Competition Within and Between Hatching Chorots of a Treehole Mosquito

• Published in: Ecology (Durham) 1982-12, Vol.63 (6), p.1751-1760
• Main Author: Livdahl, Todd P.
• Format: Article
• Language: English
• ISSN: 0012-9658; 1939-9170
• DOI: 10.2307/1940117

Aspects of population growth rates are examined for cohorts of the treeholes mosquito Aedes triseriatus, reared in field containers under different conditions of larval density, concentration of natural treehole fluid, and in the presence or absence of a late—hatching cohort of larvae. Density and fluid concentration produced similar and independent significant competitive effects on each measure of cohort success, including female mass, development time, and survival to the adult stage, as well as on a composite index of performance. The sensitivity of first—cohort development time to high density and dilute fluid was reduced by the presence of the second cohort, and first—cohort survivorship responses to fluid concentration and density suggest an enhanced performance in dilute medium and intermediate density due to the addition of the second cohort. A composite index did not detect these complex interactions of experimental factors, suggesting that overall population growth rates for the first cohort respond to density and food in a very simple manner. The second cohort experienced total mortality in the presence of high first—cohort density, dilute medium, or the incidental oviposition of another treehole mosquito, Anopheles barberi, and never matched the success of the first cohort, even under conditions of low density and concentrated fluid.