The importance of beta diversity in local gall-inducing arthropod distribution

Abstract

-Many studies over the past twenty years have documented the richness of arthropod galling species around the world, and some have proposed hypotheses to explain local and global patterns of galling species richness. However, few studies have been directed toward understanding how the gall-inducing species are locally distributed. The aim of this study was to determine the distribution of gall-inducing arthropods species at Coiba National Park, a tropical habitat on the Pacifi c coast of Panama. Our results suggest that more gall-inducing species had an aggregated distribution, and gall-inducing arthropod diversity shows a strong beta diversity component. Geographic distance was not correlated with similarity in gall-inducing species composition between the studied sites. This fact has important implications when trying to estimate gall-inducing arthropod richness and general patterns, and could cause contradictory results for hypotheses that attempt to explain the local and global patterns of galling species richness.KEY WORDS: Coiba Island, geographic distribution, Panama, plant communityThe induction of plant gall is the result of a complex association between insects and plants (Shorthouse et al 2005). Galls represent a complex series of interactions between the tissues of a plant and another living organism, more frequently an insect. The understanding of these interactions involves studies in many scientifi c fi elds, from systematics to ecology, but also morphology, physiology, biological control, evolutionary biology or agricultural and forest entomology (Mani 1964. Gallinducing species are excellent models for ecological studies due to their abundance, diversity and sessile habit, which make them easier to census than free-feeding herbivores and thus allowing species diversity comparisons among different habitats (Fernandes & Price 1988).During the past twenty years, many studies have documented galling insect lists and galling species richness around the world (see Veldtman & McGeoch 2003. There are also data regarding factors that affect local and regional gall richness and thus infer global patterns in local number of insect galling species . However, few studies have been directed toward understanding how the gall-inducing species are locally distributed. Understanding spatial patterns of species distribution is a crucial topic in ecology and conservation biology; for instance, when predicting species richness from local to regional scales (Gering & Crist 2002). An important problem when comparing studies of gallinducing arthropods richness is the use of different sampling methods (Dalbem & Mendonça 2006). But, independent of sampling methods, one result that remains consistent across all studies is that local distribution of gall-inducing arthropods shows low similarity between the sampled sites (see Blanche & Westoby 1996, Gonçalves-Alvin & Fernandes 2001, Cuevas-Reyes et al 2003, Medianero et al 2003. This low similarity between the sampled sites has important implications when trying t...

Galling Insects of the Brazilian Páramos: Species Richness and Composition Along High-Altitude Grasslands

“…and Westoby 1996, Gonçalves-Alvim and Fernandes 2001, Medianero et al 2010, Carneiro et al 2014. The results of this work corroborate such evidence.…”

“…An as of yet unexplored way of understanding patterns and mechanisms of spatial distribution of galling insect richness and composition is how local and beta diversity contribute to regional species diversity (Medianero et al 2010, Carneiro et al 2014. Beta diversity is defined as the change in species composition between sites and (i.e., a relationship between regional and local diversity) can occur exclusively through two processes: turnover and nesting (Baselga and Orme 2012).…”

“…While turnover refers to the replacement of species from one site to another, nestedness refers to the loss or gain of species, which makes the species of one site a subgroup of those of a richer site (Baselga 2010). Understanding the dimension of the contribution of beta diversity to regional diversity, as well as the predominant processes responsible for beta diversity -whether nestedness or turnover -may help in understanding how galling insect-plant interactions respond to changes to the environmental or at other geographic scales (Whittaker 1972, Medianero et al 2010, Carneiro et al 2014, Coelho et al 2017.…”

“…(i) Richness of galling insects decreases with altitude (Fernandes and Price 1988) (ii) Richness of galling insects increases with plant richness (Southwood 1960(Southwood , 1961Samways 1996, 1998;Gonçalves-Alvim and Fernandes 2001;Oyama et al 2003;Cuevas-Reyes et al 2004b) (iii) Variation in regional diversity of galling insects and host plants is predominantly a consequence of its β-component (Medianero et al 2010, Baselga and Orme 2012, Carneiro et al 2014) (iv) Turnover is the main mechanism driving the beta diversity of both galling insects and plants (Medianero et al 2010, Carneiro et al 2014, Coelho et al 2017 Methods…”

Neotropical Insect Galls: Status of Knowledge and Perspectives

“…1993 ). Few studies have addressed the relationship between local and regional galling species richness in the Neotropics (e.g., Almeida et al 2004 ; see also Price 1991 ;Medianero et al 2010 ;Mendonça 2011 ). As more studies on the distribution of hosts and gallers are brought to light in the dozens of vegetation types across the Neotropics, we will be able to better understand the community structure of the galling insects in the region.…”