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Updated: Apr 28, 2026
Determining the Egg Fertilization Rate of Bemisia tabaci Using a Cytogenetic Technique
Published on: April 1, 2019
Competitive ability and fitness differences between two introduced populations of the invasive whitefly Bemisia
Yi-Wei Fang1, Ling-Yun Liu1, Hua-Li Zhang1
1Key Lab of Integrated Crop Pest Management of Shandong Province, College of Agronomy and Plant Protection, Qingdao Agricultural University, Qingdao, China.
Insights
Cardinium-uninfected whiteflies (B. tabaci Q) outcompeted infected ones, showing higher fitness. This explains the dominance of uninfected populations in Shandong, China, suggesting Cardinium impacts whitefly population dynamics.
Area of Science:
- Entomology
- Microbial Ecology
- Population Genetics
Background:
- Long-term field surveys in Shandong, China, indicate a low infection rate of Cardinium in Bemisia tabaci Q populations.
- This observation prompts investigation into the competitive dynamics and fitness of Cardinium-infected (C+) versus Cardinium-uninfected (C-) B. tabaci Q.
Purpose of the Study:
- To compare the competitive ability between C+ and C- B. tabaci Q populations.
- To assess reproductive isolation between C+ and C- B. tabaci Q.
- To determine the relative fitness of C+ and C- B. tabaci Q populations.
Main Methods:
- Competition experiments over several generations.
- Cross-breeding experiments to study reproductive isolation.
- Two-sex life table analysis to compare population fitness.
Main Results:
- C+ B. tabaci Q populations exhibited weaker competitive ability compared to C- populations.
- No reproductive isolation was observed between C+ and C- B. tabaci Q populations.
- The C- B. tabaci Q population demonstrated significantly higher fitness than the C+ population.
Conclusions:
- Differences in competitive ability and fitness between C+ and C- populations likely explain the recent dominance of C- whiteflies in Shandong.
- Further research is warranted to fully elucidate the role of Cardinium in Bemisia tabaci population dynamics.
Background:
Our long-term field survey revealed that the Cardinium infection rate in Bemisia tabaci Q (also known as biotype Q) population was low in Shandong, China over the past few years. We hypothesize that (1) the Cardinium-infected (C+) B. tabaci Q population cannot efficiently compete with the Cardinium-uninfected (C-) B. tabaci Q population; (2) no reproductive isolation may have occurred between C+ and C-; and (3) the C- population has higher fitness than the C+ population.
Methodology And Results:
To reveal the differences in competitive ability and fitness between the two introduced populations (C+ and C-), competition between C+ and C- was examined over several generations. Subsequently, the reproductive isolation between C+ and C- was studied by crossing C+ with C- individuals, and the fitnesses of C+ and C- populations were compared using a two-sex life table method. Our results demonstrate that the competitive ability of the C+ whiteflies was weaker than that of C-. There is that no reproductive isolation occurred between the two populations and the C- population had higher fitness than the C+ population.
Conclusion:
The competitive ability and fitness differences of two populations may explain why C- whitefly populations have been dominant during the past few years in Shandong, China. However, the potential role Cardinium plays in whitefly should be further explored.
