Host plant relationships of Aphis gossypii Glover (Hemiptera: Aphididae) in Australia.
Aphis gossypii is morphologically variable and polyphagous, and is a vector of many plant viruses. The ability of A. gossypii from different host plants and geographical areas within Australia to colonize a range of host plants in the laboratory was investigated. Samples differed in their success rates on particular laboratory hosts, but there was no absolute host specificity. Colonisation was significantly more likely if the previous host was of the same species, but hosts of the same plant family were not equally suitable. The success rate of colonisation increased when aphids were repeatedly transferred to plants of the same species, suggesting that conditioning was occurring. When aphids were placed on 'poor hosts' such as broad bean [faba bean], or on stressed plants, they gave birth to offspring which developed into very small 'yellow dwarf' adults. While some populations showed variant alleles, allozyme electrophoresis did not group aphids from different geographic or host plant sources, nor indicate the presence of sibling species.