A 3D Analysis of Flight Behavior of Anopheles gambiae sensu stricto Malaria Mosquitoes in Response to Human Odor and Heat

Female mosquitoes use odor and heat as cues to navigate to a suitable landing site on their blood host. The way these cues affect flight behavior and modulate anemotactic responses, however, is poorly understood. We studied in-flight behavioral responses of females of the nocturnal malaria mosquito Anopheles gambiae sensu stricto to human odor and heat. Flight-path characteristics in a wind tunnel (flow 20 cm/s) were quantified in three dimensions. With wind as the only stimulus (control), short and close to straight upwind flights were recorded. With heat alone, flights were similarly short and direct. The presence of human odor, in contrast, caused prolonged and highly convoluted flight patterns. The combination of odor+heat resulted in longer flights with more landings on the source than to either cue alone. Flight speed was greatest (mean groundspeed 27.2 cm/s) for odor+heat. Odor alone resulted in decreased flight speed when mosquitoes arrived within 30 cm of the source whereas mosquitoes exposed to odor+heat maintained a high flight speed while flying in the odor plume, until they arrived within 15 cm of the source. Human odor evoked an increase in crosswind flights with an additive effect of heat at close range

Biting force in cichlids : A discussion of the planar model of barel (1983)

Some consequences of a definition of the 'static biting force' in cichlid fishes by BAREL (1983) are explored. A free-body diagram of the lower jaw shows that apart from the forces of the food and the jaw adductor muscle on the jaw other forces are needed to obtain static equilibrium. The introduction of joint forces solves this problem. Our analysis also shows that in many biting activities a locomotor force is required. Starting from an alternative definition for the static biting force, quite different results may be obtained for the space requirements of the jaw adductor muscle and the lower jaw as compared to those of BAREL.</p