Ants of Kenya

This webpage is the regional project page for Kenya. A list of species can be found here Kenya

The most recent study to assess the Kenyan ant fauna is: Hita Garcia, F.; Wiesel, E.; Fischer, G. 2013. The ants of Kenya (Hymenoptera: Formicidae) - faunal overview, first species checklist, bibliography, accounts for all genera, and discussion on taxonomy and zoogeography. Journal of East African Natural History 101:127-222. DOI: 10.2982/028.101.0201 This webpage is based on this publication. There are 596 species in 63 genera from 12 ant subfamilies known from Kenya.

Generic Diversity Table
The following table provides an accounting of the number of species for each genus. The last column of the table, Taxonomic Status, provides some idea of the taxonomic status of the genera. Good means that the number of species given here is likely a good estimate of the generic diversity, fair means revisionary work is needed but the genus is not likely to be much more diverse and poor indicates there remains much uncertainty in regards to the number of species for the genus. More information about each genus is also given in the text that follows this table. Links are provided that will easily move between the table and text for each entry.

Genera are organized by subfamily (listed in alphabetical order), and are listed in alphabetical order within each subfamily. The ordering of the rows can be changed to show other arrangements by clicking on a heading.

Generic Accounts
Genera are organized by subfamily (listed in alphabetical order), and are listed in alphabetical order within each subfamily.

Aenictus
The Old World genus Aenictus is distributed in the Afrotropical, Palaearctic, Oriental and Indo-Australian regions (Gotwald, 1982, 1995; Shattuck, 2008). Currently, it comprises 148 species worldwide, of which 40 are found in the Afrotropical region (Shattuck, 2008; Bolton, 2012). In Kenya there are six valid species, two subspecies and three unidentified morphospecies from Kakamega. These species numbers should however be regarded with caution, since the taxonomy of this genus is in a state of confusion. Most species were described on the basis of a single unassociated caste or sex. This might indicate that the real number of species is significantly lower since it is very likely that the unknown castes from an already described species were not adequately recognised but described as different species. Emery (1910) provided a list of the then known fauna, and some species or unknown sexual forms were described some decades ago (Gotwald & Cunningham-van Someren, 1976; Gotwald & Leroux, 1980; Campione et al., 1983). Nevertheless, no modern taxonomic revision is available for the Afrotropical region, and without keys the identification to species level is often difficult or impossible.

Aenictus are small, blind, monomorphic army ants that live in colonies with hundreds or thousands of workers and seem to be specialised predators of ants or other social insects (Wilson, 1964; Gotwald, 1982, 1995). Despite the large colony size, they are generally inconspicuous due to their hypogaeic lifestyle and appear to be comparatively rare on a local scale (Shattuck, 2008). Like other army ants, they display nomadism, and migrate to new nesting sites after depletion of prey colonies in their environment. Furthermore, Aenictus possesses specialised dichthadiiform queens with an increased egg-laying ability and new colonies arise through colony fission (Gotwald, 1982, 1995).

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Aenictogiton
The genus Aenictogiton is of extraordinary interest within the Afrotropical region. The genus occurs in Central, South, and East Africa, and is biogeographically limited to the Afrotropical region (Brown, 1975; Parr et al., 2003; Hita Garcia et al., 2009). Material of Aenictogiton is generally scarce, and consists solely of male specimens. Brown (1975) already stated the complete lack of knowledge concerning the female castes, which, despite intensive search efforts, have not been discovered until the present day. The known species richness appears comparatively small, with just seven described species (Brown, 1975), although a good number of unidentifiable and possibly undescribed specimens located in several museum collections await taxonomic examination and possibly description as new species. The taxonomy of the genus can be regarded as unsatisfactory since it was never revised after the initial species descriptions (Emery, 1901; Forel, 1913; Santschi, 1919b, 1924). The only Kenyan species is an unidentified male-based morphospecies recorded from the Kakamega Forest.

The biology of this enigmatic genus remains an almost complete mystery. Brown (1975) mentioned the possibility that these ants are subterranean or otherwise strongly cryptobiotic; we fully agree since no foraging worker nor any trace of a colony could ever be found. Phylogenetic and morphological affinities to the army ant genus Dorylus suggest an army-ant-like lifestyle, although there is no current evidence for this. However, most males were collected from light traps close to forest localities, indicating that Aenictogiton might prefer forested habitats.

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Stigmatomma
The genus Stigmatomma is of global distribution and holds currently around 60 described species (Yoshimura & Fisher, 2012). Since Brown (1960) it was considered to be a junior synonym of Amblyopone Erichson, but it was recently revived to genus rank (Yoshimura & Fisher, 2012). In the Afrotropics it seems to be relatively species-poor with only three described species (Brown, 1960; Gotwald & Levieux, 1972), but it should be mentioned that more than 13 undescribed forms exist in several museum collections (Brian Fisher, personal communication). Two unidentifiable and possibly undescribed species are known from the Kenyan coast. Although Brown (1960) reviewed the genus (as Amblyopone) on a global basis, he did not provide a revision of the Afrotropical fauna. One species was described later, but outside of a generic framework (Gotwald & Levieux, 1972). As a consequence, the genus is in need of a modern taxonomic revisionary work.

Members of this genus, as most amblyoponines, are specialised predators, which are thought to hold several ancestral anatomical and behavioural character states (Fisher, 2003). Stigmatomma species are known to live a hypogaeic lifestyle as predators of chilopods (Gotwald & Levieux, 1972) and in addition, are known as "dracula ants" that feed on their own larvae (Fisher, 2003; Saux et al., 2004). Queens can be observed to perform a form of non-destructive cannibalism by cutting a hole in the larval integument to feed on the exuding hemolymph. This however does not seem to harm the larvae, which continue growing and eventually emerge as normal adults.

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Cerapachys
The genus Cerapachys is widely distributed across the World's tropics and subtropics, although most of the 146 known species occur in the Old World (Brown, 1975; Bolton, 2012). Although treated by Brown (1975) on a global base, the taxonomy of this genus is far from satisfactory, especially for the Afrotropical region. Brown (1975) listed around 20 described species from this region and presented an identification key to the worker caste, but postponed a formal revision until more material would become available. He also presented some doubts on the species status of some species, and mentioned the existence of several undescribed species. Unfortunately, since then no more works on Afrotropical Cerapachys have been published. Consequently, the identification to species level with Brown's (1975) key is often unreliable. At present, we recognise eight valid species and two morphospecies for Kenya.

Cerapachys ants are specialised predators of other ants that conduct raids to attack prey nests. They retrieve captured larvae and pupae, less commonly also adults, to their own colony and store them as food (Hölldobler, 1982; Brown, 1975). Wilson (1958) and later Brown (1975) raised the question of whether Cerapachys and other members of the subfamily are nomadic, and proposing that nomadism might have evolved as special adaptation in ant-hunting cerapachyines in order to avoid depletion of prey. Members of this genus can be encountered in a variety of habitats ranging from humid rainforests to arid savannah grasslands or semi-deserts, and nests are generally constructed in the ground or in rotten wood (Brown, 1975).

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Simopone
Simopone is distributed in the Afrotropical, Malagasy, Oriental, and Indo-Australian regions and it holds 38 described species (Brown, 1975; Kutter, 1976, 1977; Bolton & Fisher, 2012), of which most are found in the Afrotropical and Malagasy regions. In their recent revision of the genus Bolton and Fisher (2012) list 18 species for the Afrotropical region. Currently, three species are known to occur in Kenya, which are only known from the Kakamega Forest. On the basis of the recent revision by Bolton and Fisher (2012), the taxonomy of the genus is in an excellent condition, and very good identification keys are now available for workers and queens.

Simopone seem to be rare, arboreal ants and presumably nocturnal (Bolton, 1973a; Brown, 1975; Kutter, 1977; Bolton & Fisher, 2012). Knowledge on the natural history of most species is very limited, but from some species it is known that they are specialised predators of other ants (Brown, 1975; Bolton & Fisher, 2012).

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Sphinctomyrmex
Although Sphinctomyrmex occurs in the tropics of the New and Old World, only 22 described species are known and these are mainly distributed in Australia (Brown, 1975; Bolton, 2012). Brown (1975) listed just two valid species for the Afrotropical region, but mentioned another three undescribed species. Unfortunately, the two described species are only known from males and the other species mentioned by Brown remain undescribed until today. Additionally, in Kenya two unidentified and probably new worker-based species were sampled in the Kakamega Forest. As a consequence, it is not possible to identify any worker-based Sphinctomyrmex from the Afrotropical region, and a modern taxonomic revision that associates workers, queens, and males is highly desirable. Unfortunately, knowledge on the ecology of the African species is fairly limited. They appear to be rare ants that nest in the ground or rotten wood and were mainly collected from the leaf litter (Bolton, 1973a; Brown, 1975). Some species from Australia seem to be comparatively army-ant-like and have more or less dichthadiiform queens; these species perform mass raids on other ants and are presumably nomadic (Brown, 1975; Buschinger et al., 1990).

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Axinidris
Axinidris is endemic to the Afrotropical region, and seems to be zoogeographically mostly restricted to the Guineo-Congolian rainforest belt from West Africa to the Kakamega Forest in Western Kenya, with few species occurring also in Eastern or Southern Africa (Snelling, 2007). A total of 21 species are known (Bolton, 2012). Interestingly, all eight species known from Kenya are only found in the Kakamega Forest in Western Kenya (Snelling, 2007; Hita Garcia et al., 2009) and four of these are also endemic to this rainforest. This genus is in an almost perfect taxonomic situation, with a revision by Shattuck (1991) and a more recent one by Snelling (2007), allowing easy identification to species.

The genus Axinidris is an arboreal genus with an omnivorous diet (Shattuck, 1991; Snelling, 2007) and its members seem to prefer moist rainforest habitats where they nest in hollow, living or dead stems, or in rotten wood (Snelling, 2007).

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Tapinoma
The genus Tapinoma comprises 64 described species that are distributed worldwide (Bolton, 2012). The Afrotropical region holds 13 described species (Robertson, 2000). There are four valid species and two subspecies known from Kenya and we found two additional morphospecies from Arabuko Sokoke. Species level identification of African species is generally problematic due to the lack of any modern taxonomic revisionary works.

Most Tapinoma species are arboreal and some live in close associations with myrmecophyte plants (Wheeler, 1922; Bolton, 1973a). In addition, they seem to be generalised foragers (Brown, 2000).

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Technomyrmex
Technomyrmex is of moderate size with 93 described species, which are distributed throughout all tropical and sub-tropical zones, mainly in the Afrotropical, Oriental and Indo-Australian regions (Bolton, 2012). Around one third of them occur in sub-Saharan Africa, from which 25 are endemic to this region (Bolton, 2007), and, at present, we recognise nine valid and one undescribed species from Kenya. Recently, Bolton (2007) revised the genus for the West Palaearctic and Afrotropical regions and presented a key to the worker caste.

The majority of Technomyrmex species nest and forage arboreally or sub-arboreally and even the few species that nest in soil or leaf litter forage on trunks and in the canopy (Bolton, 2007). Some specialised myrmecophilous plants have been reported to house Technomyrmex species (Hölldobler & Wilson, 1990), but to what extent this might be true for the Kenyan species remains unknown. The diet mainly consists of hemipteran honeydew, though most species also feed on dead or living arthropods or their brood (Bolton, 2007).

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Dorylus
This genus is distributed throughout the Old World tropics and subtropics, but the majority of species are found in the Afrotropical zoogeographical region (Gotwald, 1982, 1995). The taxonomic condition of Dorylus, especially for the African continent, can be classified as chaotic and useless for identification purposes. On a global basis, 59 species and 68 subspecies are recognised (Bolton, 2012), although the taxonomic validity of many of these taxa is highly questionable. The problem is that most descriptions were based on a single caste, and careful examination of taxa in order to find evidence for conspecificity among these is very rare (Schöning et al., 2008). Also, no modern taxonomic revision is available, which dramatically increases the difficulties to identify Dorylus to species level. Nevertheless, identification to subgenus level can be well performed with the keys provided in Gotwald (1982). At present, we recognise around 15 species, seven subspecies and two morphospecies from Kenya but this number will likely change with future taxonomic modifications and new discoveries.

The army ant genus Dorylus is mostly known for the spectacular swarm raids performed by some epigaeic species, mostly belonging to the subgenus Anomma, better known as "driver ants". These species perform huge swarm raids along the ground and lower vegetation with hundreds of thousands of blind, polymorphic workers to hunt down a great variety of prey taxa in large quantities, predominantly invertebrates (Gotwald, 1982, 1995). However, many more species within the genus live and hunt hypogaeicly and these army ants are generally less visible than their epigaeic relatives (Berghoff et al., 2002). Hypogaeic species hunt in columns and many species are known to be specialised predators of other social insects, such as termites or other ants (Darlington, 1985; Gotwald, 1982, 1995; Schöning & Moffett, 2007). Almost all species of Dorylus, like other army ant genera, live in monogynous colonies with dichthadiiform queens that have a massive egg-laying capacity, e.g. three to four million eggs per month in “driver ant” queens (Raignier & van Boven, 1955). In addition, Dorylus colonies migrate in irregular intervals to new nesting sites and new colonies emerge through colony fission (Gotwald, 1982, 1995).

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Acropyga
Despite their cryptic lifestyle Acropyga, are found in all zoogeographical regions and at present 40 species are known (LaPolla, 2004a; Bolton, 2012). The genus was recently globally revised and just three species are recognised from the Afrotropical region (LaPolla, 2004a; LaPolla & Fisher 2005). LaPolla and Fisher (2005) drew attention to this seemingly depauperate Afrotropical Acropyga diversity, especially when compared with the over a dozen species known from the Oriental and Neotropical regions. Whether this low diversity is typical for the Afrotropics or just a sampling artefact due to insufficient collecting still remains unclear. All three Afrotropical species can be well identified with the key provided in LaPolla & Fisher (2005). Only one species, Acropyga silvestrii , which is widespread in the whole Afrotropical region, is known from Kenya (Hita Garcia et al., 2009).

Acropyga are usually small, cryptic, slow-moving ants that live a hypogaeic lifestyle predominantly in forest habitats (Prins, 1982; LaPolla & Fisher, 2005). The genus is also well known for its close association with mealybugs that are tended for their honeydew on underground plant roots (LaPolla et al., 2002). This relationship is so close that virgin queens take along a mealybug between their mandibles when they leave their birth nest to establish a new colony. (LaPolla et al., 2002; LaPolla & Fisher, 2005).

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Anoplolepis
Anoplolepis is a relatively small genus with only nine valid species (Bolton, 2012), which are predominantly distributed in the Afrotropical region, with fewer species in the Malagasy and Oriental regions and some introduced in other regions. Only one species is listed from Kenya, namely Anoplolepis custodiens, which shows a wide distribution range from Southern Africa to Kenya and Somalia (Prins, 1982). This species is also known as the "common pugnacious ant" because of its aggressiveness and fast movements. It is very common in South African orchards and vineyards (Prins, 1982) where it was early regarded as a pest (Arnold, 1922). There is no modern revision available for this genus on an Afrotropical basis, although Prins (1982) presented a taxonomic treatment for the South African species. Unfortunately, he only provided a key to the queen and male castes.

These formicines are epigaeic and active ants that forage on the ground or the vegetation. Their diet is comparatively variable since they feed on a variety of small arthropods but also on honeydew produced by aphids or coccids (Prins, 1982).

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