WANG Xuechun, YANG Shuhan, YIN Shi, CUI Jiafeng, LUO Zhiwen,2

Diversity and Selectivity of Flower-visiting Insects in Xipu Forest Park

WANG Xuechun1, YANG Shuhan1*, YIN Shi1, CUI Jiafeng1, LUO Zhiwen1,2**

(1. School of Life Sciences, Jiamusi University, Jiamusi 154007, China; 2. Institute of applied insect, Jiamusi University, Jiamusi 154007, China)

[] This study was conducted to understand the species and quantity of flower-visiting insects in Xipu Forest Park, supplement the data of local flower-visiting insects, and fill the research gap of flower-visiting insects in the Lesser Hinggan Mountain. [] The methods of route survey and sample plot survey were used to investigate the community of flower-visiting insects, and the method of net catching was used to collect flower-visiting insects and record relevant data. [] A total of 1 526 flower-visiting insects belonging to 79 species, 27 families and 9 orders were found. Among them, Lepidoptera was the most, accounting for 40.51%, while Odonata, Mantodea, Hemiptera and Thysanoptera are the least. The results showed that the insect diversity index and insect dominance index were higher in the flower cultivation area, the insect evenness index was highest in the lawn area, and the flower-visiting insects in arbor area and flower shrub area were more similar. Rosaceae had the most flower-visiting insects, followed by Compositae, Cruciferae and Leguminosae. [] The study provides scientific basis and data support for the rational development and utilization, biodiversity protection and sustainable development of forest parks.

flower-visiting insects; community diversity; Xipu Forest Park

【Research significance】Nectar plants are an important part of terrestrial biological communities. They are symbiotic and coevolutionary with flower-visiting insects, and constitute the energy transfer between substances in the ecosystem[1]. As pollinators of nectar plants, flower-visiting insects play an important role in nature[2]. Therefore, protecting the diversity of flower-visiting insect community is of great significance to maintain the balance of natural ecology[3].【Previous research progress】It was summarized the relationship between insects and nectar plants that plants provided food sources and habitats for insects and play an ecological protection role, while insects pollinated and reproduced plants[4]. Kevan found that the behavior of insects visiting flowers mainly depends on the characteristics of nectar plants, such as the color and smell of flowers, the quality of nectar and pollen[5]. It was speculated in the study of pollinators’ behavior of visiting flowers that the visiting insects would benefit the floral characteristics of nectar plants as the main clue to search for host plants. In the community, the visiting insects would decide which nectar plants to choose according to different conditions[6]. It was told that the factors of insects’ selection tendency to nectar plants community were floral characteristics, flower density, plant density, etc., which made the nectar plants more attractive. The source plants evolved in the direction of easy nectar collection and pollination[7]. Although many scholars have done a lot of research on nectar plants and flower-visiting insects, there is still a lack of in-depth research on the effects of nectar plant population and flower characteristics on the selectivity of flower-visiting insects.

【Starting point of this study】Xipu Forest Park is rich in nectar plants and has a wide range of insect species. Taking the flower-visiting insect community in Xipu Forest Park as the research object, the author investigated the number of flower-visiting insects in four sample plots, observed their selection behavior for nectar plants and analyzed diversity index and similarity index of communities.【Key problems to be solved】Through the investigation of important flower-visiting insect species in Xipu Forest Park, the gap in the research of flower-visiting insects in the Lesser Hinggan Mountain area will be filled, and scientific basis and data support are provided for the rational development and utilization of forest parks, protection of biodiversity and sustainable development. At the same time, through preliminary research on the selectivity of flower-visiting insects to nectar plants, it provides important background information for the rational development and utilization of nectar plant resources, the development of new pollinating insects, and provides relevant help for in-depth exploration of the mechanism of flower-visiting insects.

1 Overview of the study area

Xipu Forest Park is located on the outskirts of Jiamusi City, in the middle of the Lesser Hinggan Mountain. It is rich in trees and insects, and the environment is relatively primitive. It has certain typical characteristics in the entire the Lesser Hinggan Mountain ecosystem. Xipu Forest Park is a modern urban forest park with relatively primitive vegetation. It was planned and constructed on the basis of the original garden nursery and woodland. It retained most of the wild woody and herbaceous plants in the environment at that time, and also cultivated a large number of gardening flowers. It is a place for local residents to entertain and relax, and has a certain value of resource protection and sightseeing.

Xipu Forest Park is located in the mid-temperate continental monsoon climate zone, with four distinct seasons, rain and hot in the same period, warm summers and rainy days, and long cold winters. The annual average temperature is 3 ℃, the frost free period is about 140 days, the annual average precipitation is 529 mm, and the sunshine hours are 2 584 h[8]. Rich in climate resources, it is an ideal living environment for various animal and plant resources. The plants in the park belong to the flora of Changbai Mountain and the Lesser Hinggan Mountain. The vegetation types include coniferous forests, broad-leaved forests, mixed coniferous and broad-leaved forests and meadows[9]. There are abundant nectar plant resources here, which provide a food source and habitat for the survival of flower-visiting insects.

2 Survey methods

2.1 Insect survey

The community of visiting insects was investigated by the method of line survey and sample plot survey. The visiting insects on nectar source plants in open space and glades on both sides of the line were collected and recorded during the flowering period. The method of net catching was used to collect the flower-visiting insects[10], recording the species, quantity, habitat and activities of the collected flower-visiting insects. The collected insects were stored in triangular bags and brought back to the laboratory. The collected visiting insect samples are made into insect specimens, and the existing classification materials such as reference books, retrieval tables, manuals and maps are used to complete identification[11-12].

2.2 Behavior observation of visiting insects

Six 4 m×4 m sample plots were randomly set, and the observation time was from 8:00 am to 16:00 pm. The six sample plots were observed in a circular manner, and each sample plot was observed for four times, each observation for 20 min, and one cycle was observed every 2 hours. Recorded the species, times and behaviors of flower-visiting insects, the visiting time and process were recorded with electronic devices such as stopwatch and video camera[13-14].

2.3 Data processing

Community diversity index (): According to Shannon-Wiener diversity index formula:

（1）

— important value();is the number of individuals of species I;is the totalnumber in the community.

Evenness index (): According to Pielou evenness index formula:

（2）

—Shannon-Wiener diversity index;—number of species.

Dominance index () : According to Berger-Parker dominance index formula:

（3）

— population number of dominant species;— the sum of the populations of all species.

Community similarity () was calculated by Jaccard similarity coefficient formula, which is as follows:

(＋＋) （4）

In the formula,— the number of species in plot a;-- the number of species in plot b;—Number of species in common between the two plots.

The diversity and similarity were analyzed by DPS 7.0 professional statistical analysis software.

3 Results and analysis

3.1 Community composition of flower-visiting insects

The results showed that 1 526 flower-visiting insects belonging to 79 species, 27 families and 9 orders were found in the typical plots in Xipu forest park(Table 1). Among them, Odonata (1 family, 1 species), Mantodea (1 family, 1 species), Orthoptera (1 family, 2 species), Hemiptera (1 family, 1 species), Coleoptera (4 families, 15 species), Lepidoptera (8 families, 32 species), Diptera (5 families, 11 species), Hymenoptera (5 families, 15 species), Thysanoptera (1 family, 1 species). Lepidoptera was the most species, accounting for 40.51% of all species, while dragonflies, mantis, Hemiptera and Thysanoptera were the least, accounting for 1.27% of all species. The main reason was related to the differences of altitude, temperature, precipitation, nectar plant resources and other factors in Xipu forest park.

Four typical plots were selected in Xipu Forest Park, including arbor area, flower shrub area, lawn area and flower cultivation area. The species and quantity of flower-visiting insects in different habitats are shown in Table 1.

According to the investigation results, 104 species and 1 526 species of flower-visiting insects were observed in the arbor areas, flower shrub areas, lawn areas and flower cultivation areas,The species and quantities of flower-visiting insects observed in four different areas were different. Among them, 517 insects of 35 species were observed in the flower growing area, and 203 insects of 17 species were observed in the tree growing area. Based on the investigation of flower-visiting insect community in Xipu Forest Park, the species of flower-visiting insects were very abundant, the living environment is suitable for the survival of flower-visiting insects, the community structure is complex and diverse, and the growth state of flower-visiting insects is good. Therefore, the Xipu Forest Park’s ecological environment has the very high scientific research value.

Table 1 Statistics of flower-visiting insects in Xipu Forest Park

I, arbor area; II, flower shrub area; III, lawn area; IV, flower cultivation area

3.2 Studies on the selectivity of flower-visiting insects

The survey found that Rosaceae had the most flower-visiting insects, followed by Compositae, Brassicaceae and Leguminosae. Among them, the nectar plants with light flower color, abundant nectar, strong smell and large inflorescence are more popular with most flower visitors. In addition, it was found that different flower-visiting insects had differences in choosing nectar plants to visit. Coleopteran beetles are usually distributed on light-colored flowers such as yellow and white, and the flowers emit a strong smell. Lepidopteran butterflies tend to visit flowers with bright colors and low odor, while moths tend to open flowers with light colors and strong fragrance at night. Hymenoptera prefers to visit flowers with high nectar and pollen content. This makes the distribution of flower-visiting insects on different nectar plant communities uneven, which to a certain extent shows that flower-visiting insects have selective access to flowers.

Flower features also have a certain guiding effect on flower-visiting insects, such as the color and size of the petals, the structure and roughness of the petal surface, and the angle of inclination of the flower. Insects choose different nectar plants to visit according to their own physiological conditions. Lepidopteran insects have longer siphon mouthparts and can feed on honey from deep corollas, while Hymenoptera chewing mouthparts are shorter and often feed on shallow corolla pollen and nectar. During the research process, many cavities of different sizes were found at the base of the red corolla, which many scholars call the thief hole[15]. When some insects encounter a long and narrow corolla that is not easy to eat, they will make a hole in the base of the corolla to feed on nectar. This nectar stealing behavior is more efficient than feeding from the front of the corolla.

3.3 Diversity and similarity analysis of flower-visiting insect communities

The Diversity index(), Evenness index()and Dominance index()of visiting insects in different habitats of Xipu Forest Park are shown in Table 2.

Table 2 Comparison of ecological indexes of insect community in Xipu Forest Park

I, arbor area; II, flower shrub area; III, lawn area; IV, flower cultivation area

Among them, the diversity index () and dominance index () of the flower cultivation area were the highest, while the evenness index () of the lawn area was the highest, which reflected that the richness of nectar plants in the flower cultivation area was higher, which was consistent with the flower-visiting behavior of insects.

The similarity index () of flower-visiting insect communities in the investigated sample plots of Xipu Forest Park is shown in Table 3. The similarity index of arbor area and flower shrub area was the highest, and that of arbor area and flower cultivation area was the lowest.

Table 3 Comparison table of similarity index of different flower-visiting insects in Xipu Forest Park

I, arbor area; II, flower shrub area; III, lawn area; IV, flower cultivation area

4 Discussion

After a long period of evolution in the natural environment, the ecological environment of Xipu Forest Park is relatively stable, and the community structure is complex and diverse. The general characteristics of flower-visiting insects in the park are rich in species and large number, but the distribution of flower-visiting insects in different habitats is different, which is related to the difference of plant types, which indicates that the structure of flower-visiting insect community is directly affected by plant types[16]. In the study, we found that the number and behavior of flower-visiting insects are closely related to the temperature. In the month of high temperature, the number of nectar plants and flower-visiting insects are more, and the behavior of flower-visiting is more frequent. In May, due to the low temperature and less nectar plants, the number of flower-visiting insects collected was very small, and there was no flower-visiting behavior. From June to August, with the increasing temperature, the number of flower-visiting insects began to increase. At the beginning of September, most nectar plants withered, and the number of flower-visiting insects decreased significantly by the first three months.

According to the survey, due to tourism development and human activities, the nectar plant resources in Xipu forest park have been damaged to a certain extent, which has a great negative impact on the flower-visiting insect resources. Therefore, it is particularly important to formulate effective protection policies. We should strengthen the protection of biodiversity in Xipu Forest Park and improve the protection system of biodiversity in Xipu forest park. At the same time, we should strengthen publicity to enhance people's awareness of biodiversity protection, make people fully realize the importance of protecting animal and plant resources and consciously participate in biodiversity and natural environment protection[17-18].

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Date of receipt: 01-10-2021

Date of modify: 03-02-2021

Fund projects: Heilongjiang Provincial Natural Science Foundation (c2016054), Jiamusi University Science and Technology Research General Project ( JMSUJCMS2016-014).

About the author: Wang Xuechun (1999—), graduate, engaged in entomology, 937947066@qq.com; *Co-first author, Yang Shuhan (1999—), undergraduate, engaged in entomology research, 852322104@qq.com; **Corresponding author: Luo Zhiwen, associate professor, master supervisor, iamusiluozhiwen@126.com.

Code of Chinese Library Classification Number: Q968.1

Document Identification:A

Article Number：2095-3704（2021）01-047-06

WANG X C, YANG S H, YIN S, et al. Diversity and selectivity of flower-visiting insects in Xipu Forest Park[J]. Biological Disaster Science, 2021, 44(1):47-52.