Effect of narcosis with CO2 on the ovarian development in queens of Apis mellifera (Hymenoptera, Apini)

Author(s)

Abdalla, Fabio Camargo ^[1] ; Berger, Bruno

Affiliation

^[1] Universidade Estadual Paulista (UNESP). Campus de Rio Claro. Instituto de Biociências. Departamento de Biologia - Brasil

• Document type: Journal article
• Source: Sociobiology; v. 45, n. 2, p. 261-270, Aug. 2005.
• Field of knowledge: Biological Sciences - Morphology

Abstract

Exposure of 1,4,7 and 10 day-old virgin queens of Apis Mellifera Linné 1758 for 1 minute with CO2, accelerated their ovarian development, having a similar effect as mating on the initial formation of the ovarian follicles. In 3 day-old queens the exposure to CO2 enhanced the initial stage of germ cell differentiation into oocytes and nurse cells in the ovarioles, a developmental stage only seen in 5 day-old untreated virgin queens, the age at witch they are ready to mate. In 10 day-old untreated virgin queens, some regions of the ovarioles presented tissue disorganization and many cells with pycnotic nuclei. However, narcotized virgin queens of same age did not present such a ovary degeneration. Conversely, they showed nitid folicle formation, arising in the ovarioles initial differentiation between nurse and oocyte chambers, although still without vitellogenesis. The accelerative effect of CO2 is limited to the ages near to those proper for mating, since 15 and 18 day-old treated virgin queens presented ovaries with extensive regions of high tissue disorganization and great number of cells with pycnotic nuclei. According to the results, the narcosis presented three levels of effect on the ovary of honeybee virgin queen: 1. accelerated the germ cell differentiatiation, 2. preserved the tissue integrity even after the queen mating period and 3. stimulated the initial differentiation of vitelarium. This later condition was only seen in untreated queens after mating. All these effects are not maintained in the queenis kept virgin beyond 15 days old. (AU)