Intertidal gobies acclimate rate of luminance change for background matching with shifts in seasonal temperature

Abstract

1. Rate of colour change and background matching capacity are important functional traits for avoiding predation and hiding from prey. Acute changes in environmental temperature are known to impact the rate at which animals change colour, and therefore may affect their survival.2. Many ectotherms have the ability to acclimate performance traits such as locomotion, metabolic rate and growth rate with changes in seasonal temperature.However, it remains unclear how other functional traits that are directly linked to behaviour and survival respond to long-term changes in temperature (within an individual's lifetime).3. We assessed whether the rate of colour change is altered by long-term changes in temperature (seasonal variation) and if rate of colour change can acclimate to seasonal thermal conditions. We used an intertidal rock-pool goby Bathygobius cocosensis, to test this and exposed individuals to representative seasonal mean temperatures (16 or 31°C, herein referred to cold-and warm-exposed fish respectively) for 9 weeks and then tested their rate of luminance change when placed on white and black backgrounds at acute test temperatures 16 and 31°C.We modelled rate of luminance change using the visual sensitives of a coral trout Plectropmus leopardus to determine how well gobies matched their backgrounds in terms of luminance contrast to a potential predator. 4. After exposure to long-term seasonal conditions, the warm-exposed fish had faster rates of luminance change and matched their background more closely when tested at 31 than at 16°C. Similarly, the cold-exposed fish had faster rates of luminance change and matched their backgrounds more closely at 16°C than at 31°C. This demonstrates that rate of luminance change can be adjusted to compensate for long-term changes in seasonal temperature. 5. This is the first study to show that animals can acclimate rate of colour change for background matching to seasonal thermal conditions. We also show that rapid changes in acute temperature reduce background matching capabilities. Stochastic changes in climate are likely to affect the frequency of predator-prey interactions which may have substantial knock-on effects throughout ecosystems.

The Connotation and Realization Path of Ecological Civilization Education in Chinese Universities under the Background of Mobile Internet

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Species richness patterns in Fijian bees are explained by constraints in physiological traits

“…However, most Homalictus species, even those at mountain tops, had heat tolerances higher than 40°C, which is warmer than the highest air temperature on record in Fiji (35°C recorded in January 2013 by Nausori weather station). High temperatures are known to have sublethal effects on an individual’s survival and fitness before they reach their critical upper thermal limits (da Silva et al 2020, van Heerwaarden and Sgrò 2021), and these sublethal effects may ultimately determine species’ elevational ranges. Additionally, the behaviour of ground-nesting bees (such as Homalictus ) can be strongly impacted by ground surface temperatures (Antoine and Forrest 2021), which can far-exceed air temperatures (Kearney 2019), potentially altering the frequency at which bees can enter and leave their nests, thus impacting their elevational distributions.…”

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