## 2 Materials and Methods
### The Barometric Chamber and Its Components  
The barometric chamber is an acrylic box 900 mm long, 700 mm high, and 400 mm deep made of acrylic sheets with a thickness of 8 mm (Figure 3). All surfaces of the box are transparent to allow the filming of arthropod behavior or interactions between arthropods and plants. The front wall of the chamber works as a lid that is attached to the chamber with bolts. Between the lid and the chamber, 6-mm sealing tape was installed to minimize air leakage. In one of the lateral walls, there are entry points for the inlet/outlet of air and wire connections for sensors installed inside the chamber.  
Figure 3: Schematic of the barometric chamber components: (1) pressure/vacuum air pump; (2) pressure and vacuum proportional valves; (3) wire connections; (4) barometric chamber box; (5) barometric chamber lid; (6) sealing tape; (7) bolts.  
Figure 2: Range of values and natural fluctuations of barometric pressure (hPa) at Piracicaba ( São Paulo state, Brazil), from January 2017 to December 2021, used as a historical dataset for defining the operational requirements of the barometric chamber.  
A Millipore model WP61 vacuum/pressure pump is used to increase or decrease the pressure in the barometric chamber. The air pump is a continuously running constant air flow type unit for use with laboratory equipment [25]. The air pump has a positive pressure port and a negative one. According to the manufacturer, the pump has the following specifications: a maximum vacuum of 67.7 kPa at a flow rate of 4 L min\({}^{-1}\) and a maximum pressure of 140 kPa at a flow rate of 16 L min\({}^{-1}\). Values of both pressure and vacuum decrease as the flow rate increases, as shown in the curve of pressure versus flow rate that characterizes the pump [25]. The air pump power supply is 127 V/60 Hz.  
Air flow control within the chamber is achieved using two proportional solenoid valves, one operating as the pressure control valve and the other as the vacuum control valve. The valves were manufactured by ASCO and have the following specifications: Series 202, model Posiflow, directly operated, \(\frac{1}{4}^{\prime\prime}\) pipe size, 4 mm orifice size, two-way, and normally closed (catalog number SCG202A004V [26]). The flow across these valves is proportional to an input control signal that ranges from 0 to 24 Vdc and may be obtained by pulse width modulation (PWM) at 300 Hz frequency.  
The barometric pressure inside the chamber was monitored by a Young model 61302V (Young, Traverse City, MI, USA) barometric pressure sensor with a resolution of 0.01 hPa [27]. The sensor was set to operate in the range from 850 to 1050 hPa in which voltage output varies from 0 to 5000 mV. Equation (1) is given by the manufacturer to convert the analogue signal into barometric pressure.  
\[\text{hPa}=0.04\text{ mV}+850 \tag{1}\]  
Temperature and air humidity within the chamber were monitored by a DHT22 sensor (accuracy: temperature = 0.5 \({}^{\circ}\)C, air humidity = 2%). The chamber itself does not have temperature control but is installed inside a room where an air conditioning system keeps the air temperature steady. During all experiments reported, the room temperature was maintained at 25 \(\pm\) 1 \({}^{\circ}\)C.