A preliminary study of population trends in insects of Leucaena leucocephala (Lam) Dewitt. (Leguminosae)

Date

4-1982

Degree

Bachelor of Science in Biology

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Victor P. Gapud

Abstract

A classification for pod maturity was proposed and used to deter-mine the oviposition preferences of Araecerus fasciculatus Oegeer and other insects which infest ipil-ipil. The occurrence of ipil-ipil in-sects appeared to exhibit certain trends which are closely associated with the stages of pod development. Stage 1 pods were hardly attacked by insects, while Stage 2 pods showed eggs oviposited by A. fasciculatus. Its larvae pupated as early as Stage 3 and emerged into adults at Stages 4 and 5. Populations of A. fasciculatus were followed by populations of a moth and a minute beetle species, thus, forming a pattern of insect succession. Predatory mites and parasitic wasps were found to parasitize unidentifiable insects. Fungal infections on all pod stages were more prevalent in July and August. Changes in mean densities of ipil-ipil insects, based on randomly collected pods, did not indicate any clear trends which could provide predictive interpretations of insect fluctuations with respect to time. However, they have provided evidence of the succession of secondary feeders after A. fasciculatus ha infested the pods. The populations of the secondary feeders depend on the A. fasciculatus population. A pattern of a new beetle population and adult emergence appeared to agree with the development of immature to mature pods. It was not confirmed, however, where the new populations of A. fasciculatus came from. a better sampling program based on the coefficient of variation value and the desired number of samples at a 10% standard error was recommended.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Thesis

Document Type

Thesis

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