Diploptera punctata ( Eschscholtz, 1822 )

Li, Xinran & Wang, Zongqing, 2015, A taxonomic study of the beetle cockroaches (Diploptera Saussure) from China, with notes on the genus and species worldwide (Blattodea: Blaberidae: Diplopterinae), Zootaxa 4018 (1), pp. 35-56 : 39-43

Diploptera punctata ( Eschscholtz, 1822)

( Figs. 2–3 , 17–21 , 31–36 , 54–55 , 80 )

Blatta punctata Eschscholtz, 1822: 86 , locality “Sandwichsinseln”, = Sandwich Islands, now Hawaiian Islands; Kirby, 1904: 151, syn. of Leucophaea surinamensis (L.) ; Princis, 1950: 162, placed in Diploptera . [not Blatta punctata Charpentier, 1825 ]

Blatta dytiscoides Serville, 1839: 102 , locality “ Nouvelle-Hollande ”, = New Holland, now Australia; Walker, 1869: 125, placed in Diploptera .

Prosoplecta (Diploptera) silpha Saussure, 1864a: 325 .

Diploptera silpha: Saussure, 1864b: 178 , fig. 28, locality “ Australie ”, = Australia; Walker, 1869: 125, synonymized with D. dytiscoides .

Eleutheroda dytiscoides: Brunner von Wattenwyl, 1865: 265 , fig. 29; Walker, 1869: 125, placed in Diploptera .

Diploptera dytiscoides: Walker, 1869: 125 ; Brunner von Wattenwyl, 1893: 41; Bruijning, 1947: 210, 239; Bruijning, 1948: 41, 152, fig. 22.

Diploptera punctata: Princis, 1950: 162 .

Diagnosis. D. punctata is unspotted and relatively large among the species known in Diploptera , and may look like D. elliptica sp. n. at first sight but can be distinguished by the pronotum with posterolateral angles. Also it may be mixed up with D. minor , D. erythrocephala or D. parva , which are small-sized and have yellowish to reddish brown legs instead of dark ones.

Description. General. Size medium. Lectotype, sex unknown, left and right tegmen length × width 11.8mm × 4.4mm. Male, overall length (= body length) 17.4–19.0mm; pronotum length × width 4.1mm × 7.5mm − 4.3mm × 7.9mm; tegmen length 12.0–13.0mm. Female, overall length 19.5−22.8mm; body length 19.5−22.5mm; pronotum length × width 4.4mm × 7.5mm − 4.9mm × 8.2mm; tegmen length 15.6−17.5mm.

Body blackish brown to black. Antenna brownish; apical part of clypeus and basal part of labrum yellowish brown. Tegmina brownish, always lighter than pronotum. Tarsi brown. Cerci brownish.

Pronotum and tegmina setose. Pronotum subtrapezoidal, with posterior margin emarginate near posterolateral angles, lateral borders subsided. Tegmina with moderately dense small punctations throughout and larger and distinct ones at basal area, especially basocostal area, reaching nearly, exactly, or exceeding the end of abdomen, sometimes depending on whether the abdomen is retracted or stretched. Hindwing with AP1 and AP2 reaching the outer margin.

Male. Sclerite L3’ with basal part broad and suddenly narrowing to the curved part, resulting in an obtuse angle at the inner margin; the apex of hook curved and pointing outward.

Variation of male genitalia. Main variations occur in sclerites L2’. Main sclerite of L2’ varies in degree of curvature, whilst the apical sclerite is more or less irregular, with the margin near the main sclerite uneven and sometimes irregularly serrated, since it is diversiform in sclerotization.

Distribution. Hawaii, Australia, Samoa, Indonesia, Malaysia, Philippines, China (Hainan Island and southwest of the mainland), Vietnam, Cambodia, Thailand, Burma, Sri Lanka.

Taxonomic notes. In the original description of D. silpha by Saussure (1864a), basal 12 segments of antennae are darker than the rest, but the character was not found or not distinct among examined individuals of D. punctata except for some from Guangxi, China, which may represent high contrast in this species. Unfortunately, the antennae are lost in the syntype of D. silpha ; the body structures left in the syntype are only the pronotum, the tegmina, one hindwing and one leg and a half, which direct us to a D. punctata . Since the color pattern of antennae appears to be of intraspecific uniformity among other species, it remains uncertain whether D. silpha is an independent species or not.

Remarks. D. punctata has become commonly recognized by insect physiologists and pet-keepers, and is called Pacific beetle cockroach, but its natural history in the wild remains mysterious to our knowledge, aside from its harm to Pinales in Hawaii ( Fig. 55 ). They gnaw the bark of branches, often completely girdling them, resulting in yellow or dead foliage ( Hebard 1922; Fullaway et al. 1972). Among the materials from China, most of the specimens from Yunnan were collected via canopy fogging. This may indicate that the Yunnan population of D. punctata is a canopy dweller, or at least active in the canopy.

This species also exhibits possible positive phototaxis since they can be found at light in the evening ( Browne 1942; Jianyue Qiu’s personal observation, 2015).

In 2003 and 2004, some Diploptera sp. which look almost the same as D. punctata were collected from Nakornpathom Province in Thailand (see asterisk in Fig. 1 ). These insects were found mainly on trees, especially coconut trees, in the grooves between the stalk of the leaves and the trunk; some were also on the wall in the bright light of fluorescence lamp. Subsequently Dr. Stephen S. Tobe’s lab (University of Toronto) discovered that they seemed to be reproductively isolated from the lab population of D. punctata , which originated from Hawaii (personal communications with Witoon Wattananit (Silpakorn University) and Dr. Stephen S. Tobe, 2014). Dr. Tobe’s lab went on the studies on both the Hawaiian and Thai populations of Diploptera and performed cross experiments to probe into their relationship; Lenkic et al. (2008) found that the two populations, which were recognized as conspecific in their paper, showed a capacity of two-way breeding but a hybrid breakdown had arisen. However, reproductive compatibility and isolation must be affected by the laboratory condition and thus a long-term lab population cannot fully represent the species in the wild. Considering that the Thai and Hawaiian populations are interfertile and morphologically almost identical, we propose a continuance of the views by previous taxonomists to regard these two populations, as well as those from other localities including China, Indo- China, Malay Archipelago and Pacific Islands, to be conspecific.

On the other hand, Lenkic et al. (2008) also found the genetic divergence between the Thai and Hawaiian populations in a fragment of the mitochondrial 16S rRNA gene to be as surprisingly large as 8.6% (or 11.7%, when corrected by PAUP* under GTR+G model), which could even indicate a distinct interspecific divergence rather than that between conspecific populations. Even if the two populations represent naturally alien species to each other, the divergence is too large between sibling species. Lenkic et al. (2008) speculated that the populations of D. punctata are in the process of speciation. We just agree with them and, it must be interesting and significant to perform further research on D. punctata , which is a magic model species in insect physiology and biogeography.

Type materials examined. LECTOTYPE ( ZMMU) of Blatta punctata designated here, with label “ LECTOTYPE Blatta punctata Eschscholtz, 1822 des. Conlin McCat 2014”, sex unknown, “I. Sandwich” (= Inseln Sandwich = Sandwich Islands, now Hawaiian Islands), also a determination label “ Periplaneta sp.?” [special note: Conlin McCat is identical with the author Xinran Li. The author uses the former in daily life and communications but his institute forces the use of the latter on him]; SYNTYPE ( MHNG) of Prosoplecta silpha , male, “N. Holl.” (= Nouvelle-Hollande = New Holland, now Australia).

Other materials examined. China, Yunnan: 1 female ( IESWU), Xishuangbanna, Xiaomengyang, 850m, 1957. X.8, coll. Shu-Yong Wang; 1 sex unknown ( IESWU), Xishuangbanna, Damenglong, 650m, 1958. V.5, coll. Shu-Yong Wang; 1 female (IOZCAS), Xishuangbanna, Mengla, 620–650m, 1959. VI.11, coll. Fa-Cai Zhang; 3 females ( MHBU), Mengla, Wangtianshu, 2007. VIII.6–7, coll. Guo-Dong Ren, Wen-Jun Hou, Ya-Lin Li; 1 male & 1 female ( Figs. 17–18 , 31 ) ( IESWU, ex IOZCAS), Menglun, Anogeissus acuminata plantation (about 20 yr.), 21°53.993′, 101°16.810′, 2007. VIII.19, coll. Guo Zheng; 1 male ( Figs. 32–36 ) ( IESWU, ex IOZCAS), Menglun, G213 (national road), 594m, 21°53.794′, 101°17.152′, 2009. XI.27, coll. Guo Tang, Zhi-Yuan Yao; 1 female ( IESWU), Mengla, Shangyong, Longmencun, 2015. V.9, coll. Jian-Yue Qiu. China, Guangxi: 1 female ( CAU), Longzhou, Nonggang, 240m, 1982. V.18, coll. Xin-Li Wang; 1 female ( ZSCIQ), Shangsi, Shiwandashan (=Shiwan Mountains), 2014. V.1, coll. Ke-Liang Wu; 1 male ( Fig. 80 ) ( IESWU), Longzhou, Nonggang National Nature Reserve, light trap, 2015. VI.29, coll. Lu Qiu, Qi-Kun Bai; 1 male 1 female ( IESWU), Jingxi, Renzhuang, Tengmaocun, Longlitun, light trap, 2015. VII.11, coll. Jian-Yue Qiu. China, Hainan: 2 females (IOZCAS), Tunchang, Xinxing, 1957. VI.13; 1 male ( IESWU), 1997. V.25, coll. Mao-Fa Yang; 1 female (IOZCAS), Yinggeling, Hongxincun, 440m, 19.07°N, 109.52°E, 2007. XII.4, coll. Jian Yao; 1 male (IOZCAS), Ledong, Jianfengling, Huxiaolongyin, 707m, 18.74472°N, 108.85962°E, yellow-disk trap?, 2009. V.21, coll. Ting-Yu Hu; 1 male 1 female (IOZCAS), Baisha, Yinggeling, 600m, 2011. IV.27, coll. Wen-Xin Lin.

Figures

FIGURE 1. Distribution of Diploptera in China and Southeast Asia. The precise localities are painted black, whilst the imprecise ones are in white; each type locality is marked with a ring; the (sub) species are indicated by numbers in alphabetical order: 1 D. bicolor, 2 D. elliptica sp. n., 3 D. erythrocephala, 4 D. maculata, 5 D. minor, 6 D. naevus sp. n., 7 D. nigrescens guani subsp. n., 8 D. nigrescens nigrescens, 9 D. parva, × D. punctata; asterisk stands for the habitat of the Thai D. punctata (see the text).

FIGURES 2 – 16. Pronota of Diploptera spp. & subspp. presented in monochrome, i. e., white indicates unicolor or lighter coloration, whilst black is for darker portion. 2 – 3 D. punctata; 2 male; 3 female; 4 – 5 D. minor; 4 female; 5 male; 6 D. erythrocephala, male; 7 – 8 D. parva; 7 male; 8 female; 9 D. naevus sp. n., male; 10 D. nigrescens nigrescens, male; 11 – 12 D. nigrescens guani subsp. n.; 11 male; 12 female; 13 D. bicolor, male; 14 D. maculata, female; 15 – 16 D. elliptica sp. n.; 15 male; 16 female. (Dashed lines indicate depression. Scale bar = 2 mm)

FIGURES 17 – 30. Diploptera spp. & subspp. distributed in China. 17 – 18 D. punctata, female from Yunnan, Menglun; 19 – 21 D. punctata, lectotype (ZMMU) from Hawaii instead of China, photographed by Dr. Andrey L. Ozerov, copyright ZMMU, published with permission; 22 – 24 D. elliptica sp. n.; 22 – 23 male holotype from Yunnan, Cangyuan, Banhong; 24 female paratype from Yunnan, Mengla, Mohan; 25 – 26 D. naevus sp. n., male holotype from Xizang, Motuo, Beibeng; 27 – 28 D. nigrescens guani subsp. n., male holotype from Guangxi, Chongzuo, Daqingshan; 29 – 30 D. nigrescens nigrescens, male syntype (NTU) from Taiwan, photographed by Yi-Ho Liu and downloaded from NTU website, copyright Insect Museum Digital Archives Project, Department of Entomology, National Taiwan University. (Scale bars = 5 mm.)

FIGURES 31 – 36. D. punctata (Eschscholtz, 1822) from China, Yunnan, Menglun. 31 hind wing, female, with grey coloration indicating sclerotization; 32 – 36 male; 32 terminal segment of dorsal abdomen, in ventral view; 33 subgenital plate in dorsal view; 34 – 36 phallic sclerites in dorsal view; 34 sclerites R’; 35 sclerites L 2 ’; 36 apex of left complex hook, showing sclerite L 3 ’. (ce. = cercus, m. = membranous, p. p. = paraprocts, st. = stylus; other abbreviations as indicated in the text. Scale bars = 10 mm for 31, 1 mm for 32 & 33, 500 µm for 34 – 36.)

FIGURES 54 – 56. 54 D. punctata eating lemon peel in Hawaii, 2006. XI. 29, image by Forest & Kim Starr (University of Hawaii); 55 Cypress with damage by D. punctata in Hawaii, 2005. VII. 11, image by Forest & Kim Starr (University of Hawaii); 56 D. nigrescens nigrescens Shiraki, 1931 from Taiwan, Chiayi County, Tashan (= Xiaotashan), about 1200 m, photographed by Gaga (Taiwan). The insect was found near a light trap but not on the curtain.

FIGURE 80. A male D. punctata in repose near light trap. Photographed by Lu Qiu in Nonggang National Nature Reserve in Guangxi, China. We are very lucky to get this timely photo just before the present paper is published. This is a light-colored individual of the species. Its large abdomen was retracted to be wholly covered by the tegmina when it became a specimen.