Male mating preference of two cryptic species of the herbivorous insect Eccritotarsus catarinensis

ABSTRACT

When using biological control against pest populations, more than one biocontrol agent might be introduced simultaneously. This could be counterproductive in the event of negative interactions between the biocontrol agents. Within and between species interactions have a strong impact on mating behaviour and reproduction, and can have an impact on the effectiveness of biological control. We studied the reproductive compatibility between two geographically isolated strains (Brazil and Peru) of Eccritotarsus catarinensis (Heteroptera: Miridae), a biocontrol agent against the invasive aquatic weed, Eichhornia crassipes. By performing inter- and intra-species mating experiments, we investigated whether or not males from each of the cryptic species would be able to distinguish between partners from either species, and if they would mate with partners from the opposite species. Our results showed the decrease in lifetime fecundity, and most importantly, the lack of production of offspring from eggs resulting from forced hybridisation. We showed that Peruvian males mated only with females from their own species, and did not mate with females from the Brazilian species. In contrast, Brazilian males mated equally with females from both species, but needed significantly more time in order to commence a mating, and no offspring were produced from eggs resulting from hybridisation. Although future studies demand more rigorous controls, our results indicate asymmetrical sexual isolation between the two species. We speculate on mechanisms involved in reproductive isolation in the two cryptic species, and the possible implications for effective biocontrol, and include some morphological measurements that might support our assumptions.

KEYWORDS:

• Asymmetrical sexual isolation
• biological control
• body size
• male mating preference
• reproductive incompatibility

Acknowledgements

We thank Joan van Baaren for her valuable comments and suggestions to improve previous versions of this article.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was supported by funding from Rhodes University, as well as the South African Research Chairs Initiative of the Department of Science and Technology and the National Research Foundation of South Africa.