Relationship between Climate Change and Cannibalistic Gastropod Behavior

Indirect effects of climate change altered the cannibalistic behaviour of shell-drilling gastropods in Antarctica during the Eocene

Gregory P. Dietl, Judith Nagel-Myers, and Richard B. Aronson

Summarized by Joseph Ferreira. Joey is a senior at the University of South Florida in Tampa. Joey is pursuing his B. S in geology and is planning on finding a job either in the hydrology or seismology field. He has aspirations of owning his own business one day providing geo surveying services to companies in need of them. In his free time, Joey enjoys playing guitar and hanging out with his friends and family.

What data were used? The samples in this study included nearly 2,000 Naticidae Falsilunatia gastropod (snail) shells that were preserved well enough to show bore holes made from the cannibal snails. These samples were from a time frame in the Eocene that experienced mass cooling event. These samples came from 108 different localities in Seymour Island, Antarctica.

Methods: The prediction made during the start of this study suggested that the cooling temperatures would result in a decrease in the cannibalistic behaviors of these gastropods; meaning,  the colder temperatures would make it more difficult for the mollusk to maintain a productive activity level. To test their hypothesis, each drill hole found on the gastropods (complete or incomplete) was counted and the frequency of cannibalism was found by dividing the number of drilled samples by the total number of specimens in the group. The scientists looked at how frequent the drilled holes were in the specimens and also the body size of each specimen. They connected these specimens to a time either before, during, or after the known cooling event. They then looked to see if there were any significant changes in the frequency of these cannibalistic drill holes.

Figure showing Seymour Island in Antarctica (image A) where the study took place along with (image B) a sample with a perfectly drilled hole and a sample with an incomplete drill hole from another Falsilunatia gastropod. Image C shows one of the cannibalistic snails from multiple angles.

Results: When comparing the number of attacked specimens from before, during, and after the cooling event that occurred nearly 41 million years ago, the frequency of cannibalistic tendencies did not decrease or increase, but they remained stagnant. There was a very slight increase in frequency, but this increase was not statistically significant, meaning the increase was not big enough to cause concern or to blame the temperature change. This result came was a surprise because the way that these naticids drill holes into their prey’s shell involves a chemical reaction to dissolve the carbonate shell. The cooling temperatures were thought to slow down this chemical reaction hence slowing down the rates of cannibalistic tendencies between these creatures. However, this was not the case, the rates of cannibal attacks remained steady during the cooling event.

Why is this study important?  This study is important because it gives us a better understanding of how climate change can potentially affect species’ behaviors and tendencies. Even though the Falsilunatia’s cannibalistic behaviors were not affected by the cooling temperatures, it still shows some insight on how not all creatures are drastically affected by cooling events. Understanding the correlation between climate change and species behavior can help us gauge what we will expect to see in different animals’ behaviors as today’s climate change is in full effect.

The big picture: This study was set out to find the relationship between an Eocene cooling event and the cannibalistic behaviors of Falsilunatia gastropods. Although finding no direct effect from the cooling temperatures, this is still an excellent example of how we can use the behaviors of ancient creatures and their response to global climate alterations to predict how today’s animals will respond to more recent climate change.

Citation: Dietl G.P., Nagel-Myers J., Aronson R.B., 2018 Indirect effects of climate change altered the cannibalistic behaviour of shell-drilling gastropods in Antarctica during the Eocene: Royal Society Open Science, v. 5, 181446.


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