Male-killing bacterium in a fifth ladybird beetle, Coleomegilla maculata (Coleoptera:Coccinellidae).
Inherited symbionts which selectively cause the death of male hosts are found widely across the Insecta. Previous studies have shown a single, but different micro-organism to be responsible for male-killing in each taxonomic group studied. We here produce evidence that within a group of insects, the Coccinellidae, there is more than one causal agent of male lethality. We report a novel observation of a male-killing trait in the species Coleomegilla maculata. Six of 26 crosses were found to produce a female-biased sex ratio associated with a low egg hatch-rate. The trait was matrilinearly inherited and was observed to be tetracycline-sensitive. However, tests which indicate the presence of a Rickettsia, previously found to cause male-killing in another member of the Coccinellidae, Adalia bipunctata, proved negative. We therefore conclude that the phenomenon of male-killing is multicausal, within, as well as between, taxonomic groups of the Insecta.
Hurst
G D
GD
Department of Entomology, Iowa State University, Ames 50011, USA.
Hammarton
T C
TC
Obrycki
J J
JJ
Majerus
T M
TM
Walker
L E
LE
Bertrand
D
D
Majerus
M E
ME
D000818:Animals; D001419:Bacteria / Q000187:drug effects / Q000235:genetics; D018407:Bacterial Physiological Phenomena; D001427:Bacterial Toxins; D001483:Base Sequence; D001517:Coleoptera / Q000235:genetics / Q000382:microbiology* / Q000502:physiology*; D003433:Crosses, Genetic; D017931:DNA Primers; D005798:Genes, Bacterial; D007814:Larva / Q000378:metabolism; D008297:Male; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012281:Rickettsia / Q000235:genetics; D012744:Sex Ratio; D013559:Symbiosis; D013752:Tetracycline / Q000494:pharmacology
D001427:Bacterial Toxins; D017931:DNA Primers; D013752:Tetracycline