Morin effects on Aedes aegypti lipid metabolism and its effects on reproductive physiology.
Flavonoid; triacylglycerol; fatty acid synthase
The use of plant-derived allelochemicals has emerged as a promising alternative for insect
control, owing to their non-toxicity to humans and the environment. Morin, a flavonoid
primarily extracted from plants of the Moraceae family, has exhibited a wide range of
applications in model organisms. This compound has demonstrated efficacy in inhibiting fatty
acid synthase and ecdysone 20-monooxygenase, enzymes crucial for the insect life cycle. Fatty
acid synthase plays a fundamental role in lipid metabolism, synthesizing long-chain fatty acids
from Malonyl-CoA molecules and forming complex lipids such as triacylglycerols (TAGs). In
insects, this lipid synthesis is critical in various life cycle events including reproduction, flight,
and development. In this study, we investigated the effects of morin ingestion in Aedes aegypti,
the primary vector of several arboviruses, including those causing Dengue, Zika, Chikungunya,
and Yellow Fever. For this purpose, a feeding approach was employed, with mosquitoes being
fed and separated at 24-, 48-, 72-, and 96-hours post-emergence. Additionally, females and
males were kept in separate cages throughout the assay. Through this, it was possible to assess
the TAG content of the whole body and fat body of the insects, along with the relative
expression levels of fatty acid synthase (fas1) and triacylglycerol lipase (tagl1). This approach
revealed that the effects of feeding varied according to the sex and age of the mosquitoes. While
females did not show a reduction in lipid content in the fat body after morin ingestion, males
exhibited lower levels of triacylglycerols. Therefore, we investigated the effects of morin-fed
males on copulation, finding that females mated with treated males laid fewer eggs and had a
reduced hatching rate. In summary, our findings indicate that morin feeding was more effective
in males than in the pre-vitellogenic period of females. The results related to fecundity and
fertility highlight morin as a promising molecule for studies on insect control of interest, both
in public health and agro-economic contexts.