Colobopsis leonardi

This is a dominant species that forms large colonies in the canopy of trees. It is a member of the Colobopsis cylindrica group, a set of species that employ a novel defensive strategy. Minor workers of these so called exploding ants will, when threatened, flex their gasters so hard that they rupture. This releases a toxic chemical mixture that they then attempt to smear on their antagonists.

Distribution based on Regional Taxon Lists
Indo-Australian Region: Borneo, Indonesia, Malaysia, Philippines, Singapore. Oriental Region: India, Laos, Myanmar, Thailand. Palaearctic Region: China.

Biology
A study by Zettel et al, (2018), in southern Thailand (Khao Chong Botanical Garden, Trang Province), provided insight into the diet of this species. This field study showed that ants from the Colobobopsis cylinderica group (the exploding ants) do in fact prey on and forage for animal prey. This novel finding dispels the previous suggestion that this group of ants may not forage at all for solid food. The studied colony was found in a fallen branch (Figure 1) of a rambutan tree (Nephelium lappaceum L., Sapindaceae). Presumably this was an arboreal nest that had fallen from the tree, but it was not clear if this was the entire colony or one of a number of nests. The branch had a total length of more than five metres and a width of about 20 cm. Nest entrances were distributed along the branch. Entrances were one or two closely positioned holes with a diameter of ca 3–5 mm. A trail between two entrances was used by foraging workers continuously and in high frequency in both directions, constituting the majority of the observed worker activity. On the morning of June 6 (2016), various termite species offered along this trail were taken by workers. These were killed by a single forager and carried away. Other insects and woodlice offered along the ant trail were also carried to the nest, with some cut into fragments before transport or only their liquid or soft inner parts consumed or carried, respectively. Pieces of earthworms were accepted as well. All of these prey items were collected from around the nesting area. No instances of suicidal defensive behaviour (autothysis) were recorded during the experiments. All small prey items were taken up with the mandibles, lifted and brought to the nest entrance by single workers. Cooperation for dragging larger items was never observed. In contrast, the transport of medium-sized items, which could be dragged but not lifted by a single worker was slowed down or made almost impossible by further workers. In one instance, a single worker tried to drag the remains of a beetle pupa to the nest, but was hindered to do so for more than 20 minutes by other workers who tried to do the same. Only when the activity on the trail became low, the worker brought the item into the nest.

Nomenclature

 * pilosa. Formica pilosa Smith, F. 1857a: 54 (w.) BORNEO. [Junior primary homonym of pilosa Olivier, above.] Replacement name (first available): leonardi Emery, 1889b: 515 (see there). Combination in Colobopsis: Mayr, 1862: 691; in Camponotus: Dalla Torre, 1893: 247; in C. (Colobopsis): Forel, 1912i: 90. Senior synonym of pubescens: Emery, 1900d: 706.
 * pubescens. Colobopsis pubescens Mayr, 1862: 691 (q.) INDONESIA (Sulawesi). Mayr, 1867a: 68 (w.). [Unresolved junior secondary homonym of Formica pubescens Fabricius, above.] Junior synonym of pilosa: Emery, 1900d: 706.
 *  leonardi. Camponotus (Colobopsis) leonardi Emery, 1889b: 515, pl. 11, figs. 22, 23 (s.w.) MYANMAR. Karavaiev, 1929c: 243 (m.). [Junior synonyn of pilosa Smith, F. 1857a: 54 (and its junior synonym pubescens Mayr, 1862: 691). However, as both these earlier names are themselves junior homonyms within Camponotus, leonardi becomes the first available name for this taxon: Bolton, 1995b: 108. Combination in Colobopsis: Ward, et al., 2016: 350. See: Forel, 1893b: 437; Dalla Torre, 1893: 248; Emery, 1900d: 706; Wheeler, W.M. 1919e: 115; Emery, 1921a: 25; Emery, 1925b: 149.] Current subspecies: nominal plus gracilenta, grisea.

References based on Global Ant Biodiversity Informatics

 * Abe T., S. Yamane, and K. Onoyama. Ants collected on the Krakatau Islands 100 years after the great eruptions. Biogeography 14: 65-75.
 * Andersen, S.B., S. Gerritsma, K. M. Yusah, D. Mayntz, N. L. Hywel-Jones, J. Billen, J. J. Boomsma and D. P. Hughes. 2009. Ephemeral Windows of Opportunity for Horizontal Transmission of Fungal Symbionts in Leaf-Cutting Ants. Evolution 63(9):2235-
 * André E. 1892. Voyage de M. Chaper à Bornéo. Catalogue des fourmis et description des espèces nouvelles. Mém. Soc. Zool. Fr. 5: 46-55.
 * Borowiec L., and S. Salata. 2019. Next step in the invasion: Trichomyrmex mayri (Forel, 1902) new to the Philippines (Hymenoptera: Formicidae). Annals of the Upper Silesian Museum in Bytom Entomology 28(3): 1-3.
 * Chapman J. W. 1965.  Studies on the ecology of the army ants of the Philippines genus Aenictus Schuckard (Hymenoptera: Formicidae). Philippine Journal of Science. 93: 551-595.
 * Chapman, J. W., and Capco, S. R. 1951. Check list of the ants (Hymenoptera: Formicidae) of Asia. Monogr. Inst. Sci. Technol. Manila 1: 1-327
 * Chen Y. Q., Q. Li, Y. L. Chen, Z. X. Lu, X. Y. Zhou. 2011. Ant diversity and bio-indicators in land management of lac insect agroecosystem in Southwestern China. Biodivers. Conserv. 20: 3017-3038.
 * Emery C. 1888. Catalogo delle formiche esistenti nelle collezioni del Museo Civico di Genova. Parte terza . Formiche raccolte dal sig. Elio Modigliani in Sumatra e nell'isola Nias. Annali del Museo Civico di Storia Naturale 25: 528-534.
 * Emery C. Formiche raccolte da Elio Modigliani in Sumatra, Engano e Mentawei. Annali del Museo Civico di Storia Naturale 40: 661-722.
 * Emery, C.. "Formiche raccolte da Elio Modigliani in Sumatra, Engano e Mentawei." Annali del Museo Civico di Storia Naturale Giacomo Doria (Genova) (2) 20, no. 40 (1900): 661-722.
 * Fontanilla A. M., A. Nakamura, Z. Xu, M. Cao, R. L. Kitching, Y. Tang, and C. J. Burwell. 2019. Taxonomic and functional ant diversity along tropical, subtropical, and subalpine elevational transects in southwest China. Insects 10, 128; doi:10.3390/insects10050128
 * Forel A. 1886. Études myrmécologiques en 1886.. Annales de la Société Entomologique de Belgique. 30: 131-215.
 * Forel A. 1903. Les fourmis des îles Andamans et Nicobares. Rapports de cette faune avec ses voisines. Rev. Suisse Zool. 11: 399-411.
 * Forel A. 1911. Fourmis nouvelles ou intéressantes. Bull. Soc. Vaudoise Sci. Nat. 47: 331-400.
 * Forel A. 1912. Ameisen aus Java beobachtet und gesammelt von Edward Jacobson. III. Theil. Notes Leyden Mus. 34: 97-112
 * Forel A. 1913. Wissenschaftliche Ergebnisse einer Forschungsreise nach Ostindien ausgeführt im Auftrage der Kgl. Preuss. Akademie der Wissenschaften zu Berlin von H. v. Buttel-Reepen. II. Ameisen aus Sumatra, Java, Malacca und Ceylon. Gesammelt von Herrn Prof. Dr. v. Buttel-Reepen in den Jahren 1911-1912. Zoologische Jahrbücher. Abteilung für Systematik, Geographie und Biologie der Tiere 36:1-148.
 * Forel A. 1915. Fauna Simalurensis. Hymenoptera Aculeata, Fam. Formicidae. Tijdschr. Entomol. 58: 22-43.
 * Itino T., and S. Yamane. The vertical distribution of ants on canopy trees in a Bornean lowland rainf forest. Tropics 4(2/3): 277-281.
 * Jaitrong W., B. Guenard, E. P. Economo, N. Buddhakala, and S. Yamane. 2016. A checklist of known ant species of Laos (Hymenoptera: Formicidae). Asian Myrmecology 8: 1-32. DOI: 10.20362/am.008019
 * Jaitrong W.; Nabhitabhata, J. 2005. A list of known ant species of Thailand. The Thailand Natural History Museum Journal 1(1): 9-54.
 * Karavaiev V. 1933. Ameisen aus dem Indo-Australischen Gebiet, VII. Konowia 11: 305-320.
 * Mathew R., and R. N. Tiwari. 2000. Insecta: Hymenoptera: Formicidae. Pp. 251-409 in: Director; Zoological Survey of India (ed.) 2000. Fauna of of Meghalaya. Part 7. [State Fauna Series 4.] Insecta 2000. Calcutta: Zoological Survey of India, 621 pp.
 * Mohanraj P., M. Ali, and K. Veerakumari. 2010. Formicidae of the Andaman and Nicobar Islands (Indian Ocean: Bay of Bengal). Journal of Insect Science 10: Article 172
 * Mohanraj, P., M. Ali and K. Veenakumari. 2010. Formicidae of the Andaman and Nicobar Islands (Indian Ocean: Bay Of Bengal). Journal of Insect Science 10:172.
 * Overbeck, H. (1924). A List of Ants from Singapore and Neighbouring Places. Journal of the Malayan Branch of the Royal Asiatic Society 2 (1):25-40.
 * Pfeiffer M.; Mezger, D.; Hosoishi, S.; Bakhtiar, E. Y.; Kohout, R. J. 2011. The Formicidae of Borneo (Insecta: Hymenoptera): a preliminary species list. Asian Myrmecology 4:9-58
 * Ran H., and S. Y. Zhou. 2011. Checklist of Chinese Ants: the Formicomorph Subfamilies (Hymenoptera: Formicidae) (I). Journal of Guangxi Normal University: Natural Science Edition. 29(3): 65-73.
 * Santschi F. 1928. Fourmis de Sumatra, récoltées par Mr. J. B. Corporaal. Tijdschrift voor Entomologie 71: 119-140.
 * Smith, F.. "Catalogue of the hymenopterous insects collected at Sarawak, Borneo; Mount Ophir, Malacca; and at Singapore, by A. R. Wallace." Journal of the Proceedings of the Linnean Society of London, Zoology 2 (1857): 42-88.
 * Stitz H. 1925. Ameisen von den Philippinen, den malayischen und ozeanischen Inseln. Sitzungsberichte der Gesellschaft Naturforschender Freunde zu Berlin 1923: 110-136.
 * Wheeler W. M. 1909. Ants of Formosa and the Philippines. Bulletin of the American Museum of Natural History 26: 333-345.
 * Wheeler W. M. 1919. The ants of Borneo. Bulletin of the Museum of Comparative Zoology 63:43-147.
 * Yamane S. 2013. A Review of the ant fauna of the Krakatau Islands, Indonesia. Bull. Kitakyushu Mus. Nat. Hist. Hum. Hist. Ser: A, 11: 1-66
 * Zryanin V. A. 2011. An eco-faunistic review of ants (Hymenoptera: Formicidae). In: Structure and functions of soil communities of a monsoon tropical forest (Cat Tien National Park, southern Vietnam) / A.V. Tiunov (Editor). – M.: KMK Scientific Press. 2011. 277 р.101-124.