TY - JOUR
T1 - Key-factor/key-stage analysis of long-term life table data for a fruit gall midge, Asphondylia sphaera (Diptera
T2 - Cecidomyiidae)
AU - Yukawa, Junichi
AU - Miyamoto, Kazuhisa
AU - Yamaguchi, Takuhiro
AU - Takesaki, Ken
AU - Uechi, Nami
AU - Matsuo, Kazunori
N1 - Funding Information:
We thank Keizi Kiritani (Emeritus Researcher, NARO Institute for Agro-environmental Sciences, Japan) for his suggestions for population studies of the gall midge, Kohji Yamamura (National Institute of Agro-Environmental Sciences, Tsukuba, Japan) for giving us guidance on how to use the key-factor/key-stage analysis, and Keith M Harris (former Director of the International Institute of Entomology, UK) for his critical reading of an early draft. Many former students of the Entomological Laboratory, Kagoshima University, Japan helped us in the field surveys, to whom we are indebted. We thank persons in charge of Shiroyama Park (Kagoshima City Office) and Saburo Hosoyamada (Terayama Station for Education and Research on Nature, Kagoshima University, Japan) (retired) for their arrangement in the field surveys. Our thanks are also due to Makoto Tokuda (Saga University) for his information on the alternate year flowering of L. japonicum in Kagoshima, and Midori Tuda (Kyushu University) for providing us with some references. This study was supported in part by the grants-in-aid (No. 02660052) to JY from the Japan Society for the Promotion of Sciences.
Publisher Copyright:
© 2016 The Royal Entomological Society
PY - 2016/10/1
Y1 - 2016/10/1
N2 - 1. Population dynamics of Asphondylia sphaera Monzen (Diptera: Cecidomyiidae), a species that induces fruit galls on Ligustrum japonicum (Oleaceae), was studied from 1970 to 1996 in broad-leaved evergreen forests in Kagoshima, southern Japan. The numbers of fruit galls and emerging adults fluctuated greatly from year to year along with alternate year flowering of the host plant. 2. To detect density-dependent and independent forces operating on the A. sphaera population and to assess the relative strength of top-down and bottom-up effects, we used the method of Key-factor/key-stage analysis, which allowed us to avoid various problems of the conventional key-factor analysis. 3. Five factors and seven stages were distinguished in the life tables. Key-factor/key-stage analysis indicated that the number of flower buds made the largest contribution to the annual changes in total survival rate by operating through the proportion of eggs and first instars that survived abortion of host flower buds and flowers, which contributed most to density-dependency. 4. The population dynamics of A. sphaera has been strongly influenced by the bottom-up effects of both the abundance of flower buds and the abortion of flowers of L. japonicum. 5. A top-down effect of Bracon asphondyliae Maeto (Hymenoptera: Braconidae) was weakly density-dependent and contributed less to the total survival rate. Abiotic factors, such as summer and winter temperatures and the effect of typhoons were negligible.
AB - 1. Population dynamics of Asphondylia sphaera Monzen (Diptera: Cecidomyiidae), a species that induces fruit galls on Ligustrum japonicum (Oleaceae), was studied from 1970 to 1996 in broad-leaved evergreen forests in Kagoshima, southern Japan. The numbers of fruit galls and emerging adults fluctuated greatly from year to year along with alternate year flowering of the host plant. 2. To detect density-dependent and independent forces operating on the A. sphaera population and to assess the relative strength of top-down and bottom-up effects, we used the method of Key-factor/key-stage analysis, which allowed us to avoid various problems of the conventional key-factor analysis. 3. Five factors and seven stages were distinguished in the life tables. Key-factor/key-stage analysis indicated that the number of flower buds made the largest contribution to the annual changes in total survival rate by operating through the proportion of eggs and first instars that survived abortion of host flower buds and flowers, which contributed most to density-dependency. 4. The population dynamics of A. sphaera has been strongly influenced by the bottom-up effects of both the abundance of flower buds and the abortion of flowers of L. japonicum. 5. A top-down effect of Bracon asphondyliae Maeto (Hymenoptera: Braconidae) was weakly density-dependent and contributed less to the total survival rate. Abiotic factors, such as summer and winter temperatures and the effect of typhoons were negligible.
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U2 - 10.1111/een.12331
DO - 10.1111/een.12331
M3 - Article
AN - SCOPUS:85032069074
SN - 0307-6946
VL - 41
SP - 516
EP - 526
JO - Ecological Entomology
JF - Ecological Entomology
IS - 5
ER -