Schwarziana quadripunctata

Schwarziana quadripunctata is a small, stingless bee found in a stretch of the South American Amazon from Goiás, Brazil, through Paraguay, to Misiones, Argentina. This highly eusocial insect constructs earthen nests in the subterranean level of the subtropical environment, an unusual feature among other stingless bees. The species ranges in sizes from and feeds on a diverse diet of flowering plants found abundantly on the forest floor, including guacatonga (Casearia sylvestris) and the mistletoe species Struthanthus concinnus. Schwarziana quadripunctata was first described by the French entomologist and former president of the French Entomologist Society Amédéé Louis Michel le Peletier in 1836. Although originally placed in the genus Trigona, more recent taxonomic evaluations have since placed it under its current genus, following the 1943 work of Padre J.S. Moure, occasionally referred to as "the Father of Brazilian Bee Taxonomy". However, some still consider the term Schwarziana as a subgenus rather than genus and instead incorrectly classify it under the closely related genus Plebeia. The closest relative of S. quadripunctata is the species Schwarziana mourei, determined through morphological and genetic evidence collected in the early twenty-first century. Until recently (2015) it was believed that these were the only two existing species under the genus Schwarziana in the world. However, two more species were discovered in the high altitude environment of South America – S. bocainensis in southeastern Brazil and S. chapadensis in central Brazi. The stingless bee S. quadripunctata varies in size from . Worker bees and dwarf queens tend to be on the lower end of this spectrum while queens tend to lie on the higher end. Dwarf queens and workers tend to have an average weight of about 30 mg, but have been known to weigh as much as 40 mg or as little as 22 mg. Mated queens (those in charge of the nest) are, in comparison, much larger. The average queen bee weighs in at about 130 mg.