How well can relative specialistRhagoletis flies learn to discriminate fruit for oviposition?

We show that blueberry maggot females [Rhagoletis mendax(Curran)], apple maggot females [Rhagoletis pomonella(Walsh)], and walnut husk fly females [Rhagoletis suavis(Loew)], all relative specialists in range of fruit species attacked in nature, are able to learn to discriminate between types of fruit in which they oviposit. It appears, however, that these relative specialists express less capacity to learn fruit characters than relative generalist tephritids. This difference in expression of learning ability may be associated in part with differences in assignments species are asked to learn. Apparent differences in learning capability between relative specialist and relative generalist tephritids may therefore depend as much upon differences in the physical and chemical nature of host fruit as upon species differences in the adaptive value of learning.     

Do female fruit flies (Drosophila serrata) copy the mate choice of others?

Female mate-choice copying is a social learning phenomenon whereby a female's observation of a successful sexual interaction between a male and another female increases her likelihood of subsequently preferring that male. Although mate-choice copying has been documented in several vertebrate species, to our knowledge it has not yet been investigated in insects. Here, we investigated whether female mate-choice copying occurs in the fruit fly Drosophila serrata, a model system for the study of mate preferences and the sexual selection they generate. We used two complementary experiments in which focal females were given a choice between two males that differed in either their apparent (as determined visually by the focal female) or actual recent mating success. Mate-choice copying was evaluated by testing whether focal females mated more frequently with the ‘preferred’ male as opposed to the other male. In both experiments, however, we found no evidence for mate-choice copying. We discuss possible reasons for the apparent absence of mate-choice copying in this species.     

Drug preparation in evidence? An unusual plant and bone assemblage from the Pompeian countryside, Italy

In 1996 a farmhouse (villa rustica) was excavated near Pompeii (Naples, southern Italy). The villa had the typical characters of other farmhouses of the same period (ca A.D. 79) found in the area. The content of one of thedolia (storage vats) found in the cellar is discussed here and an interpretation of the assemblage is provided. The deposit found at the bottom of the storage vat produced a high percentage of seeds of plants known for their medicinal properties, such asPapaver somniferum (opium poppy). Associated with the residue there were also bones of reptiles and amphibians. It is suggested that the assemblage may represent the residue of a medicinal preparation. Its content includes many plants used in the preparation of ancient drugs calledMithridatium andTheriac. Further indirect archaeological evidence that supports this hypothesis will also be discussed.     

Where's the evidence?

Science is in large part the art of careful measurement, and a fixed measurement scale is the sine qua non of this art. It is obvious to us that measurement devices lacking fixed units and constancy of scale across applications are problematic, yet we seem oddly laissez faire in our approach to measurement of one critically important quantity: statistical evidence. Here I reconsider problems with reliance on p values or maximum LOD scores as measures of evidence, from a measure-theoretic perspective. I argue that the lack of an absolute scale for evidence measurement is every bit as problematic for modern biological research as was lack of an absolute thermal scale in pre-thermodynamic physics. Indeed, the difficulty of establishing properly calibrated evidence measures is strikingly similar to the problem 19th century physicists faced in deriving an absolute scale for the measurement of temperature. I propose that the formal relationship between the two problems might enable us to apply the mathematical foundations of thermodynamics to establish an absolute scale for the measurement of evidence, in statistical applications and possibly other areas of mathematical modeling as well. Here I begin to sketch out what such an endeavor might look like.     

Evaluating quantum yield and ultraviolet–visible reflectance in baby pumpkins: Implications for oviposition behavior of pumpkin fruit flies

Frugivorous insects utilize both olfactory and visual cues to locate their host plants. Although volatiles have been extensively studied for detecting infested fruits, the role of visual cues in oviposition site selection remains mostly unknown among frugivorous insects. To investigate physiological changes in a host plant, we measured the quantum yield and reflectance of three wavelengths of light (350, 450 and 520 nm) after puncturing the surfaces of commercially grown pumpkins using insect pins during two different seasons outdoors. Quantum yields did not show significant differences between undamaged and simulated oviposition sites. Two wavelengths within the visual spectrum were similar between the two treatments. However, photon counts at 350 nm, in the ultraviolet range, were 1.76 fold higher in simulated oviposition sites than in undamaged sites, which was consistently observed across three field seasons. Considering that frugivorous insects and other phytophagous insects recognize the 350 nm wavelength for host identification and oviposition, we conclude that the disparities in ultraviolet reflectance can serve as a baseline for assessing the actual oviposition response of fruit flies. This finding contributes to the role of visual cues in the oviposition behavior of frugivorous insects and the development of a nondestructive detection method for pumpkin fruit flies.     

How do flies tolerate microorganisms in the gut?

Although gut epithelia are in constant contact with a large number of microbe-derived immune elicitors such as peptidoglycan, they do not mount an intense immune response. In this issue of Cell Host & Microbe, Lhocine et al. (2008) report that the PIMS gene product induces immune tolerance by reducing the availability of the peptidoglycan receptor in the plasma membrane. These findings provide a novel insight into the molecular mechanisms by which the host gut maintains balanced host-microbe interactions.     

What can humans learn from flies about adenomatous polyposis coli?

Somatic or inherited mutations in the adenomatous polyposis coli (APC) gene are a frequent cause of colorectal cancer in humans. APC protein has an important tumor suppression function to reduce cellular levels of the signaling protein beta-catenin and, thereby, inhibit beta-catenin and T-cell-factor-mediated gene expression. In addition, APC protein binds to microtubules in vertebrate cells and localizes to actin-rich adherens junctions in epithelial cells of the fruit fly Drosophila (Fig. 1). Very little is known, however, about the function of these cytoskeletal associations. Recently, Hamada and Bienz have described a potential role for Drosophila E-APC in cellular adhesion, which offers new clues to APC function in embryonic development, and potentially colorectal adenoma formation and tumor progression in humans.     

Do nuclear and renewable energy improve the environment? Empirical evidence from the United States

The central focus of this article is to assess the dynamic effects of nuclear and renewable energy consumption on CO₂ emissions, for a given level of income and energy consumption. We apply an autoregressive distributed lag (ARDL) approach to cointegration to U.S. data from 1960 to 2010. We find that nuclear energy consumption indeed reduces CO₂ emissions in both the short- and long-run, while renewable energy consumption does only in the short-run. We also find that income increases CO₂ emissions in the long-run after showing the environmental Kuznets curve (EKC) initially in the short-run. Finally, energy consumption is found to have a negative impact on reducing CO₂ emissions in the short- and long-run.     

The evolution of generalization? Parasitoid flies and the perils of inferring host range evolution from phylogenies

It is widely assumed that high resource specificity predisposes lineages toward greater likelihood of extinction and lower likelihood of diversification than more generalized lineages. This suggests that host range evolution in parasitic organisms should proceed from generalist to specialist, and specialist lineages should be found at the 'tips' of phylogenies. To test these hypotheses, parsimony and maximum likelihood methods were used to reconstruct the evolution of host range on a phylogeny of parasitoid flies in the family Tachinidae. In contrast to predictions, most reconstructions indicated that generalists were repeatedly derived from specialist lineages and tended to occupy terminal branches of the phylogeny. These results are critically examined with respect to hypotheses concerning the evolution of specialization, the inherent difficulties in inferring host ranges, our knowledge of tachinid-host associations, and the methodological problems associated with ancestral character state reconstruction. Both parsimony and likelihood reconstructions are shown to provide misleading results and it is argued that independent evidence, in addition to phylogenetic trees, is needed to inform models of the evolution of host range and the evolutionary consequences of specialization.     

Structural evidence that the small subunit found associated with the TL antigen is β 2-microglobulin

Comparative tryptic peptide mapping and partial amino-terminal primary sequence analysis of the light chain component associated with the TL antigens showed that the small subunit of TL was identical to the ₂m light chain associated with the H-2K or D product of the same strain. Peptide comparison of the ₂m from the Tla products of an A strain X-ray induced leukemia RADA1 (Tla ^a) and of a C57BL/6 strain X-ray induced leukemia ERLD (Tla ^b) showed differences to the extent of 25–35% in their peptides. This is consistent with previous results showing ₂m allelic variations between these mouse strains. The data prove the structural identity of the ₂m molecules from TL and H-2K, D antigens as well as reveal the strain specific polymorphism of the ₂m associated with these products.     

Is the anthophyte hypothesis alive and well? New evidence from the reproductive structures of Bennettitales

Bennettitales is an extinct group of seed plants with reproductive structures that are similar in some respects to both Gnetales and angiosperms, but systematic relationships among the three clades remain controversial. This study summarizes characters of bennettitalean plants and presents new evidence for the structure of cones and seeds that help clarify relationships of Bennettitales to flowering plants, Gnetales, and other potential angiosperm sister groups. Bennettitales have simple mono- or bisporangiate cones. Seeds are borne terminally on sporophylls. They have a unique structure that includes a nucellus with a solid apex, no pollen chamber, and a single integument, and they are clearly not enclosed by a cupule or other specialized structures. Such features differ substantially from Gnetales, flowering plants, and the seed fern Caytonia, providing no compelling evidence for the origin of the angiospermous carpel. Cladistic tests were performed to assess the strength of the "anthophyte hypothesis" and possible relationships of Bennettitales, Gnetales, and Caytonia to flowering plants. Our results do not support the anthophyte hypothesis for the origin of angiosperms by a transformation of fertile organs that were already aggregated into a cone or flower-like structure. However, the anthophyte topology of the seed plant tree continues to be supported by morphological analyses of living and extinct taxa.