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Adult population parameters and life tables of an epilachnine beetle (Coleoptera: Coccinellidae) feeding on bitter cucumber in Sumatra
Author(s) -
Abbas Idrus,
Nakamura Koji
Publication year - 1985
Publication title -
population ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.819
H-Index - 59
eISSN - 1438-390X
pISSN - 1438-3896
DOI - 10.1007/bf02515469
Subject(s) - biology , coccinellidae , instar , parasitism , population , pupa , larva , horticulture , botany , biological dispersal , zoology , host (biology) , predator , ecology , predation , demography , sociology
Summary The population dynamics of an epilachnine beetle, which is closely related to Epilachna sparsa Dieke (henceforth called “sp. C”) and feeds on bitter cucumber Momordica charantia , was studied by mark‐recapture of adults and the construction of life tables. The study was repeated three times, i.e., March–May, July–September and October–December in 1982, in Padang, Sumatra, Indonesia. After the establishment of the host plants, adults of “sp. C” soon colonized, and each study period ended in the death of the plants due to defoliation by the larvae and adults. The estimated mean length of residence of adults ranged from 6–11 days, but this was probably much shorter than the actual longevity, because the adults were so active that they flew away, or dropped off the plants, when they were approached or slightly disturbed. Life tables indicated that egg mortality ranged from 17.8–53.9%, and a parasitic wasp Tetrastichus sp. B made up 41.1–64.2% of egg mortality. Two wasps, Tetrastichus sp. C and Pediobius foveolatus killed 1.2–19.4% (7.6–100%) * of 4th instars and only the latter species attacked the pupae, killing 24.6–59.1% (45.1–72.4%). Parasitism and starvation by overcrowding contributed most to the total mortality from egg to adult emergence, which ranged from 89.4–99.5%. “Sp. C” had a higher diversity and level of parasitism than the Japanese species, E. vigintioctopunctata . The high dispersal power of “sp. C”, coupled with the prolonged l x −m x schedules shown under laboratory conditions, was advantageous for exploiting the food plant which was available throughout the year, but was rather patchily distributed in space.