Vrijenhoekia balaenophila, a new hesionid polychaete from a whale fall off California

Vrijenhoekia balaenophila gen. nov., sp. nov. (Polychaeta, Hesionidae) is described from a whale carcass at near 3000 m depth in Monterey Canyon off the coast of California. The phylogenetic relationships of V. balaenophila are assessed in a parsimony analysis of morphological data together with nucleotide data from 28S rDNA, 16S rDNA and cytochrome oxidase I genes. Within the hesionids V. balaenophila belongs to Psamathini, where it is the sister group to Sirsoe . Among psamathins it is morphologically distinguished by having six glandular lip pads around the mouth opening, papilla-shaped neuropodial lobes on segment 3, extreme length of the dorsal cirri, and by a characteristic growth pattern in which the maximum number of segments is already formed in subadults, and further growth takes place through size increase of the segments.  © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society , 2008, 152 , 625–634.     

Age-related changes in thoracic mass: possible reallocation of resources to reproduction in butterflies

In nectar-feeding butterflies, reproductive potential is usually thought to depend on the size of the reproductive reserves in the abdomen, the adult food quality and, for females, the amount of resources received in the spermatophores at mating. Recent findings show that thorax mass and nitrogen content decrease with age in some butterfly species, and that thorax resources may be used for reproduction in the butterfly Pieris napi , just as in some other insects. In order to determine whether this is a general pattern and ascertain how it relates to the investment of resources in reproduction we studied the dynamics of thorax and abdomen mass changes in 11 Swedish butterfly species. By regressing thorax and abdomen mass on age of field-collected specimens, we show that loss of mass from both the thorax and the abdomen is a common phenomenon among nectar-feeding temperate zone butterflies under natural conditions. We argue that our results indicate that resources from flight muscles can be reallocated to reproduction by these butterflies, thus increasing their reproductive potential. Within species, females use proportionately more resources from the thorax than do males, as expected from the difference in investment of resources in reproduction. Among males we expect species with a higher reproductive investment to have a larger decrease in thorax and abdomen mass, and our data indicate that this is the case. Looking at the change in relative thorax mass, our results suggest that the use of resources from the thorax does not affect flight performance negatively, something that could constrain the use of muscle resources.  © 2005 The Linnean Society of London, Biological Journal of the Linnean Society , 2005, 86 , 363–380.     

Phylogenetic approaches in coevolution and biogeography

I review phylogenetic approaches to problems in coevolution and biogeography, illustrating with case studies. In coevolution, genealogical trees are essential in differentiating between ancient and recent associations, in identifying cospeciation events, and in studying host-switching patterns. Cospeciating associations are of particular interest because they allow powerful tests of molecular clocks and accurate comparison of evolutionary rates across groups of organisms. In biogeography, phylogenies can help reconstruct the distribution history of individual groups and identify past geological events that have affected the evolution of entire communities. Parsimony analysis in coevolution and biogeography should be based on identification of different types of events, each of which is associated with a specific cost. Similar event-based methods are applicable to coevolutionary and biogeographic inference, as well as in the mapping of gene trees onto organism trees. The discussed examples span a variety of organisms and spatiotemporal scales: primate pin worms, HIV, pocket gophers and their lice, aphids and their bacterial symbionts, gall wasps and their host plants, the root of the tree of life, the historical biogeography of the Holarctic, and the geographical origin of our own species.