Bosmina longirostris

About: Bosmina longirostris is a research topic. Over the lifetime, 458 publications have been published within this topic receiving 15814 citations. The topic is also known as: Bosmina longirostris.

Predation, Body Size, and Composition of Plankton

Abstract: ARTICLES Organic Fluorine Chemistry: C. G. Krespai.................................. Expanding rapidly, the science of these compounds has assumed both theoretical and practical importance. The Biological Synthesis of Cholesterol: K. Bloch .............................. Predation, Body Size, and Con-mposition of Plankton: J. L. Brooks and S. I. Dodson ... The effect of a marine planktivore on lake plankton illustrates theory of size, competition, and predation. 7

Possibility of N or P limitation for planktonic cladocerans: An experimental test

Abstract: Threshold food N : C or P : C ratios, below which net production is N or P limited, were calculated for two cladocerans, Daphnia galeata and Bosmina longirostris, based on the N and P contents of body tissue and the C balance between ingestion and net production rates under experimental conditions with various food concentrations from 0.05 to 2.50 mg C liter-‘. With changing food concentration, the threshold N: C and P: C ratios for D. galeata changed in weight ratio from 0.039 to 0.077 and 0.0067 to 0.0120, respectively, with the lowest value at the high food concentration. Changes in threshold ratios for B. longirostris, however, were small and mean values were 0.085 and 0.0080 for the N: C and P: C ratios. As a result, the threshold N: C ratio for D. galeata was lower than for B. longirostris at high food concentrations, while the P : C ratio for B. longirostris was lower than for D. galeata at lower food concentrations. Although the threshold elemental ratios calculated here are theoretically minimum estimates, they were higher than the lower end of the sestonic elemental ratios in some lakes, suggesting that it is not unusual for these cladocerans to be N or P limited at certain periods of the year. Sestonic elemental ratios may have potential importance in determining the community structure of zooplankton.

Fish predation on bosmina longirostris: body-size selection versus visibility selection'

Abstract: We examine the effects of fish predation on a population of Bosmina longiros- tris (0. F. Muller), a small, limnetic cladoceran, in Gatun Lake, Panama. We test the relative importance of two different modes of predator selection: body-size selection, in which fish choose the largest of otherwise identically appearing individuals, and visibility selection, in which fish choose individuals having the greatest amount of body pigmentation. In B. longiros- tris, this pigmentation is most heavily concentrated in the large, black, compound eye of these otherwise transparent animals. We find that these predators are feeding according to visibility selection and that body-size selection is of negligible importance under these circumstances. We then discuss the general applicability of these findings, and the evolutionary consequences for prey populations under this type of selective pressure.

Large nonlethal effects of an invasive invertebrate predator on zooplankton population growth rate.

Abstract: We conducted a study to determine the contribution of lethal and nonlethal effects to a predator's net effect on a prey's population growth rate in a natural setting. We focused on the effects of an invasive invertebrate predator, Bythotrephes longimanus, on zooplankton prey populations in Lakes Michigan and Erie. Field data taken at multiple dates and locations in both systems indicated that the prey species Daphnia mendotae, Daphnia retrocurva, and Bosmina longirostris inhabited deeper portions of the water column as Bythotrephes biomass increased, possibly as an avoidance response to predation. This induced migration reduces predation risk but also can reduce birth rate due to exposure to cooler temperatures. We estimated the nonlethal (i.e., resulting from reduced birth rate) and lethal (i.e., consumptive) effects of Bythotrephes on D. mendotae and Bosmina longirostris. These estimates used diel field survey data of the vertical gradient of zooplankton prey density, Bythotrephes density, light intensity, and temperature with growth and predation rate models derived from laboratory studies. Results indicate that nonlethal effects played a substantial role in the net effect of Bythotrephes on several prey population growth rates in the field, with nonlethal effects on the same order of magnitude as or greater (up to 10-fold) than lethal effects. Our results further indicate that invasive species can have strong nonlethal, behaviorally based effects, despite short evolutionary coexistence with prey species.

Effects of Food Availability and Fish Predation on a Zooplankton Community

Abstract: The effects of fish predation and food availability on population densities and demography of zooplankton were investigated in Dynamite Lake, Illinois, USA, a lake with a high density of size-selective planktivorous fish and low food levels. Fish predators (bluegill sunfish) and food levels (phytoplankton) were manipulated in replicated, factorial- design field experiments during two summers (1980 and 1981). Overall, population densities of zooplankton were affected much more by manipulations of food availability than by manipulations of fish predation. The cladocerans Bosmina longirostris, Ceriodaphnia lacustris, and Diaphanosoma birgei were greatly increased in density by elevated phytoplankton levels in both years, in the presence and absence of fish. Demographic analysis in 1981 revealed that increased densities in response to elevated food levels resulted from both an increase in birth rates (Bosmina, Diaphanosoma) and a decrease in mortality rates (Ceriodaphnia, Diaphanosoma). The rotifers Lecane and Mon- ostyla also increased dramatically in response to elevated phytoplankton densities. Co- pepods were less responsive to manipulations of food levels, but several taxa exhibited increases in density in response to increased phytoplankton abundance. Few species were reduced in density by fish predation. Ceriodaphnia density was reduced by fish more than any other species in the entire community, and the density of even this species was much more affected by food availability. In terms of percent change relative to controls, increased food availability had much more of an effect than fish predation on the density of most zooplankton species and on total zooplankton abundance. Fish predation had several effects on the size structure and life history traits of the cladocerans. All three species attained larger sizes when fish were excluded than when fish were present. Cladoceran individuals also initiated reproduction at a smaller size and produced smaller offspring in the presence of fish. The reductions in mean body size, size at maturity, and offspring size in the presence of fish were most pronounced in Diapha- nosoma and Ceriodaphnia, the two largest species. Smaller body size and size at maturity apparently allow the cladocerans to reproduce before reaching a size at which they become vulnerable to size-selective fish predators. Larger size at first reproduction and larger off- spring size in the absence of fish may be a response to invertebrate predators, which assume more importance in the absence of fish and prey most heavily on smaller size classes. Flexibility in these life-history traits allows the cladocerans to withstand what appears to be intense size-selective predation by planktivorous fish.