VARIABILITY OF INSECT HERBIVORY ON TRICLISSIA GILLETI

ABSTRACT

Herbivory can be said to be a process by which activities such as reduction of plant materials, transfers mass and so on is carried out. In almost all ecosystems, its observed that insects are the main herbivores and their effects on the primary production can be said to equal or even exceed that of entire vertebrate grazers in the grasslands. The understanding of herbivory was derived from three (3) sources; (1) fossilised plants that serves as evidence (2) critical analyses and observation of plants debruising fossil animal faeces (3) construction of herbivore mouth parts. Previous studies have been carried out by several scientists on variability of insect herbivory in plants. For instance, Woof et al., (2001) conducted a study that shows the response of herbivores to changes in regional climates during Paleogene and Eocene. Nathaniel.P. et al., (2014) did a research to show the variable effects of temperature on insect herbivory. During the course of this study, Nigeria Institute for Oil and Palm Research. Edo State, Nigeria (NIFOR) was the site for the research experiment. Specific data on T.gilleti were collected using adequate materials like 2 pegs, a 1m x 1m square quadrant, rope etc., Data’s were collected for thirty (30) focal plant and thirty (30) neighbouring plants using a data sheet and pencil. The following parameters are contained in the data collected (a) Transect distance (b) sub transect distance (c) Focal plant coverage in % (d) other plant coverage in % (e) Number of plant in quadrant (f) Height of focal and nearest neighbour plant etc. In the first site with highest number of T.gilleti spotted, the transect with two (2) pegs were fastened. After which the square quadrant was thrown randomly. Data obtained were subjected to normality of various test using Shapiro-Wilks and levene’s test. While when it (data) violates the assumptions of homogeneity and normality (p<0.05) non- parametric test such as MannWhitney U and Kruskal-Wallis multiple comparison test was used to separate statistical data. The results obtained were explained in words and by aids of diagram statistically. While the correlation test, the results shows some weak and strong correlation between various data. The highlight of the study shows the variability of insect herbivory on T,gilleti. A similar research shows herbivory in plants varies from one plant to the other and even among individuals of the same species. Also, it was observed that the quality of leaf tissues may affect the feeding behaviour and development of insect herbivores.