Application of Dyar’s Law to Determine Nymphal Instars of Macrotermes bellicosus (Smeathman) [Isoptera: Termitinae]

Bandiya, H. M.^1*, Danjumma, B. J.¹, Yahaya, M. M.¹, Bello, A.² & Baki, A. S.³

¹Department of Biological Sciences, Usmanu Danfodiyo University, Sokoto
²Department of Veterinary Anatomy, Usmanu Danfodiyo University, Sokoto
³Department of Microbiology, Usmanu Danfodiyo University, Sokoto

Dr. Bandiya, H. M., Department of Biological Sciences, Usmanu Danfodiyo University, Sokoto.

Keywords: Dyer’s Law; Macrotermes bellicosus; Nymphs; Growth Ratio

Abstract

Observations on the nymphal instars of Macrotermes bellicosus were made to determine the applicability of Dyar’s law. Fifty nymphs each of various sizes were collected from three different mounds of M. bellicosus. The nymphs were sorted and then placed in Petri dishes separately. The heads widths of the nymphs were measured using micrometer slides. The recorded head widths were then plotted on a graph to observe if the growth ratio in head width follows a geometric progression in agreement with the Dyar’s law. Based on the frequency distribution of the width of the head capsule of the nymphs, 12 nymphal instars were recognised.The nymphal growth shows a geometrical progressive increase in the head width of the nymphs in successive instars with a growth ratio of 1.14 following Dyar’s Law. This suggests that the nymphs of M. bellicosus showed a geometric progression in agreement with Dyar’s Law.

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