Life cycle and reproductive aspects of the orb web spider Alpaida variabilis (Araneae: Araneidae)

Abstract

The life cycle of the orb-weaving spider Alpaida variabilis was studied in greenhouse conditions. Several male-female pairs and egg-sacs obtained in the field were confined in raising chambers. We estimated that the duration of the life cycle of A. variabilis, from egg hatching to death was 179 days for males and 250 for females. Seven and eight instars were detected for each sexto reach maturity. This stage had an average duration of 20 days for males, while for females it was 90 days. lt was observed that females construct only one yellow egg-sac where they lay approximately 76.5 ± 34 eggs; with a range of 105 eggs (between 23 and 128 eggs). The eggs have a 60.5% of viability and a gestation period of 11 to 17 days. Mating behavior is described and is similar to that reported for the family Araneidae. For individuals kept in greenhouse conditions, the sex ratio was 1.13: 1 (females: males), while in the field it was 2.46: l.