Premium
Direct positive effect of invertebrate predators on birth rate in Daphnia studied with a new method of birth rate analysis
Author(s) -
Polishchuk Leonard V.
Publication year - 1995
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.1995.40.3.0483
Subject(s) - predation , daphnia , biology , invertebrate , cladocera , ecology , branchiopoda , zoology , avian clutch size , birth rate , crustacean , reproduction , population , demography , sociology , research methodology
Three natural Daphnia populations in which the previously established impact of invertebrate predators on the death rate (but not on the birth rate) were investigated. Two other cladoceran populations primarily affected by food were used for comparison. The effect of predators on the per capita birth rate of Daphnia was detected by decomposing changes in birth rate into components dependent on changes in egg development rate, mean clutch size, and proportion of adults and then comparing them. This method revealed short‐term changes in the proportion of adults, which dominated changes in birth rate. The effect can be attributed to size‐selective feeding of the invertebrate planktivores that normally prey on young daphnids, and it did not occur in food‐dependent cladocerans. Invertebrate predation pressure tends to increase the per capita birth rate of Daphnia, which may provide a mechanism that stabilizes prey.