BLOOD-ENGORGEMENT KINETICS OF 4 ANOPHELINE MOSQUITOS FROM TRINIDAD, WEST-INDIES

The blood-feeding kinetics of Anopheles albitarsis, An. aquasalis, An. bellator and An. homunculus were determined under laboratory conditions using females collected from two sites in Trinidad. Many An. aquasalis, An. albitarsis and An. bellator completed probing within 30 s but An. homunculus averaged >50 s. Anopheles albitarsis (68.3 s), An. aquasalis (67.0 s) and An. homunculus (77.7 s) took similar times to fill their guts but All. bellator took longer (106.5 s). More than 75% of the An. albitarsis, An. aquasalis and An. homunculus but only 51% of the An. bellator showed apparent prediuresis. Anopheles aquasalis exhibited the shortest mean duration of prediuresis (77.3 s) and An. homunculus the longest (152.9 s). Most individual mosquitoes spent less time filling their guts than in prediuresis. Overall, An. aquasalis exhibited the shortest total feeding time (135.7 s) and An. homunculus the longest (197.0 s). There was a considerable degree of variation among individuals of each species in their ability to agglutinate human erythrocytes immediately upon blood engorgement. For ex-ample, within the same feeding experiments, some individuals agglutinated <25% of the ingested erythrocytes whereas others agglutinated greater than or equal to 90%. The parity of the field-collected anophelines had no significant effect on probing, duration of blood-feeding, duration of prediuresis, or erythrocyte agglutination. The inter- and intra-specific variations in blood-feeding and erythrocyte processing observed for the four species of field-collected anophelines from Trinidad are discussed in terms of vector competence and the evolution of these behaviours.