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Juvenile survival of a planktonic insect: effects of food limitation and predation
Author(s) -
FISCHER JANET M.,
MOORE MARIANNE V.
Publication year - 1993
Publication title -
freshwater biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 156
eISSN - 1365-2427
pISSN - 0046-5070
DOI - 10.1111/j.1365-2427.1993.tb00786.x
Subject(s) - copepod , predation , biology , juvenile , predator , instar , ecology , plankton , zooplankton , zoology , larva , crustacean
SUMMARY1 An experiment was conducted to investigate potential impacts of food limitation and copepod predation on juvenile survival of Chaoborus purtctipennis . We tested the hypotheses that: (i) juvenile survival of Chaoborus is influenced more by copepod predation than by starvation in a productive environment, and (ii) food limitation and predation interact to affect survival. 2 Effects of food concentration (approximately 800, 1400 and 2300 microzooplankton 1‐ −1 ) and predator density (0, 1 and 2 Mesocydops edax 1‐ −1 ) on Chaoborus development and survival were evaluated using a 3 × 3 factorial design. Jars containing lake water, the appropriate food and predator treatments, and two Chaoborus (<12h old) were rotated on a plankton wheel at 25°C. Survival and developmental stage were monitored daily until all individuals had either died or moulted to instar II. 3 Predation by Mesocydops was the major source of mortality, causing 87.5% of Chaoborus deaths over all treatments. Chaoborus mortality was significantly higher in treatments with Mesocydops (67–100%) than in predator‐free treatment (0–13%). 4 Development time was significantly longer in the low‐density food treatment than in the highest food treatment. 5 No significant interaction between food limitation and predation was detected. 6 These results suggest that predation by copepods may limit recruitment of juvenile Chaoborus in productive lakes.