Spartocera batatas (Fabricius) (Hemiptera: Coreidae) : newly established in Florida

Spartocera batatas (Fabricius) was found for the first time in the USA in Homestead, Florida, in 1995. Records from Brazil, British Guiana, Colombia, Dominica, Dominican Republic, Ecuador, Grenada, Jamaica, Martinique, Panama, Peru, Puerto Rico, Saba, and Venezuela also are reported. The bug can be a pest of sweet potato, Ipomoea batatas

Dipsocoridae (Heteroptera) found for the first time in Florida

Dipsocorid bugs were found in samples collected from suction traps (Allison and Pike 1988) in a citrus nursery near LaBelle, Hendry County, Florida. In all, five specimens were collected: 15-22-X- 2001 (1 male), 22-29 X 2001 (1 female), 9-16-XI- 2001 (2 females), 16-21-XI-2001 (1 female). This is the first record of the family Dipsocoridae in Florida. Specimens are deposited in the Florida State Collection of Arthropods (FSCA)

On coherent systems of type (n,d,n+1) on Petri curves

We study coherent systems of type $(n,d,n+1)$ on a Petri curve $X$ of genus $g\ge2$. We describe the geometry of the moduli space of such coherent systems for large values of the parameter $\alpha$. We determine the top critical value of $\alpha$ and show that the corresponding ``flip'' has positive codimension. We investigate also the non-emptiness of the moduli space for smaller values of $\alpha$, proving in many cases that the condition for non-emptiness is the same as for large $\alpha$. We give some detailed results for $g\le5$ and applications to higher rank Brill-Noether theory and the stability of kernels of evaluation maps, thus proving Butler's conjecture in some cases in which it was not previously known.Comment: 33 page

New examples of twisted Brill-Noether loci I

Our purpose in this paper is to construct new examples of twisted Brill-Noether loci on curves of genus $g\ge2$. Many of these examples have negative expected dimension. We deduce also the existence of a new region in the Brill-Noether map, whose points support non-empty standard Brill-Noether loci.Comment: 20 pages, 2 figures. Comments welcom

Stability of projective Poincare and Picard bundles

Let $X$ be an irreducible smooth projective curve of genus $g\ge3$ defined over the complex numbers and let ${\mathcal M}_\xi$ denote the moduli space of stable vector bundles on $X$ of rank $n$ and determinant $\xi$, where $\xi$ is a fixed line bundle of degree $d$. If $n$ and $d$ have a common divisor, there is no universal vector bundle on $X\times {\mathcal M}_\xi$. We prove that there is a projective bundle on $X\times {\mathcal M}_\xi$ with the property that its restriction to $X\times\{E\}$ is isomorphic to $P(E)$ for all $E\in\mathcal{M}_\xi$ and that this bundle (called the projective Poincar\'e bundle) is stable with respect to any polarization; moreover its restriction to $\{x\}\times\mathcal{M}_\xi$ is also stable for any $x\in X$. We prove also stability results for bundles induced from the projective Poincar\'e bundle by homomorphisms $\text{PGL}(n)\to H$ for any reductive $H$. We show further that there is a projective Picard bundle on a certain open subset $\mathcal{M}'$ of $\mathcal{M}_\xi$ for any $d>n(g-1)$ and that this bundle is also stable. We obtain new results on the stability of the Picard bundle even when $n$ and $d$ are coprime.Comment: One typo corrected; final version accepted for publication in Bull. London Math. So