During the past two decades, onion thrips, Thrips tabaci Lindeman (Thysanoptera: Thripidae), has become a global pest of increasing concern in commer

Onion thrips, Thrips tabaci Lindeman, 1889 (Thysanoptera: Thripidae) is a pest of economic importance traditionally treated as a polyphagous, cosmopolitan single species. Recent genetic evidence, however, suggests that it is rather a cryptic species complex of three lineages referred to by their host association and displaying different biological and ecological characteristics: leek-associated 1, leek-associated 2 and tobacco-associated. This study reviews host plant associations and distribution of the lineages of this cryptic species complex and discusses its consequences from an agronomical perspective. Overall, leek-associated 2 lineage has the broadest host range, including major crops from different plant families, and it is the only lineage with a confirmed worldwide distribution. Leek-associated 1 lineage shares some host plants with leek-associated 2. It is often found in Allium crops and its geographic distribution is limited to a few dozen countries. Finally, tobacco-associated lineage has only been collected from tobacco and their associated weeds in central and east Europe, and the Middle East. Additionally, this work presents a list of 391 plant species on which breeding and development of T. tabaci occurs, regardless of lineage. These host plant species belong to 64 different families, most importantly Asteraceae, Fabaceae, Brassicaceae, Poaceae, and Solanaceae.

Onion thrips, Thrips tabaci Lindeman (Thysanoptera: Thripidae), is an important pest on onion and cabbage. Two reproductive modes—arrhenotoky and thelytoky—are

Onion thrips, Thrips tabaci Lindeman (Thysanoptera: Thripidae), is a worldwide pest of onion, Allium cepa L. In field studies on onion resistance con

Populations of Thrips tabaci are known to have two sympatric but genetically isolated reproductive modes, arrhenotoky (sexual reproduction) and thelytoky (asexual reproduction). Herein, we report behavioral, ecological and genetic studies to determine whether there is gene flow between arrhenotokous and thelytokous T. tabaci. We did not detect significant preference by arrhenotokous males to mate with females of a particular reproductive mode, nor did we detect significant behavioral differences between arrhenotokous males mated with arrhenotokous or thelytokous females in their pre-copulation, copulation duration and mating frequency. Productive gene transfer resulting from the mating between the two modes was experimentally confirmed. Gene transfer from arrhenotokous T. tabaci to thelytokous T. tabaci was further validated by confirmation of the passage of the arrhenotokous male-originated nuclear gene (histone H3 gene) allele to the F₂ generation. These behavioral, ecological and genetic studies confirmed gene transfer from the sexual arrhenotokous mode to the asexual thelytokous mode of T. tabaci in the laboratory. These results demonstrate that asexual T. tabaci populations may acquire genetic variability from sexual populations, which could offset the long-term disadvantage of asexual reproduction.

Although it is generally assumed that one or a few matings are sufficient to maximize female fitness and that mating is generally assumed to be costly to females, multiple matings of females have been reported across a wide and taxonomically diverse set of animals. Here, we investigated female mating frequency and male harassment rate in arrhenotokous Thrips tabaci. In addition, the cost to females of mating, multiple matings, and male harassment to females was evaluated. We found that T. tabaci females mated multiple times during their lifetime and were subjected to a high rate of male harassment at all the ages we tested. Mating was costly to females in terms of reducing longevity and delaying the initiation of egg laying, although mating did not affect the survivorship and longevity of males. Furthermore, continual exposure to males also resulted in a fitness cost to mated females in terms of delayed egg production and reduced fecundity. Virgin females of arrhenotokous thrips produce only male progeny whereas mated females of arrhenotokous thrips produce males from unfertilized eggs and females from fertilized eggs. However, multiple matings did not allow females to fertilize a larger proportion of their eggs to increase the female offspring ratio. Our study demonstrates the conflicts between the occurrence of multiple matings and the cost of sexual activities. This raises questions about the evolution of multiple matings and polyandry in this species. Furthermore, these findings suggest that such phenomena may occur in other animal species and influence the evolution of their mating systems.