Diacamma cyaneiventre

Small colonies (214 ± 80 workers, including one gamergate) can be found in open areas in southern India (André et al. 2001).

Distribution based on Regional Taxon Lists
Oriental Region: India.

Biology


André et al. (2006) - Diacamma cyaneiventre has small colonies of about 214 ± 80 (±SD) workers, that inhabit open areas in southern India. Behavioral and genetic data suggest that monoandry is the rule in Diacamma species (Peeters and Higashi, 1989; Fukumoto et al., 1989; André et al., 2001). The nests are long-lived underground structures (up to 50 cm, C. Peeters, unpubl. data) composed of many chambers. Nest entrances are surrounded by a conspicuous mound of soil and pebbles, and can thus easily be found. For purposes of thermoregulation, the workers regularly carry the brood in the upper chambers next to the nest entrance, as already noted in another Diacamma by Wheeler, 1915. An existing gamergate is replaced by a newly eclosed nestmate worker after her death or after colony fission. After a replacement, colonies go through short-lived periods in which two matrilines of sisters co-occur. This is a situation which can be described as serial polygyny.

In Diacamma, the single gamergate is replaced by one of her daughters (or occasionally by a sister). From a long-term genetic survey of nests of D. cyaneiventre, André et al. (2006) estimated the rate of gamergate turnover as well as the lifespan of workers and gamergate tenure using a maximum likelihood model. We compared the genotypes of two cohorts of workers sampled at 2 and 16 months interval from the same nests, using five microsatellite markers. To improve the accuracy of the estimates, we also added the nests from the same population sampled only once and analysed by André et al. (2001). The model indicates that one nest houses the same colony at two different sampling dates. The likelihood of the model was maximal for a probability of gamergate change = 0.005 per day (i.e. a gamergate tenure of 200 days) and a worker lifespan of 60 days, indicating that the gamergate‘s tenure is about 3 times longer than workers’ expected lifespan in the population studied. Moreover, genetic analysis of the gamergate and brood in three colonies excavated completely reveals that colony fission can occur just after a gamergate replacement, with the sister of the old gamergate reproducing in the new propagule.

Doums et al. (2002) used both mitochondrial and microsatellite markers to assess the consequence of restricted female dispersal (due to the evolutionary replacement of winged queens by gamergates) at three geographical scales: within a given locality (< 1 km), between localities within a given region (< 10 km) and between regions (> 36 km). Within a locality, a strong population structure was observed for mitochondrial DNA (mtDNA) whereas weak or nonexistent population genetic structure was observed for the microsatellites (around 5% of the value for mtDNA). Male gene flow was estimated to be about 20–30 times higher than female gene flow at this scale. At a larger spatial scale, very strong genetic differentiation for both markers was observed between localities — even within a single region. Female dispersal is nonexistent at these scales and male dispersal is very restricted, especially between regions. The phylogeographical structure of the mtDNA haplotypes as well as the very low genetic diversity of mtDNA within localities indicate that new sites are colonized by a single migration event from adjacent localities, followed by successive colony fissions. These patterns of genetic variability and differentiation agree with what is theoretically expected when colonization events are kin-structured and when, following colonization, dispersion is mainly performed by males.

Nomenclature

 *  cyaneiventre. Diacamma cyaneiventre André, 1887: 293 (w.) INDIA. Subspecies of rugosum: Forel, 1900d: 318. Revived status as species: Bingham, 1903: 78.

References based on Global Ant Biodiversity Informatics

 * André J. B., C. Peeters, and C. Doums. 2001. Serial polygyny and colony genetic structure in the monogynous queenless ant Diacamma cyaneiventre. Behav. Ecol. Sociobiol. 50: 72-80.
 * 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
 * Dias R. K. S. 2002. Current knowledge on ants of Sri Lanka. ANeT Newsletter 4: 17- 21.
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 * Rajan P. D., M. Zacharias, and T. M. Mustak Ali. 2006. Insecta: Hymenoptera: Formicidae. Fauna of Biligiri Rangaswamy Temple Wildlife Sanctuary (Karnataka). Conservation Area Series, Zool. Surv. India.i-iv,27: 153-188.
 * Tiwari R. N. 1999. Taxonomic studies on ants of southern India (Insecta: Hymenoptera: Formicidae). Memoirs of the Zoological Survey of India 18(4): 1-96.
 * Tiwari, R.N. 1999. Taxonomic studies on ants of southern India (Insecta: Hymenoptera: Formicidae). Memoirs of the Zoological Survey of India 18(4):1-96