This research was carried out at Komaba Campus (35.66006N 139.68521E; at an altitude of approximately 35 m above sea level) of the University of Tokyo, Meguro City, Tokyo, Japan, which is situated within the center of Tokyo and surrounded by highly urbanized environments including residential quarters and business complexes (Figs 1, 2​). The total site area of the campus is 25.4 ha, within which approximately 50 buildings, four athletic fields, and a few artificial pools are present. The study site was located in a warm-temperate climate zone and had an annual mean temperature of 15.4 °C and annual mean precipitation of 1,528.8 mm (Japan Meteorological Agency 2014). The vegetation is generally mosaic and characterized by various species of herbs as well as deciduous/evergreen and broadleaf/coniferous trees (Figs 2, 3, 4, 5, 6).

Figure 1.  

Locations of the Komaba Campus and six reference sites in Tokyo, Japan.

Figure 2.  

The aerial photograph of the Komaba Campus (taken in 2009 by the Geospatial Information Authority of Japan).

Figure 3.  

An example of a campus sampling point, indicating as "pic1" in Fig. 2.

Figure 4.  

An example of a campus sampling point, indicating as "pic2" in Fig. 2.

Figure 5.  

An example of a campus sampling point, indicating as "pic3" in Fig. 2.

Figure 6.  

An example of a campus sampling point, indicating as "pic4" in Fig. 2.

All specimens were collected by our research group (TI, MUS, KKY, and TK) using the following methods: net sweeping (including visual searches), UV light trap (using a high-intensity discharge lamp), and Tullgren funnels. The net sweeping method was used 41 times from April 2013 to May 2014 for a maximum of two hours per day in the daytime. The light trap method was carried out eight times from May 2013 to February 2014 for 1–1.5 hours per day shortly after sunset. Insects collected by the net sweeping and light trap methods were killed with ethyl acetate soon after capture. Sampling of the leaf litter fauna was carried out on November 28, 2013. Shortly after sampling, the leaf litter heteropterans were extracted from the sample by using Tullgren funnels, and fixed in plastic bottles filled with 60–70% ethanol. The extraction period was two days. All specimens were dried at room temperature and mounted for morphological examination.

Species identification and the determination of postembryonic developmental stage and sex were performed under a stereoscopic microscope (Olympus SZ61, Tokyo, Japan) by TI, using Ishikawa et al. (2012), Hayashi and Miyamoto (2005), Yasunaga et al. (1993), and Yasunaga et al. (2001) as primary references, together with the original descriptions and/or redescriptions of each species, as necessary. For accurate identification, observations of the genitalia, if needed, were made under the stereoscopic microscope and an optical microscope (Olympus BX41) after dissection. The genitalia were preserved in small plastic tubes containing glycerin and mounted on pins with their respective specimens. All specimens examined are preserved in the Insect Collection (IC) at the Komaba Museum, the University of Tokyo, Meguro City, Tokyo, Japan (KMUT). Classification and nomenclature of taxa follow Aukema and Rieger (1995), Aukema and Rieger (1996), Aukema and Rieger (1999), Aukema and Rieger (2001), Aukema and Rieger (2006) and Aukema et al. (2012), and the family level classification within the superfamily Lygaeoidea follows Henry (1997). The arrangement of higher taxa from infraorder to family follows Ishikawa et al. (2012) and is in alphabetical order within families.

The similarities in species composition (occurrence or absence) were examined using a similarity index, Jaccard distances of assemblage, for the Komaba Campus and six localities in Tokyo as reference sites (Table 1). Based on the Jaccard distances, the species compositions were compared among sites by cluster analysis with group averaging. These analyses were conducted using the ‘vegdist’ function in the ‘vegan 2.0-9’ package and ‘hclust’ function in the ‘stats 3.0.2’ package implemented in the R 3.0.2 software environment (R Core Team 2013).