Fecundity is the reproductive output of a female, given per day (oviposition rate) or over her life. Small mites lay a few eggs a day for one to three weeks, while a single noctuid moth such as the corn earworm can lay hundreds to a few thousand eggs. Temperature and host quality change fecundity strongly.
In practice
Fecundity alone misleads. What matters is how early the eggs come: a female laying most of her eggs in her first days pushes r_m much higher than one spreading the same total over weeks. Over-fertilised, nitrogen-rich soft growth tends to raise fecundity in sap and cell feeders (Grower practice, supported in other crops).
Don't confuse with
- Fertility: eggs that hatch, not just eggs laid.
- R0: daughters that survive, after mortality.
Tetranychus urticae, the commonest cannabis mite indoors: a 0.5 mm sap-feeder that stipples leaves pale and spins webbing, breeding fastest in hot, dry rooms.Helicoverpa zea, a moth caterpillar that bores into developing cannabis flowers outdoors, leaving frass that triggers bud rot; growers call it budworm.The average number of female offspring a female produces in her lifetime after mortality: the population's multiplication per generation.A record of survival and egg-laying at each age for a cohort of pests at set conditions, from which development time, fecundity and r_m are calculated.The per-day rate at which an unchecked pest population multiplies under set conditions, from a life table; N(t) = N0 x e^(r_m x t).The share of offspring that are female; because only females lay eggs, a female-biased ratio speeds population growth.
