\u3ci\u3eAgonopterix Alstroemeriana\u3c/i\u3e (Oecophoridae) and Other Lepidopteran Associates of Poison Hemlock \u3ci\u3e(Conium Maculatum)\u3c/i\u3e in East Central Illinois

Poison hemlock (Conium maculatum) (Apiaceae), a noxious Eurasian weed extensively naturalized throughout North America, is characteristically attacked by few insects. Over the past two decades, an introduced oecophorid caterpillar, Agonopterix alstroemeriana, has been reported infesting poison hemlock, its sole host in its area of indigeneity, in parts of the northeastern and western United States. We report for the first time evidence of established midwestern populations of this species. We also report poison hemlock as a host plant for the polyphagous lepidopterans Eupithecia miserulata, Trichoplusia ni, and Spilosoma virginica

A Native Hymenopteran Predator of \u3ci\u3eAgonopterix Alstroemeriana\u3c/i\u3e (Lepidoptera: Oecophoridae) in East-Central Illinois

Agonopterix alstroemeriana is a European oecophorid moth that defoliates poison hemlock (Conium maculatum), a noxious Eurasian weed extensively naturalized throughout temperate Australia, New Zealand, North America, and South America. Throughout western North America, and increasingly in the Midwest and Northeast, A. alstroemeriana has been utilized in poison hemlock eradication programs. We report, for the first time, predation on A. alstroemeriana by Euodynerus foraminatus (Hymenoptera: Eumenidae), a native solitary wasp that paralyzes these and other lepidopteran larvae and uses them to provision its nests. The presence of an effective predator may reduce the impact of A. alstroemeriana in biological control programs

Host plant selection by a monophagous herbivore is not mediated by quantitative changes in unique plant chemistry : Agonopterix alstroemeriana and Conium maculatum

Host plant selection by ovipositing females is a key process determining the success of phytophagous insects. In oligophagous lepidopterans, host-specific plant secondary chemicals are expected to be dominant factors governing oviposition behavior; distinctive compounds can serve as high-contrast signals that clearly differentiate confamilial hosts from non-hosts increasing the accuracy of host quality evaluation. Agonopterix alstroemeriana (Clerk) (Lepidoptera: Oecophoridae) and Conium maculatum L. (Apiaceae) form an extremely specialized plant-herbivore system, with A. alstroemeriana monophagous on C. maculatum, a plant with few other insect herbivores at least in part due to its virtually unique capacity among plants to produce piperidine alkaloids. Here we have studied the response of A. alstroemeriana oviposition to unique host plant secondary metabolites, piperidine alkaloids, and widespread compounds, mono- and sesquiterpenes, in a concentration-dependent fashion. Rates of oviposition were negatively correlated with Z-ocimene concentrations. To confirm the deterrent properties of this monoterpene for A. alstroemeriana oviposition, we conducted a choice experiment using artificially damaged C. maculatum plants, with higher emission of volatiles, and undamaged control plants. Damaged plants were less preferred as oviposition sites compared to the controls. The lack of association between oviposition and piperidine alkaloids, defenses unique to Conium species, suggests that quantitative changes of these species-specific chemicals do not play a predominant role in host selection by the monophagous A. alstroemeriana

Geographical variation in alkaloid production in Conium maculatum populations experiencing differential herbivory by Agonopterix alstroemeriana

Conium maculatum, a Eurasian weed naturalized in North America, contains high concentrations of piperidine alkaloids, which act as chemical defenses against herbivores. In the United States, C. maculatum was largely free from herbivory until approximately 30 years ago, when it was re-associated via accidental introduction with a monophagous European herbivore, the oecophorid caterpillar Agonopterix alstroemeriana. At present, A. alstroemeriana is found in a continuum of re-association time and intensities with C. maculatum across the continent; in the Pacific Northwest, A. alstroemeriana can cause severe damage, resulting in some cases in complete defoliation. Studies in biological control and invasion biology have yet to determine whether plants re-associated with a significant herbivore from the area of indigeneity increase their chemical defense investment in areas of introduction. In this study, we compared three locations in the U.S. (New York, Washington and Illinois) where C. maculatum experiences different levels of herbivory by A. alstroemeriana to determine the association between the intensity of the interaction, as measured by damage, and chemical defense production. Total alkaloid production in C. maculatum was positively correlated with A. alstroemeriana herbivory levels; plants from New York and Washington, with higher herbivory levels, invested two and four times more N to alkaloid synthesis than did plants from Illinois. Individual plants with lower concentrations of alkaloids from a single location in Illinois experienced more damage by A. alstroemeriana, suggestive of a preference on the part of the insect for plants with less chemical defense. These results suggest that A. alstroemeriana may act either as a selective agent or inducing agent for C. maculatum and increase its toxicity in its introduced range

Why do leaf-tying caterpillars abandon their leaf ties?

Leaf-tying caterpillars act as ecosystem engineers by building shelters between overlapping leaves, which are inhabited by other arthropods. Leaf-tiers have been observed to leave their ties and create new shelters (and thus additional microhabitats), but the ecological factors affecting shelter fidelity are poorly known. For this study, we explored the effects of resource limitation and occupant density on shelter fidelity and assessed the consequences of shelter abandonment. We first quantified the area of leaf material required for a caterpillar to fully develop for two of the most common leaf-tiers that feed on white oak, Quercus alba. On average, Psilocorsis spp. caterpillars consumed 21.65 ± 0.67 cm2 leaf material to complete development. We also measured the area of natural leaf ties found in a Maryland forest, to determine the distribution of resources available to caterpillars in situ. Of 158 natural leaf ties examined, 47% were too small to sustain an average Psilocorsis spp. caterpillar for the entirety of its development. We also manipulated caterpillar densities within experimental ties on potted trees to determine the effects of cohabitants on the likelihood of a caterpillar to leave its tie. We placed 1, 2, or 4 caterpillars in ties of a standard size and monitored the caterpillars twice daily to track their movement. In ties with more than one occupant, caterpillars showed a significantly greater propensity to leave their tie, and left sooner and at a faster rate than those in ties as single occupants. To understand the consequences of leaf tie abandonment, we observed caterpillars searching a tree for a site to build a shelter in the field. This is a risky behavior, as 17% of the caterpillars observed died while searching for a shelter site. Caterpillars that successfully built a shelter traveled 110 ± 20 cm and took 28 ± 7 min to find a suitable site to build a shelter. In conclusion, leaf-tying caterpillars must frequently abandon their leaf tie due to food limitation and interactions with other caterpillars, but this is a costly behavior

Psychological assessment of mothers and their daughters at the time of diagnosis of precocious puberty

BACKGROUND: Concerns about psychological distress are often used to justify treatment of girls with precocious puberty, but there is little evidence to support these concerns. The extent to which psychological problems are associated with central precocious puberty (CPP) compared with other forms of early puberty in girls has likewise not been established. METHODS: Girls presenting with untreated CPP, premature adrenarche (PA) or early normal puberty (ENP) were recruited from our pediatric endocrine clinic along with their mothers. Child psychological adjustment was assessed by child self-report and parent report. Parent self-reported personality, anxiety, and depression were also assessed. Differences between groups were explored using one-way ANOVA and Dunnett's T3 test. RESULTS: Sixty-two subjects (aged 7.5 ± 1.4 years, range 4.8-10.5) were enrolled, of whom 19 had CPP, 22 had PA, and 21 had ENP. Girls with ENP were significantly older (8.9 ± .9 years) than girls with CPP (6.9 ± 1.1 years, p < .001) and PA (6.6 ± 1.0 years, p < .001). Girls with PA had significantly higher BMI z-scores (1.7 ± .8) than girls with CPP (1.1 ± .6, p = .01) and ENP (1.2 ± .6, p = .04). More girls with PA and ENP were from racial minorities (47% and 50% respectively) than girls with CPP (32%). No group differences were found for any child measure of psychological adjustment. However, mothers of girls with PA scored significantly higher than mothers of girls with ENP on one measure of depression (p = .04) and stress (p = .01). CONCLUSIONS: While mothers of girls with PA report increased psychological distress on some measures, no differences in psychological adjustment were found at baseline amongst the girls themselves. Whether these results will change as puberty progresses in the PA and ENP groups or with treatment of CPP is unknown. Long-term prospective studies are needed in order to further investigate psychological correlates of early puberty in girls

Extending the applicability of the dose addition model to the assessment of chemical mixtures of partial agonists by using a novel toxic unit extrapolation method

This article has been made available through the Brunel Open Access Publishing Fund.Dose addition, a commonly used concept in toxicology for the prediction of chemical mixture effects, cannot readily be applied to mixtures of partial agonists with differing maximal effects. Due to its mathematical features, effect levels that exceed the maximal effect of the least efficacious compound present in the mixture, cannot be calculated. This poses problems when dealing with mixtures likely to be encountered in realistic assessment situations where chemicals often show differing maximal effects. To overcome this limitation, we developed a pragmatic solution that extrapolates the toxic units of partial agonists to effect levels beyond their maximal efficacy. We extrapolated different additivity expectations that reflect theoretically possible extremes and validated this approach with a mixture of 21 estrogenic chemicals in the E-Screen. This assay measures the proliferation of human epithelial breast cancers. We found that the dose-response curves of the estrogenic agents exhibited widely varying shapes, slopes and maximal effects, which made it necessary to extrapolate mixture responses above 14% proliferation. Our toxic unit extrapolation approach predicted all mixture responses accurately. It extends the applicability of dose addition to combinations of agents with differing saturating effects and removes an important bottleneck that has severely hampered the use of dose addition in the past. © 2014 Scholze et al

Genotoxic mixtures and dissimilar action: Concepts for prediction and assessment

This article has been made available through the Brunel Open Access Publishing Fund. This article is distributed under the terms of the creative commons Attribution license which permits any use, distribution, and reproduction in any medium, provided the original author(s)and the source are credited.Combinations of genotoxic agents have frequently been assessed without clear assumptions regarding their expected (additive) mixture effects, often leading to claims of synergisms that might in fact be compatible with additivity. We have shown earlier that the combined effects of chemicals, which induce micronuclei (MN) in the cytokinesis-block micronucleus assay in Chinese hamster ovary-K1 cells by a similar mechanism, were additive according to the concept of concentration addition (CA). Here, we extended these studies and investigated for the first time whether valid additivity expectations can be formulated for MN-inducing chemicals that operate through a variety of mechanisms, including aneugens and clastogens (DNA cross-linkers, topoisomerase II inhibitors, minor groove binders). We expected that their effects should follow the additivity principles of independent action (IA). With two mixtures, one composed of various aneugens (colchicine, flubendazole, vinblastine sulphate, griseofulvin, paclitaxel), and another composed of aneugens and clastogens (flubendazole, doxorubicin, etoposide, melphalan and mitomycin C), we observed mixture effects that fell between the additivity predictions derived from CA and IA. We achieved better agreement between observation and prediction by grouping the chemicals into common assessment groups and using hybrid CA/IA prediction models. The combined effects of four dissimilarly acting compounds (flubendazole, paclitaxel, doxorubicin and melphalan) also fell within CA and IA. Two binary mixtures (flubendazole/paclitaxel and flubendazole/doxorubicin) showed effects in reasonable agreement with IA additivity. Our studies provide a systematic basis for the investigation of mixtures that affect endpoints of relevance to genotoxicity and show that their effects are largely additive.UK Food Standards Agenc