Differential Hind Leg Development in Apis mellifera Castes.

Author(s)

Ana Durvalina Bomtorin

• Document type: Master's Dissertation
• Press: Ribeirão Preto.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina de Ribeirão Preto (PCARP/BC)
• Defense date: 2009-03-11

Examining board members

Zila Luz Paulino Simoes; Helena Maria Marcolla Araujo; Tiana Kohlsdorf

• Advisor: Zila Luz Paulino Simoes

Abstract

Diphenism in the honey bee, Apis mellifera,resultsfromdifferential feeding of female larvae. Among the morphological differences, the hind legs of workers have structures that is used for carrying pollen and propolis, e.g. the corbicula, while the queens hind legslack thisstructures. The corbicula is an expanded region of the tibia deprived of bristles, which has a single bristle in the middle that seems to have a sensorial function. Using scanning electronic microscopy, we found that the leg structures and bristles of the corbicula are already formed in browneyed pupa. Microarray analysis has demonstrated that five of 240 differentiallyexpressed genesin developing castes are potentially related to the caste differences in leg development (ataxin2, cryptocephal, dachshund, grunge and Retinoic and fat acid Binding Protein). Using qPCR, we analyzed the expression of abdominalA, ataxin2, cryptocephal, grunge, Retinoic and fat acid Binding Protein and ultrabithorax genes during hind leg development. cryptocephal, ataxin2, grunge and Retinoic and fat acid Binding Protein genes, which are involved in imaginal disc elongation and bristle formation and are inhibited by juvenile hormone, were not found to be differentially expressed. However, ultrabithorax and abdominalA are over expressed in workersin the early pupalstage. By using immunohistochemistry, Ubx was localized in the tibia and basitarsus of prepupae of workers and in the basitarsus of pre pupae of queens. The pattern of Ubx expression suggests that this Hox gene is a key player in leg structuresformation and caste differentiation in A.mellifera. (AU)