The induction of diapause in Moina by species-specific chemical cues

ISSN： 1386-2588

Source： Aquatic Ecology, Vol.41, Iss.2, 2007-06, pp. : 255-261

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Abstract

The ability to change the reproduction mode and produce diapausing eggs, which is prevalent in many zooplankton species, significantly impacts on the evolution and ecology of aquatic communities. The production of diapausing eggs is controlled by multiple effects of biotic and abiotic factors, including infochemicals. We have investigated the effects of chemicals exuded by conspecifics and ecologically close competing congers, Moina brachiata and M. macrocopa, which coexist in the same water body, and by larger Cladocera species (Daphnia magna) on the change of reproduction mode, specific growth rate and fecundity of M. brachiata and M. macrocopa females. The production of gametogenetic eggs in both species was detected only in waters from crowded cultures of conspecifics. The water from crowded cultures of conspecifics reduced the specific growth rate of the juvenile females of both species that later switched to gametogenesis. While it either did not affect (in M. macrocopa) or even increase (in M. brachiata) the specific growth rate of the juvenile females that later reproduced by parthenogenesis. Females of M. macrocopa released significantly fewer neonates in the water from crowded cultures of conspecifics than in all other treatments, while the fecundity of M. brachiata females was the same in all treatments. To understand the phenomenon of diapause induction under the effect of chemical cues in zooplankton, a link between laboratory tests and ecological research should be established, and the chemical composition of the signals should be determined.