Communication interference between non-related sympatrically occurring noctuidae moth species

JUÁREZ M. L.; FERNÁNDEZ, P.; RUIZ M. J.; GOANE L.; VILLAGRÁN, M. E.; ARCE, O.; PÁEZ JEREZ, P.; GROOT, A.T.; VERA, M.T.

Congreso; 1st Joint Meeting ISCE/ALAEQ; 2016

In moths, female-emitted sex pheromones allow the attraction of conspecific males. Specificity is achieved by a combination of unique components in specific ratios and sometimes also by interspecific behavioural antagonists. Heterospecific pheromone compounds that cause inhibition of male upwind flight has been detected in a few cases between taxonomically unrelated species. In Northwest Argentina, three economically important pest species co-occur sympatrically on soybean crop: Chrysodeixis includens (Walker), Rachiplusia nu (Guenée) and Anticarsia gemmatalis (Hübner). Pheromonal compounds are known for C. includens and A. gemmatalis but not for R. nu. Given the possible practical application of using antagonistic behaviour for pest management, we evaluated the response of C. includens males to its own pheromone in presence of the twopheromone components of A. gemmatalis (Z3Z6Z9-20Hy and Z3Z6Z9-21Hy). We alsoexplored the response of A. gemmatalis and R. nu to these blends. Field experiments were conducted with traps baited with a synthetic blend that mimics the pheromone of C. includens and different ratios of the pheromone of A. gemmatalis. Experiments were set up in two soybean commercial fields in Argentina. The addition of Z3Z6Z9-20Hy and Z3Z6Z9-21Hy inhibited the catches of C. includens males by its own pheromone in one field but not in the other field. For A. gemmatalis, we found no inhibitory effect of the compounds of C. includens pheromone. Interestingly, for R. nu, we found a dosedependent response. In both fields, the C. includens blend with high concentrations ofZ3Z6Z9-20Hy and Z3Z6Z9-21Hy significantly reduced R. nu males? captures. Ourresults showed an antagonistic effect of heterospecific sex pheromone compounds of A. gemmatalis in C. includens and R. nu. This inhibitory effect between taxonomically distant species can play a role in avoiding competition. To our knowledge, this is the first report on the attraction of R. nu to specific pheromonal blends.