Leptogenys binghamii Forel, 1900

Hamer, Matthew T., Lee, Jonathan Hon Chung, Tse, Cheung Yau Leo, Silva, Thiago S. R. & Guénard, Benoit, 2024, The Leptogenys Roger, 1861 (Formicidae, Ponerinae) of Hong Kong SAR with additional records from Guangdong, China, ZooKeys 1202, pp. 169-211 : 169-211

Leptogenys binghamii Forel, 1900

Figs 5 A, C , 9 , 20 A

Leptogenys (Lobopelta) binghamii Forel, 1900 f: 310 (w.) Myanmar.

Lobopelta binghamii : Bingham 1903: 58.

Leptogenys (Lobopelta) binghamii : Emery 1911 e: 102.

Ergatoid description.

With characters of worker but head as wide anteriorly as posteriorly; pronotum wider than remaining mesosoma in dorsal view; mesosoma stout and robust, less elongated as worker; petiole nodiform, distinctly higher than long in lateral view; about as wide as long in dorsal view. Metasomal segments III – VII enlarged, segment III distinctly wider than petiole. Same colour as the worker.

Measurements.

Worker (n = 14); HL 1.66 – 1.84; HLL 1.31 – 1.47; HLA 0.24 – 0.3; HW 1.18 – 1.33; CML 0.31 – 0.39; SL 1.94 – 2.13; AII 0.21 – 0.33; AFI 0.43 – 0.51; AFII 0.37 – 0.41; EL 0.31 – 0.36; ML 0.84 – 1.03; PrL 1.04 – 1.25; PrH 0.77 – 1.13; PrW 1.04 – 1.2; WL 2.76 – 3.1; PeL 0.8 – 1.04; PeH 0.95 – 1.18; PeW 0.77 – 0.92; DPL 0.87 – 0.95; CI 69.36 – 74.97; CLI 17.58 – 22.49; SI 156.26 – 166.48; OI 21.98 – 26.37; LPI 104.64 – 124.38; DPI 84.67 – 98.51.

Ergatoid paratype (n = 1): HL 1.67; HLL 1.29; HLA 0.31; HW 1.25; CML 0.39; SL 1.77; AII 0.23; AFI 0.39; AFII 0.31; EL 0.34; ML 0.96; PrL 1.03; PrH 0.76; PrW 1.04; WL 2.56; PeL 0.75; PeH 1.06; PeW 0.62; DPL 0.83; CI 74.7; CLI 23.33; SI 141.31; OI 26.49; LPI 142.49; DPI 73.98.

Morphological variation.

Little to no variation, other than morphometric values, were detected in the specimens examined from Hong Kong.

Comparative notes.

Leptogenys binghamii is a relatively large, highly sculptured species, with distinctly linear mandibles, small anteriorly positioned eyes and highly angulated lateral clypeal lobes which makes it recognisable within the Leptogenys found in Hong Kong. Within the wider Leptogenys fauna of the Indomalayan region, L. binghamii might be mistaken for L. punctiventris (Mayr, 1879) and L. yandii ( Xu & He, 2015) . Leptogenys binghamii is distinguishable from L. yandii by antennal flagellomere I longer than antennal flagellomere II, the longer scape, and larger overall size (5.2 – 5.7 vs 9–10 mm total length for L. yandii and L. binghamii , respectively; Xu and He 2015). Leptogenys binghamii can be differentiated from L. punctiventris by the smaller eyes, the first gastral tergite being highly punctate, lacking any smooth and shiny regions as well as total size (5 – 6 vs 9–10 mm total size for L. punctiventris and L. binghamii , respectively; Xu and He 2015). Both L. punctiventris and L. yandii are not recorded from Hong Kong. With these species presenting more meridional and occidental distributions within Asia, respectively.

Distribution.

This species is known from Myanmar (type locality), India (Assam and Meghalaya), China (Guangxi, Yunnan, and Hong Kong), and Vietnam ( Janicki et al. 2016; Guénard et al. 2017). There are no records from Guangdong, Hainan, or Macao, but its presence is expected in the first two Chinese provinces with more sampling efforts. Its presence in Macao is less likely due to the level of urbanisation and isolation of natural areas for this species to occur. The first record of L. binghamii in Hong Kong was Fellowes (1996), here we provide additional new records across the eastern limits of its range.

Ecology.

In Hong Kong, colonies have been found within decaying wood and underneath stones, predominantly within Feng Shui Woods, secondary forests and shrubland. Colonies appear relatively small, with one partial colony collection including 23 workers, 1 male, 5 cocoons, 4 larvae, and 2 eggs ( MTH collection code MTH 163). One ergatoid queen was extracted from a partial colony collection ( MTH 268). Specimens are known from pitfall traps, leaf litter, and hand collection events. This species is suspected to be a solitary foraging species, with no group hunting yet observed. However, unless nesting sites are located, L. binghamii is rarely observed diurnally and is therefore suspected to be predominately a nocturnal foraging species. A second colony, kept in captive colony consisted of 24 workers and one ergatoid queen. Workers fed upon isopod prey and showed no interest in cockroaches, millipedes, and termites. In Hong Kong, the species reaches the northern limit of its distribution range with all records found under 500 m a. s. l .. Further sampling is nonetheless required to confirm if the species can colonize higher and cooler elevations.

Material examined.

Worker (n = 52): China • 1 worker; Hong Kong SAR, Ng Fai Tong , East Central New Territories; 23 Aug. 1996; J. R. Fellowes leg.; HKBM MBS 015249 . • 3 workers; Hong Kong SAR, Pak Ngau Shek ; 24 Oct. 1996; J. R. Fellowes leg.; HKBM MBS 006888 , MBS 015265 , MBS 06604 . • 1 worker; Hong Kong SAR, Yau Ping San UK , East Central NT; 3 Oct. 1996; J. R. Fellowes leg.; HKBM MBS 015263 . • 2 workers; Hong Kong SAR, Kadoorie Farm Botanical Garden ; 22.4302, 114.1192; 280 m a. s. l.; 14 Sep. 2015; R. H. Lee leg.; Secondary forest, Pitfall trap; IBBL RHL 02700 RHL 02717 . • 1 worker; Hong Kong SAR, Lion Rock ; 22.35805, 114.17699; 150 m a. s. l.; 13 Jul. 2015; R. H. Lee leg.; Secondary forest, Pitfall trap; IBBL RHL 01659 . • 1 worker; Hong Kong SAR, Pak Tam Chung ; 22.401, 114.33; 130 m a. s. l.; 5 Jun. 2015; R. H. Lee leg.; Shrubland, Pitfall trap; IBBL RHL 02373 . • 1 worker; Hong Kong SAR, Shing Mun ; 22.39678, 114.1531; 240 m a. s. l.; 14 May. 2015; R. H. Lee leg.; Feng Shui Forest, Pitfall trap; IBBL RHL 000350 . • 1 worker; Hong Kong SAR, Pok Fu Lam ; 22.267, 114.1438; 248 m a. s. l.; 7 Jul. 2016; M. Pierce leg.; Secondary forest, Bait trap; IBBL ANTWEB 1009150 . • 1 worker; Hong Kong SAR, Lion Rock ; 22.357, 114.17504; 140 m a. s. l.; 15 Aug. 2017; R. H. Lee leg.; Secondary forest, Pitfall trap; IBBL RHL 03531 A . • 1 worker; Hong Kong SAR, Tai Po Kau ; 22.42285, 114.18082; 200 m a. s. l.; 6 Jun. 2017; R. H. Lee leg.; Secondary forest, Pitfall trap; IBBL RHL 03550 . • 4 workers; Hong Kong SAR, Ngong Ping SSSI ; 22.25364, 113.90129; 438 m a. s. l.; 24 May. 2022; M. T. Hamer leg.; Secondary forest, Nest ex. Decay wood; IBBL ANTWEB 1010110 , ANTWEB 1010111 , ANTWEB 1010112 , ANTWEB 1010113 . • 1 worker; Hong Kong SAR, Tai Mo Shan ; 22.40549, 114.16352; 468 m a. s. l.; 19 May. 2023; L. Xuan leg.; Secondary forest, Hand collection; IBBL ANTWEB 1010125 . • 5 workers; Hong Kong SAR, Tai Mo Shan ; 22.40403, 114.1069; 471 m a. s. l.; 26 Aug. 2023; M. T. Hamer leg.; Secondary forest, un. Rock; IBBL MTH 163 . • 5 workers; Hong Kong SAR, Lantau ; 22.31701, 114.0173; 179 m a. s. l.; 29 Aug. 2023; M. T. Hamer leg.; Young secondary, ex. Decaying log; IBBL MTH 221 . • 1 worker; Hong Kong SAR, Lantau ; 22.31701, 114.01733; 179 m a. s. l.; 29 Aug. 2023; M. T. Hamer leg.; Young secondary forest, Nest ex. Decay log; IBBL ANTWEB 1010173 . • 12 workers; Hong Kong SAR, Tai Mo Shan ; 22.40452, 114.10645; 490 m a. s. l.; 27 Sep. 2023; M. T. Hamer leg.; Secondary forest, ex. Soil; IBBL MTH 563 . • 1 worker; Hong Kong SAR, Tai Mo Shan ; 22.40549, 114.16352; 468 m a. s. l.; 19 May. 2023; L. Xuan leg.; Secondary forest, Hand collection; IBBL ANTWEB 1010125 .

Paratype ergatoid (n = 1): China • 1 ergatoid; Hong Kong SAR, Tai Mo Shan ; 22.40403, 114.10691; 470 m a. s. l.; 3 Sep. 2023; M. T. Hamer leg.; secondary forest, ex. Decaying log; IBBL ANTWEB 1010225 .

Figures

Figure 5. Clypeus lobes of Leptogenys binghamii and L. diminuta, as well as tergite sculpture differences between the same species A L. binghamii (RHL 01659) B L. diminuta (GYOT 070) C L. binghamii (ANTWEB 1010113) D L. diminuta (ANTWEB 1010183).

Figure 9. Leptogenys binghamii (ANTWEB 1010110) and ergatoid (ANTWEB 1010225) A worker in lateral view B worker in dorsal view C worker in head in full face view D ergatoid in lateral view E ergatoid in lateral view and F ergatoid in dorsal view.

Figure 20. Distribution maps of Leptogenys species recorded from Hong Kong A L. binghamii B L. diminuta C L. grohli D L. kitteli. The base map displayed shows tree canopy cover with the darker green areas indicating greater tree cover.