Rock-Paper-Scissors-Lizard-... Lizard? 2.0

Buckle up ladies and gentlemen, it's time for the thrilling sequel to the amazing tale of 'Rock-Paper-Scissors-Lizard-Lizard-...Lizard?'. For those of you who haven't read the original, you may want to start here. But for those of you who have, let's get started. 

Now if you've got a keen eye you may have noticed one fewer Lizard in this title. That's because the female side-blotched lizards (Uta stansburiana) only have two colour morphs. But don't worry, their fight for population dominance is no less intense. So without any further ado, I should introduce our two contestants.

The common side-blotched lizard, master of genetic Rock-Paper-Scissors. Image credit: Bryce Bradford (Flickr)

In the orange corner 

These brutal brawlers are the rapid reproducers of the species. When the orange-throated lizards lay their clutch of eggs it's not so much about who can lay the biggest, they just want to be the one to lay the most. This is called an r-selection strategy.

Now this might mean nothing to you right now, but trust me it's pretty cool. The r stands for rate and it's one half of the r/K selection theory about reproduction.

This means that these lizards ride hard and fast. r-strategists are the ones who produce lots and lots of children but don't seem to care so much about how many survive. Their children have a pretty low chance of survival but these parents don't care, they have plenty of children to replace them.

A shining example of this strategy is the glorious ocean sunfish, who can lay over 300 million eggs at a time. How many of these eggs survive? Probably not a lot of them to be honest, but their logic of "if I lay this many they can't all be eaten" seems to be highly effective.

The Ocean sunfish. Newly hatched sunfish larvae begin life at less than a gram but can grow to be up to SIXTY MILLION times larger as adults. Image credit: OpenCage (Wikimedia Commons)

In the yellow corner

These feisty fighters are the caring keepers in the group. When the yellow-throated lizards lay their eggs they aim to make them all last. They may not be able to lay as many eggs this way, but they make sure that the majority of them should make it to adulthood. This makes them the K-strategists of the species.

These lizards are willing to take it slow. They believe in quality over quantity. Now I like to think that the K in their strategy stands for Kare because they just care so damn much. Alas, it represents the much more boring Kapazitätsgrenze (German for capacity limit). The reason for this is that, with such brilliant mothering, the only thing that really limits these children is having insufficient resources available in the environment to support them. This limitation on a species population size is known as its carrying capacity.

This strategy can be seen in species such as ourselves. I mean we rarely have more than one kid at a time, and our current record for most children born at once is a measly nine. But then add to that the intensive amount of care we often put into our children. Human parents often provide a home for their children for over 18 years each, and they'll care for them for the rest of their lives. Can you imagine many other animals that would make that sacrifice?

Look at how helpless these little things are. It's a good thing they have parents who are going to look after them. Image credit: mulan (Flickr)

Showdown!

So how does this showdown go down?

It's not as clear as the male competition; there's no direct this beats that. Instead the female side-blotched lizards engage in indirect warfare.

So let's boil down what happens. When there's plenty of resources and not much competition then of course it makes sense to create as many offspring as possible to take advantage of the resources while they're still available. This is when the orange females have their time to shine.

But then it starts to go too far and with a massive population it suddenly becomes a contest of quality over quantity as all the juvenile lizards compete for a limited supply of resources. This is when the yellow-throated lizards step into the spotlight. Her big, strong offspring are more than capable of shoving the other juveniles around to get what they want. 

In the end, this leads to a rapid two-year cycle of success, with orange-throated females succeeding in small populations and large amounts of resources, and the yellow females doing the best in the big populations when the going gets tough.

Orange lizards reproduce rapidly leading to a large population with limited resources → Yellow lizards thrive in this environment whilst the population decreases and resources start to recover → This is ideal for orange lizards, and so the cycle repeats. Authors own (Created with Canva)

Just like their male counterparts, this cycle is dictated by simple genetics, with throat colour being a great example of Mendelian inheritance. Again there are three alleles (variations of a gene) involved in creating these differences: o, b, and y. However, unlike the males, this system is a lot simpler, with any female inheriting at least one of the dominant o alleles becoming an orange-throated female, and everyone else becoming yellow throated.

A quick introduction to the wonders of Mendelian genetics for the uninitiated. Don't worry if you don't understand it, here's a crash course. Image credit: Madprime (Wikimedia Commons)

If you're interested in learning more about r/K selection theory you can read more here.

For more information about these astounding lizards you can read my post about the male's rock-paper-scissors competition here.