Only have a minute? No problem. Here’s a quick overview:
But if you want to delve in further then read on!
Did you know that sexual selection is far from cooperative? We may see these beautiful videos of birds singing their hearts out, or fish taking care of their eggs in their nests, but in reality: we are all selfish for our own sex. That is what I study: the battle of the sexes.
Many of the genes that we exhibit are specific to our sex. For example: Many female frogs are larger than male frogs. The genes exhibited by female frogs make them bigger – bigger females means more eggs. But male frogs want to be smaller – get away from predators faster especially when singing to females. The genes exhibited by male frogs make them smaller. But when they mate their genes mix. So the female frogs want to make sure their daughters are bigger, but their sons are smaller. However, we don’t get to decide how our sons and daughters will exhibit these genes. So if a female has sons that exhibit the “large female genes”, the son will be at a disadvantage compared to the other males in the population. The genes between the sexes are at a constant clash – the biological term for this is “intralocus sexual conflict” meaning conflict within the genes.
Conflict between the sexes can also arise due to their behaviour. Each sex has behaviours that is more beneficial for them in terms of mating and reproduction. For example, the choosy sex – that we discussed in sexual selection 101 – wants to pick their mate. The opposite sex wants any opportunity they can to mate, and mate as much as possible – they can be less picky. So there’s this conflict in mating and remating rates. If one sex is constantly being choosy, the other sex may completely miss out on mating and never pass on their genes – a disaster in terms of evolution. This sort of conflict is referred to as “interlocus sexual conflict” meaning antagonistic coevolution. Below are a few examples of this.
Fish species, like salmon, have a male morph called a “jack salmon” or a sneaker male. During mating season, no female wants to mate with the jack salmon, because they are small. Instead females want to mate with a large, handsome salmon male. So when the female has found her male and is ready to lay her eggs, the pair gets together and spawns (mixes egg and sperm). But the jack salmon don’t want to be left with no females to mate with! So they sneak into a spawning session between a pair and release some of their sperm as well. The big male might not even notice this because the jack male looks like a female! What a sneaky bugger.
Sometimes animals can evolve extremely conflicting and selfish ways that can leave the opposite sex severely vulnerable, or even dead! A great example of this is the water strider. Water strider males can be so aggressive when it comes to mating! They will force unwilling females to mate with them by almost drowning her until she gives up OR vibrating the water in such a way that it signals to fish underwater that there is an excellent meal waiting for them on the surface. If females want to survive they must mate. How brutal!
So given all of this information what I study is the consequences of this selfish behaviour. I use arachnids – spiders, mites, and pseudoscorpions – because they exhibit some extreme forms of sexual conflict and have a fast generation cycle – to understand HOW the disadvantaged sex (like the female water strider) can evolve ways to regain an advantage. I also look at which genes are conflicting and how, through evolution, these animals try to solve this conflict.