Specific conditions are required before weapons escalate into an arms race

Evidence

Specific circumstances must fall into place before weapons launch into an arms race. Appreciating these “ingredients” reveals much about the function and diversity of nature’s most extravagant weapons, including why some species have them and most others do not. — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 137 (#corroborates, via linked claim)

In a sense, males compete with rival males regardless of whether sexual selection proceeds through female choice or male competition and, in many respects, the process—the intensity, consistency, and social nature of selection—is the same regardless. Why, then, do some species embark on a trajectory of overt competition leading to the evolution of weapons, while others end up dancing or singing with displays? Here is where the ingredients for arms races come into play, for these are the pieces that must fall into place if sexual selection is to trigger evolution of extreme weapons. The first ingredient is competition, the essence of all sexual selection. The second is economic defensibility. — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 191 (#expands, via linked claim)

Together with competition and economic defensibility, duels tip the evolutionary balance in favor of extreme weapons. This simple insight has terrific explanatory power because it provides a general rule for why particular animal species have extreme weapons, and why their close relatives may not. Like uncovering the key to an ancient encrypted cipher, we can now make sense of so much animal diversity. Specifically, we can look to the histories of groups of species to see when behaviors changed in ways that caused the arms race ingredients to fall into place. This can help explain why isolated species stand out from the rest, and it can also explain why whole groups of related species appear to enter into arms races together. Sometimes, one or more of the arms race ingredients are part of the inherited physiology of a group of species, and this can predispose them all to arms races. — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 266 (#expands, via linked claim)

Categorization

• XREF: connects to: Three conditions must align to trigger an animal weapons arms race.; Specific ecological circumstances must align before weapon arms races begin — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 137; Symmetrical one-on-one fights are a neglected prerequisite for weapon arms races — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 226 (+3 more)

Related

• Three conditions must align to trigger an animal weapons arms race. (similarity 0.97)
• Specific ecological circumstances must align before weapon arms races begin (similarity 0.94)
• Dueling plus competition and defensibility is the general rule for extreme weapons (similarity 0.92)
• Weapon evolution needs both competition and economically defensible resources (similarity 0.91)
• Intense competition without duel structure does not drive weapon evolution. (similarity 0.89)
• Balancing selection normally curbs weapon size until some lineages escape into runaway arms races (similarity 0.88)
• When balancing selection fails, bigger weapons win every round and escalate the race. (similarity 0.88)
• Symmetrical one-on-one fights are a neglected prerequisite for weapon arms races (similarity 0.88)
• Competition for reproduction drives evolution of nature’s biggest weapons (similarity 0.88)
• Identical circumstances trigger and collapse arms races in animals and humans. (similarity 0.88)
• Sexual selection can be far stronger than natural selection and drives weapon extremes (similarity 0.88)
• State arms races mirror single male-male animal contests, not evolutionary turnover (similarity 0.87)
• Arms races inevitably stall as weapon costs neutralize reproductive benefits (similarity 0.87)
• Markets and battlefields select among rifle designs like natural selection acts on weapons (similarity 0.87)
• One-on-one duels favor weapon evolution while chaotic scrambles do not. (similarity 0.87)

Broader Connections

• Specific ecological circumstances must align before weapon arms races begin #corroborates (0.85) — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 137
• Weapon evolution needs both competition and economically defensible resources #expands (0.75) — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 191
• Symmetrical one-on-one fights are a neglected prerequisite for weapon arms races #expands (0.70) — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 226
• Dueling plus competition and defensibility is the general rule for extreme weapons #expands (0.70) — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 266
• Balancing selection normally curbs weapon size until some lineages escape into runaway arms races #expands (0.60) — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 22