In a narcissistic age, it is not uncommon to think of situations in which spending too long focussed on ourselves can lead to harm. But what about fish, you might ask?
Today our paper entitled “Social cues can push amphibious fish to their thermal limits” was published in Biology Letters.
This manuscript represents an experimental field study performed in Belize this past spring examining how social information can delay the behavioural thresholds that an amphibious fish exhibits to escape from a thermally stressful environment. As natural environments are complex systems including abiotic and biotic stressors that may act synergistically, it is important to understand how these interactions operate and impact an animal’s thermal limits.
The mangrove rivulus (Kryptolebias marmoratus), in particular, is an intriguing fish since it routinely leaves the water (emerge) to avoid stressful conditions and in some instances can survive for weeks out of water. If the water gets too hot or too hypoxic, rivulus will simply jump out and chill out on land.
K. marmoratus contemplating life on land. Not quite sure yet. Photo courtesy Keri Martin, Mount Allison University.
K. marmoratus out of water – Image courtesy of Keri Martin, Mount Allison University.
In the present study, we demonstrate that the decision to emerge from water onto land is also socially sensitive.
So, what does this have to do with self-image? Studying social cues from conspecifics can be a challenge if the conspecifics jump out of water first, so we designed an experiment to provide continuous social cues, using a simple mirror placed underwater.
Supplementary Figure from manuscript
Key Finding: The presence of cues from a conspecific (produced from a mirror) caused the rivulus to delay leaving water until they reach a higher temperature. This delay is clearly a behavioural decision and not due to enhanced tolerance of warmer temperatures, since their CTmax was not sensitive to the presence of social cuing from the mirror.
This discovery is important since it demonstrates that critical behavioural decisions may affect survival in an animal living in a thermally stressful environment. Much research into thermal stress to date has focussed on individual responses but social cues are likely just as important to animals in the wild. We have only addressed what simple visual cues produced by a mirror do to their emersion behaviour. Extrapolating to how multiple cues will work is, of course, open for future investigation.
Currie, S and Tattersall, GJ. 2018. Social cues can push amphibious fish to their thermal limits. Biology Letters. Link here
K. marmoratus inhabit stress aquatic habitats and can be found often inside crab burrows.
See Dr. Andy Turko’s video from 2012. It is fascinating to watch:
On this year’s trip we took more images attempting to visualise the thermal environments inhabited by the various fish living in the Long Caye. Here is a thermal image of a crab burrow:
Thermal image of a crab burrow (central triangular region) capturing a crab leaving the burrow (bottom centre of image). Rivulus can be found cohabiting with crabs or each other. Image taken in April 2018 with a FLIR T1030K thermal imaging camera.
Ever hopeful to observe rivulus emerging spontaneously in the field we set up various camera traps and go pros and time lapse images.
The following video depicts a time lapse video (each frame 10 apart) captured with a simple IR webcam of a outdoor, artificial burrow with water, following 3 rivulus over time. You can see one emerging in the bottom part of the screen and staying out of water.
We want to acknowledge Team Rivulus and Fellow Scientists:
Dr. Patricia Wright, University of Guelph
Dr. Suzie Currie, Acadia University
Dr. Andy Turko, University of Guelph
Dr. Tamzin Blewett, University of Alberta
Dr. Emily Standen
Giulia Rossi, University of Guelph
Louise Tunnah, University of Guelph
Keri Martin, Mount Allison University
Dr. D. Scott Taylor (mangrove.org)
Itza Lodge, Long Caye, Belize