Comparative transcriptomics of the bacteriome and the spermalege of the bedbug Cimex lectularius (Hemiptera: Cimicidae)

The bedbug Cimex lectularius is notorious as a blood-feeding exoparasite of human and other warm-blooded animals. In addition to its medical and hygienic importance, C. lectularius is known for its unique biological traits, including obligate nutritional mutualism with a vitamin-provisioning Wolbachia endosymbiont and a peculiar mating habit called traumatic insemination wherein male sperm is injected into the female body cavity, migrates to the ovary, and fertilizes eggs therein. For these unique traits, novel insect organs, the bacteriome for endosymbiosis and the spermalege for traumatic insemination, have evolved in the lineage of bedbugs. We constructed cDNA libraries of the bacteriome and the spermalege of C. lectularius, and performed expressed sequence tag (EST) analyses of these peculiar insect organs. In total 4480 ESTs were compiled, which were assembled into 2989 unique sequences (USs). The following ESTs and USs were identified from the different organs: 1151 ESTs and 901 USs from the female whole body; 1098 ESTs and 879 USs from the female bacteriome; 1145 ESTs and 783 USs from the male bacteriome; and 1086 ESTs and 920 USs from the female spermalege. These EST data will provide a valuable genetic resource for understanding the developmental and evolutionary aspects of these novel insect organs.