Exploiting the Synergistic Effect of Kairomones and Light-Emitting Diodes on the Attraction of Phlebotomine Sand Flies to Light Traps in Brazil

The synergistic effect of light-emitting diodes (LEDs) and kairomones on the attraction of sand flies to light traps was evaluated. Octenol and lactic acid were used as chemical attractants. Green LEDs and the incandescent lamps were used as light attractants. Five CDC-type light traps with the respective combination of attractants (incandescent lamp, incandescent lamp + chemical attractant, green LED, green LED + chemical attractant, and chemical attractant alone [without light]) were set between 18:00 and 06:00 following a Latin square design. A total of 6,536 sand flies and 16 species were collected. The most frequent species collected was Lutzomyia longipalpis (Lutz & Neiva, 1912) (Diptera, Psychodidae) accounting for 43.21% of all individuals. Order of success (mean, SD) of lactic acid attractant fly capture was as follows: LED + lactic acid (36.83 ± 4.74), LED alone (34.87 ± 4.61), incandescent lamp + lactic acid (22.80 ± 3.19), incandescent lamp alone (12.67 ± 2.03), and lactic acid (0.46 ± 0.13). Order of success of octenol attractant fly capture was as follows: LED + octenol (37.23 ± 5.61), LED alone (35.77 ± 5.69), incandescent lamp + octenol (18.63 ± 3.28), incandescent lamp alone (14.67 ± 2.86), and octenol alone (1.80 ± 0.65). With exception of lactic acid + incandescent light, chemical synergists played no part in significantly increasing light trap capture of phlebotomine sand flies. However, the use of LEDs, with or without such attractants, provided significantly higher capture compared to the incandescent lamp with or without such chemicals, showing that LEDs are suitable and efficient light sources for surveillance and monitoring of phlebotomine sand flies in Brazil.

Centers for Disease Control-type light traps equipped with high-intensity light-emitting diodes as light sources for monitoring Anopheles mosquitoes

In this study the phototactic response of anopheline mosquitoes to different luminous intensity light-emitting diodes (LEDs) was investigated. Centers for Disease Control-type light traps were changed by replacement of the incandescent lamps by 5 mm round type green (520 nm) and blue (470 nm) LEDs of different luminous intensities: green-LED traps with luminous intensities of 10,000, 15,000 and 20,000 millicandela (mcd) and the blue-LED traps with luminous intensities of 4000, 12,000 and 15,000 mcd. Our data showed that increasing luminous intensity has an effect on the attraction of anopheline mosquitoes to light traps, highlighting the importance of taking LEDs and light sources of high luminous intensity into account when using light-trap collections in monitoring populations of Anopheles species.

The effect of luminous intensity on the attraction of phlebotomine sand flies to light traps

To improve the efficiency of light traps in collecting phlebotomine sand flies, the potential effects of luminous intensity on the attraction of these insects to traps were evaluated. Sand flies were collected with Hooper Pugedo (HP) light traps fitted with 5-mm light-emitting diodes (LED) bulbs: green (520 nm wavelength-10,000, 15,000 and 20,000 millicandela (mcd) and blue (470 nm-4,000, 12,000 and 15,000 mcd). A total of 3,264 sand flies comprising 13 species were collected. The collected species were Lutzomyia longipalpis (Lutz & Neiva) (Diptera: Psychodidae) (52.48%), Evandromyia evandroi (Costa Lima & Antunes, 1939) (Diptera: Psychodidae) (32.90%) and Micropygomyia goiana (Martins, Falcão, & Silva) (Diptera: Psychodidae) (9.76%). An increase in luminous intensity of the LEDs increased the size of the sand fly catch. The lower luminous intensity of green (10,000 mcd) attracted an average of 13.7 ± 2.8 sand flies/trap per night and the other luminous intensities accounted for a mean of 24.1 ± 4.0 (15,000 mcd) and 28.2 ± 5.0 (20,000 mcd) sand flies/trap per night. Regarding the blue wavelength, the lower luminous intensity (4,000 mcd) attracted an average of 27.4 ± 4.1 sand flies/trap per night, followed by 12,000 mcd (37.6 ± 8.7) and 15,000 mcd (40.5 ± 7.3). Based on our data, the luminous intensity of light traps should be considered when developing light traps for monitoring or controlling phlebotomine sand flies.