Mosquitoes are good for sucking blood and having babies | News from the FIU


The secret to the reproductive success of the world’s deadliest animal could lead to fewer baby mosquitoes. It could mean better pest control.

CRF Institute of Biomolecular Sciences the researchers collaborated with an international team to study the juvenile hormone, a molecule that regulates the development, reproduction and behavior of insects. They produced genetically modified products Aedes aegypti mosquitoes – carriers of deadly diseases such as yellow fever, dengue fever, and zika – which cannot make juvenile hormones. Mutants could still mate and have babies. Not as much as their juvenile hormone-producing counterparts. Researchers say a better understanding of hormonal action could trigger a new generation of mosquito control tools.

“Understanding why the juvenile hormone is so important is essential, so that we can use this information to better control insects and parasites,” said CRF. Professor Fernando G. Noriega, the corresponding author of the study.

All insects, from bees to butterflies to mosquitoes, produce the hormone in question. It plays an essential role in their development, controls different functions and dictates certain behaviors. It helps mosquito larvae to metamorphose into an adult when they are ready. It works similarly to the hormones that people depend on for puberty and for reaching sexual maturity.

Mosquitoes and their distant relatives – crabs and lobsters – both have methyl farnesoate (MF). In crustaceans, MF regulates reproduction. Insects have the ability to transform MF into a juvenile hormone, which gives them an evolutionary reproductive advantage by producing more and more offspring.

The team of biologists and chemists, including Noriega from the CRF, Marcela Nouzova, Francisco Fernandez Lima and Matthew DeGennaro – worked together to take mosquitoes back in time, where it was as if they had never evolved to produce the juvenile hormone at all.

Nouzova and Noriega

Nouzova is the lead author of the study and the mastermind behind it. She designed the experiments and led the genome editing process, creating the mutant mosquitoes for the experiments.

“In order to explore the evolutionary significance of the two hormones, we used CRISPR / Cas9-mediated mutagenesis to generate Aedes aegypti mosquitoes lacking the enzymes needed to catalyze the synthesis of juvenile hormone or methyl farnesoate and juvenile hormone, ”Nouzova said.

While mutants that only had MF reached adulthood, they lacked reproductive competence. They couldn’t keep up with the stronger, non-mutant males. Mutant females have also been affected. Normally, a female can lay up to 100 eggs after mating. In their short lifespan, they can lay three different sets, amounting to hundreds of eggs. The mutants, however, laid 50 percent fewer eggs.

The other mutants lost the ability to completely produce MF. They died as larvae and never reached adulthood. This means that the juvenile hormone is a primary regulator of mosquito reproduction, DeGennaro said.

This information on mosquito reproductive biology can help control populations of insects we want less, such as mosquitoes. It can also help us improve reproductive success and increase the insect populations we need more.

The results were published in Proceedings of the National Academy of Sciences of the United States of America.

Ayleen Barbel Fattal and Chrystian Tejedor contributed to this story.


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