Baiting Insects with Pyrrolizidine Alkaloids (PAs): A Fieldwork-Oriented Review and Guide to PA-Pharmacophagy.

Since 1890, many observations of danaine butterflies visiting dry plants of several families in the Old and New World tropics have been published. For 50 years, it has been recognised that Danainae, along with various other insects, seek out 1,2-dehydropyrrolizidine ester alkaloids (PAs) independently of and in addition to their nutritive requirements and utilise them to increase their chances for survival and biological fitness. This represents an unusual type of insect-plant relationship ("PA-pharmacophagy"), with remarkable peculiarities but also with gaps in knowledge, many of which can be filled by employing PA-baiting.

'Drone-Netting' for Sampling Live Insects.

Drones have become valuable tools for biodiversity studies by providing aerial photographs; however, for most entomological studies, images, in particular those taken remotely, are usually insufficient; rather sampling of specimens is required. We equipped a cheap off-the-shelf drone with a net bag, flew it over the ground, sweeping the vegetation, and sampled adult and larval insects as well as spiders. 'Drone-netting' proved to be a versatile method for general insect sampling, particularly in inaccessible terrains.

'Crystal Macrosetae': Novel Scales and Bristles in Male Arctiine Moths (Lepidoptera: Erebidae: Arctiinae) Filled with Crystallizing Material.

Scales, exoskeletal features characteristic of the Lepidoptera, occur in enormous structural and functional diversity. They cover the wing membranes and other body parts and give butterflies and moths their often stunning appearance. Generally, the patterns made by scales are visual signals for intra- and interspecific communication.

Twittering Pupae of Papilionid and Nymphalid Butterflies (Lepidoptera): Novel Structures and Sounds.

Pupae of numerous Papilionidae and Nymphalidae produce twitter sounds when wriggling in response to mechanical stimulation. The structural basis comprises distinct pairs of sound-producing organs (SPOs) located at intersegmental membranes of the abdomen. They differ-as the twitters do-in sampled taxa of Papilioninae, Epicaliini, and Heliconiini.

Gloora gen. nov. (Lepidoptera: Erebidae: Arctiinae: Arctiini: Ctenuchina) for several Agylla-like Arctiinae.

Gloora gen. nov. is established for Eucereon alba (Druce, 1894), Hyaleucerea mundula (Berg, 1882), Agaraea sericeum (Zerny, 1931), and Gloora canae sp.

A hypothesis to explain accuracy of wasp resemblances.

Mimicry is one of the oldest concepts in biology, but it still presents many puzzles and continues to be widely debated. Simulation of wasps with a yellow-black abdominal pattern by other insects (commonly called "wasp mimicry") is traditionally considered a case of resemblance of unprofitable by profitable prey causing educated predators to avoid models and mimics to the advantage of both (Figure 1a). However, as wasps themselves are predators of insects, wasp mimicry can also be seen as a case of resemblance to one's own potential antagonist.

Pro-toxic 1,2-Dehydropyrrolizidine Alkaloid Esters, Including Unprecedented 10-Membered Macrocyclic Diesters, in the Medicinally-used Alafia cf. caudata and Amphineurion marginatum (Apocynaceae: Apocynoideae: Nerieae and Apocyneae).

Introduction: Within the Apocynoideae (Apocynaceae) pro-toxic dehydropyrrolizidine alkaloids have been reported only in Echiteae. However, attraction of pyrrolizidine alkaloid-pharmacophagous insects suggested their presence in Alafia cf. caudata Stapf (Nerieae: Alafiinae) and Amphineurion marginatum (Roxb.

Pro-toxic dehydropyrrolizidine alkaloids in the traditional Andean herbal medicine "asmachilca".

Ethnopharmacological Relevance: Asmachilca is a Peruvian medicinal herb preparation ostensibly derived from Aristeguietia gayana (Wedd.) R.M.

Recognition of pyrrolizidine alkaloid esters in the invasive aquatic plant Gymnocoronis spilanthoides (Asteraceae).

Introduction: The freshwater aquatic plant Gymnocoronis spilanthoides (Senegal tea plant, jazmín del bañado, Falscher Wasserfreund) is an invasive plant in many countries. Behavioural observations of pyrrolizidine alkaloid-pharmacophagous butterflies suggested the presence of pyrrolizidine alkaloids in the plant.

Objective: To determine whether the attraction of the butterflies to the plant is an accurate indicator of pyrrolizidine alkaloids in G.

Stepwise evolution of resistance to toxic cardenolides via genetic substitutions in the Na+/K+ -ATPase of milkweed butterflies (lepidoptera: Danaini).

Despite the monarch butterfly (Danaus plexippus) being famous for its adaptations to the defensive traits of its milkweed host plants, little is known about the macroevolution of these traits. Unlike most other animal species, monarchs are largely insensitive to cardenolides, because their target site, the sodium pump (Na(+)/K(+) -ATPase), has evolved amino acid substitutions that reduce cardenolide binding (so-called target site insensitivity, TSI). Because many, but not all, species of milkweed butterflies (Danaini) are associated with cardenolide-containing host plants, we analyzed 16 species, representing all phylogenetic lineages of milkweed butterflies, for the occurrence of TSI by sequence analyses of the Na(+)/K(+) -ATPase gene and by enzymatic assays with extracted Na(+)/K(+) -ATPase.

The ecological context of pyrrolizidine alkaloids in food, feed and forage: an overview.

Plant-produced 1,2-dehydropyrrolizidine ester alkaloids and their N-oxides (PAs) not only cause acute poisoning of humans and livestock, but also the likely harmful cryptic effects of chronic exposure pose particular food safety risks that need to be addressed for consumer protection. In natural contexts, however, PAs cause few or no problems. Rather, these plant secondary metabolites are important elements of ecosystems and plant-animal relationships; the existence and persistence of many PA-adapted organisms, in various ways, depends on the presence of PA-containing plants or even on PAs as such.

Effects of pyrrolizidine alkaloids on the performance of plant-parasitic and free-living nematodes.

Background: Chemical nematicides such as methyl bromide have for decades played a significant role in the management of plant-parasitic nematodes. Their application is problematic because of negative environmental impacts, and therefore methyl bromide was phased out in Europe in 2005. A possible alternative to synthetically derived nematicides is seen in the use of plants and/or their secondary metabolites.

An antiaphrodisiac in Heliconius melpomene butterflies.

Gilbert (1976) suggested that male-contributed odors of mated females of Heliconius erato could enforce monogamy. We investigated the pheromone system of a relative, Heliconius melpomene, using chemical analysis, behavioral experiments, and feeding experiments with labeled biosynthetic pheromone precursors. The abdominal scent glands of males contained a complex odor bouquet, consisting of the volatile compound (E)-beta-ocimene together with some trace components and a less volatile matrix made up predominately of esters of common C16- and C18-fatty acids with the alcohols ethanol, 2-propanol, 1-butanol, isobutanol, 1-hexanol, and (Z)-3-hexenol.

Insect-synthesised retronecine ester alkaloids: precursors of the common arctiine (Lepidoptera) pheromone hydroxydanaidal.

Many pyrrolizidine alkaloid (PA)-adapted insects convert PAs sequestered from their larval host plants into "insect-PAs" in which the acid components of the alkaloids are replaced by small, branched aliphatic 2-hydroxy acids of insect origin. It has been proposed that insect-PAs are precursors of the pheromone hydroxydanaidal in male Estigmene acrea moths, but it is not clear why they are specifically required or what the structural features or chemical properties are that make insect-PAs more suitable for conversion into hydroxydanaidal than superficially similar alkaloids of plant origin. Evidence is presented that insect-PAs are also precursors of hydroxydanaidal in the polyphageous arctiine, Creatonotos transiens, and a new biosynthetic pathway to hydroxydanaidal is proposed that has a mandatory requirement for insect-PAs as intermediates.

Pyrrolizidine alkaloids of Echium vulgare honey found in pure pollen.

The pyrrolizidine alkaloids previously identified in floral honey attributed to Echium vulgare (Boraginaceae) have been detected (8000-14 000 ppm) in pure pollen collected from the anthers of Echium vulgare. Pyrrolizidine alkaloids and/or their N-oxides were isolated from the aqueous acid extracts of pollen by use of strong cation-exchange, solid-phase extraction and identified by liquid chromatographic/mass spectrometric (LCMS) analysis. The pyrrolizidine alkaloids in the pollen are present mainly as the N-oxides.