Ws. Romoser et al., The occurrence and fate of the meconium and meconial peritrophic membranesin pupal and adult mosquitoes (Diptera : Culicidae), J MED ENT, 37(6), 2000, pp. 893-896
In mosquitoes, in addition to larval and adult peritrophic membranes (PMs),
a PM (meconial peritrophic membrane or MPM1) forms in the pupa around the
meconium, the sloughed, degenerating larval midgut epithelium. Often, a sec
ond membrane (MPM2) forms in temporal proximity to adult emergence. Differe
nces in the occurrence, persistence, and timing of disappearance of the mec
onium/MPMs and gas were studied by dissecting the midgut contents from pupa
e of known ages postpupation and from adults of known ages postemergence. M
PM1 was found in all Anopheles and Culex studied and nearly all Culiseta. T
he occurrence of MPM1 varied in the Aedes species. In one series of Aedes a
egypti (L.) dissections, no fully formed MPM2 was found in any specimens. T
he occurrence of MPM2 appeared to be associated with adult emergence and va
ried among and within the seven species studied. It typically was seen in r
ecently emerged adults but was observed occasionally in old pupae. Much of
our data supports the idea that MPM2 formation is stimulated by midgut epit
helium distention.