Readings in european history ; a collection of extracts from the progress of culture in western Europe since the German invasions

UANL

DNA bar-coding reveals source and patterns of Thaumastocoris peregrinus invasions in South Africa and South America

Thaumastocoris peregrinus is a recently introduced invertebrate pest of non-native Eucalyptus plantations in the Southern Hemisphere. It was first reported from South Africa in 2003 and in Argentina in 2005. Since then, populations have grown explosively and it has attained an almost ubiquitous distribution over several regions in South Africa on 26 Eucalyptus species. Here we address three key questions regarding this invasion, namely whether only one species has been introduced, whether there were single or multiple introductions into South Africa and South America and what the source of the introduction might have been. To answer these questions, bar-coding using mitochondrial DNA (COI) sequence diversity was used to characterise the populations of this insect from Australia, Argentina, Brazil, South Africa and Uruguay. Analyses revealed three cryptic species in Australia, of which only T. peregrinus is represented in South Africa and South America. Thaumastocoris peregrinus populations contained eight haplotypes, with a pairwise nucleotide distance of 0.2-0.9% from seventeen locations in Australia. Three of these haplotypes are shared with populations in South America and South Africa, but the latter regions do not share haplotypes. These data, together with the current distribution of the haplotypes and the known direction of original spread in these regions, suggest that at least three distinct introductions of the insect occurred in South Africa and South America before 2005. The two most common haplotypes in Sydney, one of which was also found in Brisbane, are shared with the non-native regions. Sydney populations of T. peregrinus, which have regularly reached outbreak levels in recent years, might thus have served as source of these three distinct introductions into other regions of the Southern Hemisphere.

Multiple invasions of Gypsy and Micropia retroelements in genus Zaprionus and melanogaster subgroup of the genus Drosophila

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A novel association between Rhodnius neglectus and the Livistona australis palm tree in an urban center foreshadowing the risk of Chagas disease transmission by vectorial invasions in Monte Alto City, Sao Paulo, Brazil

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Biological invasions and the acoustic niche: the effect of bullfrog calls on the acoustic signals of white-banded tree frogs

Invasive species are known to affect native species in a variety of ways, but the effect of acoustic invaders has not been examined previously. We simulated an invasion of the acoustic niche by exposing calling native male white-banded tree frogs (Hypsiboas albomarginatus) to recorded invasive American bullfrog (Lithobates catesbeianus) calls. In response, tree frogs immediately shifted calls to significantly higher frequencies. In the post-stimulus period, they continued to use higher frequencies while also decreasing signal duration. Acoustic signals are the primary basis of mate selection in many anurans, suggesting that such changes could negatively affect the reproductive success of native species. The effects of bullfrog vocalizations on acoustic communities are expected to be especially severe due to their broad frequency band, which masks the calls of multiple species simultaneously.

Plant invasions research in Latin America: fast track to a more focused agenda

While many developed countries have invested heavily in research on plant invasions over the last 50 years, the immense region of Latin America has made little progress. Recognising this, a group of scientists working on plant invasions in Latin America met in Chile in late 2010 to develop a research agenda for the region based on lessons learned elsewhere. Our three main findings are as follows. (1) Globalisation is inevitable, but the resultant plant introductions can be slowed or prevented by effective quarantine and early intervention. Development of spatially explicit inventories, research on the invasion process and weed risk assessments can help prioritise and streamline action. (2) Eradication has limited application for plants and control is expensive and requires strict prioritisation and careful planning and evaluation. (3) Accepting the concept of novel ecosystems, new combinations of native and introduced species that no longer depend on human intervention, may help optimise invasive species management. Our vision of novel ecosystem management is through actions that: (a) maintain as much native biodiversity and ecosystem functionality as possible, (b) minimise management intervention to invasives with known impact, and (c) maximise the area of intervention. We propose the creation of a Latin American Invasive Plants Network to help focus the new research agenda for member countries. The network would coordinate research and training and establish funding priorities, develop and strengthen tools to share knowledge, and raise awareness at the community, governmental and intergovernmental levels about the social, economic and environmental costs of plant invasions.

Multiple invasions of Gypsy and Micropia retroelements in genus Zaprionus and melanogaster subgroup of the genus Drosophila

Abstract Background The Zaprionus genus shares evolutionary features with the melanogaster subgroup, such as space and time of origin. Although little information about the transposable element content in the Zaprionus genus had been accumulated, some of their elements appear to be more closely related with those of the melanogaster subgroup, indicating that these two groups of species were involved in horizontal transfer events during their evolution. Among these elements, the Gypsy and the Micropia retroelements were chosen for screening in seven species of the two Zaprionus subgenera, Anaprionus and Zaprionus. Results Screening allowed the identification of diverse Gypsy and Micropia retroelements only in species of the Zaprionus subgenus, showing that they are transcriptionally active in the sampled species. The sequences of each retroelement were closely related to those of the melanogaster species subgroup, and the most parsimonious hypothesis would be that 15 horizontal transfer events shaped their evolution. The Gypsy retroelement of the melanogaster subgroup probably invaded the Zaprionus genomes about 11 MYA. In contrast, the Micropia retroelement may have been introduced into the Zaprionus subgenus and the melanogaster subgroup from an unknown donor more recently (~3 MYA). Conclusion Gypsy and Micropia of Zaprionus and melanogaster species share similar evolutionary patterns. The sharing of evolutionary, ecological and ethological features probably allowed these species to pass through a permissive period of transposable element invasion, explaining the proposed waves of horizontal transfers.

Marine Seaweed Invasions : the Ecology of Introduced Fucus evanescens

Biological invasions are an important issue of global change and an increased understanding of invasion processes is of crucial importance for both conservation managers and international trade. In this thesis, I have studied the invasion of the brown seaweed Fucus evanescens, to investigate the fate and effect of a perennial, habitat-forming seaweed introduced to a coastal ecosystem. A long-term study of the spread of F. evanescens in Öresund (southern Sweden) showed that the species was able to expand its range quickly during the first 20 years after the introduction, but that the expansion has been slow during the subsequent 30 years. Both in Öresund and in Skagerrak, the species is largely restricted to sites where native fucoids are scarce. Laboratory experiments showed that the restricted spread of F. evanescens cannot be explained by the investigated abiotic factors (wave exposure and salinity), although salinity restricts the species from spreading into the Baltic Sea. Neither did I find evidence for that herbivores or epibiota provide biotic resistance to the invader. On the contrary, F. evanescens was less consumed by native herbivores, both compared to the native fucoids and to F. evanescens populations in its native range, and little overgrown by epiphytes. Instead, the restricted spread may be due to competition from native seaweeds, probably by pre-occupation of space, and the establishment has probably been facilitated by disturbance. The studies provided little support for a general enemy release in introduced seaweeds. The low herbivore consumption of F. evanescens in Sweden could not be explained by release from specialist herbivores. Instead, high levels of chemical anti-herbivore defence metabolites (phlorotannins) could explain the pattern of herbivore preference for different fucoids. Likewise, the low epibiotic colonisation of F. evanescens plants could be explained by high resistance to epibiotic survival. This shows that colonisation of invading seaweeds by native herbivores and epibionts depends on properties of the invading species. The large differences between fucoid species in their quality as food and habitat for epibionts and herbivores imply that invasions of such habitat-forming species may have a considerable effect on a number of other species in shallow coastal areas. However, since F. evanescens did not exclude other fucoids in its new range, its effect on the recipient biota is probably small.