In the life cycle of the honeybee, the development of the last day embryo to the first instar larva is a critical event that marks the essential part of early life transition.However, it is still unknown the molecular mechanism regulating the transition of embryo to larva.Therefore, the proteome and phosphoproteome of last day embryos (72 h) and first instar larvae (24 h, post hatching) were analyzed using two-dimensional gel electrophoresis, followed by multiplex fluorescent staining, mass spectrometry, bioinformatics, and quantitative real-time polymerase chain reaction.Sixty-five proteins and 34 phosphoproteins showing differential expression were identified in which 54.5% and 45.5% were upregulated in the embryos and the larvae, respectively.Proteins related to energy metabolism, development and amino acid metabolism were strongly expressed in the embryo.This suggests that the embryo requires high metabolic energy during active embryogenesis and particularly for muscle contraction and abdominal peristalsis upon hatching.The fact that, higher levels of protein expression and phosphorylation were involved in cytoskeletal, biosynthesis, protein folding, fatty acid and oxidative metabolism in the newly hatched larvae indicates their roles to ensure the fast growing of hatchling larvae.Furthermore, 56 proteins acted as key nodes in the interaction network of proteins during the transition of embryo to larva, of which eight proteins had the same expressional tendency with their encoding genes.Our data provide first evidence that the change in the level of protein expression and protein phosphorylation status play key roles to support the developmental transition from embryo to larva.It unravels the molecular event behind the firstlife cycle transition of honeybees.This significantly extends our knowledge on honeybee developmental biology and potentially helps to provide candidate proteins for reverse genetics at the early stage of development, to generate productive and desirable honeybee phenotypes.