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4. The Absence of Large Predators
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Particularly in the Carboniferous epoch, the Palaeozoic era saw quite rare big vertebrate predators. Insects were free from predation and competition, which let them reach sizes unthinkable in the presence of more powerful predators. Large insects in modern environments are readily hunted and consumed by birds, mammals, and reptiles, all of which pose hazards.
Prehistoric environments lacked big predators, so insects could occupy different ecological niches free from constant threat of being preyed upon. Larger body sizes evolved thanks to this independence since insects could develop without running the danger of being hunted. For instance, enormous predatory insects like the Meganeura were able to rule the heavens, feeding on smaller insects free from concern for more powerful predators.
Moreover, at this period the evolutionary arms struggle between prey and predators was less evident. Whereas predators evolve to capture bigger prey, greater prey often evolves in modern ecosystems to avoid predators. Insects must remain agile and tiny to escape being caught, hence this dynamic can limit their size. But the archaic surroundings let for a distinct evolutionary path, which produced enormous insects.
The dynamics changed as big creatures started to show and ecosystems developed. Larger predators' arrival put pressure on bug numbers, which reduced their sizes. Understanding the amazing expansion and evolutionary success of huge insects depends critically on the absence of major predators throughout their period.
