Census of the longhorn beetles (Coleoptera, Cerambycidae and Vesperidae) of the Macau SAR, China

Abstract An intensive census, extended over a period of approximately three and a half years, October 2017– May 2021, was conducted in the remaining green areas of the Macau SAR in order to provide an updated status of the biodiversity of longhorn beetles in this region. This insect group includes more than 36,000 species worldwide, subdivided into four families of mainly xylophagous or saproxylic insects, the Vesperidae, Oxypeltidae, Disteniidae, and Cerambycidae. They are of key importance in agricultural and forestry science, and are often used as an indicator of forest habitat health. A total of 52 species was recorded during this census, 2.6 times more than previously reported in the literature for this area. However, recorded abundances and frequency of occurrence for the various species were remarkably low, and of the 20 species previously reported for the region, some prominent ones remained unaccounted for. Among others, these include Batocera horsfieldii (Hope, 1839), Apriona rugicollis Chevrolat, 1852 [previously incorrectly reported as Apriona germarii (Hope, 1831)], Aristobia reticulator (Fabricius, 1781) [previously reported as Aristobia testudo (Voet, 1778)] and Imantocera penicillata (Hope, 1831). It is hypothesised that this may be related to the ongoing manipulation of the natural vegetation of the Macau SAR, which is rapidly being converted to plantations, city parks, and gardens. In particular, dead or dying trees and lower tree branches are systematically removed in order to improve the aesthetic appearance of these green areas. However, this process is also depriving xylophagous and saproxylic species of their essential habitats.


Introduction
Longhorn beetles represent one of the largest groupings of extant insects with more than 36,000 species currently described worldwide (Leschen and Beutel 2014;Monné et al. 2017). The four families currently recognized within this grouping (Vesperidae, Oxypeltidae, Disteniidae, Cerambycidae) are part of the superfamily Chrysomeloidea. They have been often regarded as sufficiently distinct to possibly form a separate superfamily of Cerambycoidea, but this is not supported by results of mitochondrial genomic analysis (Nie et al. 2021). The predominantly xylophagous and saproxylic habits of their larval stages make them one of the most important groups of insects in the forestry and agricultural sciences. While crepuscular and nocturnal adult longhorn beetles are generally dull and sombre-coloured in their body aspect, diurnal species are mostly ornamented to brightly coloured species that use either Batesian mimicry or aposematism to protect themselves against potential predators (Švácha and Lawrence 2014). Also, with the exception of some Lamiinae, nocturnal species generally do not feed at the adult stage, while diurnal ones often seek high energy nutrition from either flowers, leaves, bark, fermenting fruits, or sap flows. Longhorn beetles are, therefore, important as pollinators but above all as recyclers of dead wood, and their diversity and abundance are used as indicators of forest habitat health (Švácha and Lawrence 2014).
The Macau SAR has a special local government structure within the "One Country -Two Systems" dispensation of 1999. It is a very prosperous region with per-capita incomes among the highest in the world. It is, however, also one of the most densely populated places on the planet and, consequently, under enormous residential and developmental pressure (Leong et al. 2017). Despite the massive urban development that the SAR has experienced over the last few decades, some pockets of natural vegetation still occur throughout its territory, albeit in a very fragmented manner and often encroached upon by alien species. These are mainly focused around 18 areas, where remnants of subtropical forest are currently administered as city parks and gardens, or in the largest cases as country parks. The ecological conditions of these areas are currently being assessed and biodiversity records are an essential component of this process, particularly in the field of terrestrial invertebrates for which there are still insufficient data available (cf. Direcção dos Serviços de Protecção Ambiental 2020). The main objective of this study is, therefore, to provide an updated account of the longhorn beetles of the Macau SAR, based on extended and frequent field surveys, comprehensive observation gathering methods and updated identification approaches using local and global expertise. Only three other similar studies have recently been completed for this region, on the ants (Hymenoptera, Formicidae) (Leong et al. 2017), the butterflies (Lepidoptera, Rhopalocera) (Department of Green Areas and Gardens, Municipal Affairs Bureau of Macao Special Administrative Region, Guangdong Institute of Applied Biological Resources 2019) and the fruit and flower chafers (Scarabaeidae, Cetoniinae) (Perissinotto and Clennell 2021), respectively. These will hopefully stimulate further research initiatives in the region and provide the local authorities with supporting information towards their ongoing environmental management and biodiversity conservation programmes. A recent survey undertaken by the authorities has shown that the overwhelming majority of the Macau population (i.e., 79% of questionnaire returns) regards as a priority the maintenance of the ecological integrity and biodiversity of its green areas (Direcção dos Serviços de Protecção Ambiental 2020).

Materials and methods
The Macau SAR of China is biogeographically part of the Palaearctic Region, but is characterised by a subtropical climate and is close to the interface with the Oriental Region. Thus, many species that occur within its boundaries are actually also found further south and are shared with the latter region. Although the area has undergone extreme urban transformation during the last few decades, some pockets of its natural terrestrial vegetation still remain. Their plant assemblages include five vegetation types, namely coniferous forest, coniferous and broad-leaved mixed forest, evergreen broadleaved forest, evergreen and deciduous broad-leaved mixed forest, and shrub (Peng et al. 2014; Direcção dos Serviços de Protecção Ambiental 2020).
Physically, the Macau SAR occupies a total area of ca. 30 km 2 (Leong et al. 2017), which includes the Macau Peninsula, linked directly to the mainland province of Guangdong, and one larger island resulting from the merger of the two previously separated islands of Taipa (Cantonese: Tam Chai) and Coloane (Cantonese: Lou Wan) through the land reclaimed area of Cotai (Cantonese: Lou Tam) (Fig. 1). Land reclamation is an ongoing activity in the SAR, and since 1995 both the International Airport and the Hong Kong-Zhuhai-Macau Bridge Port have been added through this process to the Taipa-Coloane island complex and the Peninsula, respectively (Fig. 1). The remaining pockets of semi-natural landscape are often encroached upon by alien vegetation (Leong et al. 2017). They consist mainly of densely forested hilly outcrops intersected by networks of hiking trails, service roads and recreational facilities. The largest among the 18 areas identified are located in the Coloane area (e.g., Alto de Coloane, Barragem de Ká-Hó, and Monte de Ká-Hó) and Taipa (Taipa Grande and Taipa Pequena), but there are lesser pockets in the Peninsula as well (e.g., Colina da Guia, Colina da Barra, Parque Municipal de Mong Há, and Ilha Verde) (Figs 1, 2; cf. Direcção dos Serviços de Protecção Ambiental 2020). All these sites were visited on a regular basis during the census period, in order to provide an areal cover as comprehensive as possible of the potential habitats for longhorn beetles within the SAR.
Considering the exclusive either diurnal or nocturnal activity of most adult longhorn beetles, observations were undertaken during both daylight hours and at night. Flowers, dead trees and freshly cut branches were inspected during the hottest part of the day, in order to maximise potential encounters with beetles during their peak period of diurnal activity. At night, searches were limited to particularly brightly illuminated areas at the periphery of town, including street lights, public ablution blocks and monument spot-lights. Observations were made on an opportunistic basis from October 2017 and virtually on a daily basis during the period October 2018-May 2021. This generally involved non-manipulative methods, with photographs taken in situ as much as possible. No light traps were used, but the UV-based electric mosquito traps mounted by the authorities in each public ablution block were regularly inspected during the census. Where possible, electrocuted beetles were removed from the traps and preserved as voucher specimens for reference and identification verification purposes, along with other specimens retrieved already dead or moribund in the field. All specimens were analysed in detail and identified at the Key Laboratory of Zoological Systematics and Evolution of the Chinese Academy of Sciences in Beijing. Most of these specimens are now deposited in the National Zoological Museum of China, Institute of Zoology, Chinese Academy of Sciences (IZCAS, Beijing), while smaller collections are also housed in the Macau Anglican College (MACT, Taipa). Specimens from older collections housed in the Library of the University of Macau (Easton Collection, UMEC), at the Macau Municipal Affairs Bureau ("Collection de Instituto para os Assuntos Municipais" CIAM, Coloane) and at the Sun Yat-Sen University (SYSU, Guangzhou) were also included in the analysis.
As far as possible, photos of specimen dorsal and lateral habitus were taken in situ using a Nikon CoolPix S9700 digital camera with macro setting. However, when this was not practical in the field, specimens were photographed and measured under controlled conditions. Also, on rare occasions visual disturbances were removed from the photos using Microsoft Word 2010 (Picture Tools), in order to increase clarity and resolution of the images. All the species recorded during the census in the Macau SAR are illustrated with photos of live specimens in their natural or reconstructed setting, highlighting their key dorsal and, where possible, lateral characters. Specimen body length and maximum width were measured using a Vernier caliper, from the anterior margin of the mandibles to the apex of the pygidium and at the widest point of the elytra or pronotum, respectively. All measurements were approximated to the closest 0.5 mm. Within the text, only the original name, the essential synonyms and the currently recognised names are listed under each taxon, while for a comprehensive list of synonyms the reader is referred to the Catalogue of Chinese Coleoptera Volume IX, by Lin and Yang (2019), and the latest revision of the Catalogue of the Palaearctic Coleoptera, Volume 6/1, by Danilevsky (2020). The taxonomic structure used in these two catalogues is also followed in this work whenever an unresolved or controversial tribal or generic position exists, either in the literature or in the experts' discussion forums.
Type species. Ceresium raripilum Newman, 1842.  Remarks. This species varies in the range of 10-14 mm in total length and 2-3 mm in maximum width. In Macau, adults appear to be active mainly during late spring, in May-June, and like those of the other species in this genus they are promptly attracted to artificial light during night-time, but are also occasionally seen during the day, hidden, and possibly feeding inside thick inflorescences. In Hong Kong, the larval stages of this species are known to develop within the wood of Citrus spp. and Morus alba (Yiu 2009).  Remarks. In Macau, adults of this species are active throughout the spring and are generally found in proximity to artificial lights at night. Their range in total length is 9-11 mm, and 1.5-3 in maximum width. In nearby Hong Kong, larvae of this species bore into Citrus spp. plants (Yiu 2009). Other larval host plants include Diospyros kaki, Mallotus japonicas, Quercus acuta (Lim et al. 2014), and in Japan even cultivated Prunus salicina (Kusigemati 1985). Remarks. In Macau, this species ranges 11-13 mm in total length and 2.5-3 mm in maximum width. During the current census it has been observed mainly at night under artificial lights, however on one occasion it was found during daytime feeding on flowers of Ligustrum sinense. In nearby Hong Kong, larvae have been documented to bore into wood of Cinnamomum camphora, Citrus spp., and Melia azedarach (Yiu 2009). Liu (1992) reported them as serious pests of Punica granatum in Sichuan, but also more generally of Malus domestica, Pyrus sp. and Ricinus communis. Hác-Sá Reservoir, 1 May 2020 22:32, Eric Kwan (https://www.inaturalist.org/ observations/44495900). Remarks. In Macau, adults are active only in the spring and range in total length 9.5-15 mm and 2-4 mm in maximum width. Although they have been found mainly around artificial lights at night, they have also been observed feeding on flowers of Lonicera japonica and Gardenia jasminoides during daytime (RP & LC pers. obs.). Larval host plants include Artidesma tetrandrum, Bauhinia malabarica, Careya arborea, Heritiera minor, Lagerstroemia parviflora and Shorea robusta (Duffy 1968;Makihara et al. 2008).

Type species. Trirachys orientalis Hope, 1843
Trirachys indutus (Newman, 1842) Remarks. This species was recorded only twice during the census and the specimens exhibited a total length of 30-37 mm and a maximum width of 8-10.5 mm. It has been reported previously from the region and from Hong Kong as Aeolesthes induta (Newman, 1842) (Easton 1992;Yiu 2009;Yiu and Yip 2011 Remarks. The only specimen available in Macau collections exhibits a total length of 26 mm and a maximum width of 6 mm. Three other observations of this species from Macau were obtained from the citizen science platform iNaturalist, but unfortunately the accompanying data did not contain any information about their size or habits. In nearby Hong Kong, adults may attain a total length of 22-34 mm (Yiu 2009;Yiu and Yip 2011). Larvae are known to bore into wood of Mangifera indica, Ficus microcarpa and F. retusa (Yiu 2009;Lim et al. 2014 Remarks. According to Easton (1992), C. annularis, or bamboo longhorn, was very common in Macau in the early 1990s, particularly during 1990 when it was suggested that it may have emerged from the numerous bamboo poles used in the scaffolding of new buildings that were being constructed next to the university campus. However, during this census the species was a rare occurrence in Macau, where adults were active in spring and summer and ranged 10-14 mm in total length and 2-3.5 mm in maximum width. Chlorophorus annularis is primarily a borer of dry bamboo species belonging to several genera, but it also attacks cultivated crops and wild plant species (Friedman et al. 2008). Both larvae and adults have been introduced into several European, Middle East, African, American and Oceanian countries through bamboo canes and their derived products imported from south-east Asian countries, especially China (Suma and Bella 2018).
The main larval host plants for the species include Bambusa spp., Chimonobambusa tumidissinoda, Dendrocalamus strictus, Dipterocarpus tuberculatus, Cassia fistula, Gossypium sp., Indosasa crassiflora, Phyllostachys reticulata, Saccharum officinarum, Sinocalamus spp., Vitis spp., and Zea mays (Friedman et al. 2008;Suma and Bella 2018). Other plants utilised to a lesser extent are Albizia spp., Betula spp., Citrus spp., Derris microphylla, Liquidambar formosana, Malus sylvestris, Pyrus malus, Shorea robusta, Sinobambusa gibbosa, Spondias sp. and Tectona grandis (Duffy 1968;Makihara et al. 2008;Yiu 2009;Lim et al. 2014;Suma and Bella 2018).  Remarks. This is the only species that was found in reasonable abundance during the census, as shown by the extensive list of records above. Yet, remarkably it was not reported in the previous surveys by either Easton (1991Easton ( , 1992Easton ( , 1993 or Pun and Batalha (1997), despite Macau representing the type locality of the original description of the species by Chevrolat (1845). In Macau, adults are active during the hottest part of the day from spring till early autumn and range in total length 11-16 mm and 2.5-4 mm in maximum width.  Thomson, 1861 Demonax bimaculicollis (Schwarzer, 1925)  Remarks. In Macau, this species has so far only been recorded from Little Taipa Hill during March-April 1999 and ranges 8-11 mm in total length and 2-3 mm in maximum width. Adults appear to be active in daytime only during the early spring and have been observed mainly feeding on flowers of Mangifera sp. and occasionally also of Ligustrum sinense. Chou (2004Chou ( , 2008 reported that adults visit flowers and leaves of Acer cinnamomifolium. Mating pairs and individuals near exit holes have also been found repeatedly on dead trunks of Zanthoxylum avicennae, indicating that this is possibly one of the host plants for larval development (RP pers. obs.).

Type species. Perissus x-littera Chevrolat, 1863
Perissus indistinctus Gressitt, 1940 Fig. 19 Perissus indistinctus Gressitt, 1940a: 72  Remarks. In Macau, adult activity has been recorded from early spring till late autumn. Specimens range 7-10.5 mm in total length and 1.5-3 mm in maximum width. Adults are active during the hottest part of the day and are generally observed on dead tree branches or roots, where they crawl back and forth with extreme rapidity searching for mates and areas suitable for egg deposition. No information seems to be available in the literature on the larval food plants. Remarks. In Macau, adults appear to be active only in late spring and range in total length 23-28 mm and 6.5-8 mm in maximum width. The species is exclusively nocturnal and readily attracted to artificial lights. The larvae apparently bore into lumber and a variety of trees, such as Machilus spp., Morus alba and oaks (Yiu 2009). The species was introduced into Australia already in the 1960s (Duffy 1963) and adult specimens emerging from wood furniture and other processed timber have recently been intercepted in several European countries (Cocquempot et al. 2014).

Tribe Obriini Mulsant, 1839
Genus Kuegleria Holzschuh, 2017: 13. Type species. Obrium atricolor Pic, 1953. Kuegleria annulicornis (Pic, 1935)   Remarks. This species represents a new record for China and the broader Palaearctic Region. The two specimens recorded during this survey exhibit a total length of 6-7 mm and a maximum width of 1-1.5 mm. One specimen was active during daytime, flying above a pile of dead wood, while the second specimen was recovered from an ablution block, where it had likely been attracted by artificial lights during the night.  Remarks. In Macau, adults are active throughout the spring and summer, both during the day feeding on flowers and at night when they are attracted to artificial lights. They range in total length 10.5-13 mm and 2.5-3 mm in maximum width. There appears to be no information available in the literature on the larval food plant(s) of this species.  Remarks. In Macau, adults are active only during late spring to early summer and specimens range in total length 10-16 mm and 2-4 mm in maximum width. They feed on a variety of flowers during the hottest part of the day, including Acronychia pedunculata, Dalbergia benthamii and Elaeocarpus sylvestris. Known larval food plants include Cinnamomum camphora, Machilus spp. and Pueraria lobata (Lim et al. 2014).
Type species. Cerambyx kaehleri Linnaeus, 1758 Remarks. The only specimen observed in Macau had a total length of 16.5 mm and a maximum width of 5.5 mm. Yiu (2009) reported that the larval stages develop in bamboo canes and jujube trees. This is supported by Hua (2002)  Remarks. In Macau, adults are active from early spring till mid-autumn and range in total length 24-30.5 mm and 5-8 mm in maximum width. In the Coloane area, adults have repeatedly been observed while emerging from exit holes on dead or moribund trunks of Albizia lebbeck. In nearby Hong Kong, host plants for this species include Acacia confusa, Albizia lebbeck, Bauhinia spp. and Bombax ceiba (Yiu 2009 (Duffy 1968;Matsumoto et al. 2000;Makihara et al. 2008;Lim et al. 2014).

Subfamily Lamiinae Latreille, 1825 Tribe Acanthocinini Blanchard, 1845
Genus Rondibilis Thomson, 1857b: 306. Thomson, 1857.  Remarks. In Macau, adults are active only in late spring and range in total length 6.5-8 mm and 1.5-2 mm in maximum width. They are strictly nocturnal and readily attracted to artificial lights. No information is available in the literature on their larval host plant(s).

Tribe Apomecynini J. Thomson, 1860
Genus Apomecyna Dejean, 1821: 108. Type species. Saperda alboguttata Megerle, 1802 (= Lamia histrio Fabricius, 1793). Remarks. In Macau, adults are active throughout spring and summer, ranging in total length 7-10 mm and 1.5-3 mm in maximum width. Like the other species of this genus, A. l. longicollis is nocturnal and readily attracted to artificial lights. There is no published information on its larval host plant(s). Remarks. In Macau, adults have so far been recorded only in late spring and range in total length 10-12 mm and 3-4.5 mm in maximum width. In nearby Hong Kong, however, they have been observed throughout the summer and there larval food plants include Cucurbita moschata, Benincasa hispida, Luffa acutangula and Lagenaria siceraria (Yiu 2009). Elsewhere, larvae have also been found boring into stems of Coccinia indica, Luffa aegyptiaca and Trichosanthes cucumerina (Beeson 1941;Nair 1975 Remarks. Macau specimens exhibit a total length of 6.0-6.5 mm and a maximum width of 2.0-2.5 mm. The species is nocturnal and attracted to artificial lights. In the past, it has been misidentified and confused with R. honesta (Hua 2002;Chou 2004Chou , 2008 2009), with consequent mix up of their respective distribution records (Hua 2002;Lin and Yang 2019). According to Gressitt (1951), Cucumis sativus is among its host plants and in Hong Kong larvae have been found boring into stems of Cucumis melo (Yiu 2009 Remarks. This is a highly significant record, as the type locality of this species was only vaguely reported as "China" in the original description of Breuning (1939), without reference to specific region or place. The only specimen observed in Macau so far exhibits a total length of 9 mm and a maximum width of 2.5 mm. The species and individuals are readily attracted to artificial lights. In Hong Kong, a larva was reared successfully in captivity to adulthood when fed a mixture of soft dead woods (Yiu 2009 (Kumawat et al. 2015). Macau records. Taipa, University of East Asia Campus, 6 July 1991, on Block I (Easton 1991: 110;1993: 46); Macau, University of East Asia, no data, ER Easton leg (UMEC); no data, "Batocera rubus (Linnaeus), 榕八星天牛32 mm " (Pun and Batalha 1997: 64, fig Remarks. This is the largest longhorn beetle encountered in the Macau SAR during the current census, attaining a total length of 24-36 mm and a maximum width of 8-11 mm. Adults are active from late spring till mid-autumn, both during the day and night. The larvae burrow in a wide variety of forest trees, including Artocarpus heterophyllus, Careya arborea, Ficus spp. and Mangifera spp., from India through southeast Asia and south China, including Hong Kong (Easton 1991;Kumawat et al. 2015).

Tribe Desmiphorini Thomson, 1860
Genus Pseudoterinaea Breuning, 1940: 178. Pic, 1926. Pseudoterinaea bicoloripes (Pic, 1926) Fig. 33 Pseudanaesthetis bicoloripes Pic, 1926: 26 Remarks. In Macau, adults are active throughout the spring and summer and range in total length 7-8.5 mm and 2-3 mm in maximum width. Activity appears to be mainly during night time, when specimens are readily attracted to artificial lights. No information is available in the literature on the larval food plant(s) of this species.

Type species. Pseudanaesthetis bicoloripes
Genus Sophronica Blanchard, 1845: 160. Type species. Sophronica calceata Chevrolat, 1855 Remarks. This is a new record for China. The specimen observed at Coloane exhibits a total length of 9 mm and a maximum width of 2.5 mm. Adult activity is presumably nocturnal and the specimen in question was obviously attracted to artificial light. No information is available in the literature on the larval food plant(s) or general biology of this species.

Tribe Dorcaschematini J. Thomson, 1860
Genus Olenecamptus Chevrolat, 1835: 134. Chevrolat, 1835(= Saperda biloba Fabricius, 1801. Fig. 36 Olenecamptus bilobus taiwanus L. S. Dillon & E. S. Dillon, 1948: 229, pl Remarks. In Macau, adults are active from late spring to late summer and range in total length 11.5-20 mm and 2.5-5 mm in maximum width. According to Yiu (2009) Gressitt, 1940 Fig. 37 Exocentrus alboguttatus subconjunctus Gressitt, 1940a: 184 attracted to artificial lights at night, but are also active during daytime when they can be observed crawling and mating on dead tree twigs and branches. In nearby Hong Kong, where in the past this species has been erroneously reported as E. guttulatus subconjunctus, the larval host plants include Acacia farnesiana, Mallotus spp. and Morus alba (Yiu 2009;Yiu and Yip 2011). Remarks. In Macau, adults seem to be active only in late spring and range in total length 4-5 mm and 1.5-2 mm in maximum width. Like in its congeneric species above, individuals are active both during the daytime and at night, when they are readily attracted to artificial lights. No information is available on its larval food plant(s). Remarks. The only specimen observed in Macau during this study exhibits a total length of 13 mm and a maximum width of 4 mm. In Hong Kong, adults have been reported feeding on Miscanthus sp. (Yiu 2009 (Easton 1991: 110;1993: 49); Macau, University of East Asia, no data, ER Easton leg (UMEC x3); no data, "Anoplophora chinensis (Forster), 星天牛34 mm " (Pun and Batalha 1997: 64, fig Remarks. Easton (1993) reported that this species was common in Macau during the period 1991-1993. Despite having a very wide distribution range and being regarded as a pest and invasive species in some countries, it is now a rather scarce occurrence in Macau, where adults are active only from late spring to early summer. It ranges in total length 24-35 mm and 10.5-13 mm in maximum width. This species is often referred to as "the citrus longhorn beetle" (Easton 1991(Easton , 1993 and its larvae are considered a serious pest of citrus in Hong Kong and adjacent mainland China (Hill et al. 1982). In Macau, where citrus trees are very scarce, it has been suggested that larvae may complete their growth in wood of Melia azedarach (Easton 1993). The larvae of this species are actually extreme opportunists in their diet and consume a large variety of woody plants, including horticultural species, and adults are therefore often encountered in city gardens and farms (Yiu 2009

Remarks.
Only one specimen was observed in Macau during the entire study period, exhibiting a total length of 20 mm and a maximum width of 6 mm. Adults seem to be active in late spring and mainly at night, being attracted to artificial lights. There is no published information on its biology.   (Huang et al. 2002). Oriental Region: Laos (Breuning 1962a;Rondon and Breuning 1970). Remarks. Since this species was originally described on the basis of a single specimen, Rondon and Breuning (1970)  hybrid between the more common and widely distributed Eutaenia trifasciella (White, 1850) and E. corbetti Gahan, 1893. It differs from the closely related E. trifasciella from Hong Kong mainly by having the apical four antennomeres with basal parts lightly testaceous rather than completely black and the black marking on pronotum extending to both anterior and posterior margins, instead of forming only a middle transverse black stripe. In Macau, adults are active only in late spring and range in total length 20.5-23 mm and 6-7 mm in maximum width. They are strictly diurnal and feed on the bark of coastal shrubs (RP & LC pers. obs.).  Remarks. In Macau, adults are active mainly at night and only in late spring; they range in total length 18-21 mm and 6-7.5 mm in maximum width. In Hong Kong, larvae reportedly bore into Pinus massoniana and carry the pine-wood nematode Bursaphelenchus xilophilus, which is a pest of pine plantations (Yiu 2009). Other larval food plants include Abies firma, A. holophylla, Cedrus deodara, C. libani, Cryptomeria japonica, Juniperus sp., J. chinensis, Larix sp., Larix gmelinii, Malus asiatica, M. pumila, Morinda umbellata, Picea sp., P. excelsa, P. morinda, Pinus armandii, P. banksiana, P. densiflora, P. elliottii, P. khasya, P. koraiensis, P. luchuensis, P. massoniana, P. rigida, P. strobus, P. taeda, P. thunbergii, P. yunnanensis and Quercus sp. (Lim et al. 2014;Lin and Yang 2019). and mating on dead tree surfaces. In Hong Kong, Mangifera indica and Derris spp. have been reported as food plants for the larvae of this species (Yiu 2009   Remarks. In Macau, adults are active only in mid to late spring and range in total length 10-15 mm and 4-6 mm in maximum width. They are both nocturnal, being readily attracted to artificial lights, and diurnal, crawling and mating on dead tree branches and trunks. In Hong Kong, larvae have been found boring into various trees, including Mallotus philippensis, Morus alba and Prunus persica (Yiu 2009 (Gressitt, 1940) Fig. 47 Enispia tholana Gressitt, 1940a: 157, pl. 4, fig. 11. TL: China (Hainan); TD: CASF.

A B
Remarks. In Macau, adults seem to be active only in late spring and range in total length 8-13 mm and 3-5 mm in maximum width. Individuals have so far only been found around artificial lights, indicating a predominant nocturnal activity. Hua (2002) Gressitt, 1940 Fig. 49 Pterolophia kaleea inflexa Gressitt, 1940b: 11, pl Remarks. Only one female specimen was found during the census period and this exhibited a total length of 6.5 mm and a maximum width of 2 mm. The species

A B
appears to be mainly nocturnal and attracted to artificial lights. Hua (2002)  Remarks. The only two specimens observed in Macau exhibited a total length of 9-9.5 mm and a maximum width of 4 mm. Its general morphology matches rather well that of Pterolophia cervina Gressit, 1939 from Guangdong, which was recently considered as a synonym of Praonetha consularis Pascoe, 1866(Weigel et al. 2013. It also resembles closely P. (Mimoron) brevegibbosa Pic, 1926 from Lantau Island, Hong Kong (Hayashi 1982, pl. 2, fig. 6). So, it is possible that all of them actually represent A B Figure 49. Pterolophia kaleea inflexa Gressitt, 1940 (Duffy 1968;Hua 2002).  Remarks. In Macau, adults are active from early spring till mid-autumn and range in total length 11-15 mm and 4-6 mm in maximum width. The species is mainly nocturnal and promptly attracted to artificial lights. In Hong Kong, larvae of this species bore into wood of Morus alba (Yiu 2009   Remarks. This species has been recorded only three times in Macau during the current census, in late spring and late summer. Adult activity is mainly during the hottest part of the day, when individuals promptly take off in flight when disturbed in the forest undergrowth, or display thanatosis if captured (Yiu 2009;pers. obs.). The only specimen that could be measured had a total length of 13 mm and a maximum width of 4 mm. Remarks. In Macau, adults are active during daytime from early spring till midautumn and range in total length 16-23 mm and 2.5-4 mm in maximum width. The larvae of this species are known stem-borers of a variety of plants, including Bambusa spp., Schima superba and Vernicia fordii (Hua 2002). Remarks. This species is rather scarce in Macau, having been observed only three times and only in mid spring. Adults are active during daytime and range in total length 14-18 mm and 2.5-4 mm in maximum width. The only larval host plant reported so far for this species is Sassafras tzumu (Hua 2002).

Discussion
A total of 52 longhorn beetle species was recorded during this census, 2.6 times more than previously reported in the literature for this area (Easton 1991(Easton , 1992(Easton , 1993Pun and Batalha 1997;Lin and Yang 2019). Among these, two are new records for China and one also for the entire Palaearctic Region. These findings are undoubtedly due mainly to the exceptional observation efforts undertaken in this study during the past 3.5 years, with diurnal and nocturnal visits to key areas conducted on a daily basis. By comparison, in nearby Hong Kong a total of 137 species has been recorded thus far (Yiu 2009;Yiu and Yip 2011;Lin and Aston 2014). This is expected, as the total surface area of the Hong Kong SAR is ca. 36 × larger than that of Macau and exhibits a much larger diversity of vegetation types and habitats (Dudgeon and Corlett 1994). It is noteworthy that despite their close geographic proximity, these two regions of the Pearl River Delta actually ex-

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hibit a distinct difference in their longhorn beetle composition, as already pointed out for instance in the historical reports by Easton (1991Easton ( , 1992Easton ( , 1993. It is also likely that some species do not have viable resident populations in Macau and that their occasional presence there may be due to stray specimens landing randomly during their dispersal flights from either the Hong Kong islands or the Chinese mainland (i.e., Guangdong Province). There are, however, still species that while previously recorded from Macau were not encountered during the current census. These include Imantocera penicillata (Hope, 1831), Aristobia approximator (Thomson, 1865), Apriona germarii (Hope, 1831), Batocera horsfieldi (Hope, 1839), Pothyne rugifrons Gressitt, 1940(Easton 1991, 1993Pun and Batalha 1997) and Pterolophia (Pterolophia) crassipes (Wiedemann) (Hua 2002;Lin and Yang 2019). Imantocera penicillata was reported in the accounts by both Easton (1991Easton ( , 1993 and Pun and Batalha (1997), with the former author observing this species attracted by artificial lights to the Taipa university buildings and to breadfruit or jackfruit trees (Artocarpus spp.) on the island of Coloane (Easton 1993). Indeed, several old specimens of this species are still housed in the UMEC and CIAM collections, as testimony of its historical presence in the region. Pothyne rugifrons and B. horsfieldi were only reported in Pun and Batalha (1997), and a few specimens of both species collected in the 1980s-1990s at Coloane are currently housed in the CIAM collection. The first species is known to occur also in nearby Hong Kong, while B. horsfieldi has not been recorded there yet (Yiu 2009;Yiu and Yip 2011) but is known to occur throughout mainland China (Lin and Yang 2019). On the other hand, A. germarii and A. approximator, reported in Pun and Batalha (1997) and Easton (1992), respectively, both appear to represent erroneous identifications. They do not occur in south-eastern China and therefore the correct species involved are actually A. rugicollis Chevrolat, 1852 and A. reticulator (Fabricius 1781), respectively, which are well known from nearby Hong Kong albeit reported in the past literature as either A. germarii the first, or with its invalid synonym of "A. testudo (Voet, 1778)" the second (Yiu 2009;Yiu and Yip 2011). Similarly, Pterolophia (P.) crassipes (Wiedemann, 1823) was first mentioned from Macau by Gemminger and Harold (1873), and subsequently also included in the catalogues of Hua (2002) and Lin and Yang (2019). However, it was not found in any of the more recent studies, including this survey, and therefore it is presumed that its initial Macau identification may have been erroneous.
On the more concerning side, this census has also revealed that while longhorn species diversity in Macau is remarkably higher than previously reported, the relative abundance and frequency of occurrence of most species is actually extremely low. This is an unfortunate development that is currently being reported from across the whole world, as the so-called "insect apocalypse" (Jarvis 2018;Cardoso et al. 2020). This drastic global reduction in insect abundance and biomass has been attributed to several compounding causes, chiefly habitat loss and fragmentation, intensive use of pesticides, light, air, and noise pollution as well as climate change (Samways et al. 2020).
In Macau, all these factors are exacerbated by high human population density and sophisticated infrastructure. Most of the beetle species observed during this study are predominantly nocturnal in their adult activity, and, therefore readily attracted to artificial lights. Thus, like in all nocturnal insects their orientation and navigation are disrupted when light pollution interferes with the natural light from the moon or stars they generally use for these purposes (Cardoso et al. 2020). Changes in natural light/ dark cycles also de-synchronise vital activities, such as feeding and egg-laying, and cause temporal mismatches in mutualistic interactions (Owens and Lewis 2018). To add to this, UV-light mosquito traps, like those deployed in all public ablution blocks in Macau, attract and electrocute a wide variety of non-target insects, including all the nocturnal longhorn beetles that can pass through the protective grid of these traps (RP & LC pers. obs.). An inordinate proportion of specimens observed during this census were also found crushed by vehicles or pedestrians on roads and paths under artificial illumination, killed by thermal shock on the surface of incandescent spot-lights or otherwise dismembered by insectivore birds at illuminated sites in the early morning hours.
As virtually all the longhorn beetles found in this region are xylophagous or saproxylic, with larval development depending entirely on availability of dead or dying trees that are preferably still standing (Nieto and Alexander 2010), adequate management of the remaining forest patches is of critical importance in Macau. Unfortunately, these habitats which are already extremely reduced and fragmented are under increasing pressure from recreational infrastructure development and aesthetic sanitation. Dead, damaged, and diseased trees are systematically removed and shredded for compost, or alternatively cut to small pieces and left on the ground. While the latter option may offer some habitat space for a limited number of xylophagous and saproxylic species, the vast majority of them will be prevented from colonising this wood, as ground-based predators such as ants, spiders and centipedes will rapidly take over. These trees, which are often veteran, are normally replaced with young trees, but these are planted in a plantation-type manner, with ample space between each other and all understorey continuously removed in between. Trees are also regularly pruned of their lower branches, in order to accelerate their growth in height. To quote from one of the latest "Scientists' Warning to Humanity" publications: "forest recovery entails more than just the trees, but also the epiphytes, a natural understorey, dead wood, and leaf litter... restoration should aim at a natural age structure, including veteran trees... as forests have high structural diversity, possess many microhabitats, and create sheltered microclimates allowing many species to co-exist under optimal conditions" (Samways et al. 2020).