Seasonal and Circadian Dynamics
In temperate climates the seasonal activity will include the season from April to October in the Old World. Whereas in tropical and neotropical climates, sand fly activity is registered the whole year.
The circadian activity of the adult fly is crepuscular and nocturnal. Many species bite most actively immediately after sunset, but others have been observed to bite after midnight. But this time peak is not universal.
Depending on the area, and especially the time one hour before until one hour after sunset is the main feeding time, whereas other authors extend this time period of activity over the whole night Noli (1999). During day cool and humid resting places are sought (Killick-Kendrick and Killick-Kendrick, 1999).
For the seasonal activity, between one and two peaks of population can be observed in phlebotomines. Taking into account that various phlebotomine species have been classified as reported and suggested vectors of leishmaniosis, seasonal activity and thus risk of transmission stretches between spring and autumn.
Generally, depending on the area, temperature, humidity and diverse other environmental factors, sand fly activity can vary to a great extent and thus making general considerations in times very difficult.
Host Seeking Behaviour
In contrast to mosquitoes (and tsetse flies) only minimal data exists in the field of sand fly attraction to the host.
In the field of host seeking behaviour in sand flies, measurements of host preference or anthrophily have mainly been performed by the identification of bloodmeal origin from wild caught female sand flies or the use of human and animal baits (e.g., Christensen and Herrer, 1980; Quinnell et al., 1992; Montoya-Lerma and Lane, 1996; Campbell-Lendrum et al., 1999). But bloodmeal data has to be interpreted with caution (Pinto et al., 2001), as it reflects not only innate vector preferences, but also the relative abundance and accessibility of host species in the local environment. For a more obvious judgement of the preferences reflected by different bloodmeals the forage ratio and the host selectivity index have been designed.
Generally adult phlebotomines reportedly exhibit specific activity periods for events such as host-seeking, sugar- and blood-feeding, mating, and oviposition. Flight activity is triggered by daily changes in light intensity (Chaniotis et al., 1971) and further modified by other abiotic factors such as temperature, relative humidity, cloud cover, rain, and wind velocity (Hoogstraal et al., 1962; Quate, 1964). Most phlebotomine sand flies are crepuscular and nocturnal biters (Chaniotis et al., 1971). Feeding, however, is discontinuous and sporadic within the course of a single evening (Rosabal and Trejos, 1965; Chaniotis et al., 1971).
Direct evidence for odour-mediated host preferences results from studies on different attraction to a range of animal baits in the field (Christensen and Herrer, 1973; Quinnell et al., 1992; Montoya-Lerma and Lane, 1996; Campbell-Lendrum et al., 1999), or to extracted volatiles of different hosts in the laboratory (Hamilton and Ramsoondar, 1994; Rebollar-Tellez et al., 1999).
The spectrum of hosts, which is sought by sand flies is very wide. The most important hosts are rodents, dogs and man, due to the capacity of being a zoonotic reservoir for Leishmania. Apart from these, domestic livestock, other carnivores, as well as reptiles and amphibia also belong to the host spectrum. Some hosts like gerbils, hyraxes and sloths, e.g., have been proven to be important.
References
Introduction
Killick-Kendrick R: Biology of Leishmania in phlebotomine sandflies. In: Lumsden WHR, Evans DA (eds.): Biology of the Kinetoplastida. Vol. 2, Academic Press, London, New York, 1979, pp. 395-460,
Lewis DJ, Domoney CR: Sugar meals in Phlebotominae and Simuliidae. Proc R Ent Soc Lond. A 1966, 41, 175-179
Seasonal and Circadian Dynamics
Killick-Kendrick R, Killick-Kendrick M: Biology of sand fly vectors of Mediterranean canine leishmaniasis. In: Killick-Kendrick R (ed.): Canine leishmaniasis: an update. Proc. Int. Can. Leishm. Forum, Barcelona, Spain, 1999, Intervet Int., Boxmeer, The Netherlands, 1999, 26-31
Noli C.: Leishmaniose des Hundes. Waltham Focus 1999, 9, 16-24
Host Seeking Behaviour
Christensen HA, Herrer A: Attractiveness of sentinel animals to vectors of leishmaniasis in Panama. Am J Trop Med Hyg. 1973, 22, 578-84
Hamilton JGC, Ramsoondar TMC: Attraction of Lutzomyia longipalpis to human host odours. Med Vet Entomol. 1994, 8, 375-80
Montoya-Lerma J, Lane RP: Factors affecting host preference of Lutzomyia evansi (Diptera: Psychodidae), a vector of visceral leishmaniasis in Colombia. Bull Entomol Res. 1996, 86, 43-50
Quinnell RJ, Dye C, Shaw JJ: Host preferences of the phlebotomine sandfly Lutzomyia longipalpis in Amazonian Brazil. Med Vet Entomol. 1992, 6, 195-200
