香港嘉道理农场次生林区碰撞诱捕网和黑光灯捕虫器采集所得鞘翅目甲虫多样性比较

Diversity comparisons of beetles (Insecta: Coleoptera) between impact flight trap and ultraviolet light trap in the secondary forest at Kadoorie Farm, Hong Kong

本文根据1990-1995年在香港嘉道理农场次生林区采集的昆虫标本,首次分析了鞘翅目及其优势科的种类、数量和季节性变化,以及由碰撞诱捕网和黑光灯捕虫器采集所得甲虫在种类、数量和季节性上的差异。在13 260号标本中,已鉴定到科的有 13 253号,分属45科,231种。其中,朽木甲科(Alleculidae)、毛蕈甲科(Biphylli-dae)、丸甲科(Byrrhidae)、坚甲科(Colydiidae)、拟球甲科(Corylophidae)、隐食甲科(Cryptophagidae)、水缨甲科(HydroscaPhidae)、伪叶甲科(Lagriidae)、薪甲科(Lathridiidae)、泽甲科(Limnichidae)、黑蕈甲科(Zopheridae)等11个科为香港地区的首次报道,约占本次调查科总数的25％。分析表明:(1)该次生林区的鞘翅目甲虫以蛀本性为主。天牛科(Ceramhycidae)、瓢虫科(Coccinellidae)、象甲科(Curculionidae)、花蚤科(Mordellidae)、金龟甲科(Sca-abaeidae)、小蠹科(Scolytidae)等6科均为多样性较高(种类≥15或者个体数量≥200)的优势科。(2)鞘翅目个体数量季节性明显,每年自2月开始数量逐渐增加,6-7月为甲虫发生的高峰期,8月显著减少。各优势科甲虫的季节性也存在一定的差异,庞大的小蠹标本数量(85％)说明在此调查期间该科正处于大发生时期。(3)黑光灯捕虫器所捕的甲虫科类和种类较之碰撞诱捕网所捕?

Kadoorie Farm and Botanical Garden is located in the New Territories, on the mainland of Hong Kong. During 1990 - 1995 impact flight (IM) and ultraviolet light (UV) traps were set for several consecutive periods to study abundance, diversity, and phenology of the Class Insecta. We report here these features for the Order Coleoptera and some major beetle families, and compare variation in these features for beetles between IM and UV traps. About 13000 specimens were collected belonging to 45 families (subfamilies) and 231 species. About 25% of these families are recorded from Hong Kong for the first time: Alleculidae, Biphyllidae, Byrrhidae, Colydiidae, Corylophidae, Cryptophagidae, Hydroscaphidae, Lagriidae, Lathridiidae, Limnichidae, and Zopheridae. Most of the beetles collected in the secondary forest are woodborers both in number and kind (either xylophagous or saprophytophagous), in contrast with the majority of phytophagous beetles collected by sweep nets in a nature reserve across the border in nearby China's Mainland. The Margalef (1958) rich- ness index indicates that Mordellidae, Coccinellidae, Curculionidae, Cerambycidae, Chrysomelidae, Elateridae, Carabidae, Staphylinidae, Corylophidae, Buprestidae, Nitidulidae, Scolytidae, and Tenebri- onidae are the richest families in species in decreasing order (d>1.5). The Shannon-Wiener (1949) diversity index indicates that Mordellidae, Coccinellidae, Curculionidae, Staphylinidae, Elateridae, Chrysomelidae, Cerambycidae, Carabidae, Nitidulidae, and Buprestidae are the most diverse families in decreasing order (H'>1.5). The Pielou (1975) evenness index indicates that Mordellidae, Coccinelli- dae, Curculionidae, Staphylinidae, Elateridae, Chrysomelidae, and Cerambycidae are the most balanced families in diversity and abundance in decreasing order (J>0.3). The Berger-Parker (1970) domi- nance index indicates that Scolytidae, Cerambycidae, Bostrichidae, Scarabaeidae, and Curculionidae are the most abundant families in number of individuals in decreasing order (D>1.5%). Overall, Ceram- bycidae, Coccinellidae, Curculionidae, Mordellidae, Scarabaeidae, and Scolytidae are the major families in the secondary forest with number of species≥15 or number of individuals≥200. Over 85% of all specimens were bark beetles during the study period, suggesting an outbreak of Scolytidae in the seconda- ry forest. Seasonal patterns of the Coleoptera are conspicuous. Abundance of beetles began to increase in Feb- ruary and drastically decreased in August, but peak occurrence differed between IM and UV traps. Those caught by UV had a distinct peak in June, while those caught by IM peaked in July. Beetles in each of the major families also showed different seasonal patterns of abundance. Families with one single species comprise over 50% of the beetle families. Captures by different traps are often mutually exclusive. About 30% of the beetle families were caught by only IM traps, while 10% were caught by only UV traps. Of the remaining 26 families, 11 had at least one species that was mutually exclusively captured by different traps. In total, 65% of the 45 families contained species trapped by one method but not by the other. Scolytidae had the greatest abundance in both IM and UV traps. Mordellidae had the highest species diversity in IM traps, while Coccinellidae had the highest spe- cies diversity in UV traps based on the richness, diversity, and evenness indices. The value (1.67) of the Shannon-Wiener index for the order Coleoptera is within the normal range, but lower than the neigh- boring area where beetle specimens were collected by sweep nets. IM captures overwhelmingly outnumbered UV captures. This could be the result of more IM traps and longer operating periods than UV traps. However, the values of the Shannon-Wiener diversity and Pielou evenness indices are about 85% and 120% higher for UV than IM traps, respectively. This indi- cates that it is important to use different trapping methods in a bio