Influence of leaflet age in anatomy and possible adaptive values of the midrib gall of &lt;i&gt;Copaifera langsdorffii&lt;/i&gt; (Fabaceae: Caesalpinioideae)

Denis Coelho De Oliveira,Rosy Mary Dos Santos Isaias

doi:10.15517/rbt.v57i1-2.11322

Abstract

Gall inducing insects most frequently oviposit in young tissues because these tissues have higher metabolism and potential for differentiation. However, these insects may also successfully establish in mature tissues as was observed in the super-host Copaifera langsdorffii. Among C. langsdorffii gall morphotypes, one of the most common is a midrib gall induced by an undescribed species of Cecidomyiidae. Following this 'host plant and gall-inducing insect' model, we addressed two questions: 1) Do the age of the tissues alter the gall extended phenotype? 2) Do gall morphological and anatomical features influence the adaptive value of the galling insect? For anatomical and histometrical studies, transverse sections of young and mature, galled and ungalled samples were prepared. Galls in young leaflets presented higher potential for cell division and greater nutritive reserves, whereas galls in mature leaflets perhaps provide more protection against natural predators and desiccation. Host organ age at the time of oviposition may influence plant cell fates and consequently the interpretation of the adaptive value of insect galls.

Highlights

Entomogenous galls are originated by abnormal cell development in host species organ regulated by the action of a parasitic insect, which obtains directly or indirectly, shelter, food, and protection (Rohfritsch 1992, Isaias 1998)
The midrib gall of Copaifera langsdorffii was formed by a swelling of the central portion of leaflet lamina, with an ostiole placed along the whole extension of the gall (Fig. 2a)
YLG and MLG insignificantly differed in their size and shape (Fig. 3c)

Summary

Introduction

Entomogenous galls are originated by abnormal cell development in host species organ regulated by the action of a parasitic insect, which obtains directly or indirectly, shelter, food, and protection (Rohfritsch 1992, Isaias 1998). Because galls are formed through cell hypertrophy, tissue hyperplasia, developmental inhibition or cytological changes in response to the attack of the galling organisms (Mani 1964), it seems clear that the mechanisms of growth activation or inhibition should be related to hormonal balance under the influence of the continuous feeding activity of the insect (Fosket 1994, Hartley 1998)

Objectives

Methods

Results

Conclusion