US Long-Term Ecological Research Network
Juvenile survival of a planktonic insect: effects of food limitation and predation
Year of Publication
1993
DOI
10.1111/j.1365-2427.1993.tb00786.x
Volume
30
Number of Pages
35-45
1. 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 (\textless12h 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.