Vertebrate growth plasticity in response to variation in a mutualistic interaction

Abstract

Vertebrate growth can be phenotypically plastic in response to predator–prey and competitive interactions. It is unknown however, if it can be plastic in response to mutualistic interactions. Here we investigate plasticity of vertebrate growth in response to variation in mutualistic interactions, using clown anemonefish and their anemone hosts. In the wild, there is a positive correlation between the size of the fish and the size of the anemone, but the cause of this correlation is unknown. Plausible hypotheses are that fish exhibit growth plasticity in response to variation in food or space provided by the host. In the lab, we pair individuals with real anemones of various sizes and show that fish on larger anemones grow faster than fish on smaller anemones. By feeding the fish a constant food ration, we exclude variation in food availability as a cause. By pairing juveniles with artificial anemones of various sizes, we exclude variation in space availability as a single cause. We argue that variation in space availability in conjunction with host cues cause the variability in fish growth. By adjusting their growth, anemonefish likely maximize their reproductive value given their anemone context. More generally, we demonstrate vertebrate growth plasticity in response to variation in mutualistic interactions.

Review of housing and husbandry of anemonefishes for use in research

“…Additionally, many laboratories provide some form of breeding substrate because it seems to increase reproduction. The provision of a healthy anemone, even a surrogate anemone, might also be essential to getting clownfish to behave more naturally and perform well in the laboratory (Beldade et al ., 2017; Cortese et al ., 2020; Norin et al ., 2018; Rueger et al ., 2022).…”

“…Providing enrichment in the tank is often associated with the addition of substrate or natural items like sand and reef rock. The presence of natural substrate along with an anemone seem to be very important factors in creating an environment conducive to the welfare of the fish and successful reproductive behaviour (Beldade et al ., 2017; Nguyen et al ., 2019; Rueger et al ., 2022). Indeed, the provision of a live anemone, even an easy‐to‐rear surrogate that the fish species does not normally associate with in the field, seems to result in a much more natural suite of behaviours than provision of fake anemones (Rueger et al ., 2022).…”

“…The presence of natural substrate along with an anemone seem to be very important factors in creating an environment conducive to the welfare of the fish and successful reproductive behaviour (Beldade et al ., 2017; Nguyen et al ., 2019; Rueger et al ., 2022). Indeed, the provision of a live anemone, even an easy‐to‐rear surrogate that the fish species does not normally associate with in the field, seems to result in a much more natural suite of behaviours than provision of fake anemones (Rueger et al ., 2022). Live food may also be provided to adult broodstock as a form of enrichment, but it is not commonly provided by many facilities.…”

“…The presence of natural substrate along with an anemone seem to be very important factors in creating an environment conducive to the welfare of the fish and successful reproductive behaviour (Beldade et al, 2017;Nguyen et al, 2019;Rueger et al, 2022).…”

“…Indeed, the provision of a live anemone, even an easy-to-rear surrogate that the fish species does not normally associate with in the field, seems to result in a much more natural suite of behaviours than provision of fake anemones (Rueger et al, 2022). Live food may also be provided to adult broodstock as a form of enrichment, but it is not commonly provided by many facilities.…”