
Hi there, Yesterday I watched a video about bees dying after they sting their targets, and I actually read Biology as my main subject for about 2 years in high school [flexxxxx😂] and my mind kept thinking, why do they die? How evolution made them die? And more importantly, can we explain this with some math? Because I read a quote:
“When you can measure what you are speaking about, and express it in numbers, you know something about it, when you cannot express it in numbers, your knowledge is of a meager and unsatisfactory kind; it may be the beginning of knowledge, but you have scarely, in your thoughts advanced to the stage of science.” ― Lord Kelvin
So let the journey begin…
First of all, let’s clarify something: not all bees die when they sting. Only honey bees do. Other bees, like bumblebees or carpenter bees, can sting multiple times without losing their stingers. So why are honey bees different?
Why do bees die???
The answer has to do with the structure of their stingers and the way they defend their colonies. Honey bees have barbed stingers that are attached to their abdomens. When they sting a mammal, the stinger gets stuck in the skin and cannot be pulled out. As the bee tries to fly away, it rips off part of its abdomen, leaving behind the stinger, the venom sac, and some internal organs. This causes the bee to die shortly after.
Why did evolution made them die when they sting?
But why would evolution favor such a suicidal strategy? Well, it turns out that it’s not so bad for the colony as a whole. Honey bees are social insects that live in large groups with a single queen and thousands of workers.
This is where the math comes in. In 1964, a biologist named W.D. Hamilton proposed a formula to explain how altruism can evolve in nature. He called it the rule of kin selection. The formula is:
rB > C
where r is the coefficient of relatedness between two individuals, B is the benefit of the altruistic act for the recipient, and C is the cost of the act for the actor.
According to this rule, an altruistic act will be favored by natural selection if the benefit for the recipient multiplied by the relatedness is greater than the cost for the actor.
In the case of honeybees, r is 0.75, B is the number of sisters that are saved by the sting, and C is 1 (the loss of life). So, if a honeybee stings a mammal that is attacking the colony, it will be worth it if it saves at least 1/0.75 = 1.33 sisters. In reality, a single sting can deter or kill a predator that could otherwise harm hundreds or thousands of bees. So, the benefit is much greater than the cost.
Genetic Relatedness Math (Kin Selection):
Each bee gets 50% of its genes from its mother (the queen) and 50% from its father (a drone).
A worker bee shares 50% of its genes with its mother (the queen) and 50% with its sister (another worker bee) through the shared mother.
The father (drone) contributes its entire set of genes to its offspring.
So, relatedness between two worker bees (sisters) is calculated as:
Relatedness from mother’s side: 0.5 (50% of genes from the mother, shared by both)
Relatedness from father’s side: 0.5 * 0.5 = 0.25 (since the father’s genes are identical among his offspring)
Total relatedness: 0.5 (mother) + 0.25 (father) = 0.75 or 75%
The workers are all sisters that share 75% of their genes with each other. This means that they are more closely related to each other than to their own offspring. Therefore, by sacrificing themselves to protect the colony, they are ensuring the survival of their genes in their sisters.
This high relatedness is why worker bees prioritize helping their sisters over having their own offspring, which is known as kin selection.
Conclusion
Of course, this is a simplified explanation that does not take into account other factors like environmental conditions, genetic variation, or behavioral complexity. But it gives us an idea of how math can help us understand why bees do what they do.
I hope this post has also satisfied that scratch of your head like mine’s . If you have any questions or comments, feel not free to leave them below because I dunno anything more than this man🤷♀️. And don’t forget to subscribe to my blog for more questions that pop randomly in your head-related content. Thanks for reading!