropsyche saxonica were studied in the Vrbovecký brook (Czech Republic) during one 24-hour period on 22nd and 23rd October 2004. The larvae were hand-picked at 6-hour intervals. The ratio maximum foregut width/head capsule width was used to determine gut fullness. A one-way ANOVA revealed significant differences in gut fullness among V instar larvae collected at different times. Mean value of the ratio was higher for the larvae collected at dusk and at dawn indicating their crepuscular activity. No significant differences were recorded for IV instar larvae. The contents of larval foreguts were analysed using millipore filter technique. There were no differences in gut contents among the V instar or among the IV instar larvae collected at different times. But the difference between gut contents of V instar and IV instar larvae was significant. Amorphous detritus was the most important food source for IV instars whereas V instars fed mainly on animal food |
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