Species Megalostomis dimidiata

Megalostomis dimidiata Lacordaire, 1848

3 spp. n. of Mex. (2)

10 mm (large for a chrysomelid)

Det. E. G. Riley

c. TX to C. Amer. - Map (2)(3)

Range in south TX overlaps with that of the range of Atta texana - Map per USDA Forest Service

Adults associated with Acacia, Prosopis, Senna (Fabaceae) (legumes) (4)

Larval stage associated with leaf-cutter ants, Atta texana. (Walter et al. 1938) (5)

E. G. Riley reports having seen this sp. at Welder Wildlife Refuge, Texas, clipping leaves and that they dropped to the ground. He suspects that the dropped leaves may have had eggs on them and the Atta ants may have picked up the leaves and taken them into their nests. (EGRiley, pers. comm. to MAQ, 2014)

Walter et al. (1938) report, "The larvae of Megalostomis major are casebearers. Their cases, standing out from the walls of the runways like small rounded pegs, present one of the most curious features in the [Atta texana] ant nests. The case is made of a thin layer of soil firmly cemented together and, as the larva grows, built up, ring upon ring, from a shallow shell-like cover into a deep inverted cup. That of a mature larva is 12 to 14 mm long and 7 to 8 mm in diameter near the outer, rounded end and tapers uniformly to 5 to 6 mm at the open end, which is cut off square and held tightly against the wall by the enclosed larva. Before pupation this end is cemented to the wall and closed with a thin layer of cement just within the rim of the case. The larvae are most abundant in the older runways, especially those discolored by long use, where they apparently feed on the waxy accumulation's from the ants." (6)

Other two spp. in this genus occur in AZ-NM (2)

Moldenke, A.R. 1970. A Revision of the Clytrinae of North America North of the Isthmus of Panama (Coleoptera: Chrysomelidae). Stanford University, Stanford. 310 pp.

Walter, E.V., L. Seaton, and A.A. Mathewson. 1938. The Texas leaf-cutting ant and its control. USDA Circular No. 494: 1-18. (6)