Population-specific patterns of toxin sequestration in monarch butterflies from around the world

Monarch butterflies are one of the preeminent examples of a toxin-sequestering animal, gaining protection against predators via cardenolides obtained from their milkweed host plants. Although cardenolide sequestration by monarchs has been studied in ecological, physiological, and phylogenetic contexts, relatively little research has surveyed genetic variation in the ability to sequester, nor has monarch sequestration been studied in relation to divergent host plant assemblages or variation in exposure to predation. Here, we use the monarch's recent global range expansion to test hypotheses about how cardenolide sequestration evolves over relatively contemporary time scales. First, we test for whether sympatric monarch/milkweed combinations have a sequestration advantage by rearing six geographically disparate monarch populations on six associated milkweed host species and measuring levels of sequestered cardenolides in a set of 440 adult butterflies. Second, we use monarchs from Guam - an oceanic island where birds have been functionally extirpated for approximately 40 years - to test hypotheses about how exposure to avian predation affects cardenolide sequestration. We find little overall evidence for increased sequestration on sympatric hosts. However, one monarch population (Puerto Rico) shows strong support for cross-host tradeoffs in sequestration ability, primarily driven by limited sequestration of polar cardenolides from two temperate North American milkweeds (Asclepias syriaca and A. speciosa). Monarchs from Guam show some evidence for reduced cardenolide sequestration in both a cross-island comparison of wild-caught butterflies as well as population-level comparisons of greenhouse-reared butterflies. Our results suggest that there is substantial genetic variation in sequestration ability (both within and between monarch populations) and that evolutionary history and contemporary species interactions may influence patterns of cardenolide sequestration.

Wenn Bestäuber in die Klemmfalle geraten

Seidenpflanzen haben Blüten mit sogenannten Klemmfallen. Geraten Insekten in die schmalen Spalten, ziehen sie beim Herausreißen von Rüsseln oder Beinen Pollenpakete (Pollinien) mit aus der Blüte. Beim Besuch einer neuen Blüte bleiben diese Pollinien an den Narben hängen. Die Wirkweise der Klemmfallen von Asclepias syriaca wurde fotografisch dokumentiert.

Identifying synergies and antagonisms between plant defense traits in Asclepias syriaca

As a general rule, plants defend against herbivores with multiple traits. The defense synergy hypothesis posits that some traits are more potent when co-expressed with others, compared to their independent potency. However, this hypothesis has rarely been tested outside of synergies within a class of particular phytochemicals, and seldom under field conditions. We tested for synergies between multiple defense traits of common milkweed (Asclepias syriaca) by assaying the performance of two specialist herbivores on plants in natural populations. We employed both standard regression and exploratory analysis using a novel application of Random Forests that allowed us to detect synergies between defense traits. In hypothesis testing, we found the first empirical evidence for a previously hypothesized synergy between one pair of co-expressed defense traits (latex and cardenolides), but not another (latex and trichomes). When exploring all potential interactions between pairs of traits we found eight synergies and five antagonisms in predicting herbivore performance. Half of the identified synergies involved carbon, which is the basis of several defenses including chemical and physical barriers to feeding, and also essential nutrients. Our findings suggest that defense synergies could explain co-expression of latex and cardenolides in milkweeds. This synergy may be common among the diverse plant species that employ latex as a defense. Future studies should test carbon-based synergies, which our work suggests are prevalent, as well as the other synergies identified in our exploratory analysis. Our analytic approach provides a general, flexible framework for more broadly discovering and predicting the coexpression of traits through their synergistic function.

Results of the vir collecting mission in Adygea and Kuban in september 2018

Twenty-six habitats in the Western Caucasus have been examined. Fifty-nine samples of seeds of cultivated plants, their wild relatives, and 77 herbarium specimens have been collected. Some of the samples are landraces of Phaseolus beans (Phaseolus vulgaris L.), spring garlic (Allium sativum L.), shallots (Allium ascalonicum L.), hot pepper (Capsicum annuum L. var. longum (DC.) Sendtn.), chickpea (Cicer arietinum L.), grass pea (Lathyrus sativus L.), etc. Another part of the samples are cultivated plants forms of folk breeding, e.g., cucumber (Cucumis sativus L.), tomato (Lycopersicon esculentum L.), etc. Samples of such wild relatives of cultivated plants as Lactuca serriola L., Prunus spinosa L., Cicerbita racemosa (Willd.) Beauverd, Asclepias syriaca L., Lathyrus sylvestris L., etc. were included in the VIR collections.

Bioactive Constituents and Potency of Aqueous-Methanolic Extract of Asclepias syriaca on Plasmodium falciparum Infected Albino Rats

High mortality rate couple with the economic effect of deadly Plasmodium falciparum caused by malaria necessitated this study. Evaluation of bioactive constituents and antimalarial properties of the aqueous-methanolic extract of Asclepias syriaca (A. syriaca) was investigated. Bioactive constituents were determined by GC-MS analytical detector. Albino rats were five in each group of six groups (A-E) in which group A was non-infected with P. falciparum (negative control). Groups B, C, D, E were infected with 1×107/ml P. falciparum without treated, treated with standard drugs of 20mg of chloroquine/kg, 100, 200 and 400mg of extracted A. syriaca/kg, respectively. Hematological and biochemical parameters of Plasmodium falciparum infected albino rats were determined. Aqueous-methanolic extract of A. syriaca leaf made up of high content of pyrimidine, quinolone and silane derivatives with synergetic properties with potency for therapeutic of malarial and viral infectious diseases. MCV, PLA, RBC, total protein and albumin were significantly elevated upon infected P. falciparum and gradually increases with dosage and time when treated with chloroquine and A.syriaca leaf extract but vice visa for the case WBC and creatinine. Parasitemia level significantly declined when administered with chloroquine and A, syriaca leaf extract for 36 hours. Hence serves as an effective medication in place of chloroquine due to its availability, avoidable and as a source of relevant medications to Plasmodium spp and viral infectious diseases.

Influence of Asclepias syriaca on soil nematode communities

The main goal of this study was to evaluate the impact of the invasive common milkweed (Asclepias syriaca L.) on soil nematode communities. The research was carried out in 2018 and 2019 in an ecosystem of permanent grassland in the basin of the Laborec River in land registries of Drahňov, a Vojany village in southeastern Slovakia. The ecosystem contained a total of 64 species of free-living and parasitic nematodes. The most prevalent trophic groups were bacterial feeders (Acrobeloides nanus), followed by plant parasites (Helicotylenchus digonicus and Pratylenchus pratensis), fungal feeders (Aphelenchus avenae), and omnivores (Eudorylaimus carteri). The number of nematode species, the composition of trophic groups and the structure of communities in areas with invasive plants were similar to those in areas with native vegetation during the two years of observation.