Sexual Behavior of the Sugarcane Hairy Borer, Hyponeuma taltula (Lepidoptera: Erebidae): Evidence for a Female-Released Sex Pheromone.

The sugarcane hairy borer, Hyponeuma taltula (Schaus, 1904), attacks the base of sugarcane and causes the death of the apical bud, a symptom known as "dead heart." In recent years, there has been significant infestation in Brazilian sugarcane crops. With the purpose of finding methods for controlling and/or monitoring the pest for the sustainable cultivation of sugarcane, we characterized the mating behavior of H. taltula and confirmed the release of a sex pheromone by this insect. Sexual activity was observed between the second and ninth hour of scotophase, during which female calling caused the onset of male courtship behaviors and increased their frequency. An ethogram was built showing that males perform seven observable steps: (1) wing flapping, (2) walking with wing flapping, (3) flying, (4) flying towards the female, (5) landing near the female and walking around her, (6) attempting copulation, and (7) copulation (mating). Female sex gland extracts also triggered attraction and male courtship behaviors. These results thus confirm that the female abdominal gland produces a sex pheromone and that the presence of this pheromone in the air is needed to initiate the male courtship sequence. The sexual behavior of H. taltula is compatible with control and/or monitoring methods using female sex pheromones.

Design, synthesis, molecular docking and biological evaluation of thiophen-2-iminothiazolidine derivatives for use against Trypanosoma cruzi.

In this study, we designed and synthesized a series of thiophen-2-iminothiazolidine derivatives from thiophen-2-thioureic with good anti-Trypanosoma cruzi activity. Several of the final compounds displayed remarkable trypanocidal activity. The ability of the new compounds to inhibit the activity of the enzyme cruzain, the major cysteine protease of T. cruzi, was also explored. The compounds 3b, 4b, 8b and 8c were the most active derivatives against amastigote form, with significant IC50 values between 9.7 and 6.03µM. The 8c derivative showed the highest potency against cruzain (IC50=2.4µM). Molecular docking study showed that this compound can interact with subsites S1 and S2 simultaneously, and the negative values for the theoretical energy binding (Eb=-7.39kcal·mol(-1)) indicates interaction (via dipole-dipole) between the hybridized sulfur sp(3) atom at the thiazolidine ring and Gly66. Finally, the results suggest that the thiophen-2-iminothiazolidines synthesized are important lead compounds for the continuing battle against Chagas disease.