Practical importance for conservation of insect diversity in China

Insects are one of the most important groups in the natural world. They affect the life and welfare of humans in many different ways. While some insects are referred to as pests, others are beneficial to humans. For example, they may serve a function as pollinators of many cultivated plants, as natural enemies of harmful species, or as producers of valuable materials such as honey and silk. Several insect species, however, are not currently known as being harmful or beneficial. Nevertheless they are extremely important as essential components of both natural and modified ecosystems. In China, only 1% of insect species described are major pests. The majority of insects are either neutral or beneficial to humans. China, with its vast territory, diverse climate and ecosystems, is amongst the richest countries in insect diversity. However, as a result of the economic and population growth and development, Chinas insect diversity is now faced with habitat degradation, species extinction, and a decline in the natural enemies of harmful pests. These problems are due to the expansion of agriculture, urbanization, industrialization, pollution, mining, tourism, introduced species, hunting, and the illegal trade in endangered species. In order to exploit the beneficial components of insects as biological resources and to effectively control their harmful aspects, many national strategies, legal actions and capacity-building activities have been developed and implemented. These efforts work towards the goal of insect diversity conservation in China.     

Habitat conversion and galling insect richness in tropical rainforests under mining effect

Human-induced habitat change is the main cause of species loss and can have severe effects on plant communities and the associated herbivore fauna. In this study, we investigated the effects of habitat conversion due to mining on communities of galling insects in areas of tropical rainforest in the Brazilian Amazon. We sampled galling insects in the Floresta Nacional de Saracá Taquera, Pará, Brazil, where forest plateaus are used by the Mineração Rio do Norte Group to extract bauxite. Our results show that human-induced habitat change via mining activities increased the local species richness of galling insects. We also found that after impact there was greater species richness of galling insects closer to the forest edge than in the forest interior. Changes in plant physiology and in the diversity of natural enemies in human-modified habitats, along with the endophagous life-form, might account for the high incidence of galling in human-disturbed habitats. This result highlights the importance of understanding how different insect groups respond to human activities, since such idiosyncrasies might have profound effects on the species’ patterns of ecological interactions and in the outcomes of those interactions.     

Insects on the brink of a major discontinuity

Population surges and local extinctions are not uncommon among insects. In response to climatic changes in the past, insects have often shifted their ranges. This long-term range shifting and the vagaries of short-term weather makes reserve selection unrealistically rigid for many species. Although some insect species are surviving in reserves, others have disappeared from such small areas because of adverse weather. In contrast, many other insects depend on localized disturbance for survival. In response to anthropogenic disturbance, some native insects have become more abundant and widespread, such as Orthoptera in response to grazing and burning, and some Odonata in response to aquatic weeds and water impoundment. The effect of some exotic invasive insects on some native ecosystems is of major concern. Human-induced insect population crashes and species extinctions are becoming more common and widespread, and exacerbated by the synergistic effect of the various local impacts with global changes. A major insect population and species extinction discontinuity is beginning to take place. Yet, there is also an increase in range and abundance of some other insects. The world is becoming increasingly species-poorer and more homogenous in its insect fauna.     

Biogeography and species richness of endophagous insects associated with Proteaceae in South Africa

The endophagous insects associated with Proteaceae of the Cape fynbos were compared to endophage assemblages from more northern non-Capensis Proteaceae. Insects were collected from Proteaceae in the Cape on a regular basis and additional records obtained from insect collections. Northern samples were collected more opportunistically or records were obtained from collections or through personal communication. The Cape fynbos genus Protea is utilized by many more insect taxa than the non-fynbos Protea species. The fynbos Proteaceae has very few species in common with the northern Proteaceae, yet each has many of their own distinct species. This suggests that the fynbos endophage insect fauna is distinct from that of the other regions. It appears that the high diversity of host plants in the fynbos has contributed to generating high, local endophagous insect diversity.     

Do Eucalyptus plantations host an insect community similar to remnant Eucalyptus forest?

Abstract We examined the potential of forest plantations to support communities of forest‐using insects when planted into an area with greatly reduced native forest cover. We surveyed the insect fauna of Eucalyptus globulus (Myrtaceae) plantations and native Eucalyptus marginata dominated remnant woodland in south‐western Australia, comparing edge to interior habitats, and plantations surrounded by a pastoral matrix to plantations adjacent to native remnants. We also surveyed insects in open pasture. Analyses focused on three major insect orders: Coleoptera, Lepidoptera and Hymenoptera. Plantations were found to support many forest‐using insect species, but the fauna had an overall composition that was distinct from the remnant forest. The pasture fauna had more in common with plantations than forest remnants. Insect communities of plantations were different from native forest both because fewer insect species were present, and because they had a few more abundant insect species. Some of the dominant species in plantations were known forestry pests. One pest species (Gonipterus scutellatus) was also very abundant in remnant forest, although it was only recently first recorded in Western Australia. It may be that plantation forestry provided an ecological bridge that facilitated invasion of the native forest by this nonendemic pest species. Plantation communities had more leaf‐feeding moths and beetles than remnant forests. Plantations also had fewer ants, bees, evanioid wasps and predatory canopy beetles than remnants, but predatory beetles were more common in the understory of plantations than remnants. Use of broad spectrum insecticides in plantations might limit the ability of these natural enemies to regulate herbivore populations. There were only weak indications of differences in composition of the fauna at habitat edges and no consistent differences between the fauna of plantations adjacent to remnant vegetation and those surrounded by agriculture, suggesting that there is little scope for managing biodiversity outcomes by choosing different edge to interior ratios or by locating plantations near or far from remnants.     

论我国昆虫多样性的保护与利用

本文论述了保护昆虫多样性的意义、我国昆虫多样性的基本特点及面临的问题、昆虫多样性的保护战略和利用对策。文中强调指出,昆虫是生物界的一个主要类群,在我国,需要防治的害虫大约只占全部昆虫种类数的1%,其余种类对人类都是有益或者是中性的,它们不仅可以作为显花植物的传粉者、为人类提供食物和各种工业原料,而且可以作为许多害虫或杂草的天敌,以及用于环境净化和科学研究。我国由于地域辽阔,生境复杂,因此,昆虫种类极为丰富,珍稀物种及有益昆虫较多。然而,由于受到人类活动的干扰,我国昆虫多样性面临着生境遭到破坏,物种濒于灭绝,天敌大量减少等问题。为了有效地保护和利用我国的昆虫资源,作者提出了一些战略和对策。     

The terrestrial arthropods of Mauritius: a neglected conservation target

Entomology in Mauritius has historically been linked with the agricultural and medical fields but concern should now be directed towards the conservation of native forest insects given that they are key components of the local ecosystem. Despite its young age, small size and remoteness, the island has a well-developed native insect fauna with a high proportion of endemic species. A majority of the insect orders are represented on the island. We document the current state of knowledge for Mauritian arthropods, with particular focus on the Coleoptera. This is the most diverse order locally with 1,032 species. In addition, it is the best catalogued historically, providing a framework for future conservation studies to evaluate the current status of this group. We explore the current threats facing the native insect fauna and highlight the needs for concern on this vital component of local biodiversity. We recognize that the initial step for conserving the native insects will depend largely on the establishment of a local taxonomic knowledge base with international expert input.     

Species diversity of insects in Japan: Their origins and diversification processes

Japan is considered a global hot spot of biodiversity. With regard to species diversity, insects are no exception. To date, more than 32,000 insect species have been identified in Japan, while around 100,000 species of insects are estimated to inhabit this country. In this paper, we outline background factors having contributed to diversification of Japanese insects. Of course, the high degree of Japanese insect diversity is the result of many complex factors. In addition to the humid Asian monsoon climate and the extensive latitudinal gradient of habitats, the extremely complex geological history has contributed as an important factor to generate and maintain the high species diversity and endemism. In particular, the independent origins of northeastern and southwestern Japan from the Eurasian continent have greatly contributed to the diverse composition of Japanese insect fauna. To highlight the importance of this process, we introduce some case studies and previously published papers focusing on several insect groups with low dispersal ability. Those cases indicate that the geological history of Japan has played an important role in the differentiation of Japanese insect species. Besides such geological factors, climatic and ecological factors in combination have contributed to the formation of Japanese insect fauna in complicated ways and produced its particularly high degree of biodiversity. The knowledge compiled here will provide useful information for future studies aiming to understand more deeply the processes of speciation and faunal formation of Japanese insects.     

Turtles in trouble. Conservation ecology and priorities for Australian freshwater turtles

The Australian freshwater turtle fauna is dominated by species in the family Chelidae. The extant fauna comprises a series of distinct lineages, each of considerable antiquity, relicts of a more extensive and perhaps diverse fauna that existed when wetter climes prevailed. Several phylogenetically distinctive species are restricted to single, often small, drainage basins, which presents challenges for their conservation. Specific threats include water resource development, which alters the magnitude, frequency, and timing of flows and converts lentic to lotic habitat via dams and weirs, fragmentation of habitat, sedimentation, nutrification, and a reduction in the frequency and extent of floodplain flooding. Drainage of wetlands and altered land use are of particular concern for some species that are now very restricted in range and critically endangered. The introduced European red fox is a devastatingly efficient predator of turtle nests and can have a major impact on recruitment. In the north, species such as the northern snake-necked turtle are heavily depredated by feral pigs. Other invasive animals and aquatic weeds dramatically alter freshwater habitats, with consequential impacts on freshwater turtles. Novel pathogens such as viruses have brought at least one species to the brink of extinction. Species that routinely migrate across land are impacted by structural simplification of habitat, reduction in availability of terrestrial refugia, fencing (including conservation fencing), and in some areas, by high levels of road mortality. We report on the listing process and challenges for listing freshwater turtles under the Australian Environment Protection and Biodiversity Conservation Act, summarize the state of knowledge relevant to listing decisions, identify the key threatening processes impacting turtles, and identify key knowledge gaps that impede the setting of priorities. We also focus on how to best incorporate First Nations Knowledge into decisions on listing and discuss opportunities to engage Indigenous communities in on-ground work to achieve conservation outcomes.     

Urbanization increases floral specialization of pollinators

Understanding how urbanization alters functional interactions among pollinators and plants is critically important given increasing anthropogenic land use and declines in pollinator populations. Pollinators often exhibit short‐term specialization and visit plants of the same species during one foraging trip. This facilitates plant receipt of conspecific pollen—pollen on a pollinator that is the same species as the plant on which the pollinator was foraging. Conspecific pollen receipt facilitates plant reproductive success and is thus important to plant and pollinator persistence. We investigated how urbanization affects short‐term specialization of insect pollinators by examining pollen loads on insects’ bodies and identifying the number and species of pollen grains on insects caught in urban habitat fragments and natural areas. We assessed possible drivers of differences between urban and natural areas, including frequency dependence in foraging, species richness and diversity of the plant and pollinator communities, floral abundance, and the presence of invasive plant species. Pollinators were more specialized in urban fragments than in natural areas, despite no differences in the species richness of plant communities across site types. These differences were likely driven by higher specialization of common pollinators, which were more abundant in urban sites. In addition, pollinators preferred to forage on invasive plants at urban sites and native plants at natural sites. Our findings reveal indirect effects of urbanization on pollinator fidelity to individual plant species and have implications for the maintenance of plant species diversity in small habitat fragments. Higher preference of pollinators for invasive plants at urban sites suggests that native species may receive fewer visits by pollinators. Therefore, native plant species diversity may decline in urban sites without continued augmentation of urban flora or removal of invasive species.     

Effects of anthropogenic habitat disturbance on local pollinator diversity and species turnover across a precipitation gradient

Anthropogenic habitat disturbance can have profound effects on multiple components of forest biotas including pollinator assemblages. We assessed the effect of small-scale disturbance on local richness, abundance, diversity and evenness of insect pollinator fauna; and how habitat disturbance affected species turnover across the landscape and overall diversity along a precipitation gradient in NW Patagonia (Argentina). We evaluated the effect of disturbance on overall pollinator fauna and then separately for bees (i.e. Apoidea) and non-bee pollinators. Locally, disturbed habitats had significantly higher pollinator species richness and abundances than undisturbed habitats for the whole pollinator assemblage, but not for bees or non-bees separately. However, significant differences in species richness between habitats vanished after accounting for differences in abundance between habitat types. At a local scale Shannon–Weaver diversity and evenness did not vary with disturbance. A β diversity index indicated that, across forest types, species turnover was lower between disturbed habitats than between undisturbed habitats. In addition, rarefaction curves showed that disturbed habitats as a whole accumulated fewer species than undisturbed habitats at equivalent sample sizes. We concluded that small patches of disturbed habitat have a negligible effect on local pollinator diversity; however, habitat disturbance reduced β diversity through a homogenization of the pollinator fauna (in particular of bees) across the landscape.     

Why are there so many insect species? Perspectives from fossils and phylogenies

Over half of all described species are insects, but until recently our understanding of the reasons for this diversity was based on very little macroevolutionary evidence. Here I summarize the hypotheses that have been posed, tests of these hypotheses and their results, and hence identify gaps in knowledge for future researchers to pursue. I focus on inferences from the following sources: (i) the fossil record, normally at family level, and (ii) insect phylogenies, sometimes combined with: (iii) the species richness of insect higher taxa, and (iv) current extinction risks. There is evidence that the species richness of insects has been enhanced by: (i) their relative age, giving time for diversification to take place; (ii) low extinction rates. There is little evidence that rates of origination have generally been high or that there are limits on numbers of species. However, the evidence on macroevolutionary rates is not yet so extensive or coherent as to present unequivocal messages. As regards morphological, ecological, or behavioural hypotheses, there is evidence that diversity has been enhanced by (iii) flight or properties resulting from it like enhanced dispersal, (iv) wing folding, and (v) complete metamorphosis. However, in all these cases the evidence is somewhat equivocal, either because of statistical issues or because evidence from different sources is conflicting. There is extensive evidence that diversity is affected by (vi) the ecological niche. Comparative studies indicate that phytophagy generally increases net diversification rates, and reduces extinction risk. However, niche specialization is also associated with an increase in extinction risk. Small body size (vii) is often associated with low extinction risk in comparative studies, but as yet there is no solid evidence that it consistently enhances net rates of diversification. Mouthpart diversity (viii) has generally increased over time in the insects, but cannot explain the apparent great increase in diversity seen in the Cretaceous and Tertiary. Sexual selection and sexual conflict (ix) are two processes that are widespread in insects, and there is comparative evidence linking both to increased diversification. Although some comparative evidence links tropical distributions (x) to increased rates of diversification, the extent to which latitudinal richness gradients are unusual in insects is equivocal. There is little to no direct evidence from fossils and phylogenies that insect diversity has generally been affected by (i) sensory- or neuro-sophistication, (ii) population size or density, (iii) generation time or fecundity, (iv) the presence of an exoskeleton or cuticle, (v) segmentation or appendage diversity, (vi) adaptability or genetic versatility, though all of these remain plausible hypotheses awaiting further tests. The data suggest that the insect body ground plan itself had no direct effect on insect diversity. Thus, whilst studies to date have given substantial understanding, substantial gaps still remain. Future challenges include: (i) interpreting conflicting messages from different sources of data; (ii) rating the importance of different hypotheses that are statistically supported; (iii) linking specific proximate to specific ultimate explanations and vice versa; and (iv) understanding how different ultimate hypotheses might be dependent on each other.     

Multi‐scale responses to warming in an experimental insect metacommunity

In metacommunities, diversity is the product of species interactions at the local scale and dispersal between habitat patches at the regional scale. Although warming can alter both species interactions and dispersal, the combined effects of warming on these two processes remains uncertain. To determine the independent and interactive effects of warming‐induced changes to local species interactions and dispersal, we constructed experimental metacommunities consisting of enclosed milkweed patches seeded with five herbivorous milkweed specialist insect species. We treated metacommunities with two levels of warming (unwarmed and warmed) and three levels of connectivity (isolated, low connectivity, high connectivity). Based on metabolic theory, we predicted that if plant resources were limited, warming would accelerate resource drawdown, causing local insect declines and increasing both insect dispersal and the importance of connectivity to neighboring patches for insect persistence. Conversely, given abundant resources, warming could have positive local effects on insects, and the risk of traversing a corridor to reach a neighboring patch could outweigh the benefits of additional resources. We found support for the latter scenario. Neither resource drawdown nor the weak insect‐insect associations in our system were affected by warming, and most insect species did better locally in warmed conditions and had dispersal responses that were unchanged or indirectly affected by warming. Dispersal across the matrix posed a species‐specific risk that led to declines in two species in connected metacommunities. Combined, this scaled up to cause an interactive effect of warming and connectivity on diversity, with unwarmed metacommunities with low connectivity incurring the most rapid declines in diversity. Overall, this study demonstrates the importance of integrating the complex outcomes of species interactions and spatial structure in understanding community response to climate change.     

Conserving insect assemblages in urban landscapes: accounting for species-specific responses and imperfect detection

Understanding how global environmental change impacts insect biodiversity is central to the core principals of conservation biology. To preserve the ecosystem services provided by insects in cities, it is crucial to understand how insect species are influenced by the degree of urbanization of the surrounding landscape. Using a hierarchical occupancy–detection model, we estimated the effect of urbanization on heteropteran bug species richness and occupancy, an approach that concurrently accounts for species-specific responses and imperfect detection. We found that species richness decreased along a gradient of increasing urbanization. This trend corresponded well with species-specific trends, as approximately two-thirds of all herbivores and predatory species experienced a strong mean negative response to urbanization. These results indicate that many species are potentially at risk of local extinction as cities grow and expand in the future. A second group of species, however, showed a weak mean negative response, indicating that they are ubiquitous urban species that thrive regardless of the surrounding degree of urban disturbance. Our research suggests that as cities develop, many of the species that are currently present will become less likely to occur, and therefore assemblages in the future are likely to become more simplified. In order to preserve or increase insect biological diversity in cities, it is critical to understand how individual species are influenced by urbanization. Our finding that insects display species-specific responses to urbanization has important repercussions for decision makers charged with preserving and improving urban biodiversity and the deliverance of ecosystem services in cities.     

Insect diversity of a Costa Rican dry forest: why keep it,and how?

The dry forest of the 108 km2 Santa Rosa National Park in northwestern Costa Rica contains as many as 13 000 species of insects (including 3140 species of moths and butterflies) sustained by and sustaining about 700 species of plants and 400 species of vertebrates. These insects require explicit conservation attention. They are more than just decorations on the plants; rather, they are the building blocks and glue for much of the habitat. They are the food for much of the carnivore community, and the insect species are not merely interchangeable bits of nutrients. They are major killers of seeds, and thereby influence both the plant species composition of a habitat and prevent the better competitors from taking it over. They are the primary pollinators and are specific enough to be neither interchangeable nor replaceable with other animals; the seeds resulting from their pollination activities are major animal foods in the habitat. They are a diverse, puzzling, complex, intrinsically attractive, and major part of the intellectual display offered by tropical wildlands, the display that will be the eventual foundation for most of the reason why tropical wildlands will be retained as such in the future.
The retention and maintenance of insect species richness in a tropical wildland is strongly rooted in the preservation of plant species richness, in maintaining habitat mosaics (different members of which are used by a given insect in different seasons), in preserving a large diversity of habitats, and in recognizing the threat posed by insect crop associates in nearby agricultural lands.     

昆虫多样性的保护现状与趋势

昆虫是自然界中种类最多的动物,在生态系统中具有重要的作用,但是昆虫在生物多样性保护中没有受到应有的重视.多个实例证明,很多昆虫种类处在数量下降甚至绝灭的状态.究其原因,人类的认识不足是导致昆虫多样性保护未受重视的主要原因,栖息地破坏是昆虫濒危的主要原因.由于昆虫生活史的特殊性,其保护策略与大型动物的保护有很大不同.昆虫多样性的保护可以与人类活动共存.     

The Neglect of Parasitic Hymenoptera in Insect Conservation Strategies: The British Fauna as a Prime Example

Parasitic Hymenoptera, the major group of insects having the parasitoid life style, are extremely species rich and of wide significance in terrestrial ecosystems. Although the nature of their role with respect to species richness and stability in their host communities is unclear, the evidence that parasitoids can have a profound impact on host populations is incontestable. Because parasitic Hymenoptera are typically very specialised and occupy a high trophic level, species in this group are likely to be particularly vulnerable to local or even global extinction. That their particular conservation needs and extinction risks are rarely considered stems largely from our ignorance of them, both taxonomically and biologically. In Britain, parasitic Hymenoptera comprise about 25% (or perhaps significantly more) of the total insect fauna. The view is advanced that neglect consequent on the continuing poor knowledge of parasitic Hymenoptera in such an otherwise well-studied fauna is a serious conservation problem, undermining the rationality of various current conservation initiatives and analyses. Recommendations to redress this are made.     

Mosquito Vector Diversity across Habitats in Central Thailand Endemic for Dengue and Other Arthropod-Borne Diseases

Recent years have seen the greatest ecological disturbances of our times, with global human expansion, species and habitat loss, climate change, and the emergence of new and previously-known infectious diseases. Biodiversity loss affects infectious disease risk by disrupting normal relationships between hosts and pathogens. Mosquito-borne pathogens respond to changing dynamics on multiple transmission levels and appear to increase in disturbed systems, yet current knowledge of mosquito diversity and the relative abundance of vectors as a function of habitat change is limited. We characterize mosquito communities across habitats with differing levels of anthropogenic ecological disturbance in central Thailand. During the 2008 rainy season, adult mosquito collections from 24 sites, representing 6 habitat types ranging from forest to urban, yielded 62,126 intact female mosquitoes (83,325 total mosquitoes) that were assigned to 109 taxa. Female mosquito abundance was highest in rice fields and lowest in forests. Diversity indices and rarefied species richness estimates indicate the mosquito fauna was more diverse in rural and less diverse in rice field habitats, while extrapolated estimates of true richness (Chao1 and ACE) indicated higher diversity in the forest and fragmented forest habitats and lower diversity in the urban. Culex sp. (Vishnui subgroup) was the most common taxon found overall and the most frequent in fragmented forest, rice field, rural, and suburban habitats. The distributions of species of medical importance differed significantly across habitat types and were always lowest in the intact, forest habitat. The relative abundance of key vector species, Aedes aegypti and Culex quinquefasciatus, was negatively correlated with diversity, suggesting that direct species interactions and/or habitat-mediated factors differentially affecting invasive disease vectors may be important mechanisms linking biodiversity loss to human health. Our results are an important first step for understanding the dynamics of mosquito vector distributions under changing environmental features across landscapes of Thailand.     

Non-native plants rarely provide suitable habitat for native gall-inducing species

For insect herbivores, a critical niche requirement—possibly the critical niche requirement—is the presence of suitable host plants. Current research suggests that non-native plants are not as suitable as native plants for native herbivores, resulting in decreases in insect abundance and richness on non-native plants. Like herbivores, gall-forming insects engage in complex, species-specific interactions with host plants. Galls are plant tissue tumors (including bulbous or spindle-shaped protrusions on leaves, stems and other plant organs) that are induced by insects through physical or chemical damage (prompting plants to grow a protective tissue shell around the insect eggs and larvae). As such, we hypothesized that gall-inducing insect species richness would be higher on native than non-native plants. We also predicted higher gall-inducing insect species richness on woody than herbaceous plants. We used an extensive literature review in which we compiled gall host plant species by genus, and we assigned native or non-native (or mixed) status to each genus. We found that native plants host far more gall-inducing insect species than non-native plants; woody plants host more gall-inducing species than herbaceous plants; and native woody plants host the most gall-inducing species of all. Gall-inducing species generally are a very cryptic group, even for experts, and hence do not elicit the conservation efforts of more charismatic insects such as plant pollinators. Our results suggest that non-native plants, particularly non-native woody species, diminish suitable habitat for gall-inducing species in parallel with similar results found for other herbivores, such as Lepidopterans. Hence, the landscape-level replacement of native with non-native species, particularly woody ones, degrades taxonomically diverse gall-inducing species (and their inquilines and parasitoids), removing multiple layers of diversity from forest ecosystems.

     

Insect herbivores associated with Baccharis dracunculifolia (Asteraceae): responses of gall-forming and free-feeding insects to latitudinal variation

The spatial heterogeneity hypothesis has been invoked to explain the increase in species diversity from the poles to the tropics: the tropics may be more diverse because they contain more habitats and micro-habitats. In this paper, the spatial heterogeneity hypothesis prediction was tested by evaluating the variation in richness of two guilds of insect herbivores (gall-formers and free-feeders) associated with Baccharis dracunculifolia (Asteraceae) along a latitudinal variation in Brazil. The seventeen populations of B. dracunculifolia selected for insect herbivores sampling were within structurally similar habitats, along the N-S distributional limit of the host plant, near the Brazilian sea coast. Thirty shrubs were surveyed in each host plant population. A total of 8 201 galls and 864 free-feeding insect herbivores belonging to 28 families and 88 species were sampled. The majority of the insects found on B. dracunculifolia were restricted to a specific site rather than having a geographic distribution mirroring that of the host plant. Species richness of free-feeding insects was not affected by latitudinal variation corroborating the spatial heterogeneity hypothesis. Species richness of gall-forming insects was positively correlated with latitude, probably because galling insect associated with Baccharris genus radiated in Southern Brazil. Other diversity indices and evenness estimated for both gall-forming and free feeding insect herbivores, did not change with latitude, suggesting a general structure for different assemblages of herbivores associated with the host plant B. dracunculifolia. Thus it is probable that, insect fauna sample in each site resulted of large scale events, as speciation, migration and coevolution, while at local level, the population of these insects is regulated by ecological forces which operate in the system.