Breeding and population biology of Armadillo officinalis (Isopoda: Oniscidea) in Benghazi, Libya

The breeding of Armadillo officinalis in Libya, coincides with the spring rains, a rise in relative humidity, atmospheric temperature, and day length; and lasts from April to September with a cessation during the hot summer months of June and July. Sexes were distinguished in individuals from 4 mm in length, on the basis of secondary sexual characters. The total number of eggs produced and the total number of young that left the brood pouches are correlated with the body lengths of the gravid females. The average incubation period was 32 days and brood mortality 4•2%. Females carried two to three broods in a year. The newly hatched young had a body length of 1•7 mm and growth was rapid during the early developmental stages. Descriptive accounts were furnished for the period October 1988 to October 1989, on the percentage distribution of size classes based on body length measurements of immature, male, female and ovigerous females, together with details of the standing crop and production of embryos. Sex ratio in the first year age group showed a preponderance of males over females, while in the 1-2-year-old group, females outnumbered males. These findings are discussed in the light of information available on various other species of woodlice.