Banca de DEFESA: YGOR HENRIQUE DA SILVA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : YGOR HENRIQUE DA SILVA
DATE: 28/02/2024
TIME: 14:30
LOCAL: https://meet.google.com/xhy-wtpy-gqx e dependências do LQEPV
TITLE:

Action of Different Growth Disruptors on Larvae and Fed Females of Rhipicephalus sanguineus lato sensu

KEY WORDS:

Dog tick, dip test, chitin synthesis inhibitors

PAGES: 51
BIG AREA: Ciências Agrárias
AREA: Medicina Veterinária
SUBÁREA: Medicina Veterinária Preventiva
SUMMARY:

The dog tick, Rhipicephalus sanguineus, is an important vector of pathogens relevant to veterinary medicine and public health. The main form of control is the use of chemicals with tick-killing action, however, some of these are neurotoxic to vertebrates. However, compounds from the group of growth disruptors (GDs) demonstrate safety in use in vertebrates by acting on arthropod coat enzymes (chitin). In this context, the objective of this study was to evaluate the use of fluazuron, novaluron, teflubenzuron and triflumuron, compounds belonging to the group of GDs, on larvae and females fed on ticks of the species R. sanguineus. For this purpose, larvae and females fed on R. sanguineus were exposed to different concentrations of the GDs compounds fluazuron, novaluron, teflubenzuron and triflumuron and, subsequently, changes were observed in the inhibition of ecdysis (larvae) and reproductive efficiency (females). For larvae, 30 larvae were immersed in concentrations ranging from 0.009 - 10 µg/mL for fluazuron and 78.125 - 40,000 µg/mL for the compounds novaluron, teflubenzuron and triflumuron, subsequently placed in 3 mL syringes and incubated in a climate-controlled chamber. with a temperature of 27±1ºC and humidity of 80±10% for 21 days to later verify ecdysis inhibition. Each concentration had eight repetitions. For females, 20 fed females, divided into two replications with 10 specimens, were immersed for five minutes in concentrations ranging from 0.7 - 3,000µg/mL for the fluazuron compound and 78,125 - 40,000 µg/mL for the novaluron compounds, teflubenzuron and triflumuron were subsequently weighed, identified and incubated under the same conditions described for larvae. After this period, each posture was weighed and placed individually in identified 3 mL syringes and incubated again under the same conditions described for larvae. Finally, the hatchability of the larvae was read and the reproductive efficiency of these females exposed to these GDs was verified. As results, inhibition of the ecdysis of R. sanguineus larvae was observed with 100% of fluazuron at a concentration of 10 µg/mL and 98.7% of novaluron at a concentration of 40,000 µg/mL, while the compounds teflubenzuron and triflumuron did not interfere in the larval ecdysis. In relation to R. sanguineus females, only GD fluazuron demonstrated an action on reproductive efficiency, observing a larval hatching LC50 of 347.7 µg/mL. In conclusion, activity of fluazuron and novaluron was observed on the ecdysis of larvae fed on R. sanguineus, with fluazuron at a concentration 30,660.14 times lower than novaluron and no activity of the compounds teflubenzuron and triflumuron. Among the compounds studied, only fluazuron demonstrated action on females fed on R. sanguineus, affecting the reproductive efficiency and hatchability of the larvae. 

COMMITTEE MEMBERS:
Presidente - 1173660 - FABIO BARBOUR SCOTT
Interna - ***.630.647-** - BARBARA RAUTA DE AVELAR - UFRRJ
Interna - 2929889 - THAIS RIBEIRO CORREIA AZEVEDO
Externo à Instituição - FERNANDO DE ALMEIDA BORGES - UFMS
Externo à Instituição - GUILHERME MARCONDES KLAFKE