//
you're reading...

Biology

Increasing resilience, one cannibal at a time

 

Mnemiopsis leidyi comb jelly
https://commons.wikimedia.org/wiki/File:Comb_jelly_2.jpg

Javidpour, J., Molinero, J.C., Ramirez-Romero, E., Roberts, P., Larsen, T. 2020. Cannibalism makes invasive comb jelly, Mnemiopsis leidyi, resilient to unfavourable conditions. Comm. Biol. https://doi.org/10.1038/s42003-020-0940-2

 

A jelly by any other name

Mnemiopsis leidyi comb jelly
https://commons.wikimedia.org/wiki/File:Mnemiopsis_leidyi_2.jpg

Ctenophores, also known as comb jellies, sea gooseberries, or Venus’ girdle, are a globally distributed phylum of marine invertebrates that range in size from mm’s to 1.5 m’s. Despite looking like jellyfish, they are only distantly related. Like jellyfish, comb jellies have a soft, gelatinous body that is often transparent. Unlike jellyfish, they swim mouth-forward, beating their rows of comb-like cilia. Used for feeding and locomotion, the combs scatter light creating a rainbow effect (Fig. 1).

 

 

A warty walnut

Mnemiopsis leidyi, the warty, or walnut, comb jelly, is a species native to the western Atlantic, that has invaded European and Asian regions. This slow-moving species has a lobed body, four rows of combs, and is hermaphroditic. The species also undergoes bloom-and-bust population cycles, and has a transient anus that appears as needed!

Mnemiopsis leidyi comb jelly
https://commons.wikimedia.org/wiki/File:Meerwalnuss5.jpg

M. leidyi populations diminish quickly and have no known benthic resting stages or overwintering strategies. In its newly invaded range, M. leidyi persists >15º further north (58ºN) than its native range (42º), making retaining nutrient stores critical to winter survival. This is why scientists were surprised to discover that invasive comb jellies were using (rather than storing) precious resources to produce late-season offspring. Offspring, which were more than likely to die off in a few weeks.

 

 

 

The Study

Photographic evidence of M. leidyi undergoing cannibalistic behaviour
(Javidpour et al., 2020)

Javidpour et al. conducted a mixture of field and laboratory studies in the Kiel Fjord, south-western Baltic Sea (the invasive range). In the field, they observed and sampled at a high frequency during pre-bloom and post-bloom periods. After each tow, samples were fixed, counted, and measured. In the lab, adults and were incubated with 15N enriched larvae to track feeding (isotopic labeling).

In the lab, adults had increased levels of 15N, relative to the control group. In the field, photographs taken while sampling show intraspecific larvae within the adults’ lobes. In other words, both study methods provided strong evidence that M. leidyi cannibalize their larvae, but only after other resources have diminished.

 

But why?

Researchers hypothesize that producing offspring – while resources are abundant – is an overwintering strategy.

  1. Juveniles feed on microplankton
  2. Adults feed on mesoplankton (predators of the larvae)
  3. Doubled resource utilization draws down stocks, outcompeting other species
  4. Resources are depleted
  5. Juveniles die
  6. Adults have another nutrient source (their well-fed babies)

M. leidyi bloom-and-bust cycle
Adapted from Javidpour et al., 2020

 

Cannibalistic behaviour has not been documented in native populations of M. leidyi. It is, therefore, possible that cannibalism is an adaptation allowing the invasive population to survive at the higher latitudes they have invaded.

 

Golden Rules of Cannibalism

While there are numerous documented instances of cannibalism throughout the animal kingdom, this strange phenomenon typically follows three general rules.

  1. Juveniles consumption is most frequent
  2. Occurrence coincides with a decrease in other food resources
  3. Fittest individuals have greater success

 

 

 

 

 

 

 

 

 

Discussion

One Response to “Increasing resilience, one cannibal at a time”

  1. A very interesting summary – well presented. Cannibalism on younger year-classes is common in many fishes but I had not considered in jellyfish – which are not made of jelly and are not fish. Really inappropriate common names abound in biology.

    Posted by Raymond Buckley | May 19, 2020, 1:23 pm

Post a Comment

Instagram

  • by oceanbites 3 months ago
    Happy Earth Day! Take some time today to do something for the planet and appreciate the ocean, which covers 71% of the Earth’s surface.  #EarthDay   #OceanAppreciation   #Oceanbites   #CoastalVibes   #CoastalRI 
  • by oceanbites 4 months ago
    Not all outdoor science is fieldwork. Some of the best days in the lab can be setting up experiments, especially when you get to do it outdoors. It’s an exciting mix of problem solving, precision, preparation, and teamwork. Here is
  • by oceanbites 5 months ago
    Being on a research cruise is a unique experience with the open water, 12-hour working shifts, and close quarters, but there are some familiar practices too. Here Diana is filtering seawater to gather chlorophyll for analysis, the same process on
  • by oceanbites 6 months ago
    This week for  #WriterWednesday  on  #oceanbites  we are featuring Hannah Collins  @hannahh_irene  Hannah works with marine suspension feeding bivalves and microplastics, investigating whether ingesting microplastics causes changes to the gut microbial community or gut tissues. She hopes to keep working
  • by oceanbites 6 months ago
    Leveling up - did you know that crabs have a larval phase? These are both porcelain crabs, but the one on the right is the earlier stage. It’s massive spine makes it both difficult to eat and quite conspicuous in
  • by oceanbites 7 months ago
    This week for  #WriterWednesday  on  #Oceanbites  we are featuring Cierra Braga. Cierra works ultraviolet c (UVC) to discover how this light can be used to combat biofouling, or the growth of living things, on the hulls of ships. Here, you
  • by oceanbites 7 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Elena Gadoutsis  @haysailor  These photos feature her “favorite marine research so far: From surveying tropical coral reefs, photographing dolphins and whales, and growing my own algae to expose it to different
  • by oceanbites 8 months ago
    This week for  #WriterWednesday  on Oceanbites we are featuring Eliza Oldach. According to Ellie, “I study coastal communities, and try to understand the policies and decisions and interactions and adaptations that communities use to navigate an ever-changing world. Most of
  • by oceanbites 8 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Jiwoon Park with a little photographic help from Ryan Tabata at the University of Hawaii. When asked about her research, Jiwoon wrote “Just like we need vitamins and minerals to stay
  • by oceanbites 8 months ago
    This week for  #WriterWednesday  on  #Oceanbites  we are featuring  @riley_henning  According to Riley, ”I am interested in studying small things that make a big impact in the ocean. Right now for my master's research at the University of San Diego,
  • by oceanbites 8 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Gabby Stedman. Gabby is interested in interested in understanding how many species of small-bodied animals there are in the deep-sea and where they live so we can better protect them from
  • by oceanbites 9 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Shawn Wang! Shawn is “an oceanographer that studies ocean conditions of the past. I use everything from microfossils to complex computer models to understand how climate has changed in the past
  • by oceanbites 9 months ago
    Today we are highlighting some of our awesome new authors for  #WriterWednesday  Today we have Daniel Speer! He says, “I am driven to investigate the interface of biology, chemistry, and physics, asking questions about how organisms or biological systems respond
  • by oceanbites 9 months ago
    Here at Oceanbites we love long-term datasets. So much happens in the ocean that sometimes it can be hard to tell if a trend is a part of a natural cycle or actually an anomaly, but as we gather more
  • by oceanbites 10 months ago
    Have you ever seen a lobster molt? Because lobsters have exoskeletons, every time they grow they have to climb out of their old shell, leaving them soft and vulnerable for a few days until their new shell hardens. Young, small
  • by oceanbites 11 months ago
    A lot of zooplankton are translucent, making it much easier to hide from predators. This juvenile mantis shrimp was almost impossible to spot floating in the water, but under a dissecting scope it’s features really come into view. See the
  • by oceanbites 11 months ago
    This is a clump of Dead Man’s Fingers, scientific name Codium fragile. It’s native to the Pacific Ocean and is invasive where I found it on the east coast of the US. It’s a bit velvety, and the coolest thing
  • by oceanbites 12 months ago
    You’ve probably heard of jellyfish, but have you heard of salps? These gelatinous sea creatures band together to form long chains, but they can also fall apart and will wash up onshore like tiny gemstones that squish. Have you seen
  • by oceanbites 12 months ago
    Check out what’s happening on a cool summer research cruise! On the  #neslter  summer transect cruise, we deployed a tow sled called the In Situ Icthyoplankton Imaging System. This can take pictures of gelatinous zooplankton (like jellyfish) that would be
  • by oceanbites 1 year ago
    Did you know horseshoe crabs have more than just two eyes? In these juveniles you can see another set in the middle of the shell. Check out our website to learn about some awesome horseshoe crab research.  #oceanbites   #plankton   #horseshoecrabs 
WP2Social Auto Publish Powered By : XYZScripts.com