The presence of pheromones has been reported for several spider species but their persistence in field conditions has scarcely been studied. We test the activity and persistence of female sex cues outdoor in the tarantula Eupalaestrus weijenberghi (Thorell, 1894), using male courtship as an indicator of cue attraction. We studied female silk fields in two conditions: protected and exposed and in both we found a long persistence of sex signals, up to 55 and 46 days, respectively. We discuss the nature and adaptive significance of these cues.