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Behavioral mechanisms controlling vertical migration in Daphnia
Author(s) -
Young Stephen,
Watt Penelope
Publication year - 1993
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1993.38.1.0070
Subject(s) - diel vertical migration , daphnia , excursion , morning , predation , biology , fish <actinopterygii> , daylight , ecology , environmental science , fishery , crustacean , botany , physics , optics , political science , law
We used infrared video monitoring to study cladoceran vertical migration in laboratory tanks exposed to natural and simulated daylight cycles. There are changes in the behavior patterns at different times of the year, with both Daphnia magna and Daphnia longispina showing increased vertical migration and greater average depth later in the year. This change in behavior pattern is due to temperature, not daylength, changes. Our animals show a complex endogenous migration pattern, with a strong downward excursion in the middle of the night, another before dawn, and then a morning rise, of which only the last depends on a visual stimulus. We propose that the morning rise acts as a correcting movement bringing animals to a depth just safe from visual predators. The midnight sinking is unlikely to be due to a random spreading‐out process. Fish taste cues enhanced the dawn excursion, but not the midnight one. Responses to fish cues were most pronounced for D. magna at low temperatures.