Asymmetric Mating Interactions Drive Widespread Invasion and Displacement in a Whitefly

Abstract

The role of behavioral mechanisms in animal invasions is poorly understood. We show that asymmetric mating interactions between closely related but previously allopatric genetic groups of the whitefly Bemisia tabaci, a haplodiploid species, have been a driving force contributing to widespread invasion and displacement by alien populations. We conducted long-term field surveys, caged population experiments, and detailed behavioral observations in Zhejiang, China, and Queensland, Australia, to investigate the invasion process and its underlying behavioral mechanisms. During invasion and displacement, we found increased frequency of copulation leading to increased production of female progeny among the invader, as well as reduced copulation and female production in the indigenous genetic groups. Such asymmetric mating interactions may be critical to determining the capacity of a haplodiploid invader and the consequences for its closely related indigenous organisms.

Testing for reproductive interference in the population dynamics of two congeneric species of herbivorous mites

“…This asymmetric mating interaction and the capacity to adjust the sex ratio in favour of the population increase in biotype B are expected to be key features of biotype B driving its widespread invasions and displacement, and this expectation is supported by long-term field surveys and population experiments in cages (Liu et al, 2007). In our study, T. evansi males showed mating preference to T. urticae females, whereas T. urticae males prefer conspecific females.…”

“…increased by adding males of the same or different biotype to a pair, the pair of biotype B increased the number of copulations and consequently increased the proportion of female progeny regardless of the biotype of additional males, however, the pair of indigenous biotypes (ZHJ1 and AN) decreased the number of copulations and the proportion of female progeny when additional males were biotype B (Liu et al, 2007). This asymmetric mating interaction and the capacity to adjust the sex ratio in favour of the population increase in biotype B are expected to be key features of biotype B driving its widespread invasions and displacement, and this expectation is supported by long-term field surveys and population experiments in cages (Liu et al, 2007).…”

“…However, most of the inter-sexual interactions between species are asymmetric , and this can allow invasive species to overcome the disadvantage of small colony size. Recently, biotype B of the whitefly, Bemisia tabaci, invaded and displaced indigenous biotypes of the species in Zhejiang (China; indigenous biotype is ZHJ1) and Queensland (Australia; indigenous biotype is AN; Liu et al, 2007). Behavioural observations revealed asymmetric mating interactions between invasive and indigenous biotypes: when the proportion of males in the offspring When both species were released on a tomato plant together (panels a and b), the interaction between species, reproductive status and time had a significant effect on the number of female mites (likelihood ratio test, species  reproductive status  time: w 2 ¼ 19.261, df ¼ 1, Po0.001).…”

Asymmetric isolating barriers between different microclimatic environments caused by low immigrant survival

“…Asymmetric mating interactions can have consequences for the maintenance of diverging populations, especially after a period of separation. If one population or incipient species would have higher competitive ability and advantages in mating interferences upon secondary contact, that group is more likely to displace the other group through competitive exclusion [48]. One outcome of this could be asymmetric gene flow between populations that could permit inland males to invade coastal environments, but not vice versa ( figure 1).…”

Web-Mediated Interspecific Competition Among Spider Mites

“…Intraspecific competition between B biotype and other biotypes of B. tabaci (De Barro et al 2006;Pascual 2006;Liu et al 2007) has been well studied with indications that intraspecific competition plays an important role in whitefly biology and evolution (De Barro 2005;De Barro et al 2006;Jiu et al 2007). Interspecific competition between B. tabaci and other herbivores has also been investigated.…”