calc_sxj: Age-Stage Survival Rate s_xj

In insectecol: Insect Ecology Data Analysis Toolkit

Age-Stage Survival Rate s_xj

Description

Calculates the age-stage survival rate: the proportion of the original cohort that is alive and in developmental stage j at age x, s_xj = n_xj / N, where n_xj is the number of individuals of age x in stage j. This is the fundamental curve set of the age-stage, two-sex life table: because individuals of the same age may be in different stages, s_xj describes the cohort much better than a single l_x curve.

Usage

calc_sxj(lt)

Arguments

lt	A life_table object returned by lifeTable_read.

Details

The returned data frame has one row per age class (day) and one column per stage, in the order of the stage names returned by get_stage_names (immature stages first, then "Female" and "Male").

Value

A data frame of age-stage survival rates (values in [0, 1]): rows = ages in days, columns = developmental stages.

References

Chi, H. and Liu, H. (1985) Two new methods for study of insect population ecology. Bull. Inst. Zool. Acad. Sin 24(2), 225-240.

Chi, H. (1988) Life-table analysis incorporating both sexes and variable development rates among individuals. Environmental Entomology 17(1), 26-34.

See Also

get_stage_names, calc_lx, lifeTable_plot

Examples

f <- system.file("extdata", "lifetable_example.csv", package = "insectecol")
lt <- lifeTable_read(f)
head(calc_sxj(lt))

insectecol documentation built on Oct. 5, 2026, 5:08 p.m.