Galls in Brazilian Mountains: New Reports and Perspectives

Plant architecture influences gall abundance in a tropical montane plant species

“…The abundance of the hosts, and therefore the abundance of resources, might have influenced the occurrence and establishment of this gall-inducing insect, as suggested by the plant density hypothesis (Cuevas-Reyes et al 2004). This hypothesis predicts that because gall-inducing insects are species-specific, the abundance of hosts influences the abundance of galls (Cuevas-Reyes et al 2004;Carneiro et al 2014), as found in our study system. Some previous studies with gall-inducing insects in the Atlantic forest have suggested that Rubiaceae is a host for several galls (Lebel et al 2008;Maia et al 2014) although only Lopesia galls were found in Galianthe plants all along the gradient.…”

“…Contrary to our expectations, however, architectural complexity and gall abundance did not decrease with increased altitude. Previous studies have found an inverse relationship between gall richness and/or abundance and altitude (e.g., Fernandes & Price 1988;1991;1992;Blanche & Ludwig 2001;Carneiro et al 2014) as well as altitude and architectural complexity (Homeier et al 2010). Classical studies as those of Fernandes & Price (1988;1991;1992) suggest that gall abundance usually decrease with altitude due to the sensitivity of gall-inducing insects to changes in humidity and temperature associated to increased altitude.…”

“…Plants with higher architectural complexity might exhibit greater abundance and/or resource quality for herbivores (Price 1997). Increased height as well as variation in the patterns of branching -parameters commonly used and also combined to determine plant architectural complexity (see Gonçalves-Alvim et al 1999;Marquis et al 2002;Espírito-Santo et al 2007) -are closely related to the amount of active meristems in a plant (Larson & Whitham 1997;Carneiro et al 2014), which directly influences gall richness and abundance. The presence of active meristems facilitates the morphological alterations caused by gall formation such as cell hypertrophy and hyperplasia and previous studies have shown that galls cannot be initiated in already developed tissues (Fernandes & Santos 2014).…”

“…Classical studies as those of Fernandes & Price (1988;1991;1992) suggest that gall abundance usually decrease with altitude due to the sensitivity of gall-inducing insects to changes in humidity and temperature associated to increased altitude. More recent studies such as Carneiro et al (2014) have suggested, however, that altitude might influence gall abundance only in xeric habitats, as the morphological structure created by the gall actually protects the growing larvae against climatic harsh and natural enemies (Price et al 1987;Fernandes & Price 1991;Carneiro et al 2014).…”

Senescent stem-galls in trees of Eremanthus erythropappus as a resource for arboreal ants

“…Furthermore, the presence of galleries and stem-galls within the twigs (created by borer and gall inducing insects) are an excellent advantage and help greatly in the construction of nests by arboreal ants (Fernandes et al 1988;Araújo et al 1995;Oliveira & Freitas 2004;Schoereder et al 2010). As in the cerrado, the high diversity of galls in other plant formations such as the Atlantic forest (Coelho et al 2013;Carneiro et al 2014) and dry forests (Coelho et al 2013) suggest that these galls can be widely used by ants in these environments. Therefore, the pre-formed cavities left behind by ecosystem engineers, such as galls, can act as an important resource which optimizes the efforts and the potential of local ant colonies, thus affecting the composition, richness and abundance of their population.…”