Question Arthropod Heart Rates are Now Detectable

Tracking insect and bug health in a heartbeat from a digital camera
Published July, 10th, 2025
By University of South Australia
unisa.edu.au/media-centre/Releases/2025/tracking-insect-and-bug-health-in-a-heartbeat-from-a-digital-camera/

What is it?
'In a world-first pilot study, researchers from the University of South Australia (UniSA) have used video footage of insects to extract their heart rates without touching or disturbing them.'

Who figured it out?
'Led by UniSA PhD candidate Danyi Wang and her supervisor Professor Javaan Chahl, the study demonstrates that subtle body movements captured on standard digital or smartphone cameras can be analysed to reveal accurate and detailed cardiac activity in a range of insect species.'

How does it work?
'Taking footage from smartphones, social media videos and digital cameras, the researchers used sophisticated signal processing methods to monitor the heart activity of ants, bees, caterpillars, spiders, grasshoppers and stick insects.'

'The extracted heart rates closely matched the physiological ranges recorded via traditional techniques, validating the system’s accuracy.'

'Advanced image processing techniques, including motion tracking algorithms and magnification, were applied to detect tiny movements associated with heartbeats. These signals were analysed using spectral filtering and transformed into frequency data to isolate the heart rate.'

'One of the most impressive validations came from caterpillar recordings, where the team compared their video-derived cardiac signals to data from infrared contact sensors in previous studies. The shapes and frequencies were almost identical.'


Why?
“Insects are vital to our ecosystems, and understanding their physiological responses to environmental change is essential,” Wang says.

'Unlike traditional methods that require physical contact or immobilisation, this technique allows insects to remain free, without disrupting their natural behaviour.'

“Non-invasive cardiac monitoring offers tremendous potential; not just for studying insect health, but also for understanding environmental stressors, pesticide effects, or even the wellbeing of social insects like ants and bees, where heart signals can provide insights into colony health and behaviour.”

Published Research: onlinelibrary.wiley.com/doi/10.1002/arch.70076

From the Research Article:

Extracting Cardiac Activity for Arthropods Using Digital Cameras: Insights From a Pilot Study
Published 8th of July, 2025
By Danyi Wang and Javaan Chahl

Abstract:
'Arthropods are vital to ecosystems and are among the most diverse and abundant living creatures on Earth. Understanding their physiological processes, such as cardiac activity, is essential for studying their health, behavior, and responses to environmental changes. Traditional methods of monitoring cardiac signals often rely on invasive or contact techniques that require immobilization, which limits applicability of the methods in long-term studies and disrupts the insect's natural behavior. This study proposes a noninvasive, video system to extract cardiac signals from insects by analyzing subtle body movements. The results closely align with reference data obtained from established methods, validating the system's accuracy and feasibility. The study provides a foundation for developing cost-effective, noninvasive tools that preserve insects’ natural behavior welfare while offering new opportunities for ecological and physiological research.'

Methods:
'We collected data from three sources: (1) Spiders from the authors’ houses, (2) publicly available online videos from YouTube and Facebook including bees, ants and caterpillars and (3) arthropods filmed at the zoo, including stick insects, grasshoppers, and spiders.

For the authors’ collection, spiders were placed in transparent containers at an indoor temperature of approximately 25°C. They were allowed to build webs and were filmed while sitting motionless on their webs, showing no intention to move for hours, which can be considered a “rest” state (Davis and Vu 2025). They were filmed using a smartphone camera, which was mounted to ensure steady recording. After filming, the spiders were immediately released into their natural environment.

For zoo recordings, a Nikon DC600 camera mounted on a tripod was used to film stick insects, grasshoppers, and spiders. All videos were recorded in 1920 × 1080 resolution at 30 frames per second (fps). The species we collected are shown in Figure 2.'

Figure 2: Data collection: (a) Ant(Myrmecia pyriformis and Camponotus japonicus); (b) Grasshopper(monistria pustulifera); (c) Stick Insects (Extatosoma tiaratum); (d) Caterpillar (Aedia leucomelas and Sphingidae); (e) Honey Bee (Apis mellifera); (f) Wolf Spider (Lycosidae and Hogna lenta); (g) Redback spider(Latrodectus hasselti).

'Variations in either the body muscles or the dorsal vessel, driven by cardiopulmonary activity, result in reflected intensity values in frame sequences. The Figure 3 illustrates the framework for extracting cardiopulmonary signals from the insect's body movement in video frames.'

Figure 3: System framework.

'First the MOSSE Tracker (Bolme et al. 2010) is applied to tracking the ROI (Region of Interest) to avoid loss of target due to adult insects generally moving around. After drawing a bounding-box for the tracking target of the insect's body, a MOSSE filter was initialized. Then the filter updates the tracked target with each following frame.

Secondly, the ROI is cropped, and the color space is converted from RGB to YCbCr. To enhance the subtle body movements associated with cardiac activity, we apply Eulerian Video Magnification (EVM) Wu et al. 2012).'

'To reduce motion noise, particularly since EVM can amplify background noise, such as the subjects movements or background reflections, a moving average filter is applied to the raw signal'

'A fifth-order Butterworth band pass filter is applied to the stabilized signal
, targeting the specific heart rate range of different insects. Finally, the Fast Fourier Transform (FFT) is used to identify the heart rate frequency corresponding to the highest power of the spectrum within a specified frequency band.'

Results:
'For all subjects, the extracted heart rates fall within their respective normal ranges, validating the reliability of the imaging system for these species. Some species, such as spiders, show higher variability (75 ± 27 b/m). The range of extracted spider heart rates is well within the normal range, and the higher standard deviation may indicate that there is a large difference in heart rates across different spider species. For instance, Davis and Vu (2025) measured 79 inactive spiders across four species, reporting heart rates ranging from 39 to 168 beats/min, also shows variations in baseline heart rates within each species. The system consistently produces results that match literature-reported ranges, which supports its potential application for noninvasive cardiac monitoring in arthropod.'

Read the full article here: onlinelibrary.wiley.com/doi/10.1002/arch.70076