The seasonal dorsal patch of males of the Curaçaoan long-nosed bat, Leptonycteris curasoae, which exhibits variability in size, shape, and chemical complexity, is a trait associated with courtship and mating in this species. This recently discovered structure develops exclusively during the mating season that occurs once a year between November and December in populations of L. curasoae from northern Venezuela. Although the dorsal patch that develops in males has unique chemical characteristics possibly involved in female attraction, we suggest that this trait also sends distinct visual cues regarding the health status of males. We evaluated the postulated association between dorsal patch shape (symmetry) and ectoparasite load (streblid batflies) in males of L. curasoae. To do so, we quantified the shape of dorsal patches on males to test the hypothesis that streblid load was related to this variable. Over 2,000 streblid batflies of two different species (Nycterophilia coxata and Trichobius sphaeronotus) were recovered from 130 individuals ( = 16 streblids/bat). Among these batflies, N. coxata was the most abundant species found on L. curasoae (2,042 individuals, 95.0% prevalence). Males with dorsal patches had significantly lower batfly loads when compared with males without dorsal patches and with females. Males with the most symmetrical dorsal patches also had the lowest batfly loads. Our results suggest that the odoriferous dorsal patches produced in males of L. curasoae also convey visual cues to female mates as signals of good health.