I’ve been inspired to write about a sighting just seven metres away from the REGUA office. What seemed to be a huge ant, never spotted here before, was photographed on a leaf. We currently have an inventory of ants being carried out by Rural Federal University of Rio de Janeiro (UFRRJ) researchers. To my surprise, close examination of the antennae and feeding apparatus from the photograph revealed this ‘odd’ ant to actually be hemipteran bug – an incredible ant mimic!
It has been identified as the nymph (juvenile stage) of the Neotropical Soybean Bug Neomegalotomus parvus (Westwood, 1842) (HEMIPTERA: Alydidae), or Percevejo Formigão in Portuguese.
According to Costa Lima’s Insetos do Brasil, only the immature stages are ant mimics. Alydidae bugs, or other primitive coreoids, are closely related to Leguminosae. They are not species-specific to any Leguminosae and feed on different leguminous plants (Schaefer 1980, Schaefer & Mitchell 1983), including soy beans, with potential to reach pest status.
In the field, adults were found on carrion and faeces of animals. In a soybean field in Bela Vista do Paraíso, PR, N. Parvus were found aggregating (30 to 40 individuals) in dog faeces at the time of soybean harvest. Alydidae may feed on faeces or carrion under extreme conditions when their primary food source (legumes) is not available.
The ecological reason for why the nymphs are perfect mimics of ants is still unknown. So here is an interesting theme for research.
LIMA, COSTA. 1940. Insetos do Brasil. 2 Tomo, Hemípteros, ESCOLA NACIONAL DE AGRONOMIA, SÉRIE DIDÁTICA N.º 3, figs. + 351 pp.
VENTURA, MAURÍCIO U., JOVENIL J. SILVA & ANTÔNIO R. PANIZZI. 2000. Scientific Note: Phytophagous Neomegalotomus parvus (Westwood) (Hemiptera: Alydidae) Feeding on Carrion and Feces. An. Soc. Entomol. Brasil 29: 839-841.