Temperature effects on foraging efficiency of range expanding mosquitoes: A functional response study

Aedes aegypti, the yellow fever mosquito, is a vector for diseases such as dengue, filariasis, and chikungunya. This species has expanded in subtropical and temperate regions due to its adaptability to various climatic and environmental conditions. As ectotherms, their growth and survival depend on food availability and climatic conditions within aquatic systems that support their larval stages. However, there is limited understanding of these aspects, particularly in expanding ranges.

This study investigated the foraging success of invading A. aegypti mosquitoes using functional response (FR), which measures the rate of change in feeding rate with resource density. The Time-to-Capture method, a new FR approach, was applied to fourth instar larvae at three temperature gradients (28°C, 32°C, and 36°C) in Nebraska, USA. Individual larvae, starved for 24 hours, were placed in deep-well slides with distilled water and offered 12 fish food flakes (250 μm size). The slides were placed under a coin microscope to record larval activities for 2 hours in an incubator set to the respective temperatures.

Results showed that the space clearance rate increased with rising temperatures up to a point, then declined at the highest temperature. This indicates temperature-dependent efficiency in resource utilization, with moderate temperatures favoring high feeding efficiency. Conversely, handling time decreased with increasing temperature, suggesting a rise in maximum feeding rate as temperature rose. These findings underscore the importance of temperature as a key factor influencing the foraging dynamics of A. aegypti larvae, with potential implications for their survival and proliferation in various environmental contexts.