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Why can insect populations change more dramatically from year to year than bird or mammal populations?

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Zenaida macroura: mouring doves — ecology Mourning doves (*Zenaida macroura*) on their nest protected within the prickly branches of a cactus in the Sonoran Desert, Arizona, U.S.

Insect populations often experience more dramatic year-to-year fluctuations than those of birds or mammals primarily due to differences in life-history strategies and reproductive potential.

Insects are frequently characterized as r-selected species, which are governed by their biotic potential—the maximum reproductive capacity of an organism. These species typically have short life spans, reach maturity quickly, and produce large numbers of offspring. Because of these traits, insects possess a much higher intrinsic rate of natural increase (r) compared to larger animals like mammals or birds, which are generally K-selected species. K-selected species tend to have stable populations that fluctuate near the carrying capacity of their environment, supported by longer life spans and extended parental care.12

Furthermore, insect populations are highly sensitive to external environmental factors, such as weather, which can cause sudden, massive surges or rapid crashes in numbers. While competition for resources eventually regulates these populations, insects often undergo unpredictable, explosive growth before such density-dependent factors take effect.34