Piloting an Automatic Moth Trap

Just in time for the end of insect season, the Monitoring Demonstrating Sites (MDS) team of ARISE deployed an Automatic Moth Trap (AMT) at ARTIS Amsterdam Royal Zoo (image 1). The AMT is a prototype insect camera developed by Aarhus University in Denmark. It captures images during the night when insect motion is detected on the white screen in front of the camera. The images are sent over the internet through a data pipeline to long term storage in the SURF Data Archive. In addition, the images can be viewed in a custom-made web portal hosted on a virtual machine at the University of Amsterdam, created by MDS Data Scientist Julian Evans. The purpose of piloting the AMT is two-fold: (1) to test out the sensor in terms of technical constraints and deployability; and (2) to assess what insect biodiversity it captures.

The Automatic Moth Camera deployed at ARTIS Amsterdam Royal Zoo.

As the AMT is a prototype, therefore, it required a number of changes to suit our requirements for deployment. Engineers from the UvA Technology Centre, Edwin Baaij (hardware) and Gerrit Hardeman (software), water-proofed the camera, added functionalities such as an automatic light switch, as well as adapted the camera to send data over the internet. These changes were crucial to be able to deploy the camera so that it could function semi-autonomously in the field. As such, currently the AMT is connected to power supply and internet at ARTIS, is outside 24/7, and does not require manual control of the lights

To better understand how the AMT functions in the field, it was piloted at ARTIS for a few weeks (September-October 2022). It was deployed alongside a DIOPSIS insect camera (read more about the DIOPSIS insect cameras in our blog post here), as well as a Vlinderstichting LED Emmer (VLE). The VLE is a bucket with a funnel and LED lights to attract night insects, and it was placed outside approximately once a week throughout the pilot (image 2). The insects fly inside through the funnel, but struggle to get out. Egg cartons are placed inside to give them a place to hide. The VLE is a non-invasive sampling method, in which the insects are photographed using a phone camera in the morning to later identify, and then released.

Vlinderstichting LED Emmer deployed at ARTIS Amsterdam Royal Zoo. Image by Jitske Schreijer.

The comparison between the three sensors (AMT, DIOPSIS, VLE) provides us with insight into their suitability for monitoring insect biodiversity. The differences in the combination of hardware and software in these monitoring methods may affect which species they capture (image 3). The three sensors use different light spectrums, screen colors/capture methods, and they also work on different time scales. The AMT uses a UV light and a ring light on a white screen and only captures images of insects at night. DIOPSIS has a yellow screen with UV lights as well as lights with a spectrum range of 2700 Kelvin (similar to a normal bulb light), and captures images 24/7. The VLE uses a UV light strip with no background, and is used approximately once a week. Among others, these factors impact the power supply required to keep the sensors running, as well as the volume of data captured. Consequently, this pilot should yield insights into the optimal set-up that would allow for a more in-depth and methodological comparison next year.

Images captured by: the Automatic Moth Trap (left), DIOPSIS (middle), and by phone of insects in the Vlinderstichting LED Emmer (right).

These technical considerations of these sensors are all important to assess how autonomous and deployable these sensors are in the field, what manner of pipeline and data storage they require, what insects they attract/capture, how the data can later be used for research, as well as which sensor is most suitable for which research questions. As such, we are looking forward to better understanding these sensors, and how they can best be used in the coming years to monitor insect biodiversity in the Netherlands.