Community structure and temporal patterns of insect abundance in young oil-tree forests
Author of the article:LI Mi1, 2** HE Zhen1, 2 LI Ke3 ZHOU Gang1, 2*** LIAO Xiao-Wu4
Author's Workplace：1. Hunan Forestry Academy, Changsha 410004, China; 2. Camellia oleifera Research and Development Center of State Forestry Administration, Changsha 410004, China; 3. Yueyang Institute of Forestry Science and Research, Yueyang 414000, China; 4. Forestry Bureau of Leiyang County, Leiyang 421800, China
Key Words：Camellia oleifera, young forest, insect community structure, optimal partition, species diversity
[Objectives] To define the structure, characteristics, temporal patterns and relationships of the general insect community, pest sub-community, and natural enemy sub-community, in young Camellia oleifera forest. [Methods] A survey of the insect community was conducted using the five point sampling method from June 2014 to May 2015 and the data obtained analyzed with optimal partitioning and fuzzy clustering. [Results] A total of 1 648 individuals, belonging to 10 orders, 62 families and 137 species were collected, including 83 species of pest insects and 36 species of natural enemies. Numbers of species, individual insects, and the pest diversity index, all peaked in early June and the mid-October. There was no close synchrony, or hysteresis, between natural enemies and pest species. Pollinators were the most active species in late October. The optimization stages of the pest sub-community, natural enemy sub-community, and general insect community were respectively divided into nine (development stage-fluctuation stage-stationary stage-decline stage-transition stage- development stage-fluctuation stage-stationary stage-decline stage), six (development stage-stationary stage-decline stage- development stage-stationary stage-decline stage) and four (namely, development stage-fluctuation stage-stationary stage- decline stage) stages, and the characteristics of different stages were closely related to crop phenology and the population dynamics of each sub-community. However, fuzzy clustering showed that the general insect community, pest sub-community, and natural enemy sub-community, were divided into three stages (development stage-stationary stage-decline stage), but with differences among each community at each stage. [Conclusion] Young oil-tree forest has high insect species richness, and its insect community structure is characterized by intermittence, continuity and complexity. The crucial periods for pest management are in mid-May, and from mid to late September.