Blood-sucking flies and primate polyspecific associations

Abstract

PRIMATE polyspecific associations are likely to be an effective means of reducing the number of fly bites individual monkeys receive¹. The probability of acquiring a vector-borne disease, and the severity of that disease increases with the number of fly bites an animal receives^2–4. Bait animals placed in groups are known to attract fewer individual mosquitoes per bait individual than are bait animals placed singly^3,5. Mean group size of the mangabey, Cercocebus albigena is about 13 in Kibale Forest, Uganda, and the mean group size of Colobus badius and Cercopithecus ascanius are 50 and 35 respectively⁶. Associations of groups of these species are likely to reduce significantly the number of dipteran bites individual monkeys receive^1,7. Other explanations proposed for primate polyspecific associations include increased food location abilities, and increased predator detection and avoidance^8,9. I report here the correlation of the temporal occurrence of C. albigena polyspecific associations with the activity of biting and sucking flies, C. albigena feeding and other activities, and the temporal occurrence of attacks by the crowned eagle-hawk (Stephanoaetus coronatus) (eagles are the only known predator of these monkeys). The study was carried out in the Kibale Forest, Ngogo Reserve.