Sun Di-Bing, Li Jie, Liu Yin-Quan, Crowder David W, Liu Shu-Sheng
Ministry of Agriculture Key Laboratory of Agricultural Entomology, Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China.
Department of Entomology, Washington State University, 166 FSHN Building, PO Box 646382, Pullman, WA 99164, USA.
Bull Entomol Res. 2014 Jun;104(3):334-46. doi: 10.1017/S0007485314000108. Epub 2014 Feb 13.
Reproductive interference is one of the major factors mediating species exclusion among insects. The cryptic species Middle East-Asia Minor 1 (MEAM1) and Mediterranean (MED) of the whitefly Bemisia tabaci complex have invaded many parts of the world and often exhibit niche overlap and reproductive interference. However, contrasting patterns of competitive displacement between the two invaders have been observed between regions such as those in USA and China. Understanding the roles of reproductive interference in competitive interactions between populations of the two species in different regions will help unravel other factors related to their invasion. We integrated laboratory population experiments, behavioural observations and simulation modelling to investigate the role of reproductive interference on species exclusion between MEAM1 and MED in China. In mixed cohorts of the two species MEAM1 always excluded MED in a few generations when the initial proportion of MEAM1 was ⩾0.25. Even when the initial proportion of MEAM1 was only 0.10, however, MEAM1 still had a higher probability of excluding MED than that for MED to exclude MEAM1. Importantly, we show that as MEAM1 increased in relative abundance, MED populations became increasingly male-biased. Detailed behavioural observations confirmed that MEAM1 showed a stronger reproductive interference than MED, leading to reduced frequency of copulation and female progeny production in MED. Using simulation modelling, we linked our behavioural observations with exclusion experiments to show that interspecific asymmetric reproductive interference predicts the rate of species exclusion of MED by MEAM1. These findings not only reveal the importance of reproductive interference in the competitive interactions between the two invasive whiteflies as well as the detailed behavioural mechanisms, but also provide a valuable framework against which the effects of other factors mediating species exclusion can be explored.
生殖干扰是介导昆虫物种排斥的主要因素之一。烟粉虱复合种中的隐秘物种中东 - 小亚细亚1型（MEAM1）和地中海型（MED）已入侵世界许多地区，并且常常表现出生态位重叠和生殖干扰。然而，在美国和中国等地区观察到这两种入侵物种之间存在不同的竞争取代模式。了解生殖干扰在不同地区两种粉虱种群竞争相互作用中的作用，将有助于揭示与其入侵相关的其他因素。我们结合了实验室种群实验、行为观察和模拟建模，以研究生殖干扰在中国MEAM1和MED物种排斥中的作用。在两种粉虱的混合群体中，当初始MEAM1比例⩾0.25时，MEAM1总是在几代内排斥MED。然而，即使MEAM1的初始比例仅为0.10，MEAM1排斥MED的概率仍然高于MED排斥MEAM1的概率。重要的是，我们发现随着MEAM1相对丰度的增加，MED种群的雄性偏向越来越大。详细的行为观察证实，MEAM1表现出比MED更强的生殖干扰，导致MED的交配频率和雌性后代产量降低。通过模拟建模，我们将行为观察与排斥实验联系起来，表明种间不对称生殖干扰预测了MEAM1对MED的物种排斥率。这些发现不仅揭示了生殖干扰在两种入侵粉虱竞争相互作用中的重要性以及详细的行为机制，还提供了一个有价值的框架，可据此探索介导物种排斥的其他因素的影响。
