Abstract Stingless
bees of the genus Melipona, have long been considered an enigmatic case among social
insects for their mode of
caste determination, where in addition to larval
food type and quantity, the
genotype also has a saying, as proposed over 50 years ago by Warwick E. Kerr. Several attempts have since tried to test his Mendelian two-loci/two-
alleles segregation hypothesis, but only recently a single
gene crucial for
sex determination in
bees was evidenced to be
sex-specifically spliced and also
caste-specifically expressed in a Melipona species. Since
alternative splicing is frequently associated with
epigenetic marks, and the
epigenetic status
plays a major
role in setting the
caste phenotype in the
honey bee, we investigated here
epigenetic chromatin modification in the stingless
bee Melipona scutellaris. We used an
ELISA-based
methodology to quantify global
methylation status and
western blot assays to reveal
histone modifications. The results evidenced
DNA methylation/
demethylation events in
larvae and
pupae, and significant differences in
histone methylation and
phosphorylation between newly emerged
adult queens and
workers. The
epigenetic dynamics seen in this stingless
bee species represent a new facet in the
caste determination process in Melipona
bees and suggest a possible mechanism that is likely to link a
genotype component to the larval
diet and
adult social behavior of these
bees.