Banca de QUALIFICAÇÃO: BIANCA LIMA DE SOUSA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : BIANCA LIMA DE SOUSA
DATE: 26/08/2025
TIME: 09:00
LOCAL: Ambiente virtual
TITLE:

DESENVOLVIMENTO DE LARVAS DO LAMBARI AMAZÔNICO Astyanax bimaculatus (LINNAEUS, 1758) EXPOSTAS AO AGROTÓXICO TIAMETOXAM

KEY WORDS:

ecotoxicology; tropical fish; agricultural contamination; embryo toxicity.

PAGES: 45
BIG AREA: Ciências Biológicas
AREA: Morfologia
SUBÁREA: Embriologia
SUMMARY:

Neonicotinoid insecticides have been increasingly detected in tropical surface waters, but their impact on native fish remains largely unknown. This study evaluated the toxicity of thiamethoxam (TMX) on embryos of the Amazonian lambari Astyanax bimaculatus, a model species for reproductive and ecotoxicological studies. Fertilized embryos were exposed, in a static system, to 0 (control), 0.05, 0.5, 5, 10, 50 and 100 mg/L of TMX until hatching (≈ 24 h), with 200 embryos per treatment. The parameters analyzed were hatching rate and prevalence of morphological anomalies in newly hatched larvae. TMX reduced hatching in a concentration-dependent manner: doses above 10 mg/L decreased hatching success when compared to the control. In parallel, the frequency of malformations, including scoliosis, shortened tail and notochord deformities, was more evident in higher treatments. At concentrations ≥ 50 mg/L, a pesticide crust was observed on the embryos, possibly hindering chorion rupture and contributing to delayed or failed hatching. The two lowest treatments did not differ statistically from the control. These results demonstrate the high sensitivity of early stages of A. bimaculatus to TMX, reinforcing concerns about neonicotinoid contamination in Amazon basins and providing support for risk assessments and pesticide regulation in tropical freshwater ecosystems.

COMMITTEE MEMBERS:
Presidente - ***.073.508-** - DIÓGENES HENRIQUE DE SIQUEIRA SILVA - UNESP
Interno - ***.616.542-** - MOYSÉS DOS SANTOS MIRANDA - UFPA
Externo à Instituição - JAYME APARECIDO POVH - UFMS