The Food Source and Gut Bacteria Show Effects on the Invasion of Alien Pests-A Case of Bactrocera dorsalis (Hendel) (Diptera: Tephritidae)

How alien pests invade new areas has always been a hot topic in invasion biology. The spread of the from southern to northern China involved changes in food sources. In this paper, in controlled conditions, we take as an example to study how plant host transformation affects gut bacteria by feeding it its favorite host oranges in the south, its favorite host peaches and apples in the north, and feeding it cucumbers as a non-favorite host plant, thereby further affecting their fitness during invasion. The result showed that, after three generations of feeding on cucumbers, took longer to develop as a larva while its longevity and fecundity decreased and pre-adult mortality increased. Feeding it cucumbers significantly reduced the overall diversity of gut microbiota of . The relative abundance of necessary for survival decreased, while the and increased, resulting in decreased carbohydrate transport and metabolism and increased lipid transport and metabolism. Feeding and resulted in a 26% increase in pre-adult mortality and a 2-3 d increase in adult preoviposition period (APOP). Additionally, decreased the longevity of female and male adults by 17 and 12 d, respectively, and decreased fecundity by 11%. We inferred that the shifted plant hosts played an important role in posing serious harm to invading from the south to the north. Therefore, after an invasion of into northern China, it is difficult to colonize cucumbers for a long time, but there is still a risk of short-term harm. The findings of this study have established that the interactions between an insect's food source and gut bacteria may have an important effect on insect invasions.