Behavioral Responses of a Tiny Insect, the Flower Thrips Frankliniella schultzei Trybom (Thysanoptera, Thripidae), to Atmospheric Pressure Change

How tiny insects respond to prevailing rainfall events to protect themselves from water droplets is poorly known. If such insects could anticipate impending rainfall and take shelter to avoid being hit by rain drops their chances of surviving such events would be increased. Some insect species can detect atmospheric pressure changes associated with rainfall events and respond accordingly. Laboratory experiments were conducted on the flower thrips Frankliniella schultzei to discern whether they adjust their behavior in response to atmospheric pressure change. F. schultzei mating frequency and shelter seeking behaviors were assessed under a range of different atmospheric pressure regimes including, a rapid change in atmospheric pressure (50 hPa/h), designed to simulate atmospheric changes associated with cyclonic conditions, and a slower rate of change (20 hPa/h), that is commonly associated with rainfall. The mating frequency of the thrips was significantly reduced in response to rapid changes in atmospheric pressure, whereas the slower rate had no such effect. These results indicate that F. schultzei is capable of detecting atmospheric pressure changes. The shelter seeking behaviors of each sex were assessed under the same two atmospheric pressure regimes. The thrips did not seek shelter significantly more or less under either pressure regime. Field experiments are now required to clarify if the ability to detect pressure is used by these thrips to protect themselves before the onset of rainfall events.