ORIGINAL RESEARCH ARTICLE Ultrastructural analysis of the effect of mating delay on cell death in the ovaries of virgin honey bee (Apis mellifera L.) queens. Bruno Berger 1 *, Carminda da Cruz-Landim 1 . 1 Instituto de Biociências de Rio Claro, Departamento de Biologia, Universidade Estadual Paulista (UNESP), Avenida 24 A, nº 1515 Bairro Bela Vista, 13.506-900 Rio Claro, SP. Brazil. Received 14 July 2008, accepted subject to revision 23 September 2008, accepted for publication 12 October 2008. *Corresponding author: Email: parameciumsp@yahoo.com.br Summary This paper reports the effect of mating delay on the ovaries of virgin Apis mellifera queens using analysis by light and electron microscopy. The results showed that the terminal filament did not change throughout the study period, but its length decreased and germarium size increased with age of queens. Cell death events were observed in the ovaries from emergence but not in the terminal filament. Isolated cell death occurs in young queens prior to mating age, but cell death substantially increases if mating does not occur in the normal period. Two morphological types of cell death were observed: apoptosis-like death in germ line cells and autophagic-like death in somatic line cells. Cell death in germ line cells is apparently more frequent in cystocytes. Death after oocyte differentiation seems only to affect future nurse cells. Análisis ultraestructural del efecto del retraso en el apareamiento en la muerte celular en ovarios de abejas reinas vírgenes (Apis mellifera L.). Resumen Este articulo informa sobre el efecto del retraso del apareamiento en los ovarios de reinas Apis mellifera vírgenes usando análisis de microscopia óptica y electrónica. Los resultados mostraron que el filamento terminal no cambió durante el periodo de estudio, pero su longitud disminuyó y el tamaño del germarium aumentó con la edad de las reinas. Se observaron eventos de muerte celular en los ovarios desde la emergencia pero no en el filamento terminal. Muerte celular aislada ocurre en reinas vírgenes antes de la edad de apareamiento, pero ésta aumenta sustancialmente si el apareamiento no ocurre en el periodo normal. Dos tipos morfológicos de muerte celular fueron observados: muerte similar a la apoptosis en células de la línea germinal y muerte similar a la autofagia el células de la línea somática. La muerte celular en células de la línea germinal es aparentemente más frecuente en cistocistos. La muerte después de la diferenciación del oocito parece afectar únicamente a las futuras células acompañantes. Keywords: apoptosis, authophagy, honey bee queen, morphology, Apis mellifera Journal of Apicultural Research and Bee World 48(1): 60-66 (2009) © IBRA 2009 DOI 10.3896/IBRA.1.48.1.12 Introduction At emergence, the ovaries of honey bee queens consist of a very long distal terminal filament and a short proximal germarium where only early oogenesis can be observed. The vitellarium is not yet present (Berger and Adballa, 2005; Patrício and Cruz-Landim, 2002). Soon after emergence, oogenesis advances in a sequence of events that promote changes in ovary structure. In three day old virgin queens, the germarium shows cell clusters (cystocytes) which are surrounded by somatic cells forming cysts. The