Fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith), populations are monitored with a variety of commercial sex pheromone-baited traps. However, a number of trap-related variables may affect the number of FAW males captured. In this study, we tested the effect of trap design, trap size, and trap color for monitoring FAW males in corn crops in Mexico. We found that plastic jug trap (a home-made trap), captured significantly more FAW males than a commercial trap (Scentry Heliothis) and water bottle trap (another home-made trap). We also found that size of plastic jug traps (3.78, 10, or 20 liters) did not affect the captures of FAW males. Our results indicated that plastic yellow jug traps captured significantly more males than blue and black traps. Plastic jug white, red, and green traps captured a similar number of FAW males than plastic jug yellow, blue, and black traps. Plastic jug blue, white, and yellow traps captured more nontarget insects compared to black traps. The number of nontarget insects captured by green and red traps was similar and not significantly different to that caught by blue, white, yellow, and black traps. Traps captured more individuals from Diptera than Coleoptera and Hymenoptera. Overall, the results suggest that yellow plastic jug may be used for monitoring FAW males in corn and sorghum crops in Mexico.

The calling behavior, mating time, and the reproductive compatibility of virgin adults of fall armyworms, Spodoptera frugiperda (J. E. Smith), were studied in this work. Larvae were collected on maize (Zea mays L.) from six states located on the Pacific coast (Chiapas, Michoacán, and Sinaloa), on the Gulf of Mexico (Veracruz and Yucatan), and in central Mexico (Morelos). Before the experiments, insects were reared under laboratory conditions for one generation. We recorded the age at which females called for the first time, the onset time of calling, the duration of calling, the onset time of copulation, and the duration of copulation. The calling rhythms of the six populations were dissimilar. Females from all populations began to call in the second or third scotophase. The time for onset of calling and the duration of calling were significantly different among the S. frugiperda populations studied. Spodoptera frugiperda pairs from Sinaloa, Veracruz, Yucatan, and Morelos started to copulate earlier than the pairs from Chiapas and Michoacán. Pairs from Veracruz and Yucatan copulated longer than those from Michoacán, Morelos, Chiapas, and Sinaloa. Our crossing experiment using females and males from the six populations showed that individuals from different populations could copulate and produce fertile offspring. Thus, although the S. frugiperda populations showed variability in the timing of reproduction, the populations were not reproductively incompatible, which indicated that geographic distance has not led to reproductive isolation in corn-strain populations of S. frugiperda in Mexico.