Relation between plant density and arthropod density in cabbage fields |
| |
Authors: | Kohji Yamamura |
| |
Institution: | (1) Laboratory of Population Ecology, National Institute of Agro-Environmental Sciences, 3-1-1 Kannondai, Tsukuba 305-8604, Japan Tel. +81-298-38-8313; Fax +81-298-38-8199 e-mail: yamamura@niaes.affrc.go.jp, JP |
| |
Abstract: | The relationship between plant density and the abundance of arthropods was examined by planting cabbages in four densities
(0.25, 1, 4, or 8 plants per square meter). Four herbivorous species were examined: the small white butterfly Pieris rapae crucivora Boisduval, the diamondback moth Plutella xylostella (Linnaeus), the beet semi-looper Autographa nigrisigna (Walker), and the green peach aphid Myzus persicae (Sulzer). The number of spiders and the number of eggs of syrphid flies were also examined. The number of individuals per
unit ground area increased curvilinearly with increasing plant density for most arthropods. To clarify the mechanism causing
such a curvilinear increase, the oviposition behavior of Pieris rapae crucivora was examined. The oviposition process of a female was divided into three components: (1) entering the field, (2) alighting
on a plant to bend her abdomen, and (3) attaching an egg on the leaf. The first and the second components curvilinearly increased
with increasing plant density, while the third component was not influenced by the plant density. The analysis of the flight
path of P. rapae crucivora indicated that the curvilinear increase in the frequency of abdominal bending behaviors occurs since a female flies at least
about 1.3 m between successive abdominal bending behaviors, irrespective of the plant density, when the plant density is sufficiently
high.
Received: October 23, 1998 / Accepted: February 15, 1999 |
| |
Keywords: | Cabbage pests Herbivorous density Oviposition behavior Pieris rapae crucivora |
本文献已被 SpringerLink 等数据库收录! |
|