Performance of Myrmica ant colonies is correlated with the presence of social parasites

1. The performance of ant colonies depends on different factors such as nest site, colony structure or the presence of pathogens and social parasites. Myrmica ants host various types of social parasites, including the larvae of Maculinea butterflies and Microdonmyrmicae (Schönrogge) hoverfly. How these social parasites affect host colony performance is still unexplored. 2. It was examined how the presence of Maculinea teleius Bergsträsser, Maculinea alcon (Denis & Schiffermüller), and M. myrmicae larvae, representing different feeding and growth strategies inside host colonies, is associated with worker survival, the number of foragers, and colony productivity parameters such as growth and reproduction. 3. It was found that the presence of social parasites is negatively associated with total colony production and the production of ant larvae and gynes. Male production was lower only in nests infested by M. teleius, whereas the number of worker pupae was significantly higher in all types of infested colonies than in uninfested colonies. Laboratory observations indicated that nests infested by Maculinea larvae are characterised by a higher number of foragers compared to uninfested nests but we did not find differences in worker survival among nest types. 4. The observed pattern of social parasite influence on colony productivity can be explained by the feeding strategies of parasitic larvae. The most negative effect was found for M. teleius, which feeds on the largest host brood and eliminates a high number of sexual forms. The strong, adverse influence of all studied parasite species on gyne production may result in low queen production in Myrmica populations exposed to these social parasites.     

Die Vaskularisation der Kiemen von Myxine glutinosa L. (Cyclostomata)

The angioarchitecture of the gills in Myxine glutinosa L. was studied by scanning electron microscopy of vascular corrosion casts (methylmethacrylate). It was found that the afferent branchial artery may be connected to the sinus peribranchialis by a papilla. The sinus is connected to delicate vessels and sinuses, which are interposed between meridionally arranged radial arteries. These delicate vascular formations continue into the interior of the gill and form a plexus on both poles of the gill folds. Light and scanning electron microscopical studies on the vascular endothelium of the afferent vessels of the gill lamellae reveal rounded endothelial cells, which are characterized by a high content of granula, by long cellular processes and by bridge-formations towards neighbouring cells. Supporting columns within the vascular system of the lamellae were found to be set up by several spirally arranged cells. SEM observations reveal goblet cells and numerous superficial epithelial cells with various numbers of microvilli and microridges forming the epithelial surface of the gill folds.     

A new genus of Encyrtidae (Hymenoptera: Chalcidoidea) from India

A new genus, probably related to Anagyrus, is erected for a new species parasitic on mealy-bugs, the male and female of which are described.     

gerud 2.0: a computer program for the reconstruction of parental genotypes from half‐sib progeny arrays with known or unknown parents

Large groups of related progeny, as can be collected from discrete egg masses or fruits, present excellent opportunities for parentage analysis by allowing the reconstruction of parental genotypes. Current techniques of parental genotypic reconstruction require the knowledge of at least one parental genotype. Here, I present a new computer program that reconstructs parental genotypes when no parents are known, provided that the progeny array contains only full and half siblings. The prospects for successfully reconstructing parental genotypes for such progeny arrays with unknown parents are nearly as good as those for the case when one parent is known with certainty.     

STRATOCLADISTICS AND EVALUATION OF EVOLUTIONARY MODES IN THE FOSSIL RECORD: AN EXAMPLE FROM THE AMMONITE GENUS SEMIFORMICERAS

Abstract:  At least two predominating modes of evolution have been proposed for the Early Tithonian oppeliid ammonite genus Semiformiceras , including phyletic transformation of a single lineage ( S. darwini – S. semiforme – S. fallauxi ) and, most recently, a bifurcating or cladogenetic model of speciation. We discuss methodological obstacles in past studies that have focused on specific modes of evolution, and offer a reanalysis of the morphological data first presented by Cecca and Rouget [ Palaeontology , 49 , 1069–1080] using the stratocladistic software StrataPhy. The present analysis utilizes 11 ammonite taxa and 15 characters (14 morphological and one stratigraphic) and assesses all previous phylogenetic hypotheses, including those that recruit OTUs in ancestral or 'nodal' positions, without excluding evolutionary modes. The results cast doubt on the monophyly of S. darwini , S. semiforme and S. fallauxi , but do not follow completely the direct anagenetic progression proposed by stratophenetic hypotheses. We conclude that stratocladistics is a helpful tool for elucidating the extent of anagenesis and cladogenesis in extinct lineages owing to its capacity to reconstruct phylograms in their temporal framework, and to assess the distinctness and monophyly, not just of clades but of the OTUs themselves. Ultimately, this study addresses the novel utility of computer-assisted stratocladistic analysis in assessing evolutionary modes beyond the reach of traditional cladistic-based methodologies.     

Within-Stand Selection of Canada Lynx Natal Dens in Northwest Maine,USA

Abstract Canada lynx (Lynx canadensis) were listed as threatened in the contiguous United States under the Endangered Species Act in March 2000. Little information on lynx ecology at the southern extent of their range was available at the time of listing, and no ecological studies had been conducted in the eastern USA. Between 1999 and 2004, we investigated habitat selection at natal dens in northern Maine to address questions on the importance of forest conditions to denning requirements. We compared within-stand characteristics of 26 den sites to general characteristics of the stands containing dens. We used logistic regression to identify components within stands that distinguished natal dens from the residual stand and used the information-theoretic approach to select models that best explained lynx den-site selection. The top-ranked model had 2 variables: tip-up mounds of blown-down trees and visual obscurity at 5 m from the den (w_i = 0.92). Within-stand structure was useful for predicting lynx den-site selection in managed forests in Maine and suitable denning habitat did not appear to be limiting.     

Taphonomy and compositional fidelity of Quaternary fossil assemblages of terrestrial gastropods from carbonate-rich environments of the Canary Islands

Quaternary aeolian deposits of the Canary Islands contain well‐preserved terrestrial gastropods, providing a suitable setting for assessing the taphonomy and compositional fidelity of their fossil record over ~13 kyr. Nine beds (12, 513 shells) have been analysed in terms of multivariate taphonomic and palaeoecological variables, taxonomic composition, and the stratigraphic and palaeontological context. Shells are affected by carbonate coatings, colour loss and fragmentation. Shell preservation is size‐specific: juveniles are less fragmented and show colour preservation more commonly than adults. In palaeosols, the adult shell density correlates negatively with the proportion of fragmented adults, negatively with the proportion of juveniles, and positively with the proportion of adults with coatings. High bioturbation intensity in palaeosols is associated with low shell fragmentation and high proportion of shells with coatings. These relationships imply that high adult density in palaeosols was driven by an increase in shell production rate (related to a decrease in predation rates on adults and a decrease in juvenile mortality) and a decrease in shell destruction rate (related to an increase in durability enhanced by carbonate precipitation). In dunes, the relationships between taphonomic alteration, shell density and bioturbation are insignificant. However, dune assemblages are characterized by a lower frequency of shells with coatings and higher rates of colour loss, indicating lower shell durability in dunes than in palaeosols. Additionally, non‐random differences in the coating proportion among palaeosols imply substantial temporal variation in the rate of carbonate crust formation, reflecting long‐term changes in bioturbation intensity that covaries positively with shell preservation. Dunes and palaeosols do not differ in species abundances despite differences in the degree of shell alteration, suggesting that both weakly and strongly altered assemblages offer data with a high compositional fidelity. Carbonate‐rich terrestrial deposits originating in arid conditions can enhance the preservation of gastropods and result in fossil assemblages that are suitable for palaeoecological and palaeoenvironmental studies of terrestrial ecosystems.     

Mallard Harvest Distributions in the Mississippi and Central Flyways

Abstract: The mallard (Anas platyrhynchos) is the most harvested duck in North America. A topic of debate among hunters, especially those in Arkansas, USA, is whether wintering distributions of mallards have changed in recent years. We examined distributions of mallards in the Mississippi (MF) and Central Flyways during hunting seasons 1980–2003 to determine if and why harvest distributions changed. We used Geographic Information Systems to analyze spatial distributions of band recoveries and harvest estimated using data from the United States Fish and Wildlife Service Parts Collection Survey. Mean latitudes of band recoveries and harvest estimates showed no significant trends across the study period. Despite slight increases in band recoveries and harvest on the peripheries of kernel density estimates, most harvest occurred in eastern Arkansas and northwestern Mississippi, USA, in all years. We found no evidence for changes in the harvest distributions of mallards. We believe that the late 1990s were years of exceptionally high harvest in the lower MF and that slight shifts northward since 2000 reflect a return to harvest distributions similar to those of the early 1980s. Our results provide biologists with possible explanations to hunter concerns of fewer mallards available for harvest.     

Generic revision and phylogeny of Microweiseinae (Coleoptera: Coccinellidae)

The monophyly and phylogenetic relationships of the subfamily Microweiseinae were investigated. Twenty‐three in‐group taxa, representing all known genera of Microweiseinae (except for Microcapillata Gordon) were included in a cladistic analysis, based on 45 adult morphological characters. The parsimony analysis of the resulting data matrix supported the monophyly of Microweiseinae, Carinodulini, Serangiini and Microweiseini (inclusive of Sukunahikonini). The recognition of Sukunahikonini renders Microweiseini paraphyletic, and consequently both tribes were synonymized, retaining Microweiseini as a senior family‐group name ( syn.n. ). Genera and tribes of Microweiseinae are diagnosed thoroughly, illustrated and keys to their identification are provided. The following nomenclatural changes were made: Hikonasukuna Sasaji and Orculus Sicard are synonymized with Scymnomorphus Weise ( syn.n. ); Gnathoweisea Gordon is synonymized with Microweisea Cockerell ( syn.n. ); Hikonasukuna monticola Sasaji and Orculus castaneus Sicard are transferred to Scymnomorphus ( comb.n. ); Smilia planiceps Casey, Gnathoweisea hageni Gordon, Gnathoweisea ferox Gordon, Gnathoweisea micula Gordon and Gnathoweisea texana Gordon are transferred to Microweisea ( comb.n ). Three new genera are described: Allenius gen.n. for Allenius californianus sp.n. (type species) from Mexico and Allenius iviei sp.n. from U.S.A.; Gordoneus gen.n. (type species Gnathoweisea schwarzi Gordon from U.S.A.); and Cathedrana gen.n. (type species Cathedrana natalensis sp.n. from South Africa). The first African member of Carinodulini, Carinodulina ruwenzorii sp.n. is described. The genera Microweisea, Coccidophilus, Serangium and Delphastus are well‐known predators of sternorrynchous Hemiptera, such as scale insects (Diaspididae) and whiteflies (Aleyrodidae), and play a significant role in agricultural ecosystems as biocontrol agents. Host data and biological records are summarized for each genus.