Figure 3. Feeding Persistence of Sand Flies.
(A) Relationship between numbers of metacyclic promastigotes in Lu. longipalpis and feeding persistence. Flies were infected with L. mexicana (closed circle) or L. infantum (open triangle) amastigotes. From 4 d post-infection flies were assayed for their feeding persistence in a 10-min behavioral assay and then dissected to determine the total number of metacyclic promastigotes present. The feeding persistence of each individual fly is plotted against the number of metacyclic promastigotes they harbored. Linear correlation coefficient, r 2 = 0.504 for L. mexicana (L. m), and 0.705 for L. infantum (L. i).
(B) Feeding persistence of L. infantum–infected flies fed rabbit blood alone (open square) or infected with L. infantum amastigotes (closed square). The persistence of flies exposed individually to an anaesthetized mouse was observed daily. n = 16 sand flies per point, representing the combination of two independent experiments. Error bars 1 s.e.m.
(C) Feeding persistence of L. mexicana–infected flies, experimental design as in (B). Flies were fed rabbit blood alone (open square) or infected with L. mexicana (closed circle).
(D) Effect of Leishmania development on sand fly feeding persistence, experimental design as in (B). Flies were infected with exponential (closed square) or stationary (half square) phase L. mexicana-cultured amastigotes. Asterisks indicate values from exponential and stationary infections that are statistically significant (*p < 0.05, **p < 0.005) from blood-fed control flies using an unpaired t-test.