Kladothrips facts for kids

Kladothrips is a group of tiny insects called thrips that live in Australia. These special thrips are known for creating protective homes called galls on Acacia trees. What makes them truly unique is that some Kladothrips species live in large, cooperative groups, much like bees, ants, or termites. This kind of social living is called eusociality, and it's very rare outside of those well-known insect groups.

Different Kinds of Kladothrips

There are many different species (kinds) of Kladothrips that scientists have identified. Each one might have slightly different habits or live on different types of Acacia trees.

• Kladothrips acaciae
• Kladothrips antennatus
• Kladothrips arotrum
• Kladothrips augonsaxxos
• Kladothrips ellobus
• Kladothrips habrus
• Kladothrips hamiltoni
• Kladothrips harpophyllae
• Kladothrips intermedius
• Kladothrips kinchega
• Kladothrips maslini
• Kladothrips morrisi
• Kladothrips nicolsoni
• Kladothrips pilbara
• Kladothrips rodwayi
• Kladothrips rugosus
• Kladothrips schwarzii
• Kladothrips sterni
• Kladothrips tepperi
• Kladothrips torus
• Kladothrips waterhousei
• Kladothrips xiphius
• Kladothrips yalgoo
• Kladothrips zygus

How Kladothrips Live Together

What is Eusociality?

Some Australian gall thrips from the Kladothrips group are known to be eusocial. This means they live in highly organized societies. Eusocial insects are animals that form large, multi-generational groups. In these groups, individuals work together to raise their young. Often, some individuals give up their own chance to have babies to help the group. This is a special kind of cooperation called altruism.

For an animal to be called eusocial, it must meet three main rules:

• Different Jobs: The group must have a "division of labor" for reproduction. This means some members are the main ones who have babies, while others do not reproduce but help the colony.
• Living Together: Different generations must live together at the same time. For example, parents and their adult children might live in the same colony.
• Teamwork for Young: All members of the group must help care for the young.

Kladothrips meet all these rules. They have different types of females: some are fully winged and reproduce, some are smaller and don't reproduce. They also have some reproductive males. Different generations live together in the gall. Finally, the non-reproductive thrips, called "soldiers," protect the young.

Life in the Gall

The social life of Kladothrips starts when a winged female thrips makes a gall on an Acacia tree. She uses her mouthparts to create this special home. Often, different females will fight to control a new gall. Once a female, called the "foundress," wins, she lays her eggs inside. She also feeds on the tree's leaves (called phyllodes).

When the eggs hatch, different types of thrips emerge. Some are small and don't have full wings. These are mostly females, and they become the "soldiers." Other thrips develop full wings. These winged thrips will eventually leave the gall to find mates and start new galls.

The small, non-winged thrips are like the protectors of the gall. They have strong, barbed front legs. If the gall gets damaged or an enemy tries to get in, these soldier thrips rush to the opening. They guard the area until the gall closes up again. Scientists have seen these soldiers bravely attack and kill other insects, like a parasitic thrips called Koptothrips, that try to invade their home.

Interestingly, in gall thrips, the young are not helpless. They can actually start to take care of themselves and even help the other thrips around them. Meanwhile, the adult soldiers are busy patrolling and defending the gall. So, in a way, the young thrips also contribute to the well-being of the adults.

How Eusociality Developed

Kladothrips are very important for scientists studying how eusociality evolved. This is because they are not bees, ants, or termites, which are the most common eusocial insects. Studying Kladothrips helps scientists understand if eusociality develops in similar ways in different animal groups.

One idea about why eusociality evolved is related to how closely individuals in a colony are related. In some insects, like bees, sisters are very closely related. This might make them more likely to help each other. Kladothrips also show strong family ties within their galls. This is partly because they often breed with close relatives inside the same gall. This close family connection helps explain why both male and female thrips work together to defend their home.

Eusocial behavior can be helpful in two main ways:

• Life Insurers: Like social bees, where many individuals help ensure the survival of the queen and her offspring.
• Fortress Defenders: This is where a group defends a valuable home or food source.

The "fortress defender" idea seems to fit Kladothrips well. For this model to work, three things are needed:

• Food and Shelter Together: The home must also be a source of food. Kladothrips galls on Acacia trees provide both a safe home and plenty of food.
• Need for Defense: There must be a strong reason to defend the home from enemies. Other aggressive thrips, like Koptothrips, are known to attack and take over galls, showing a clear need for defense.
• Ability to Defend: The animals must be able to protect their home. The soldier thrips with their strong, barbed legs are perfect for defending the gall.

It's possible that the soldier thrips developed their special defense abilities even before other social behaviors. This would make sense because protecting their home is so important for their survival. Scientists have found that in different Kladothrips species, the development of soldier thrips seems to match how social their lives are. This gives strong evidence for the "fortress defender" idea.