DOI: 10.5061/dryad.sn02v6x5c
title: A species diversity dataset of beetles by three passive acquisition methods in Tei Tong Tsai (Hong Kong)

description: We based the dataset in this paper on the beetle collection from the
 sample site of Tei Tong Tsai (Hong Kong) from 1st May to 28th May 2019, a
 period of high insect diversity. A total of 16,270 beetles (photographed
 in 318 images) from 478 species belonging to 39 families were collected.
 The dataset consists of the following components: The original photo of
 the whole sample obtained at each site with each collection method, the
 morphological species identification chart, a statistical table describing
 the species and numbers of beetles collected on different dates at
 different sites using three passive acquisition methods, and a statistical
 table describing the longitude, latitude, and altitude information of each
 sampling point. We aimed to provide a database for the evaluation of
 beetle species diversity in Hong Kong and a paradigm for the effectiveness
 of passive acquisition in the beetle collection through the three
 representative methods, thus laying a foundation for biodiversity
 research.
description: <strong>Study
 sites:</strong> The
 sample site Tei Tong Tsai is located within the Island District (112°5’ E,
 22°5’ N Hong Kong, China) and connected to Lantau Country Park. The rich
 woods in Tei Tong Tsai provide a suitable environment for insects to
 survive, with rich biodiversity. Weather records (Supplement 1) for May 2019 show that the
 highest temperature was 27.2°C, the lowest was 15.7°C, the average was
 21.7°C; and the annual average rainfall was 297.8 mm. The suitable
 temperature and rainfall have created a suitable ecological environment
 and high biodiversity, establishing Tei Tong Tsai as a prime location for
 studying beetle diversity. In May 2019, a 13 sample sites were selected
 for beetle collection. All latitude and longitude formats were converted
 to degrees, minutes, and seconds.
 <strong>Experimental
 protocol:</strong><strong> </strong>In this study,
 three passive collection methods were used for beetle collection. FIT is
 an efficient collecting method for insects with strong flying abilities
 and was first developed and used abroad. MT and PT collect insects that
 are not strong flyers and live on the surface. A flight interception trap,
 a malaise trap, and 10 pitfall traps were set up to collect beetles in
 each sample site. Samples were selected to cover ecological environments
 at different longitudes, latitudes, altitudes, and distances from water
 sources. Reasonable sampling distances (depending on the terrain, with an
 interval between 100 and 200 m) were set up between sample sites to fully
 cover Tei Tong Tsai’s habitats. Due to the topography, the distance between the
 10th and 11th sample points was about 350m. The distance between two other
 close sample points was in the range of 100–200m. All three traps were based on the original
 device to maximize the advantages and achieve better collection
 results. <strong>Collection
 devices:</strong> The flight interception trap mainly comprises an
 interceptor screen (plastic net, PVC plastic glass, or plexiglas) and an
 insect specimen receiver (PVC), which is an efficient collection device
 for intercepting and collecting insects with strong flight ability. The
 detailed installation steps include the following: Firstly, punch two
 holes on the long side of the PVC screen with a hole puncher spaced about
 30 cm apart; then, fix the screen to a bamboo pole with silk, install the
 specimen receiver, fix all three, bolt the rope, and fix it in the air
 with a thick rope (the sink is about 0.5–1m from the ground). After
 installation, relevant drugs were placed inside the specimen receiver to
 poison the insects. The drugs used depend on the purpose of the study. For
 morphological studies, saline (5 mmol/L NaCl solution) or water with
 detergent is used. By contrast, DNA molecular studies use a mixture of 2%
 SDS (sodium dodecyl sulfate) and EDTA (ethylene diamine tetraacetic acid ,
 0.1mol/L, pH=8) or highly concentrated alcohol, which effectively controls
 the degradation of DNA. Currently, high-concentration alcohol, SDS and
 EDTA mixtures are commonly used. The device is widely applicable and can
 be installed in almost any habitat; however, it is best installed along
 the insects’ flight paths, including roads, rivers, or creeks between
 valleys. In this experiment, we improved this device by increasing the
 size of the water trough considering the actual situation of the sample
 site. Also, to properly conduct the molecular experiments, the reagents we
 used were a mixture of SDS and EDTA. Therefore, the improved device was
 more suitable for diverse habitats, and the insect species collected were
 abundant, reflecting good collection practices.
 Malaise traps are large
 tent-like structures constructed from thin mesh. They are among the most
 commonly used static non-attractant insect traps and insect collection
 devices. Invented by Malaise (1937) and later improved upon by Townes and
 Sharkey, these traps are important tools for insect collection and
 monitoring worldwide. The malaise trap used at the Tei Tong Tsai Country
 Park was the Townes type, which is generally set up in forest areas with
 rich habitats and relatively stable ground. The material is usually meshed
 mosquito netting fabricated into a tent-shaped insect interception field.
 The insects hit the net vertically, continue to fly upward, and are
 gradually led into the trap by the tilted top. The drug in the trap is
 usually anhydrous ethanol, which intercepts beetles with weak flying
 abilities. The pitfall trap is an effective method for
 capturing surface beetles; it is simple to use, easy to carry, and a
 common device for collection in the wild. The PT is created by digging a
 pit into the ground with the same depth as a wide-mouth plastic cup (20 cm
 high, 10 cm in diameter); The upper edge of the cup must be flushed with
 the soil surface, and a mixture of absolute ethanol is poured inside to
 collect flightless beetles. About one-quarter of the way from the top,
 small holes are punched above the wide-mouth cup to prevent the loss of
 specimens from rainwater filling the cups. The 10 sets of traps in this
 experiment were not evenly distributed, but they were all in suitable
 habitats. <strong>Specimen
 sampling:</strong> The sampling site for this study was Tei Tong
 Tsai, and the sampling period was from 1st May to 28th May (2019). FIT,
 and PTs were collected once every two days. Due to the small number of beetles collected by
 MT, mt was collected only once. All beetles were picked out and arranged
 separately after collection, added to anhydrous ethanol, preserved, and
 labeled. The beetles collected by the three passive acquisition methods
 were picked according to morphological species.
 <strong>Specimen
 identification</strong><strong>:</strong> The taxonomic
 status for the family level of all samples was determined based on the
 relevant literature. Relevant experts completed further
 identification. All the specimens collected in this study are
 currently in the zoological herbarium of the Institute of Zoology, Chinese
 Academy of Sciences (Beijing, China).
 <strong>Specimen
 photography</strong><strong>: </strong>Beetles were
 poured from the bottle and arranged separately according to the general
 species. Firstly, we used tweezers or a brush to place the beetles on
 unbreakable and unwrinkled paper (as far as possible with the backside
 upwards to keep them tight and neat, reducing the space left, and
 considering the label in the photograph). Simultaneously, we captured
 multiple photos according to the size and species of insect for the large
 specimens in the tube, adjusted the light near them to brighten the
 background, placed graph paper next to the beetles as a reference scale,
 then adjusted our Olympus camera settings to the appropriate photographing
 parameters. Finally, we inserted the photographed beetles and matching
 labels back into the tube and added anhydrous ethanol for preservation.
 The labels were set in the photos as 2019 DTZ-FIT/MT/PTX-5XX-5XX (-N), in
 which 2019 represents the collection time, DTZ represents Tei Tong Tsai,
 FIT/MT/PT signifies the collection method, X represents the number of
 sampling points, 5XX-5XX represents sampling time, and N represents the
 photo number. If a sample site had many insects on the same date and
 required more than one photo, n was used to represent the number of
 photos. After the morphological data of
 the samples were collected, their Latin name and collection information
 were recorded in a table. Each passive acquisition method corresponded to
 a table, and each table was divided into 13 sheets according to 13
 sampling points. The collection time was listed horizontally on each
 sheet, and the beetles’ species names were listed vertically (were named
 in the morphological species order as 1, 2, 3, ..., N). The number of
 beetles was recorded in the corresponding position or the data-1.zip
 file. Finally, data
 show the beetles’ biodiversity collected from each sampling site. Firstly,
 we summarized the data from each sampling point after completing the data
 statistics. Afterward, we counted the number of beetle individuals
 collected under the different passive acquisition methods at different
 points. In Fig. 4, red, blue, and green represent the number of beetle
 individuals collected by MT, PT, and FIT, respectively. Figure 4 shows
 that MT collected fewer beetles than FIT and PT. Secondly, the data of 13
 sampling points in each collecting method were summarized to obtain the
 total number of families and species collected by each method. A graph
 created in Excel 2016 displays the collection method as the horizontal
 coordinate and the number as the vertical coordinate. In the graph, red
 represents the number of families, and blue represents the number of
 species. Fig. 5 shows that FIT collected more beetle species and
 individuals than PT and MT, and MT collected the least. Thirdly, all data
 from the 13 sampling points and the three collection methods were
 summarized. The number of species collected in all families was counted.
 Families with more than ten species were selected (a total of 11
 families) for data presentation. Finally, a graphic was drawn in Excel 2016.
 Figure 6 shows that the number of species in Staphylinidae, Curculionidae,
 and Chrysomelidae accounted for a large number, and the diversity was
 relatively high.
description: This manuscript can serve as a
 reference for species diversity research on beetles in Hong Kong. The aim
 of this dataset is to provide data support for studying beetle species
 diversity in Hong Kong. This dataset can also obtain differences between
 the three collection methods by comparing the numbers of collected beetle
 species and individuals. In addition, the three passive acquisition
 methods occupy different vertical spaces, emphasizing the usefulness of
 this dataset for evaluating differences in the morphology, species, and
 numbers of beetles in different habitats. Furthermore, the external
 morphology supports quantitative analysis such as geometric morphometrics
 and mathematical morphology.