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

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