Chaoborus americanus larvae were used in laboratory experiments to assess their efficiency at decreasing mosquito larval populations. Third and fourth instar Chaoborus americanus larvae were independently fed assemblages of single prey species to test hunger and several prey species to test preference. Prey species included Daphnia and the four Aedes aegypti larval instars. The results show that Chaoborus americanus larvae will choose early instar mosquito larvae over Daphnia, however, this preference decreases as the mosquito larvae become older. Third instar Chaoborus americanus larvae will choose first instar mosquito larvae over Daphnia 76% of the time, whereas they will select third instar mosquito larvae only 30% of the time. Fourth instar Chaoborus americanus larvae will choose first instar mosquito larvae 94% of the time, and select fourth instar mosquito larvae only 3% of the time. Crowding also has an effect on feeding times; individual Chaoborus larvae take more time to ingest their prey items than do individuals within a group. Chaoborus americanus larvae are good biological control agents within a laboratory setting.

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Reduced access to atmospheric oxygen greatly increased early instar Aedes aegypti mortality. Data suggest that death was by drowning mainly because slow swimming speed and low visual acuity delayed larvae from finding access to air. Late instar larvae experienced developmental delays when food depletion in the immediate vicinity of the breathing site forced them to forage farther away. As the distance between feeding and breathing sites increased, feeding efficiency of fourth instars may have declined enough to reduce their pupation success and to cause increased pupal mortality, reduced adult emergence and sex ratio skewed in favour of males among emerging functional adults. Thus reduced access to atmospheric oxygen at the pre-imago level may reduce the vectorial capacity of emerging adult population.

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