Lutzomyia

Oct 03, 2021 Interesting Creatures in Guyana, News

Interesting Creatures…

Kaieteur News – Lutzomyia is a genus of phlebotomine sand flies consisting of nearly 400 species, at least 33 of which have medical importance as vectors of human disease. Species of the genus Lutzomyia are found only in the New World, distributed in southern areas of the Nearctic and throughout the Neotropical realm. Lutzomyia is one of the two genera of the subfamily Phlebotominae to transmit the Leishmania parasite, with the other being Phlebotomus, found only in the Old World. Lutzomyia sand flies also serve as vectors for the bacterial Carrion’s disease and a number of arboviruses.
Evolution
The genus, named after Adolfo Lutz, is known from the extinct Burdigalian (20-15 mya) species Lutzomyia adiketis found as a fossil in Dominican amber on the island of Hispaniola. It is thought that species in the genus Lutzomyia all originated in the lowland forests to the east of the Andes mountain range, and that their radiation throughout the Neotropics was sparked by dry periods of the Pleistocene, driving colonisation further north and west to areas of higher humidity and leading to reproductive isolation.
Systematics
The classification of species within the genus Lutzomyia is largely unresolved, and relies on often controversial divisions based on morphological taxonomic characters. Such analyses can suffer from polymorphisms within a species, the existence of cryptic species and the frequent lack of distinct morphological characters amongst females. Research has begun in an attempt to resolve evolutionary relationships between species in the genus, using molecular methods to create phylogenies based on ribosomal DNA sequences.
Biology
The Lutzomyia sand flies are small biting insects with a body length of up to only 3mm. They are hairy insects with their colour ranging from a near-white to near-black.
Feeding
Only the female Lutzomyia sand flies are blood-feeding, requiring the blood meal to provide the nutrients for the maturation of eggs. Therefore, it is only the females who have medical importance as vectors of disease. Both males and females require carbohydrate food, as adults, the source of which remains unclear.
The most medically important species for human disease transmission are those which predominantly favour humans as a source of blood meal. These species are known as anthropophillic and tend to feed at around dusk. However, there are examples of anthropophillic species that will attack in the daytime. The majority of anthropohillic Lutzomyia species in the Americas are exophillic, which means that they favour biting outside of homes.
Resting
The resting behaviour of Lutzomyia sand flies, like many other aspects of their biology, is important to understand for targeted, vector-based control methods to reduce transmission of Leishmaniasis. For example, residual spraying of insecticides can be targeted at known resting sites to increase effectiveness. Lutzomyia sand flies generally rest outdoors, with the type of resting site varying between species and in response to the seasons and the availability of particular microhabitats. The largest resting microhabitat is the forest floor, but sand flies will also rest in a variety of other areas, such as in the nests and burrows of mammals, within the trunks of hollow trees and inside bat caves. The resting position adopted by Lutzomyia sand flies is characteristic to the genus, with wings angling above the abdomen. (Source: Wikipedia)