We report on the insect galls on neotropical species of Baccharis (Asteraceae) and describe new kinds oi galls on Baccharis spp. of the cerrado and rupestrian fields of Brazil. Gall collections were made in several localities in Minas Gerais (Belo Horizonte, Caratinga; Lagoa Santa, Moeda, Ouro Preto, and Serra do Cip6). Baccharis may support the richest galling fauna of the neotropics (121 galling species on only 40 species of Baccharis). Nevertheless, gallers were not evenly distributed across host plant species. Four species of Baccharis alone supported 46% of the galling fauna. The most diverse fauna occurred on B. dracunculifolia (17 galls), B. concinna (15 galls), B. salicifolia (13 galls) and Baccharis sp.
Sand flies (Diptera: Psychodidae) are responsible for the transmission of protozoan parasites that cause leishmaniases. They are found predominantly in forests, but some species exploit environments that have been subject to deforestation and subsequent human colonization. Studies conducted in Brazil over the past 30 years show that some species are adapting to peri-urban and urban settings. We evaluated sand fly diversity and abundance in the rural settlement of Rio Pardo, Presidente Figueiredo Municipality, Amazonas State, Brazil. Settlement households were divided into four categories. These categories were determined by the human population density and the degree of deforestation in the immediate area. We used CDC light traps to sample the area surrounding 24 households (6 households in each category). Samples were taken on six occasions during September-November 2009 and June-August 2010. A total of 3074 sand fly specimens were collected, including 1163 females and 1911 males. These were classified into 13 genera and 52 species. The greatest abundance of sand flies and the greatest richness of species were observed in areas where human population density was highest. Our results show that changes in the human occupancy and vegetation management in rural settlements may affect the population dynamics and distribution of sand fly species, thereby affecting the local transmission of cutaneous leishmaniases.
ABSTRACT. Galling insects associated with two species of ruderal plants in urban and peri urban areas. Insects have been considered as important bioindicators of environmental changes and habitat quality. In spite of its sessile habit, easy localization, abundance and host specificity, insects that induce galls have not been utilized in studies of this nature. It was investigated the suitability of gall-inducing insects associated to two ruderal host plant species (Baccharis dracunculifolia and Vernonia polyanthes: Asteraceae) as bioindicators of habitat quality. The following questions were addressed: (i) is gall-inducing insect diversity influenced by different types of land use?; (ii) are the responses of galling insect communities different between host plants?; (iii) how does the biotic and physical features of the biotope influence the gall-inducing insect diversity? It was found 6,226 galls, belonging to six galling insect species on V. polyanthes and 11 galling species on B. dracunculifolia. No difference was found in galling species richness among land use types. Nevertheless, gall-forming insect abundance was statistically different among the biotopes studied. Insect galls were more numerous in biotopes with lower urbanization levels. Gall abundance showed a strong and positive relationship with the percentage of vegetal cover. Gall-forming insect communities on both host species showed differential responses to the different land use types. The results suggest that three factors may be involved with galling insect diversity in urban areas: (i) habitat structure in the biotope; (ii) resource abundance (host plant abundance and distribution); and (iii) frequency and intensity of management in reserves, parks, city squares, wastelands found at a given urban area.KEYWORDS. Bioindicator species; biotopes; host plants; insect galls; urban-rural gradient. RESUMO.Insetos galhadores associados a duas espécies de plantas invasoras de áreas urbanas e peri-urbanas. Os insetos têm sido considerados importantes indicadores de mudanças ambientais e da qualidade de habitats. Apesar de seu hábito séssil, fácil visualização, abundância, e especificidade de hospedeiro, insetos indutores de galhas não têm sido utilizados em estudos desta natureza. Neste estudo foi investigado o uso potencial de insetos galhadores associados a duas espécies de plantas hospedeiras ruderais (Baccharis dracunculifolia e Vernonia polyanthes: Asteraceae) como bioindicadores da qualidade de habitats. Procurou-se responder às seguintes questões: (i) A diversidade de insetos galhadores é afetada pelo tipo de uso e ocupação da paisagem (solo)?; (ii) A resposta das comunidades de insetos galhadores difere entre as duas espécies de plantas hospedeiras?; (iii) A diversidade de insetos galhadores é influenciada por características bióticas e físicas dos biótopo urbanos? Foram coletadas 6.226 galhas, pertinentes a 6 espécies de insetos galhadores associados à V. polyanthes e 11 espécies associadas à B. dracunculifolia. Não foi encontrada nenhuma difere...
A relatively large number of studies reassert the strong relationship between galling insect diversity and extreme hydric and thermal status in some habitats, and an overall pattern of a greater number of galling species in the understory of scleromorphic vegetation. We compared galling insect diversity in the forest canopy and its relationship with tree richness among upland terra firme, várzea, and igapó floodplains in Amazonia, Brazil. The soils of these forest types have highly different hydric and nutritional status. Overall, we examined the upper layer of 1,091 tree crowns. Galling species richness and abundance were higher in terra firme forests compared to várzea and igapó forests. GLM-ANCOVA models revealed that the number of tree species sampled in each forest type was determinant in the gall-forming insect diversity. The ratio between galling insect richness and number of tree species sampled (GIR/TSS ratio) was higher in the terra firme forest and in seasonally flooded igapó, while the várzea presented the lowest GIR/TSS ratio. In this study, we recorded unprecedented values of galling species diversity and abundance per sampling point. The GIR/TSS ratio from várzea was approximately 2.5 times higher than the highest value of this ratio ever reported in the literature. Based on this fact, we ascertained that várzea and igapó floodplain forests (with lower GIA and GIR), together with the speciose terra firme galling community emerge as the gall diversity apex landscape among all biogeographic regions already investigated. Contrary to expectation, our results also support the “harsh environment hypothesis”, and unveil the Amazonian upper canopy as similar to Mediterranean vegetation habitats, hygrothermically stressed environments with leaf temperature at lethal limits and high levels of leaf sclerophylly.
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