Nocturnal activity of phlebotomine sandflies (Diptera: Psychodidae) in a cutaneous leishmaniasis focus in Chichaoua, Morocco

Abstract

The nocturnal activity of phlebotomine sandflies (Diptera: Psychodidae) was studied "at an epidemic focus" on human cutaneous leishmaniasis due to Leishmania tropica Wright in Chichaoua province, in Morocco. Sandflies were collected using light and sticky-paper traps changed at 2-h intervals, inside and around houses, in August and October 2004. Overall, 633 sandflies, belonging to six species of Phlebotomus and three of Sergentomyia, were collected. Sandfly activity was nocturnal and higher at twilight. Several activity patterns were observed according to the species. Phlebotomus (Paraphlebotomus) sergenti Parrot, 1917, the suspected vector of L. tropica in this focus, was caught during each collection performed from 1900 to 0500 hours, the numbers of species caught peaked at 1900-2100 hours. There were seasonal variations of the nocturnal activity, which could be related to the variations in temperature and relative humidity.

Effects of temperature and photoperiod on daily activity rhythms of Lutzomyia longipalpis (Diptera: Psychodidae)

“…According to our results, a difference of 5°C in temperature level can produce a difference of about one hour in the onset activity and a difference of 10°C can double increase the proportion of nocturnal activity. Hence, we suggest that under periods of higher temperatures, as 30°C for example, L. longipalpis would be not only more abundant, but also more active at night, as already reported in other sandflies during warm seasons [20,28]. However, in other regions a bit far from the equatorial zone (e.g.…”

“…In sandflies, both temperature and relative humidity are important influences on daily activity among different species. In Morocco, during autumn, Phlebotomus perniciosus has greater activity during twilight, when the humidity is low (40-50%) and the temperature high (>20°C), while Phlebotomus ariasi is more abundant only after midnight when humidity is high (70-80%) and temperature low (15°C) [20]. The importance of temperature and humidity for daily activity rhythms can vary depending upon the season in some sandfly species.…”

“…Yucatan Peninsula, México; N 19° or Bella Unión-Cuarein, Uruguay; S 30°), besides the differences in temperature levels, there are also differences in day length that could reach four hours from winter (10 h of daylight) to summer (14 of daylight), according to the online database of the United States Naval Observatory (USNO) Astronomy Application Department [29]. During summer (short nights) in Morocco, Guernaoui et al described that the sandflies were active during 10 hours, whereas during autumn (longer nights), the activity extended to 14 h [20]. Our results show that a difference of four hours between different photoperiods (eg.…”

Activity Patterns of Sand Fly (Diptera: Psychodidae) Species and Comparative Performance of Different Traps in an Endemic Cutaneous Leishmaniasis Focus in Cukurova Plain, Southern Anatolia, Turkey

“…Coleman et al (2007) showed that in Southern Iraq, the peak activity period shifted from early evening (20.00-22.00 h) in April and October to late night (22.00-24.00 h) in May and June. Similarly, in Morocco the sand fly activity was found to be continuous all night in August, whereas in October the activity declined rapidly after midnight (Guernaoui et al 2006). Therefore, more detailed studies with respect to the seasonal variations and the effects of abiotic conditions, other than temperature and relative humidity, such as cloud cover, wind velocity and lunar cycle on the nocturnal activity of sand flies may improve our knowledge of the behaviour in this epidemiologically important area.…”

“…The nocturnal activity patterns of sand flies have been recorded for Old World species in many studies (Roberts 1994;Guernaoui et al 2006;Coleman et al 2007). According to our results obtained in the late summer season, sand fly activity was not significantly different over time even though total counts decreased between 04.00-06.00 h. No significant difference was found in the species prevalence throughout the nights.…”