The most important malaria vector species of Australasia, found from the Moluccas eastwards to Vanuatu, and between latitudes 0° and 17°30'S (Stone et al., 1959). It now is known to be a species complex with at least seven sibling members. These are regarded as inseparable on reliable morphological grounds but are distinguishable by allozyme electrophoresis (Foley et al., 1993, 1994). Unfortunately, to date little has been published on bionomic differences between the siblings. Only one allozyme form (hitherto known as farauti No.1) has been found in Vanuatu and, as it was from there that the original type was described (Laveran, 1902), this is accepted as An. farauti sensu stricto.

Experimental material
The adults were reared, under LD 12:12, from eggs obtained from the Ross Institute of Tropical Medicine, where a colony originating from near Rabaul, New Britain, Papua New Guinea (4°13'S) had been maintained since 1966.

Experimental regimes
LD 8:16 to LD 4:20, nine females, studied from 3 days post-emergence (10 October 1968). Recorded in LD 8:16 for days two to four, then light-on delayed 4h to give LD 4:20 until day seven.
LD 12:12 to LD 16:8, nine females, studied from 3 days post-emergence (10 October 1968). Recorded in LD 12:12 for days two to four, then light-on advanced 4h to give LD 16:8 until day six.
LD 20:4, four females, studied from 5-6 days post-emergence (10 October 1968) and recorded for days two to four.

Results and discussion
The activity patterns are shown in Figure A7 below. Except in LD 4:20, all regimes show a major E peak, with a decline in activity over the next 1.5h. This peak is more diffuse and late in LD 4:20, and similarly diffuse but early in LD 20:4. M peaks are clear at light-on in the three long L regimes. There is low level activity around 13-14h after light-off in LD 8:16; but in LD 4:20 this peak has assumed major proportions.

From field studies in New Guinea and the Solomon Islands, the peak of biting before anti-malaria operations using DDT house-spraying was around midnight. This pattern changed after DDT use to give a pattern of peak biting in the post-dusk period (Spencer et al., 1974; Taylor, 1975). This early evening biting is similar to the pattern always observed in Vanuatu (Daggy, 1945) and, thus, it seems reasonable to suggest that the post-spraying cycles in Papua New Guinea and the Solomons were due to populations of An. farauti sensu stricto. The post-spraying field activity is similar to the laboratory pattern in LD 12:12, i.e. in the daylengths normally experienced by this purely tropical species. To this can be added that the M peak coincides with the morning egress of blood-fed females from human habitations.

Figure A7

©1998, 2010 - Brian Taylor CBiol FSB FRES 11, Grazingfield, Wilford, Nottingham, NG11 7FN, U.K. Comments to dr.b.taylor@ntlworld.com

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