HOMOPLASY AS PATTERN: MULTIVARIATE ANALYSIS OF MORPHOLOGICAL CONVERGENCE IN ANSERIFORMES

Abstract— A multivariatc model for taxa and characters is presented that represents taxa as points in an ordination space such that shared derived character states define groups of taxa or regions in this space. This model is compared, in terms of concepts of information content and explanatory power, to the eladistie model that relates characters and taxa to a hierarchical pattern. While a cladogram may be identified with a phylogenetic hypothesis, the ordination pattern may be equated with hypotheses about similarities among the taxa in habitat, feeding mode, or other ecological factors.
This basic data-pattern model is appropriate for the explanation of the character convergences implied by a particular phylogenetic hypothesis. Under the assumptions of the model, the underlying ordination pattern may be inferred from the observed character data using robust ordination procedures recently developed in community ecology.
As an illustration of the method, the morphological convergences derived from a recent phylogenetic hypothesis for genera of Anseriformes are analysed. In the resulting two-dimensional ordination, the genera are arranged such that the convergenlly derived states form regions in the space. While this pattern implies that some of the taxa that are close together in the space are phylogcnetically dissimilar , taxa that are close together in the space are found to be similar in their mode of feeding. Thus, the ordination demonstrates that taxa sharing these morphological convergences tend to utilize habitat in the same way in terms of mode of feeding.
The explanatory power of the pattern and the degree of recovery of habitat information are tested against null hypotheses using Monte Carlo simulations.
Extensions of the method are discussed, including applications to studies of parasite—host relationships and to biogeography.     

Bacillus thuringiensis Sporulation at Suboptimal Temperature

Bacillus thuringiensis var. thuringiensis Berliner grown at 14 C on a chemically defined liquid medium slowly produced spores and parasporal inclusions. Sporulation ultimately attained 50 to 100% of that of cultures grown at 30 C.     

Invasive feral pigs impact native tree ferns and woody seedlings in Hawaiian forest

Invasive mammals can fundamentally alter native plant communities, especially on isolated islands where plants evolved without them. The globally invasive feral pig (Sus scrofa) can be particularly destructive to native plant communities. Tree ferns are an important understory component in many forests facilitating the establishment of a variety of species. However, the extent and effects of feral pig damage to tree ferns, and associated impacts on plant community regeneration, are largely unknown. We quantified the effect that feral pig damage has on tree fern growth, survival, and epiphytic woody seedling abundance over 1 year on 438 randomly selected tree ferns of three endemic species (Cibotium chamissoi, Cibotium glaucum, and Cibotium menziesii) in a Hawaiian montane wet forest with high tree fern and feral pig densities. Across all tree fern species, feral pigs damaged 13 % of individuals over 1 year. Compared with undamaged tree ferns, moderately- to heavily-damaged individuals had decreases of 4 to 27 % in trunk length increment and lost tenfold more fronds. Tree fern angle (standing, leaning, prone, or semi-prone) and woody seedling abundance co-varied with feral pig damage. Specifically, damaged tree ferns were more often prone or semi-prone and supported more seedlings, but also had annual mortality up to 34 % higher than undamaged tree ferns. Overall, feral pig damage had substantial negative effects on tree ferns by reducing growth and survival. Given the importance of tree ferns as regeneration sites for a variety of native plants, feral pig damage to tree ferns will likely alter future forest composition and structure. Specifically, feral pig damage to tree ferns reduces potential establishment sites for species that either regenerate preferentially as epiphytes or are currently restricted to epiphytic establishment due to ground rooting by feral pigs.     

Uncoupling protein 2 polymorphisms as risk factors for NTDs

BACKGROUND: Both environmental and genetic factors are involved in the etiology of NTDs. Inadequate folate intake and obesity are important environmental risk factors. Several folate‐related genetic variants have been identified as risk factors; however, little is known about how genetic variants relate to the increased risk seen in obese women. Uncoupling Protein 2 (UCP2) is an attractive candidate to screen for NTD risk because of its possible role in obesity as well as energy metabolism, type‐2 diabetes, and the regulation of reactive oxygen species. Interestingly, a previous study found that a common UCP2 compound homozygous genotype was associated with a threefold increase in NTD risk. METHODS: We evaluated three polymorphisms, ‐866G>A, A55V, and the 3′UTR 45 bp insertion/deletion, as risk factors for NTDs in Irish NTD cases (n = 169), their mothers (n = 163), their fathers (n = 167), and normal control subjects (n = 332). RESULTS: Allele and genotype frequencies were not significantly different when comparing NTD mothers, NTD fathers, or affected children to controls. Additionally, the previously reported risk genotype (combined homozygosity of 55VV and 3′UTR 45 bp deletion/deletion) was not present at a higher frequency in any NTD group when compared to controls. CONCLUSIONS: In our Irish study population, UCP2 polymorphisms did not influence NTD risk. Moreover, the prevalence of this allele in other populations was similar to the Irish prevalence but far lower than reported in the previous NTD study, suggesting that this previous finding of an association with NTDs might have been due to an unrepresentative study sample. Birth Defects Research (Part A), 2009. © 2009 Wiley‐Liss, Inc.