Losing the ecological context of competition can make extreme weapons vanish.

Evidence

More often, I suspect, populations persist but their weapons disappear. When a few species of stalk-eyed fly stopped roosting on hanging rootlets in Malaysian streams, two of the three arms race ingredients vanished; females stopped gathering in harems on hanging threads (they were no longer economically defensible), and fights stopped being duels. With two of the race-stimulating ingredients gone, the flies’ arms races collapsed. They lost their extreme weapons. — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 438

Categorization

• XREF: Echoes the collapse of human armor when battlefield rules changed — context determines whether weapons pay. — connects to: Weapons disappear when fights stop being duels over defensible resources; Dueling plus competition and defensibility is the general rule for extreme weapons — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 266; Species with huge weapons often show weak current selection on them. — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 433 (+6 more)

Related

• Pair bonding removes the competitive conditions that drive weapon evolution. (similarity 0.89)
• Specific ecological circumstances must align before weapon arms races begin (similarity 0.88)
• Weapons disappear when fights stop being duels over defensible resources (similarity 0.87)
• Dueling plus competition and defensibility is the general rule for extreme weapons (similarity 0.87)
• Weapon evolution needs both competition and economically defensible resources (similarity 0.87)
• Specific conditions are required before weapons escalate into an arms race (similarity 0.86)
• Competition for reproduction drives evolution of nature’s biggest weapons (similarity 0.86)
• Three conditions must align to trigger an animal weapons arms race. (similarity 0.85)
• Weapons evolve only when reproductive benefits exceed costs (similarity 0.85)
• Intense competition without duel structure does not drive weapon evolution. (similarity 0.84)
• Costly weaponry can drive a species extinct when resources degrade. (similarity 0.84)
• Arms races inevitably stall as weapon costs neutralize reproductive benefits (similarity 0.83)
• Weapon evolution is judged by competition among designs, not human survival (similarity 0.82)
• Social competition environments evolve in tandem with weapons, unlike fluctuating physical environments (similarity 0.82)
• Balancing selection normally curbs weapon size until some lineages escape into runaway arms races (similarity 0.82)

Broader Connections

• Uniformly distributed resources make territorial weapons uneconomical #exemplifies (0.80) — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 201
• Specific ecological circumstances must align before weapon arms races begin #corroborates (0.80) — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 137
• Pair bonding removes the competitive conditions that drive weapon evolution. #exemplifies (0.70) — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 439
• Dominant weapons become obsolete when their intended fights never occur #exemplifies (0.70) — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 456
• Competition for reproduction drives evolution of nature’s biggest weapons #qualifies (0.60) — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 136