Increased Caspase-3 Immunoexpression and Morphology Alterations in Oenocytes and Trophocytes of Apis mellifera Larvae Induced by Toxic Secretion of Epormenis cestri

Toxic honeydew produced by Flatidae Epormenis cestri in Uruguay has been shown to cause among honeybees (Apis mellifera) colonies a massive larva death called “River disease”, but the intrinsic mechanisms are still unknown. Because fat body cells, oenocytes and trophocytes, are known to regulated larvae metabolism, and to be affected by xenobiotics, we tested whether apoptosis of these cells can be an underlying cause of larvae death. Ten colonies were divided into two groups and fed with common honey or toxic honeydew obtained from colonies affected by “River disease”. Five-dayold larvae were collected and processed for histology and immunohistochemistry for caspase-3. The area, diameter, and immunostaining area in oenocytes and trophocytes were measured. The oenocyte and trophocyte cellular area decreased in the treated group (p=0.002; p