Army ant middens - Home and nursery of a diverse beetle fauna.

Army ants provide nourishment to a large variety of animals. This includes birds that feed on animals flushed out by army ant raids, symbiotic arthropods that consume the ants' prey or their brood, and other arthropods that scavenge on army ant refuse deposits. The latter have not received much attention, and the few published studies lack detailed species identifications. Here we provide a first systematic inventory of the beetle fauna associated with refuse deposits of Eciton army ants, with a focus on Eciton burchellii. We collected 8364 adult beetles, 511 larvae, and 24 eggs from 34 deposits at La Selva Biological Station, Costa Rica. We used a combination of DNA barcoding and morphology to identify a subset of 436 specimens to species level. The samples included several new species, and we here formally describe two water scavenger beetles (Hydrophilidae). Refuse deposits harbored a diverse beetle fauna. The identified subset consisted of 91 beetle species from 12 families, with rove beetles being the most abundant and diverse visitors. Of the 85 species found with E. burchellii, 50 species were collected from only one or two refuse deposits. Conversely, seven species were found in 10 or more refuse deposits, indicating a certain level of habitat specialization. We matched adults and immatures for 22 beetle species via DNA barcodes, demonstrating that army ant middens also serve as a beetle nursery. The present survey highlights the significant ecological function of army ants as promoters of biodiversity and their status as keystone species in tropical rainforests.

Agathidium mexicanum Hendrichs, 1979: Types rediscovered.

Agathidium mexicanum Hendrichs, 1979: 106 is the single Mexican species of Leiodidae described by a Mexican entomologist: Chemical Engineer Jorge Hendrichs. As an amateur coleopterist he made a beetle collection of 18,400 specimens, adequately labeled by his wife and daughter. Most of the specimens are now in the entomological collection of the Instituto de Biología, UNAM. He published 12 papers, one of them devoted to the description of one leiodid species: Agathidium mexicanum Hendrichs, 1979. Type specimens of A. mexicanum were collected in Estado de Mexico and Distrito Federal (now Ciudad de México) localities (type locality: Cerro Tlaloc, Estado de México). The type series as described in the original description was constituted by 13 specimens: Holotype (male), allotype (female) and, 11 paratypes (6 males and 5 females). For specific details, data of the material examined is fully included (Hendrichs 1979: 110):.