Bella moths, scientifically known as Utetheisa ornatrix often thrives in the eastern, midwestern, and central US. Its characteristic feature is its front wing- yellow with white bands each containing a black dot. Its hind wings are bright pink with black bands.
We have seen mating mechanisms in many organisms including peacocks and seahorses. In today’s article, let’s look at the dark secret behind Bella Moth’s mate attraction strategy.
Before we understand their strategy, we need to understand a poisonous group of chemicals- Pyrrolizidine alkaloids. Usually produced by certain types of plants, they are bitter and toxic. They are the leading cause of accidental cattle deaths.
Pyrrolizidine alkaloids
It is their (plants) way of communicating that no animals should eat them! If they do, they die. But strangely, the Bella moths are somehow resistant to these toxic alkaloids. They feed on the leaves and seeds of rattlebox plants which produce these pyrrolizidines. They even use these toxins to protect their eggs and deter predators. These moths go a step further to even use this to make their pheromones to attract their mates.
But how? How do they attract mates through these chemicals? How are they able to safely consume the deadly poison which kills cattle?
Genome sequencing of Bella moths
Upon sequencing the genomes of over 150 species of museum specimens, scientists wanted to find the origins of Bella moths and how their intricate wing patterns originated. could pinpoint the specific genes that could confer resistance to pyrrolizidine alkaloids.
What’s special about this study is that they have only used age-old museum specimens for their study. Such studies usually require complicated laboratory equipment.
Lifespan study
Moths usually do not live long and die shortly after breeding. However, upon studying the genomics of the Bella moth, they were able to identify genes that confer longevity and they have been passed down to the next generation too. Scientists believe they can live for up to 50 days. That is nearly 4-5 times longer than the average moth. It makes sense because even if these moths are caught, the predators often let go (thanks to their resistance to alkaloids), and the moth continues to fly.
They are mostly active during the day, which means they don’t use darkness as a way to avoid predators. Most predators dare not to meddle with this moth. When caught, these predators produce a foaming liquid.
Alkaloids and mating
Once they are ready to mate, they produce these alkaloids in the form of aerosols. They are derived from the plants producing alkaloids which they ate when they were a caterpillar. Males are attracted to this scent which attracts them to their actual source. This is followed by a short elaborate step where the males gently touch the female’s head with two retractable structures resembling dandelions. Each filament in these two structures contains pyrrolizidine alkaloids.
If the female finds the quantity of the alkaloids to be sufficient, she will mate with the male. He will then leave her with a gift called the spermatophore, containing sperms and of course, more alkaloids. The female uses this to infuse the resulting eggs with toxins in addition to infusing more alkaloids from her reserve.
The alkaloids give protection against predators. Also known as bi-parental protection, it is a rare occurrence in the insect world.
Alkaloid resistance of Bella moths
They can avoid the ill effects of the alkaloids by using a special enzyme that oxidizes the molecule making it harmless. Then how do predators die when they eat this moth? When the predators eat this moth, the process will reverse and alkaloids show their effect on the predator.
How did Bella moths get this enzyme?
Scientists discovered that Bella moths have not just one but two. They might have got the other copy through gene duplication.
Yet another pair of duplicated genes was found in Bella moths. It was found to be partially involved in defense and antioxidant properties. Sourakov, a researcher from that team suspects “these genes may be related both to the ability of bella moths to detoxify alkaloids and to their remarkable longevity”
The story of the Bella moth unveils a remarkable saga of adaptation and survival in the face of toxic challenges. By embracing poisonous pyrrolizidine alkaloids as both a shield against predators and a tool for mate attraction, these enchanting insects have woven a beautiful evolutionary tale.
Through meticulous genomic analysis and observation, scientists have illuminated the genetic underpinnings of the Bella moth’s unique traits, shedding light on the mechanisms behind its resistance to toxins and its extended lifespan.
As we marvel at the Bella moth’s colorful wings and secretive rituals, we gain insight into the diverse strategies employed by organisms to thrive in their ecosystems. Their story offers a glimpse into the awe-inspiring complexity of the natural world.
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