Plants and wasps are smarter than you think

Seedlings know when they're from the same plant, and wasps get smarter as they get tougher tasks, studies show

Courtesy of Sean O'Donnell/University of Washington
A nest of the paper wasps used in the study (Polybia aequatorialis), taken in the field near Monteverde, Costa Rica. Colonies of several thousand adult workers live in a paper nest. Workers usually start with tasks inside the nest, then on the surface. They 'graduate' to become food foragers.

Plants and pea brains can be smarter than you think. Plants like those that discriminate between siblings and strangers within their own species, that is. And pea brains like the tropical paper wasp that reorganizes its tiny brain to tackle increasingly complex tasks.

These research tidbits illustrate the fact that acquiring and using information is a fundamental aspect of organic life.

Plant siblings grow from seeds produced by the same "mother" plant. They cooperate with each other, but compete with strangers, in the struggle for food and water. That may be one reason why a batch of nursery seedlings doesn't always thrive as well as expected in the garden.
The biological distance between wasps and humans is vast. Yet, as University of Washington psychologist Sean O'Donnell points out, "some of the problems they face are similar to ours because both of us are social animals." Their brain power plasticity may help us understand our own ability to adapt to these "similar" challenges.

Dr. O'Donnell and colleagues at his university and the University of Texas had already discovered that the wasps (Polybia aequatorialis) enlarge parts of their brains when facing new more complex tasks. The research they now report in the online edition of Neurobiology of Learning and Memory describes how the wasps reorganize neural networks and interconnections as the occasion demands.

Some of those connections run for 7 to 8 millimeters in brains about the size of two sand grains. O'Donnell says, "That's packing a huge amount of computing power in a small amount of space." He adds that the animals need it because they "live in a complicated world and individuals face challenges that require a lot of brain power."

Young wasps start out working deep within the hive in a relatively simple and stable environment. They progress to working outside and then to foraging for food. The increasing complexity of tasks and environments is reflected in increasingly dense and complex neural networks in the wasps' tiny brains.

Sound familiar? O'Donnell likens the wasps' progress to the daily round for human commuters. They start out in a relatively simple home environment. Then they face the complexities of driving or taking public transport, meeting strangers, and so forth. It takes a lot more processing power to deal with the increased stimulation. Can the study of wasp brain dynamics give insight into how humans face up to this challenge? The research team needs to learn more about the wasps before they can answer that.

Botanists Harsh Bais at University of Delaware and Susan Dudley at Canada's McMaster University already knew that at least some plants can recognize their siblings. The new research they report in Communicative & Integrative Biology explains how they do it. The roots of siblings secrete distinctive chemicals. That's enough to establish a hugging relationship. Siblings often intertwine leaves while their roots grow in what seem to be food-sharing patterns. With strangers, the plants keep their distance above ground while going aggressively after the other guy's food down below.

Dr. Bais says this raises questions about how siblings grown in monoculture stands, such as corn fields, survive without competing. He speculates that, because they can recognize their neighbors, "they may balance their nutrient uptake and not be greedy." Is there a lesson here for humans?

[Editor's note: The original version of this article misstated the university where Harsh Bais teaches. It's the University of Delaware.]

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