Ants and Wasps May Have Common Ancestor


Ants and wasps may have once shared a common ancestor, according to a 2013 study published in Current Biology. For many decades, the origins of these social insects had been elusive because fossil records of ants — which are about 100 million years old — do not reveal much about what their ancestors were like. Scientists then had to compare ants with other living insects to determine their phylogeny. With hundreds of thousands of species of ants, bees, and wasps, it was almost impossible to pinpoint which species did ants evolved from. Although many agreed that ants, wasps, and bees were related, where was the solid evidence?

Thanks to the improvement of genetic technology, Philip S. Ward, Ph.D., a biologist at the University of California, Davis, and his colleagues used genetic sequencing to determine the phylogenetic relationship among ants, wasps, and bees. Based on the DNA evidence, ants are closely related to stinging wasps and bees but not to social wasps, such as yellow jackets. Ward traveled around Nevada and California to catch the insects. Using the sample, he and his colleagues sequenced more than 300 genes from one species of ant and 10 species of wasps and bees in which each species represented a different lineage. A computer was used to scan the genetic data, and it zoomed in on the mud dauber wasps as the ants’ closest relatives.

The mud dauber wasps’ behavior may offer clues to how ants and bees had evolved from a common ancestor. According to science writer Carl Zimmer, the female mud dauber wasp creates a narrow mud cylinder to protect each egg that she lays in rather than laying eggs on the ground and buzz away. The wasp then finds a prey, paralyzes it with her stinger, and carries it back to her nest inside the cylinder nest. When the wasp larva hatches out, it consumes the unfortunate prisoner. Ward and his colleagues speculated that the ancestors of ants, bees, and wasps may have delivered food to their young by bringing multiple tiny preys rather than bringing one large meal. When the young were old enough, they helped their mothers raise more offspring.

Early ants first appeared during the Jurassic period when dinosaurs ruled the land and mammals were tiny mouse-like creatures that scurried amidst the foliage. Back then, ants were uncommon compared to other insects until flowering plants evolved and spread throughout the world in the early Cretaceous period about 100 million years ago. These flowering plants provided new habitats and food sources for ants, bees, and wasps in which each species evolved to adapt to their ecological niches. Some foraged for plant materials in trees and shrubs, while others formed colonies in the forest floor. Some developed flight, gathered sustenance from flowers, and also formed social colonies.

Ants number more than 12,500 species (number may be 10,000 more) and wasps number more than 100,000 species today — quite a diverse population than stemmed from a common ancestor. DNA evidence showed that ants and their kin have adapted, diversified, and survived to their changing environment. Such an example may be currently happening as a swarm of Rasberry crazy ants descends upon southern Texas, adapting to Southern hospitality.

By Nick Ng

The New York Times
Current Biology
Annual Reviews

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