Long-term impact of exotic ants on the native ants of Madeira

1. The earliest exotic records for two notorious invasive ants, the big-headed ant ( Pheidole megacephala ) and the Argentine ant ( Linepithema humile ), both come from the Atlantic islands of Madeira, where the two species underwent population explosions in the 1850s and 1890s respectively. Researchers have long assumed that these invaders spread across all of Madeira and exterminated most or all native ants, despite no research actually documenting such impact. 2. Re-examination of first-hand nineteenth century accounts suggest that P. megacephala and L. humile may never have spread beyond coastal lowland areas, representing < 10% of Madeira’s land area. In 2002, native ants dominated most of Madeira; P. megacephala and L. humile were restricted to ≈ 0.3% and ≈ 6% of Madeira’s land area respectively. 3. Of the 10 native ant species known from Madeira, only one ( Temnothorax wollastoni ) was not present in 1999 – 2002 surveys. Although exotic ants may have exterminated T. wollastoni , it seems likely that this species still survives. 4. Thus, even after 150 or more years of residence, P. megacephala and L. humile have come to occupy only a small part of Madeira, and appear to have had little impact. 5. Most of Madeira may be too cool for P. megacephala and perhaps too moist for L. humile to dominate. Also, Madeira’s vast natural areas may generally lack weedy vegetation that can support high densities of plant-feeding Hemiptera critical for the ecological dominance of invasive ants. Finally, a dominant native ant, Lasius grandis , inhabiting ≈ 84% of Madeira, may actively exclude P. megacephala and L. humileinfo:eu-repo/semantics/publishedVersio

Preface

This collection grew out of several years of discussions during conference lunch breaks as we met and reported on the progress of our various projects with their shared focus on settler colonialism, white women and Aboriginal history. One day, we said, we must work on a book together. We had all contributed in one way or another to the debate concerning the ethics of historical research, and were challenged by the question of privilege and perspective, the importance of memory and reading against the grain of the official archives, and the moral issues surrounding the kinds of history we chose to write. We were conscious of an Indigenous argument that white historians’ incorporation of Aboriginal subjects in historical work was yet another form of neo-colonialism. In putting together a collection primarily on ‘white’ women involved in the Aboriginal domain we have sought to respond positively to such criticism.New ed

On the rotation class of knotted Legendrian tori in R

Abstract. In this paper we show how to combinatorically compute the rotation class of a large family of embedded Legendrian tori in R5 with the standard contact form. In particular, we give a formula to compute the Maslov index for any loop on the torus and compute the Maslov number of the Legendrian torus. These formulas are a necessary component in computing contact homology. Our methods use a new way to represent knotted Legendrian tori called Lagrangian hypercube diagrams. 1