First record of the genus Acropyga Roger, 1862 (Hymenoptera: Formicidae: Formicinae) in Kerala, India

: This is the first record of the ant genus Acropyga from Kerala, India. The ant was collected as a part of the research collections done in the Rosemala region of the Shendurney Wildlife Sanctuary, Kerala, India. The worker, male and queen ants have been described here. A detailed description, distribution, ecological notes, and images are also provided.

ISSN 0974-7907 (Online); ISSN 0974-7893 (Print) The genus Acropyga belong to the family Formicinae and was first reported worldwide by Roger (1862) from Sri Lanka. There are currently 41 species in this genera worldwide (AntWeb 2018). Acropyga ants are present worldwide. These ants are known for their mutualistic obligate symbiosis with mealybugs of the subfamily Rhizoecinae (Johnson et al. 2001;Kishimoto-Yamada et al. 2005). They take care of these mealybugs and feed on the exudates produced by them. They can be found in a range of habitats, from deserts to rainforests, and is largely thought to be subterranean (LaPolla 2004).
Major contributions to this genus were made by Forel (1878) by making the first description of the genus. Smith (1871) described the geographical distribution of these ants. Terayama et al. (2002) gave a species key to the East Asian species of genus Acropyga. Wang & Wu (1992) described a new species of Acropyga from China and made an identification key. Terayama (2009) gave a synopsis of the Family Formicidae of Taiwan in which a key to the Acropyga of Taiwan was given, along with a few species descriptions. Jaitrong & Nabhitabhata (2005) made a list of ant species from Thailand in which the presence of Acropyga, along with its distribution in the country was reported. Acropyga acutiventris was described in detail by LaPolla (2004).
Acropyga was first reported in India by Bingham (1903). Currently, only two species from this genus have been reported in India-A. acutiventris & A. rubescens (Bharti et al. 2016). Acropyga acutiventris has been reported from 13 states in India, mostly from the northeastern region (Bharti et al. 2016) andAndaman &Nicobar Islands (Mohanraj et al. 2010). This is the first record of this genus from Kerala and the first description from India on Acropyga, including the worker, male, and alate queen. The only other state in southern India A. acutiventris has been reported is Karnataka (Varghese 2004). J TT (8.9336N & 77.1922E) of the Shendurney Wildlife Sanctuary (Image 1). The 'Ants of Leaf Litter' (ALL) protocol (Agosti et al. 2000) was used for ant collections. These particular ant samples were collected using handpicking. The current specimens were found under a small rock in an evergreen forest region of the Rosemala region. A whole colony was found under the rock, & the workers, male & alate queen, were collected. The specimens were preserved in 70% ethanol. Identifications were done under a stereomicroscope (Labomed Luxeo 6z). The taxonomic key by Bolton (1994) was used for the identification of the genus. The species was identified using the key by LaPolla (2004). Leica S8AP0 microscope with Leica DFC 295 camera was used to capture images, and measurements were done using the Leica v4.2 software. Soil samples were collected from the site and analysed in the laboratory. The soil pH was analysed using a soil pH meter and soil organic carbon was measured using Walkley & Black method (Page et al. 1982). The soil moisture was measured using the gravimetric method (Kadam & Shinde 2005). The specimens were deposited in the zoological museum at the Department of Zoology, University of Kerala Campus, Kariavattom, Kerala, India.

Measurements
HL: Head Length. Length of the head in full-face view when measured as a straight line from the midpoint of the anterior clypeal margin and to the midpoint of the posterior margin. This excludes the clypeus.
HW: Head width. The maximum width of the head in full-face view.
EL: Eye length. The maximum length of the eye when in the same view as HL.
ML: Mesosomal length. Length of the mesosoma in side view from the posteroventral corner of mesosoma to the farthest point on the anterior face of pronotum, excluding the neck.
GL: Gaster Length. The length of the gaster in lateral view from the anterior point of the first gastral tergite to the posterior-most point of the last gastral tergite, excluding the sting.
SL: Scape Length. Length of the scape in a straight line excluding the basal constriction of the neck close to the condylar bulb.
PTL Worker description: Head: Dull yellow colour, head slightly longer than broad and rectangular. Posterior margin of the head emarginated. Scape with dense pubescence. Teeth five, mandibles striate from base to the articulation point. Eyes small. Anterior margin of the mandible lined with long hairs. Head as long as wide. Antennae 11 segmented. Eyes placed at the lower half of the head (Image 1).
Mesosoma: Smooth and shiny, long erect setae present on alitrunk except propodeum. Propodeum with small recumbent hairs. Mesonotum raised and convex above pronotum when compared to pronotum when viewed in lateral angle (Image 2-3).
Petiole: Dull yellow, thick and erect with short erect hairs. Height about same as propodeum. Gaster: Five gastral segments present, Smooth and shiny with both long erect hairs and short recumbent hairs.

Male
Male

Description
Head: Dull yellow. Mandibles with striation. Anterior clypeal margin lined with long erect hairs. Three distinct ocelli are present. Outer margin of head lined with hairs. Eyes large placed in the lower ¼ of the head. Head as long as wide. Antennae with 11 segments (including scape) (Image 7-9).
Mesosoma: Dull yellow, smooth, and shiny, covered in small erect hairs.
Petiole: Triangular, erect hairs, and with small erect hairs on the dorsal surface.
Gaster: Dull yellow & five gastral segments. Surface covered in with long recumbent hairs.
Leg: Entire leg covered in short erect hairs. Differential diagnosis: This species is morphological very similar to Acropyga rubescens, but they are Ecology Notes: The ants were found in an evergreen forest, in between two stones in the leaf litter near a small stream with low light conditions and high humidity. There were 30 worker ants, one queen and four males in the colony. The ants were docile upon disturbance showing few movements. There was no nest formation of any type as the ants were found on top of a rock covered by another rock. The ants were handpicked. There were multiple Anoplolepis gracilipes ants a few kilometers away from the nest. Soil was collected from where the ants were found. The pH of the soil was measured to be 5.53. The organic matter in the soil was analysed to be 0.04%, and the soil moisture was 24.5%.

Discussion
A total of 10 workers, one male and one alate queen were taken from the site. These ants are relatively less common in collections because of their rarity. This study extends the range of this genus to Kerala. A. acutiventris was observed in the Shendurney Wildlife Sanctuary which is a part of the Western Ghats. The collections revealed that there were multiple Anoplolepis gracilipes ants near these Acropyga ants. The presence of invasive ants has been known to cause lowered species diversity of ants (Berman et al. 2013). Anoplolepis ants have also been known to cause a decrease in the diversity of ants (Mezger & Pfeiffer 2011). It can be said that the presence of Anoplolepis ants, which act as invaders, can be detrimental to native specialist ants like A. acutiventris. It is imperative that the forest be protected and its human interference be lowered so that such invasive ants can be controlled.

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