## 4 Conclusions  
An automated barometric pressure chamber for entomology experiments was designed and evaluated.  
Weather conditions in Sao Paulo state, Brazil, indicated that barometric pressure fluctuations of \(\pm 15\) hPa from the local barometric pressure are expected to occur. Based on that information, the pressure control system was designed to allow the barometric pressure to be changed by \(\pm 15\) hPa with respect to the local barometric pressure.  
The chamber was designed for entomology experiments consisting of four stages, but other strategies or methodologies could be implemented in the algorithm. In addition, since variations in barometric pressure occur slowly in nature, the control system allows the user to set the rise/fall time (ramp), corresponding to the duration in which a change of pressure will be conditioned. The control system can reproduce slow and rapid barometric pressure  
Figure 12: Stylet sheath (violet dots) indicates food activity damage to bean pods by _E. heros_ (**a**); white holes in the leaves indicate leaf consumption by _D. speciosa_ (**b**).  
variations due to ordinary or extreme weather conditions. Changes in barometric pressure during ramp stages complied with a linear function, but other mathematical models could be easily implemented. The system can maintain, increase, and decrease the barometric pressure without depressurization.  
Short- and long-term evaluations demonstrated that the control system can adjust the target values of barometric pressure and maintain it with a stability of \(\pm\)0.1 hPa.  
The barometric pressure chamber allows phenomena to be filmed while changing the barometric pressure inside it and may be useful to entomology researchers evaluating the influence of abiotic factors on arthropod behaviors and arthropod-plant interactions.  
From the entomology experiments carried out for demonstration purposes, we observed that adult feeding of the _E. heros_, quantified by number stylet sheaths, was statistically higher under high-pressure conditions compared to the low pressure. However, the leaf consumption by _D. speciosa_ did not differ between the evaluated pressure conditions.  
Here we showed that the automated barometric chamber was useful in describing the effect of atmospheric pressure on the feeding activity of phytophagous insects, such as _E. heros_ and _D. speciosa_. When combined with other information on the bioecology of these insects, the automated barometric chamber may help to understand their way of life in the natural environment and, in the case of insect pests, assist in their management.  
Conceptualization, C.M.C. and J.M.S.B.; methodology, C.M.C., A.P.C. and E.A.d.S.; software, E.A.d.S. and A.P.C.; validation, C.M.C., A.P.C. and E.A.d.S.; formal analysis, C.M.C. and A.P.C.; investigation, C.M.C. and A.P.C.; resources, C.M.C. and A.P.C.; data curation, A.P.C.; writing--original draft preparation, C.M.C. and A.P.C.; writing--review and editing, C.M.C., A.P.C., E.A.d.S. and J.M.S.B.; visualization, C.M.C. and A.P.C.; supervision, A.P.C. and J.M.S.B.; project administration, J.M.S.B.; funding acquisition, J.M.S.B. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the Sao Paulo Research Foundation (FAPESP, grant #2014/140623). This study was supported by INCT--Semiochemicals in Agriculture (FAPESP and CNPq, grants #2014/50871-0 and #465511/2014-7, respectively).  
Not applicable.  
The authors declare no conflict of interest.