More than 200 colonies of the genus Longipeditermes were collected in our field surveys across the Sundaland region of Southeast Asia from 1998 to 2014. Two species, L. kistneri Akhtar & Ahmad and L. logipes Holmgren, are recognized and redescribed with color photographs of the workers and major soldiers. We use variation in characters of soldier caste (head capsules, antennae, and pronotum) and worker caste (antennae and mandibles) to distinguish these two species. Longipeditermes kistneri seems to prefer high-altitude forests (above 1,000 m) and has so far been found exclusively in Java and Sumatra, while L. logipes seems to prefer lowland and swamp forests and is widespread in the Greater Sundas.

Morphological characters, Nasutitermitinae, Open-air processional columns termites, species description

A termite colony typically consists of a large number of workers and defensive soldiers together with a single king and a queen. This arrangement can, however, vary with seasonal cohorts of reproductive nymphs and dispersive alates (Watson and Gay 1991; Pearce 1997). The castes within termite societies are morphologically and behaviorally specialized to perform particular tasks (Lee and Wood 1971; Grimaldi and Engel 2005) to the point where workers and soldiers are so specialized for non-reproductive helping and defensive tasks that they are considered to be functionally sterile (Roisin 2000). The sexuals, by contrast, are highly specialized for reproduction.

As the largest subfamily among the higher termites (Termitidae), Nasutitermitinae consists of more than 550 species (Emerson 1955), which belong to more than 63 genera (Collins 1989). This subfamily probably originated in the Neotropical region during the Cretaceous period (Emerson1955) and is characterized by a highly specialized defensive caste (Collins 1989) that has a modified rostrum or “nasus” (Deligne et al. 1981; Prestwich 1984). This subfamily was erected by Hare (1937), who emphasized the conspicuous prolongation on the front of the head, which is often accompanied by degeneration of mandibles and the concomitant development of a frontal gland. The development of the nasus is continuously variable among species within the Nasutitermitinae from mild prolongation, as in Syntermes, to pronounced prolongation as in Subulitermes, Convexitermes, and Nasutitermes.

Longipeditermes, in the Nasutitermitinae, is a small genus with only two species so far recorded. These are L. longipes and L. kistneri from the Sundaland area (Gathorne-Hardy 2001; Hoare and Jones 1998). Longipeditermes is, however, well known for its remarkable foraging habit. Workers and soldiers form open-air processional columns on the ground, shrubs, and tree trunks typically inside forests (Gray and Dhanarajan 1974; Hoare and Jones 1998; Miura and Matsumoto 1998; Takematsu et al. 2013; Syaukani et al. 2016). The foraging activities of both species seem to be greatest during the day (Hoare and Jones 1998), as evidenced by workers carrying packed balls of organic matter between their mandibles and returning to the nest.

In the course of our long-term inventory and taxonomic research on termites in Southeast Asia, more than 200 colonies of Longipeditermnes have been sampled from different habitats and altitudes across the Greater Sunda. In this paper, the two species of the genus are redescribed and illustrated using newly obtained nest series. Information on their life history is provided.

We examined 216 colonies of Longipeditermes from various habitats and altitudes across the Greater Sunda (Table 1; Fig. 1) . The specimens examined are deposited at the Museum Zoologicum Bogoriense (MZB), Cibinong, Indonesia; the Natural History Museum, London (UK); and the Universitas Syiah Kuala (Biology Department), Darussalam, Banda Aceh (Indonesia).

Figure 1. 

Distribution of Longipeditermes longipes (yellow dot) and L. kistneri (red dot) on the Greater Sundas, Southeast Asia.

The head, body (in profile), pronotum, and antenna of the soldier caste (preserved in 70% ethanol) were photographed using a digital microscope (KEYENCE HFVH-8000, Osaka). From these images, multifocused montages were produced using Helicon Focus v. 6.2.2 (Helicon Soft Ltd, Kharkov, Ukraine). Morphological terms and measurement characters follow those of Roonwal and Chhotani (1989), Sands (1998), Tho (1992), and Syaukani et al. (2011). We measured the characters (in millimeters): head capsule length including nasus (HLN), head capsule length excluding nasus (HL), nasus length (NL), nasus index = NL/HL, maximum head width at anterior part (HWA), maximum head width at posterior part (HWP), maximum height of head capsule excluding postmentum (HH), pronotum length (PL), and pronotum width (PW).

Longipeditermes species are distinguished from those of the other groups of Southeast Asian nasutitermitine termites by forming open-air processional foraging columns (e.g., Hospitalitermes and Lacessititermes) and by having major and minor soldiers that both have long legs and a long rostrum. No information is available for the ratio of the largest and smallest soldiers in typical colonies, but minor soldiers appear to be more numerous (Figs 34, 35). The soldier does not exhibit a clear dimorphism, but a bimodal continuum in size.

Longipeditermes kistneri was only collected from Sumatra during our intensive surveys in the Greater Sundas, although the type locality is Java. Nine colonies were found in protected forests above 1,000 m in altitude. Four nests were located among buttresses and roots of big trees (under the ground covered with decayed leaf litter and small decayed branches). This nesting habit makes it difficult to estimate the sizes of their colonies. Both soldiers and workers forage on the surface of the ground. The size of foraging columns is smaller in L. kistneri than in L. longipes. Their pale- to dark-brown body color and smaller columns make it difficult to find colonies of L. kistneri.

Longipeditermes longipes seems to prefer lowland and swamp forests and is widespread in the Greater Sundas. Nests of L. longipes are usually constructed among buttresses of trees (Fig. 36) and in dead or decayed stumps, with decayed wood debris and leaves (Fig. 37). Several subterranean nests of this species were found in Lambir Hills National Park (Sarawak, Borneo) by Miura and Matsumoto (1998). Underground nests are sometimes made from consisting of soil and litter. This species forages on the ground during the day. However, Hoare and Jones (1998) reported foraging activity at night, during which no food balls were being carried. We also found foraging columns at night; the columns consisted of limited numbers of workers carrying food balls to the nests. In typical processional foraging columns, numerous soldiers guard workers. Foraging ecology and diet of L. longipes have been poorly studied, but we know that this species feeds on leaf litter (Miura and Matsumoto 1998) and in the Pasoh Forest Reserve on the Malay Peninsula it prefers to consume older leaf litter rather than newly fallen leaves (Matsumoto and Abe 1979). We observed foraging columns consuming a mixture of bark, twigs, and decayed wood in forests of Sumatra and the Malay Peninsula.

Figures 34, 35. 

Foraging column of Longipeditermes longipes on the forest floor in Southeast Asia. Workers collecting and transporting food source from a decayed branch (34) and leaf litter (35), soldiers protecting the worker from predators such as Componotus gigas (Latreille).

Figure 36. 

Nest entrances (red arrows) of subterranean nest of Longipeditermes longipes found in SE Asia tropical forests.

Figure 37. 

Above-ground nest of L. longipes constructed in and around a dead tree stump (Shorea sp.). The cavity was fulfill with a mixture of soil, debris and litter.

In general, from the current study, we conclude that only two species of Longipeditermes (L. longipes Holmgren and L. kistneri Akhtar & Ahmad) have so far been collected in the Greater Sundas. Long legs and size dimorphism of soldier caste can help to separate this genus from other nasute termites in Southeast Asia. The condition of rostrum, head capsule, pronotum, and antennae determine the soldier caste, while the condition of antennae and left mandibles of worker caste serve to distinguish these two species. Longipeditermes kistneri seems to prefer high-altitude forests and has been found exclusively from Java and Sumatra, while L. longipes seems to prefer lowland and swamp forests and is widespread in the Greater Sundas.

We thank the Termite Research Group (Universitas Syiah Kuala, Indonesia), Sugesti, M. Rapi, Tarmizi, M. Isa, Usman, and Mat Plin (Leuser Development Program, Indonesia), Erwin Widodo (Conservation International), Epal (WWF, Indonesia), Dolly Priatna and Adnun Salampesi (Zoological Society of London), F.X Susilo, I Gede Swibawa, and Rahmat Pranoto (Lampung University), Idris Ghani and Fazli Rahim (UKM, Malaysia), Rosichon Ubaidillah and Wara Asfiya (MZB, Bogor), Teguh Pribadi (PGRI Palangkaraya University, Indonesia), and M. Shahril (USM, Malaysia) for assistance in the field and laboratory. We are grateful to Seiki Yamane (Kagoshima University Museum, Japan) for support, Paul Eggleton and David Jones (Natural History Museum, UK) and staff at the Museum Zoologicum Bogoriense (MZB, Indonesia) for allowing the first author to examine the type material. We thank to staff in the Forestry Department in Indonesia for their help and assistance during field surveys. This work was financially supported by the Leuser Development Program (LDP 1998-2001), Nagao Environmental Foundation (NEF 2006), the Ministry of Research, Technology and Higher Education RG to Syaukani (International Research Collaboration and Scientific Publication 2012–2018), Syiah Kuala University (Professor Candidate Grant 2015, H-index Publication Grant 2016, International Conference Support 2016 (DITJEN RISBANG, the Ministry of Research, Technology and Higher Education, and the Zoology Laboratory Grant 2018). Eguchi’s research activities were partly supported by Asahi Glass Foundation (Leader: Katsuyuki Eguchi; FY2017-FY2020).