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Inverse density dependence of parity rates in the onchocerciasis vector Simulium damnosum s.l.
Author(s) -
CHEKE R. A.,
YOUNG S.,
GARMS R.
Publication year - 2016
Publication title -
medical and veterinary entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 82
eISSN - 1365-2915
pISSN - 0269-283X
DOI - 10.1111/mve.12145
Subject(s) - biology , parity (physics) , onchocerciasis , simulium , vector (molecular biology) , granger causality , statistics , mathematics , ecology , larva , genetics , immunology , physics , particle physics , gene , recombinant dna
A correlation between parity rates and an index of adult numbers of Simulium damnosum s.l. (Diptera: Simuliidae) indicates an association, but does not prove causality or show the direction of any causal relationship. The question of whether adult numbers affect parity rates or vice versa is reminiscent of the age‐old query of which of the chicken and the egg came first. A method for resolving such issues based on analyses of pairs of time series was proposed by Granger in 1969. When Granger's method was applied to monthly numbers of adult female S. damnosum s.l. caught attempting to bite humans at Asubende, Ghana, and their parity rates, a significant relationship ( P = 0.005) emerged, clearly showing that parity rates were dependent on adult numbers. Implications of this inverse density dependence and the results of analyses of other similar time series are presented and discussed.