Development, Ultrastructure, and Mode of Transmission of Amblyospora sp. (Microspora) in the Mosquito*

Abstract

Amblyospora sp. in Culex salinarius (Coquillett) is transovarially transmitted and has 2 developmental sequences, 1 in each host sex. In females, the entire life cycle is restricted to oenocytes which become greatly hypertrophied due to multiplication of diplokaryotic cells durng merogony and come to lie next to ovaries. Sporulation occurs only after a blood meal is taken and is shortly followed by infection of the oocytes and subsequent transmission to the next host generation. In the male host, infections spread from oenocytes to adipose tissue where diplokaryotic cells undergo a 2nd merogony. During this merogonic cycle, number of diplokaryotic cells greatly increases and the infection is spread throughout the body of the larval host. Sporulation is initiated with physical separation of the 2 members of the diplokaryon and the simultaneous secretion of a pansporoblastic membrane. Subsequent meiotic division and morphogenesis result in formation of 8 haploid spores enclosed with a pansporoblastic membrane. Buildup of spores and subsequent destruction of host adipose tissue prove fatal to the male host during the 4th larval stage.