Overview
1ST PEER POST:
For this week’s discussion, I chose the Aedes aegypti mosquito as an example of an r-selected species. I thought mosquitoes were a good example because they reproduce very quickly and produce a large number of offspring, even though many of them will not survive. This is basically what makes an r-selected species successful—they produce a lot of offspring and increase the chances that at least some will survive and reproduce.
Aedes aegypti mosquitoes need certain resources to reproduce, especially water and blood. Female mosquitoes need a blood meal to help produce their eggs, and they lay their eggs in small amounts of water, such as water sitting in buckets, flowerpots, tires, or other containers. Once the conditions are right, mosquitoes can develop pretty quickly, which allows their population to grow rapidly.
One thing I found interesting is how these mosquitoes deal with environmental stress. If their eggs are laid somewhere that later dries out, the eggs can survive without water for a period of time. Once water becomes available again, the eggs can hatch. This is a really useful adaptation because it allows them to survive periods when water is limited instead of losing an entire generation.
There are also a lot of pressures that can affect whether the offspring survive, including predators, lack of water, temperature changes, and other environmental conditions. Instead of putting a lot of energy into caring for each individual offspring, the mosquito produces many eggs. Even if a large number of them don't survive, there is still a good chance that some will make it to adulthood and reproduce.
I think the mosquito is a good example of how different species have different ways of surviving. Their strategy may seem simple, but producing large numbers of offspring and reproducing quickly can be very effective when the environment is unpredictable.
What do you all think? Do you think producing a large number of offspring is a better survival strategy than producing fewer offspring and investing more time and energy into each one?
Centers for Disease Control and Prevention. (2024, April 16). Life cycle of Aedes mosquitoes. https://www.cdc.gov/mosquitoes/about/life-cycle-of-aedes-mosquitoes.html
Prasad, A., Sreedharan, S., Bakthavachalu, B., & Laxman, S. (2023). Eggs of the mosquito Aedes aegypti survive desiccation by rewiring their polyamine and lipid metabolism. PLOS Biology, 21(10), e3002342. https://doi.org/10.1371/journal.pbio.3002342
2ND PEER POST:
When examining reproductive strategies through an ecological lens, species selected along the r-spectrum prioritize maximum offspring quantity over individual investment. A clear example of this is the ocean sunfish, or Mola mola.
The open ocean is an unpredictable environment where resources are scattered and larval mortality is extremely high due to open-water predators. Because pelagic waters lack protective reefs or burrows, offspring are immediately exposed to starvation and predation. Investing energy into parental care or producing only a few young would lead to population collapse if those few were eaten.
To combat these pressures, a female sunfish releases up to three hundred million tiny, low-cost eggs into open water during a single spawning event. By scattering millions of buoyant eggs into ocean currents, the species relies on passive dispersal to ensure a small fraction drift into safe, food-rich areas. The tiny larvae then grow at extreme rates to quickly outgrow their most vulnerable size stage.
Ultimately, the sunfish demonstrates how r-selection works as a game of numbers. By trading parental care for massive clutch sizes, the species ensures that despite a ninety-nine percent mortality rate, enough offspring survive to sustain the population.
In your responses to your classmates, address the following:
- How did your selected species compare to your classmate's species?
- What was the most interesting thing about your classmate's species?