A new species of Poly dor a (Polychaeta: Spionidae) from the Indo-West Pacific and first record of host hermit crab egg predation by a commensal polydorid worm

A new spionid polychaete, Polydora robi, is described from intertidal and shallow subtidal areas in the Philippine Islands and Bali, Indonesia. Polydora robi belongs to the Polydora ciliata/ websteri species group and is characterized by a rounded prostomium, triangular occipital tentacle, needlelike posterior notosetae, and a pygidium with digitiform composite cirri surrounding the anus. Adults burrow into empty gastropod shells inhabited by hermit crabs. The burrows of the worms typically extend from an external opening in the apex of the shells to an opening in the central body whorls along the columella. The species was found to ingest the fertilized eggs and developing embryos attached to the pleopods of host hermit crabs. The occurrence of egg predation and the symbiotic relationship between polydorids and hermit crabs is discussed. Known egg predators of hermit crabs are reviewed.     

Cales (Hymenoptera: Chalcidoidea): morphology of an enigmatic taxon with a review of species

Calesinae is a small group of Chalcidoidea (Hymenoptera) that are parasitoids of whiteflies (Hemiptera: Aleyrodidae). One species, Cales noacki Howard, has been introduced from South America into citrus‐growing regions of North America, the Mediterranean and Africa for biological control. The remaining species are found in Australia and New Zealand: a classic Gondwanan disjunction. The subfamily consists of a single genus, Cales, which is currently unplaced within Chalcidoidea. Its taxonomic position has historically been unstable, although most often Cales is associated with Aphelinidae. Here, we present a detailed morphological study of the group with an emphasis on Australian species. Although Cales shares many characteristics with Aphelinidae, especially Coccophaginae and Eretmocerus, more studies of character systems across Chalcidoidea are needed to determine which features may be synapomorphic. Consequently, we leave Cales incertae sedis within Chalcidoidea. We also describe a new species from New Zealand, Cales berryi sp.n. , reared from the whitefly Asterochiton pittospori on lemonwood, Pittosporum eugenioides, and we present a key and review the four known species of Cales.     

Long-Term Persistence of Spent Lead Shot in Tundra Wetlands

ABSTRACT We seeded experimental plots with number 4 lead pellets and sampled these plots for 10 years to assess the settlement rate of pellets in tundra wetland types commonly used by foraging waterfowl. After 10 years, about 10% of pellets remained within 6 cm of the surface, but >50% remained within 10 cm. We predict that spent lead pellets will eventually become unavailable to waterfowl; however, it will likely require >25 years for all pellets to exceed depths at which waterfowl species may forage.     

Land clearing reduces gene flow in the granite outcrop‐dwelling lizard,Ctenophorus ornatus

An important question for the conservation of species dwelling in fragmented habitats is whether changes to the intervening landscape create a barrier to gene flow. Here, we make use of the spatial distribution of the granite outcrop‐dwelling lizard, Ctenophorus ornatus, to compare inferred levels of gene flow between outcrops in a nature reserve with that between outcrops in the adjacent agricultural land. Genetic variation, relatedness and subdivision were compared within groups of individuals from different outcrops similar in size and distance apart at each site. In the agricultural land, we found significantly lower genetic variation within outcrops and greater genetic differentiation between outcrops than in the reserve. Further, the rate at which genetic divergence between outcrops increased over geographical distance was significantly greater in the agricultural land than in the reserve. We also found that individuals were more closely related within outcrops but more distantly related between outcrops in the cleared land. These effects occur over a small spatial scale with an average distance between outcrops of less than five kilometres. Thus, even though land clearing around the outcrops leaves outcrop size unchanged, it restricts gene flow, reducing genetic variation and increasing population structure, with potentially negative consequences for the long‐term persistence of the lizards on these outcrops.     

Population genetic data suggest a role for mosquito‐mediated dispersal of West Nile virus across the western United States

After introduction, West Nile virus (WNV) spread rapidly across the western United States between the years 2001 and 2004. This westward movement is thought to have been mediated by random dispersive movements of resident birds. Little attention has been placed on the role of mosquito vectors in virus dispersal across North America. The mosquito vector largely responsible for WNV amplification and transmission of WNV in the western USA is Culex tarsalis. Here we present population genetic data that suggest a potential role for C. tarsalis in the dispersal of WNV across the western USA. Population genetic structure across the species range of C. tarsalis in the USA was characterized in 16 states using 12 microsatellite loci. structure and geneland analyses indicated the presence of three broad population clusters. Barriers to gene flow were resolved near the Sonoran desert in southern Arizona and between the eastern Rocky Mountains and High Plains plateau. Small genetic distances among populations within clusters indicated that gene flow was not obstructed over large portions of the West Coast and within the Great Plains region. Overall, gene flow in C. tarsalis appears to be extensive, potentially mediated by movement of mosquitoes among neighbouring populations and hindered in geographically limited parts of its range. The pattern of genetic clustering in C. tarsalis is congruent with the pattern of invasion of WNV across the western United States, raising the possibility that movement of this important vector may be involved in viral dispersal.     

Evolution of Delphacidae (Hemiptera: Fulgoroidea): combined‐evidence phylogenetics reveals importance of grass host shifts

The planthopper family Delphacidae is a speciose lineage of phloem‐feeding insects, with many species considered as pests of economic significance on essential world food commodities (including rice, maize, wheat, barley and sugar cane). Despite their economic importance, evolutionary relationships among delphacids, particularly those within the speciose tribe Delphacini, are largely unknown. Presented here are the results of a phylogenetic investigation of Delphacidae based on DNA nucleotide sequence data from four genetic loci (18S rDNA, 28S rDNA, wingless and cytochrome oxidase I) and 132 coded morphological characters. The resulting topologies are used to test the higher classification of Delphacidae and to examine evolutionary patterns in host–plant associations. Our results generally support the higher classifications of Delphacidae proposed by Asche, Emeljanov and Hamilton, and suggest that the rapid diversification of the Delphacini was associated with host shifts to, and within, Poaceae, and specifically from C3 to C4 grasses.     

Family‐level relationships of the spittlebugs and froghoppers (Hemiptera: Cicadomorpha: Cercopoidea)

The spittlebug superfamily Cercopoidea (Hemiptera: Cicadomorpha) comprises approximately 3000 phytophagous species (including some economically important pests of grass crops) classified among the families Cercopidae, Aphrophoridae, Epipygidae, Clastopteridae and Machaerotidae. However, the monophyly of these taxa has never been tested and the evolutionary relationships among these major lineages are unknown. Presented here are the results of the first ever phylogenetic investigation of the higher‐level relationships within Cercopoidea, based on DNA nucleotide sequence data from six loci (18S rDNA, 28S rDNA, histone 3, wingless, cytochrome oxidase I and cytochrome oxidase II) generated from exemplars of 109 spittlebug species representing all five described families, seven of eight subfamilies and 61 genera (eight additional exemplars, representing a selection of other Auchenorrhyncha taxa, were included as outgroups). The resulting topologies are used to evaluate the monophyly of each cercopoid family, and further to calculate divergence date estimates to examine the chronological origins and historical diversification of Cercopoidea. The results of this investigation suggest that: (i) four of the five described families are monophyletic; Epipygidae was recovered consistently as originating within Aphrophoridae; (ii) the exclusively Old World Machaerotidae is the most anciently diversified family of extant spittlebugs; (iii) New World Cercopidae (i.e. Ischnorhininae) constitute a derived monophyletic lineage; (iv) the genus Microsargane Fowler, classified currently within Aphrophoridae, actually belongs within Cercopidae; and (v) the origins of the major spittlebug lineages probably coincided with the breakup of Pangaea and, subsequently, Gondwana, as well as major floristic diversification such as the rise of angiosperms.     

Evolution of the perennial soybean polyploid complex (Glycine subgenus Glycine): a study of contrasts

Glycine subgenus Glycine , the sister group to the cultivated soybean and its progenitor, have received considerable study over several decades. The combination of biosystematic data and an extensive germplasm collection has provided a strong foundation for molecular systematic studies in the group, including those on allopolyploids. These studies have shown that the various polyploid taxa known from the subgenus are all part of a single large allopolyploid complex, linked by shared diploid genomes. Many elements of the complex have arisen recently, and most show evidence of recurrent origins. However, there are also many dissimilarities among even closely related polyploids. Polyploids differ from one another in such ways as number of origins, amount of allelic diversity harboured at different loci, bidirectional vs. unidirectional origins, retention of ribosomal gene homoeologues, success as measured by geographical range and abundance, and patterns of gene expression.  © 2004 The Linnean Society of London, Biological Journal of the Linnean Society , 2004, 82 , 583–597.