Vol. 4, Issue 1 (2019)
The depth of Cirina forda Westwood (Lepidoptera: Saturniidae) Pupation in the soil as a determinant factor for its mortality rate
Author(s): Muhammad IM, Ande AT
Abstract: Prepupa larvae of C. forda metamorphosed into pupae in the soil. It is reported for marketing of the processed larvae of C. forda by the people of Benue State of Nigeria. Unfortunately the penultimate larvae of C. forda is facing crucial decline challenges in the contemporary times. A study to determine part of the factors responsible for the declining of C.forda was mounted by determining the depth of pupation in the soil as determinant factor for the mortality rates of pupae in the soil, and the contribution of the depth level towards successful emergence of imago after aestivation was carried out in Lavun and Rafi local government areas of Niger State within two cropping seasons. By carefully exhuming pupae within three random quadrat throws per site and then scraping the soil within the quadrat with a hoe or shovel to a depth of 30 cm. On each site a mean pupal density was calculated and expressed as individual’s ± SD per m2. Survival rates were subsequently determined as a proportion in percentage of the total number of pupae encountered per quadrat and per site and expressed as mean ± SD%. Results showed that the pre-pupae and pupae were found within 0-15cm depth across the sites with high mortality recorded within 0-8cm depth while pupal density declined with season. Causes of shallow pupation as a result of other soil factors are being investigated.
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