| Summary: | In sandflies, the absence of the peritrophic matrix (PM) affects the rate of blood
digestion. Also, the kinetics of PM secretion varies according to species. We
previously characterised PpChit1, a midgut-specific chitinase secreted in
Phlebotomus papatasi (PPIS) that is involved in the maturation of the PM
and showed that antibodies against PpChit1 reduce the chitinolytic activity in the
midgut of several sandfly species. Here, sandflies were fed on red blood cells
reconstituted with naïve or anti-PpChit1 sera and assessed for fitness parameters
that included blood digestion, oviposition onset, number of eggs laid, egg bouts,
average number of eggs per bout and survival. In PPIS, anti-PpChit1 led to a one-day
delay in the onset of egg laying, with flies surviving three days longer compared to
the control group. Anti-PpChit1 also had a negative effect on overall ability of
flies to lay eggs, as several gravid females from all three species were unable to
lay any eggs despite having lived longer than control flies. Whereas the longer
survival might be associated with improved haeme scavenging ability by the PM, the
inability of females to lay eggs is possibly linked to changes in PM permeability
affecting nutrient absorption.
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