Lutzomyia longipalpis

Lutzomyia longipalpis is the most abundant species of sandfly occupying northeastern Brazil, representing 97.9% of all phlebotomine sand flies present there. This species is followed in descending order of abundance by L. evandroi, L. lenti, and L. sallesi. These flies are most prevalent near animal shelters, such as chicken coops and corrals. They can also be found in houses, but only in small quantities.

Humans are an important blood source for these flies, but they are also known to feed on dog, chicken, and armadillo blood. Blood from horses, guinea pigs, and humans provide the best nutrients to support L. longipalpis females in their reproduction processes. Interestingly, sand flies do not feed on the blood from cats or the opossums Monodelphis domestica. Most scientific evidence points towards L. longipalpis being eclectic feeders, signifying that they acquire blood from multiple sources.

Dangers of multiple blood meals. Although the feeding of blood is important for the maturation of oocytes, too many blood meals can also negatively impact the lifespan of females. Lutzomyia longipalpis, like most other blood-sucking organisms, ingest large amounts of blood in a single meal. A female sandfly consumes between three and ten times its body weight in one feeding. Blood is rich in proteins, consisting mainly of hemoglobin (Hb), which accounts for approximately 60% of the blood protein content. The digestion of hemoglobin results in the release of high levels of the prosthetic group heme. Heme acts as a toxic molecule that can generate oxygen-reactive species and bypass membranes due to its high permeability. Elevated levels of heme in female L. longipalpis are suspected to be the cause of increased mortality for females that have ingested multiple blood meals.

L. longipalpis has only recently (2017) been accepted as a complex of sibling species as opposed to a heterogeneous species. Earlier on, there were many doubts that L. longipalpis constituted a single species due to its wide geographic distribution over Latin America. Populations of L. longipalpis and sand flies studied within Brazil showed morphological differences. Males in the northern region of Brazil had only one pair of pale tergal spots, while those in the northeastern region of Brazil had two pairs. Thus, it was hypothesized that the species might be further broken down into two different forms. This hypothesis was confirmed through insemination experiments as males from one form of the species were unable to successfully mate with females of the other form. Since then, several studies within Brazil have been conducted to support the hypothesis that L. longipalpis is a species complex. Studies involving isoenzyme electrophoresis, genetic polymorphism assessments of DNA and mRNA, cytogenetics, analysis studies of nucleotide variation in the NADH dehydrogenase subunit 4, as well as assessments of other mitochondrial genes are all part of mounting evidence supporting the species complex hypothesis. In 2001, Lutzomyia psudolongipalpis was characterised by María Dora Feliciangeli's research group as one of the species within the complex. …