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Variacion Espacial y Temporal en la Depredacion de Semillas de Copaifera publiflora Benth. (Leguminosae: Caesalpinioideae) en Venezuela
Nelson Ramirez and Mary K. Arroyo
Vol. 19, No. 1 (Mar., 1987), pp. 32-39
Published by: Association for Tropical Biology and Conservation
Stable URL: http://www.jstor.org/stable/2388457
Page Count: 8
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The damage caused by predispersal seed predators (Apion sp., Rhinochenus brevicollis, and an unidentified moth) and postdispersal seed predators (Spermologus copaiferae and Tricorinus herbarius) is found mainly near Copaifera pubiflora (Leguminosae: Caesalpinioideae) parent trees. Predispersal seed predation increases from 34 percent near the trunk to 78 percent outside the canopy and then decreases drastically towards the outer areas where seed density declines. Postdispersal seed predation decreases from 28 to 8 percent with the distance, following seed distribution. At 11 m from the trunk, there is no seed predation. Overall effect depends on seed distribution, and it is negligible towards these outer areas where the reproductive tree grows. The effect under canopy is almost constant in each tree and changes from 30 to 50 percent among trees. The intensity of attack by S. copaiferae depends on density and exposure time. In 60 days, seed predation increases from 19 to 92 percent in a density of 19 4 seeds/m$^2$, but when the average density is higher (41.8 seeds/m$^2$), seed predation only changes slightly (from 57 to 69%). Levels of predispersal seed predation were studied in two populations during an uninterrupted four-year period. Seed predation among individuals and populations of trees is variable. In the population of El Sombrero, Apion sp. is abundant. Seed predation changes from 10 to 40 percent between 1978 and 1980. In the population of Rio Orituco, the main insect predation is R. brevicollis, but levels of predispersal seed predation were similar to those in El Sombrero between 1977 and 1980. These patterns are associated with the fruit-bearing periods previously recorded.
Biotropica © 1987 Association for Tropical Biology and Conservation