Delovanje trofičkog stresa na broj i aktivnost neurosekretnih neurona gubara

Abstract

The neuroendocrine system of phytophagous insects reacts quickly to environmental changes including changes in chemical composition of their host plants (Ivanović, Janković-Hladni 1991). In order to understand how polyphagous species change their host range it is necessary to study adaptations at the level of the neuroendocrine system. The gypsy moth Lymantria dispar L., serious forest pest, is well studied ecologically (Leonard 1974; Liebhold 1995) but its neuroendocrinology is poorly understood (Loeb, Hayes 1980). Neurosecretory cells of the medial part of the lepidopteran protocerebrum (region to which A2 neurons belong) are the source of the carbohydrate metabolism regulators such as small form of the prothoracicotrophic neurohormons (smPTTH) and adrenocorticotropic neurochormon (ACTH "like"). They provide energy for the processes that enable survival under stressful conditions (Dahlman 1973; Hansen, et al. 1986). The aim of this study was to determine the population differences in the response to an unsuitable diet (locust tree leaves) in terms of the activity and number of A2 neurosecretory neurons (nsn) in the 4th instar larvae of the gypsy moth.

Efekat nepovoljne ishrane (bagremovim lišćem) na gusenice četvrtog larvenog stupnja Lymantria dispar L. rezultirao je povećanjem broja A2 neurona kod gusenica populacije hrastove šume. Broj ovih neurona se ne menja sa promenom kvaliteta ishrane kod gusenica iz bagremove šume. Sinteza neurosekretnog materijala je intenzivnija u A2 neuronima ukoliko se gusenice obe populacije hrane, nepovoljnom hranom (lišćem bagrema).