• Grant number: 18/04916-3
• Support Opportunities: Regular Research Grants - Publications - Scientific article
• Duration: May 01, 2018 - October 31, 2018
• Field of knowledge: Biological Sciences - Parasitology - Entomology and Malacology of Parasites and Vectors
• Principal Investigator: Margareth de Lara Capurro-Guimarães
• Grantee: Margareth de Lara Capurro-Guimarães
• Host Institution: Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The technique of releasing mosquitoes (modified or not) for population suppression requires these insects to mate. However, studies are mentioning the occurrence of a second mate, which could compromise or decrease the success of such technique. The aim of this project is to use a homozygous transgenic line (with a fluorescent marker in the eyes) to demonstrate the occurrence of the second mate. Three sets of experiments were carried out to show the conditions for a mixed offspring occurrence. First, virgin female, which had contact with a transgenic male, laid eggs and then after every gonotrophic cycle had contact with a new virgin wild-type male, and every week had their eggs collect to check paternity. Here there was no occurrence of mixed offspring between the males. The second experiment, the couple was separated after 20 minutes contact, and a wild-type male replaced the first one, and this new couple remained for an overnight. As a result, few females presented mixed offspring, but it was not possible to predict the proper conditions for a mixed offspring occurrence. The final experiment had three observation groups, the first one (A), the first male had enough time to complete the copulation. The second group (B), there was an interruption 7 seconds after copulation started; and the third group (C), the copulation was interrupted just after started (around 3 seconds). For this set of experiment, A showed offspring only from the first male; B showed mixed offspring at a higher rate and C also showed mixed offspring, but the majority offspring belonged to the second mate. To conclude, the occurrence of a viable second mate and mixed offspring is only possible when the copulation is interrupted; otherwise, the first mate is responsible for offspring paternity. (AU)