|Based on Ward et al. (2014) and Blaimer et al. (2018).|
Rhopalomastix workers chew a network of tunnels under the bark of living trees where they nest. Tunnels are inhabited by large numbers of diaspidid scale insects (Yong et al. 2019). Non-specific associations with different genera of trees and diaspidids were recorded in SIngapore, Thailand and Okinawa (Japan) (C. Peeters unpublished). Rhopalomastix is the second ant genus involved in a mutualism with diaspidids, besides Melissotarsus.
Eguchi, Bui and Yamane (2011) - The worker of Rhopalomastix is easily separated from those of other known Vietnamese myrmicine genera by a combination of the following characters: frontal lobes closely approximated; eye relatively large; mesosoma box-shaped; fore- and hindfemora extremely widened and flattened distally; postpetiole broadly attached to gaster.
Keys including this Genus
Distribution and Richness based on AntMaps
The presence of diaspidid scale insects inside all nests examined is a strong suggestion that they are a source of food for the ants. However, there are no direct observations of feeding or other interactions because ants stop normal activities and take cover as soon as the tunnels are opened. The five genera of diaspidids associated with four species of Rhopalomastix in Singapore all share the remarkable characteristic that females can reach sexual maturity without secreting a hard wax shield (Yong et al. 2019). As in Melissotarsus, Rhopalomastix adult females can secrete silk that is used to secure the tunnels.
• Antennal segment count 10 • Antennal club 2 • Palp formula 1,1; 0,1 • Total dental count 2-4 • Spur formula 0, 0 • Sting present
• Antennal segment count 12 • Antennal club gradual • Palp formula 1,1 • Total dental count 0 • Spur formula 0, 0
The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.
- RHOPALOMASTIX [Myrmicinae: Melissotarsini]
- Rhopalomastix Forel, 1900a: 24. Type-species: Rhopalomastix rothneyi, by monotypy.
Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.
Eguchi, Bui and Yamane (2011) - The worker of the single Vietnamese species has the following features. Worker monomorphic; head subrectangular; frontal carina and antennal scrobe absent; frontal lobes touching or separated only by a narrow longitudinal impression; median portion of clypeus weakly convex anteriorly, lacking median clypeal seta but bearing a pair of thick and short submedian setae; mandible small, with 4 teeth; antenna 10-segmented, with 2-segmented club; scape very short, extending a little beyond midlength of head when laid backwards; eye relatively large, located well in front of midlength of side of head; mesosoma box-shaped; promesonotal suture absent dorsally; metanotal groove absent; propodeum unarmed; metapleural gland bulla large; propodeal lobe absent; fore- and hindfemora extremely widened and flattened distally; petiole nodiform, with relatively high node, anteroventrally with well-developed subpetiolar process; postpetiole much shorter than high, broadly attached to anteriormost portion of gaster; gastral shoulder absent.
- Bolton, B. 2003. Synopsis and Classification of Formicidae. Mem. Am. Entomol. Inst. 71: 370pp (page 258, Rhopalomastix in Myrmicinae, Melissotarsini)
- Eguchi, K., Bui, T.V. & Yamane, S. 2011. Generic synopsis of the Formicidae of Vietnam. Part 1 – Myrmicinae and Pseudomyrmecinae. Zootaxa 2878: 1-61. PDF
- Emery, C. 1914e. Intorno alla classificazione dei Myrmicinae. Rend. Sess. R. Accad. Sci. Ist. Bologna Cl. Sci. Fis. (n.s.) 18: 29-42 (page 40, Rhopalomastix in Myrmicinae, Melissotarsini)
- Emery, C. 1922c. Hymenoptera. Fam. Formicidae. Subfam. Myrmicinae. [part]. Genera Insectorum 174B: 95-206 (page 118, Rhopalomastix in Myrmicinae, Melissotarsini)
- Forel, A. 1900a. Un nouveau genre et une nouvelle espèce de Myrmicide. Ann. Soc. Entomol. Belg. 44: 24-26 (page 24, Rhopalomastix as genus)
- Forel, A. 1917. Cadre synoptique actuel de la faune universelle des fourmis. Bull. Soc. Vaudoise Sci. Nat. 51: 229-253 (page 242, Rhopalomastix in Myrmicinae, Melissotarsini)
- Wang, W.Y., Yong, G.W.J., Jaitrong, W. 2018. The ant genus Rhopalomastix (Hymenoptera: Formicidae: Myrmicinae) in Southeast Asia, with descriptions of four new species from Singapore based on morphology and DNA barcoding. Zootaxa 4532:301-340 (DOI 10.11646/zootaxa.4532.3.1).
- Wheeler, W. M. 1910b. Ants: their structure, development and behavior. New York: Columbia University Press, xxv + 663 pp. (page 140, Rhopalomastix in Myrmicinae, Solenopsidini)
- Wheeler, W. M. 1922i. Ants of the American Museum Congo expedition. A contribution to the myrmecology of Africa. VII. Keys to the genera and subgenera of ants. Bull. Am. Mus. Nat. Hist. 45: 631-710 (page 661, Rhopalomastix in Myrmicinae, Melissotarsini)
- Wheeler, W. M. 1929e. The ant genus Rhopalomastix. Psyche (Camb.) 36: 95-101 (page 95, Review of genus)
- Xu, Z. 1999a. Systematic studies on the ant genera of Carebara, Rhopalomastix and Kartidris in China (Hymenoptera: Formicidae: Myrmicinae). Acta Biol. Plateau Sin. 14: 129-136 (page 130, China species key)
- Yong G, Matile-Ferrero D & Peeters C 2019. Rhopalomastix is only the second ant genus known to live with diaspidid scale insects. Insectes Sociaux 66:PDF