Meliwillea bivea gen.n., sp.n. is the only known stingless bee genus endemic to Central America. External morphology and male genitalia show affinity of Meliwillea with Scaptotrigona. Its plesiomorphies and current sympatry with Scaptotrigona suggest Meliwillea is relictual and diverged in montane habitat during the Tertiary, predating the Pleistocene connection between Central and South America which allowed immigration by Scaptotrigona. Addition of Meliwillea to the list of Neotropical genera changes the phylogenetic position of Nannotrigona, making it sister to Paratrigona instead of Scaptotrigona.

Two genetic markers (the mtDNA COI-COII intergenic region and the microsatellite A7) with high levels of variability in South African and European honey bees were analyzed in wild swarms of Africanized honey bees (Apis mellifera) from Costa Rica. Allelic or haplotypic frequencies revealed high levels of genetic variability at these loci in this population. Most of the alleles were African alleles, although some European-derived alleles were also present. Differences in the frequencies of African alleles between African and Africanized samples were minor, which could be explained by founder effects occurring during the introduction of African honey bee populations into South America.
Dois marcadores genéticos (a região intergénica mitocondrial COI-COII e o microsatélite A7), com altos níveis de variabilidade em populações de abelhas melíferas da África do Sul e Europa, foram analisados em uma amostra de enxames naturais da Costa Rica. As freqüências alélicas e haplotípicas na amostra africanizada mostraram altos níveis de diversidade nestes loci. A maioria dos alelos são de origem africana, embora alguns alelos de origem européia foram observados. As mudanças nas freqüências dos alelos de origem africana entre as abelhas da África do Sul e as abelhas da população africanizada são de baixa magnitude e podem ter sido causadas pelo efeito fundador que ocorreu na introdução da abelha africana na América do Sul