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Arthropod predation limits the population density of an herbivorous lady beetle, Henosepilachna niponica ( Lewis )
Author(s) -
Ohgushi Takayuki,
Sawada Hiroichi
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/bf02515472
Subject(s) - predation , biology , predator , ecology , population density , population , herbivore , habitat , arthropod , larva , demography , sociology
Summary The possible impact of arthropod predation on inter‐population variation in adult density of a thistle‐feeding lady beetle, Henosepilachna niponica ( Lewis ) was evaluated by means of predator exclusion experiments conducted in the field. The population density of newly‐emerged adults at one habitat in the upstream area (site F) was significantly lower than at another in the downstream area (site A) although the egg density was nearly identical in the two habitats. In the habitat with lower adult density, egg mortality was higher due to higher levels of predation. A predator exclusion experiment demonstrated that arthropod predation was the main factor causing high mortality during the immature stages, and physical factors such as heavy rains were unlikely to influence larval survivals. Earwigs, ground beetles, predaceous stink bugs, and spiders were identified as the main predators in the study area. Of these, an earwig, Anechura harmandi ( Burr ) was more predominant than other predators and was significantly more abundant in the habitat with low adult densities.