Danaidal

Quantitative and qualitative effects of larval diet on male scent secretions ofEstigmene acrea, Phragmatobia foliginosa, andPyrrharctia isabella (Lepidoptera: Arctiidae).[Pubmed: 24271908]

Quantitative and qualitative variation in male pheromones ofPhragmatobia fuliginosa andPyrrharctia isabella (Lepidoptera: Arctiidae).[Pubmed: 24302048]

J Chem Ecol. 1987 Apr;13(4):807-22.

The dihydropyrrolizine pheromones, hydroxyDanaidal and Danaidal, were identified from the scent organs of malePhragmatobia fuliginosa (L.) andPyrrharctia isabella (J.E. Smith).
METHODS AND RESULTS:
Qualitative and quantitative GLC analyses were conducted on ca. 80 field-collected males of each species. The total pheromone titer was distributed bimodally in each species with most males having either a small amount (< 10 ng) of pheromone or a large amount (1-10 μg inPyrrharctia and 0.3-3 μg inPhragmatobia).Pyrrharctia males in the 1- to 10-μg range had a predominance of hydroxyDanaidal, with little if any Danaidal. MostPhragmatobia males in the 0.3- to 3-μg range had Danaidal with little if any hydroxyDanaidal. These compounds elicited a courtship response in sexually receptive females of both species. A bioassay based on this response was used to measure the thresholds of female response to these compounds.
CONCLUSIONS:
Pyrrharctia females were more sensitive to (R)-(-)-hydroxyDanaidal than to Danaidal.Phragmatobia females were more sensitive to Danaidal then to (R)-(-)-hydroxyDanaidal.

J Chem Ecol. 1989 Mar;15(3):1077-93.

METHODS AND RESULTS:
In feeding experiments with insects reared in the laboratory, the presence of the dihydropyrrolizines hydroxyDanaidal and Danaidal in the male scent organs (coremata) of the arctiids,Estigmene acrea (Drury),Phragmatobia fuliginosa (L.), andPyrrharctia isabella (J.E. Smith), was shown to depend on the presence of a source of pyrrolizidine alkaloids (PAs) in the larval diet.Phragmatobia males given an artificial diet supplemented with the powdered roots of the PA-containing plantSymphytum officinale L. (comfrey) produced more hydroxyDanaidal than Danaidal, whereas males given an artificial diet supplemented with dried whole plants of another PA-containing species,Senecio vulgaris L., produced more Danaidal than hydroxyDanaidal.Pyrrharctia males produced hydroxyDanaidal with little if any Danaidal, whether the source of PAs was comfrey orS. vulgaris. A behavioral bioassay showed that the coremata of PA-deniedPyrrharctia male progeny of PA-denied parents were pheromonally inactive, whereas those of PA-denied male progeny of PA-supplied parents (male and/or female) were often active.
CONCLUSIONS:
This indicates that a small amount of pheromone is made from PAs transferred from the female to her eggs and that males effect copulatory transfers of PAs that are, in turn, passed to the eggs by the mated female. Field observations ofPhragmatobia andPyrrharctia larvae feeding on sources of PAs were reported. The PA monocrotaline was shown to be a feeding stimulant forPyrrharctia larvae.