Sand Fly Populations Research Articles

Phosphoglucomutase polymorphism in Phlebotomus perfiliewi perfiliewi Parrot (Diptera: Psychodidae) from central and northern Italy.

Over 920 Phlebotomus perfiliewi perfiliewi from the Adriatic and Tyrrhenian sides of the Italian Apennines were examined, using starch gel electrophoresis. Of 14 enzymes, only phosphoglucomutase (PGM-E.C. 2.7.5.1.) showed significant variation in allele frequency between different localities. The genotype CC characterized over 87% of flies from the two Tyrrhenian sites (Tuscany) and in contrast was found in only 10·4 and 32·4% of P. p. perfiliewi from the two Adriatic sites (Bologna and Teramo). The DD genotype which was seen in 16·8% of flies from Bologna was present in only 1·0% of individuals from Teramo (further south along the Adriatic coast) and was not observed in the two samples of flies from the Tyrrhenian coast.The role of the Apennine mountains in isolating the populations of sandflies, the different feeding behaviour of flies on either side of the range, climatic influences and the possibility that the differences may indicate some degree of reproductive isolation are discussed.

A Transect Study of Sand Fly Populations in Panama (Diptera, Psychodidae)

Phlebotomine sand fly populations were studied over a one year period by light-trap collections along a 200 m transect at Empire Range, Panama Canal Zone. The zoophilic species Lutzomyia carpenteri (Fairchild and Hertig) was dominant during the dry season while the anthropophilic species L. panamensis (Shannon) was dominant during the wet season. Sand fly populations were strongly correlated with the degree of development of the forest cover, increasing from grassy to secondary forest biotopes and from secondary forest to mature forest biotopes.

Production of Phlebotomine Sandflies 1 on the Open Forest Floor in Panama: Hydrologic and Physiographic Relations

Breeding populations of phlebotomine sandflies (Diptera, Psychodidae) on the floor of a rain forest in Panama were studied with soil emergence traps. Supporting studies were made of physiographic and hydrologic features of the breeding habitat. The pattern of distribution of the forest litter and the composition, texture and stability of local deposits are largely determined by physiographic and hydrologic features which are operative in soil transport. The forest litter tends to be removed from steep slopes and valleys and to cumulate on gentle slopes and prominences. On hilltops the forest litter tends to occur in stable, residual deposits, while on hillsides and stream banks relatively unstable, alluvial deposits are more common. Breeding populations of Lutzomyia pessoana (Barretto), L. panamensis (Shannon), L. gomezi (Nitzulescu), and L. insolita (Fairchild and Hertig) are greater in hilltop regions, while those of L. trapidoi (Fairchild and Hertig) are greater in hillside and streamside regions. No comparable effect was noted in the case of L. rorotaensis (Floch and Abonnenc). No effects of physiographic aspect or of non-destructive inundation on breeding populations of sandflies were detected.

Production of Phlebotomine Sandflies 1 on the Open Forest Floor in Panama: The Species Complement

Breeding populations of phlebotomine sandflies (Diptera, Psychodidae) on the floor of a rain forest in Panama were studied with soil emergence traps. The species Lutzomyia trapidoi (Fairchild and Hertig) was predominant. L. panamensis (Shannon), L. gomezi (Nitzulescu), L. pessoana (Barretto), L. rorotaensis (Floch and Abonnenc), and L. insolita (Fairchild and Hertig) were regularly collected. The overall mean emergence rate was estimated at 24 sandflies/100 m2 of forest soil per day. Data are given on the sex ratios, local and seasonal effects, and associated animal taxa. The ecology and medical importance of the species complement of the forest floor habitat and the implications of the study with regard to sand fly control are discussed. It was concluded that the availability of vector sandflies is probably not the primary limiting factor in the distribution of leishmaniasis in forested areas of Panama.

Seasonal changes in populations of phlebotomine sandflies (Dipt., Psychodidae) in Kenya

An account is given of seasonal changes in the incidence and relative abundance of a number of Phlebotomine sandflies which rest in termite hills in two widely separated areas of Kenya.The annual pattern of rainfall distribution is shown to be of greater importance than the total precipitation in influencing the gross distribution and local abundance of many sandflies.Kenya sandflies fall readily into ‘ perennial ’ and ‘ rainy-season ’ groups: the former have a wide distribution and appear to breed throughout the year. The distribution of the ‘ rainy-season ’ sandflies is relatively restricted, since these species are found almost exclusively in areas with a bimodal pattern of annual rainfall; it is suggested that they may survive the intervening dry periods in larval diapause. The length rather than the severity of the dry seasons is thought to be the limiting factor in the distribution of ‘ rainy-season ’ species.Examples are given of the seasonal changes in structure of populations made up of several species sharing, in the adult form, the same termite-hill habitat.

A Study of the Sandfly Population in Endemic Foci of Infantile Kala-azar in Italy

The sandflies of the two largest Italian foci of visceral leishmaniasis, Naples and Catania, were studied.The following species were found : P. papatasii, P. perniciosus, P. sergenti, P. vesuvianus, sp. n., P. parroti var. italicus var. n.P. papatasii and P. perniciosus are the commonest sandflies in the areas examined.Out of 1,547 ♀♀ dissected none showed a natural infection with Leishmania.P. papatasii was infected with Italian strains of L. infantum by feeding on cultures through membranes. The infection rate was low, but in contrast to Indian strains of L. donovani in the same sandfly, the infection once established did not die out.