//
you're reading...

Climate Change

Offspring inherit trait developed in parents

Donelson, Jennifer M., and Philip L. Munday. “Transgenerational plasticity mitigates the impact of global warming to offspring sex ratios.” Global change biology (2015).  DOI: 10.1111/gcb.12912

Figure 1.  Cartoon of fish population control mechanisms.  Suitcases and hats are not drawn to scale.

Figure 1. Cartoon of fish population control mechanisms. Suitcases and hats are not drawn to scale.

A population of fish is a group composed of a single species that lives in the same area and interbreeds (reproduces within itself).  The size of a population is determined by how many fish are added to the population through reproduction and immigration relative to how many are subtracted through death (natural mortality, predation, and fishing) and emigration (Fig. 1).   The ratio of sexually mature males to females is an important part of successful reproduction within a population.  The optimal gender ratio can vary based on many characteristics specific to a certain species, population, and environmental attributes.  Changes to population gender ratios may be influenced by the environment even after fertilization occurs in a process termed environmental sex determination. There is growing evidence that changing environmental conditions, typically caused by humans (including the hormone pollution in waste water), may negatively impact gender ratios and reproductive success.  Temperature is the most widely studied environmental factor influencing gender ratios in offspring.  Temperature-dependent sex determination (TSD) is of concern as changing temperatures are a robustly predicted impact of climate change progression.

Many species exhibit temperature dependent gender within the range of temperatures currently experienced in the environment.  This demonstrates potential for adaptation to future temperature change scenarios.  It is important to determine what the limits are for TSD adaptation as this may predict the fate of populations under future climate change.  There are many pathways for modifying gender ratios.  Some non-genetic means include nesting site selection but others are considered “plastic” traits meaning they are adaptable but still not genetically coded into the animal’s DNA.  In vertebrates, temperature affects the expression of an enzyme complex which affects hormone production gender and ratios in offspring.

Figure 2. Experimental design (Donelson and Munday 2015).

Figure 2. Experimental design (Donelson and Munday 2015).

This study used tropical damselfish (Acanthochromis polycanthus) to test whether thermal effects experienced by parent fish would affect the gender ratios of their offspring.  They did this by attempting to answer three questions.

  1. Do future temperatures (+1.5°C and +3.0°C) affect offspring ratios? And is there a critical period in development during which those temperatures would need to be experienced?
  2. Does exposing adult pairs to warmer temperatures affect the gender ratios of offspring?
  3. Would a lifetime at warmer temperatures influence the effect of developmental temperature?

The tropical damselfish was chosen for this study because they are monogamous and have nearly equal proportions of males to females.

Figure 3. Proportion of female offspring produced when development occurred at various temperatures from hatching or 3-months post hatching (Donelson and Munday 2015).

Figure 3. Proportion of female offspring produced when development occurred at various temperatures from hatching or 3-months post hatching (Donelson and Munday 2015).

Figure 4. Proportion of female offspring produced when parents were reared at elevated temperatures for one or two generations or both reproduction and development occurred at one of the temperature treatments.   “NT” means that there was no treatment, “NR” means no reproduction occurred.  The asterisk symbols mean that there were significant differences between the treatment and the present day control (Donelson and Munday 2015).

Figure 4. Proportion of female offspring produced when parents were reared at elevated temperatures for one or two generations or both reproduction and development occurred at one of the temperature treatments. “NT” means that there was no treatment, “NR” means no reproduction occurred. The asterisk symbols mean that there were significant differences between the treatment and the present day control (Donelson and Munday 2015).

Results and Interpretations

Offspring gender ratios were approximately 0.5 when raised at present day temperatures but the proportion of females lowered significantly when raised at warmer temperatures.  These effects did not occur in the fish transferred to warmer temperatures 3 months post hatching (Fig. 3).  This suggests that the critical age for thermal exposure affecting gender ratios happens before the 3 month point.

Offspring sex ratios were also affected by the temperatures their parents were reared in (Fig. 4).  Even with just +1.5°C above mean temperatures, the proportion of females in offspring was significantly lower.  However, offspring of parent fish that were reared at high temperatures for one or two generations produced offspring at normal gender ratios. This is good news fish under climate change.  Adults that experience warm temperatures can influence their offspring’s reaction norms such that gender ratios are maintained.  Pretty cool huh? However, the scope of this ability remains untested, future warming may outpace this species’ ability to adapt and fundamentally alter normal gender ratios.

 

Discussion

No comments yet.

Post a Comment

Instagram

  • by oceanbites 6 days 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 2 weeks 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 3 weeks 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 1 month 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 2 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 2 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 2 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 2 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 3 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 3 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 4 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 4 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 5 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 5 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 6 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 6 months 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 
  • by oceanbites 7 months ago
    Feeling a bit flattened by the week? So are these summer flounder larvae. Fun fact: flounder larvae start out with their eyes set like normal fish, but as they grow one of their eyes migrates to meet the other and
  • by oceanbites 7 months ago
    Have you seen a remote working setup like this? This is a photo from one of our Oceanbites team members Anne Hartwell. “A view from inside the control can of an underwater robot we used to explore the deep parts
  • by oceanbites 8 months ago
    Today is the day of  #shutdownacademia  and  #shutdownstem  and many of us at the Oceanbites team are taking the day to plan solid actions for how we can make our organization and the institutions we work at a better place
  • by oceanbites 8 months ago
    Black lives matter. The recent murders of Ahmaud Arbery, Breonna Taylor, and George Floyd have once again brought to light the racism in our country. All of us at Oceanbites stand with our Black colleagues, friends, readers, and family. The
WP2Social Auto Publish Powered By : XYZScripts.com