Weapon size should track resource availability more than any mandatory body part

Evidence

Weapons are discretionary in another respect, too. They are not necessary for survival. Females, for example, fare just fine without them in many species, as do small males. In stark contrast with the rest of the body, which must be built regardless, no weapon growth need occur at all. This means that the sizes of weapons should be far more sensitive to the availability of resources than other, mandatory body parts. My colleagues and I tested this a few years ago by perturbing the amount of food available to growing rhinoceros beetle larvae. By restricting access to nutrients, we experimentally altered the sizes of the resource pools available to developing males, allowing us to measure just how sensitive the different body parts were. — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 338

Categorization

• XREF: connects to: Lifetime tracking of 318 stag males quantifies weapons’ fitness costs — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 313; Weapon growth is far more resource-sensitive than other body parts — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 340; Extreme weapon size is relative to body size, not absolute — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 3 (+6 more)

Related

• Weapon growth is far more resource-sensitive than other body parts (similarity 0.91)
• Arms-race weapon growth makes resource trade-offs drastically impair body functions (similarity 0.90)
• Growing large weapons diverts resources and stunts other body parts (similarity 0.89)
• Weapons grow late because development prioritizes mandatory survival expenses first (similarity 0.89)
• Infections shrink weapon growth because immunity consumes the same resource pool (similarity 0.88)
• Weapon size in animal species is under stabilizing selection, not open-ended directional selection (similarity 0.87)
• Weapons in arms races get so big they impair other bodily functions (similarity 0.87)
• Weapons evolve only when reproductive benefits exceed costs (similarity 0.86)
• Lifetime tracking of 318 stag males quantifies weapons’ fitness costs (similarity 0.86)
• Natural selection usually favors modest weapon size because cost offsets benefit (similarity 0.86)
• Weapons are better signals than body size because they vary from zero to enormous (similarity 0.86)
• Reproductive success, not survival, drives the largest animal weapons (similarity 0.86)
• Competition for reproduction drives evolution of nature’s biggest weapons (similarity 0.84)
• Weapon growth widens the gap between the best- and worst-armed males. (similarity 0.84)
• Extreme weapon size is relative to body size, not absolute (similarity 0.84)

Broader Connections

• Mobile resources deny weapons a cost-effective performance advantage #corroborates (0.75) — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 225
• Uniformly distributed resources make territorial weapons uneconomical #qualifies (0.60) — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 201
• Extreme weapon size is relative to body size, not absolute #qualifies (0.50) — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 3
• Weapon evolution needs both competition and economically defensible resources #corroborates (0.40) — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 191
• Growing large weapons diverts resources and stunts other body parts #complicates (0.40) — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 295
• Natural selection usually favors modest weapon size because cost offsets benefit #complicates (0.30) — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 21