Can electrostatic fields limit the take-off of tiny whiteflies (Bemisia tabaci)?

Electrostatic fields are abundant in the natural environment. We tested the idea that electrostatic attraction forces between tiny whiteflies (Bemisia tabaci) and the substrate could be substantial to the point of limiting their take-off. These insects are characterized by a very small body mass and powerful take-offs that are executed by jumping into the air with the wings closed. Wing opening and transition to active flight occur after the jump distanced the insect several body lengths away from the substrate. Using high-speed cameras, we captured the take-off behavior inside a uniform electrostatic field apparatus and used dead insects to calculate the electric charge that these tiny insects can carry. We show that electrostatic forces stimulate the opening of the insect's wings and can attract the whole insect toward the opposite charge. We also found that whiteflies can carry and hold an electrical charge of up to 3.5 pC. With such a charge the electrostatic field required to impede take-off is much stronger than those typically found in the natural environment. Nevertheless, our results demonstrate that artificial electrostatic fields can be effectively used to suppress flight of whiteflies, thus providing options for pest control applications in greenhouses.

Auto-correlated directional swimming can enhance settlement success and connectivity in fish larvae.

Larvae of coastal-marine fishes have been shown repeatedly to swim directionally in the pelagic environment. Yet, biophysical models of larval dispersal typically impose a Simple Random Walk (SRW) algorithm to simulate non-directional movement in the open ocean. Here we investigate the use of a Correlated Random Walk (CRW) algorithm; imposing auto-correlated directional swimming onto simulated larvae within a high-resolution 3D biophysical model of the Gulf of Aqaba, the Red Sea. Our findings demonstrate that implementation of auto-correlated directional swimming can result in an increase of up to ×2.7 in the estimated success rate of larval-settlement, as well as an increase in the extent of connectivity. With accumulating empirical support for the capacity for directional-swimming during the pelagic phase, we propose that CRW should be applied in biophysical models of dispersal by coastal marine fish-larvae.