Pyrrolizidine alkaloids in arctiid moths (Lep.) with a discussion on host plant relationships and the role of these secondary plant substances in the Arctiidae

Pyrrolizidine alkaloids (PA) have been identified in six species of Arctiidae reared on Senecio and Crotalaria. These include senecionine, seneciphylline, integerrimine, jacobine, jacozine, jacoline, jaconine and a metabolite (C₁₅H₂₅NO₅) from Senecio , and monocrotaline, trichodesmine and crispatine from Crotalaria.
The all-red aberration of Tyria jacobaeae (var. conyi) contained much less of the metabolite than normal examples of this species. Female Spilosoma lutea reared on the same plants of S. jacobaea contained markedly more jacobine and jacoline than die males.
Host plant relationships and secondary plant substances are discussed. It is suggested that the Arctiid moths' own deterrent secretions, directed against vertebrate predators, pre-adapts them for feeding on foliage likewise protected against large herbivores by toxic secondary plant substances such as cardenolides and pyrrolizidine alkaloids. These latter substances are more toxic to vertebrate than to insect herbivores, and their dual function of deterrent and insect aphrodisiac puts a premium on their sequestration and storage once a species has achieved the initial steps, and occupied the plant niche concerned. It is further suggested that the polyphagous habits of the Arctiidae result in a more equitable distribution of die secondary plant substances within the Mullerian complex concerned, thus providing a generalized warning message for the potential vertebrate predator.     

Association of restriction fragment length polymorphisms of swine leucocyte antigen class I genes with production traits of Duroc and Hampshire boars

Summary. Restriction fragment length polymorphism analyses of swine leucocyte antigen (SLA) class I genes were performed on 70 Duroc and 38 Hampshire boars from the 1986-87 national performance tests of each breed in the USA. Few boars were inbred. Southern blotting and hybridization procedures were performed on genomic DNA, isolated from white blood cells, using Pvu II endonuclease and a swine major histocompatibility complex (MHC) class I probe. Durocs had an average of 11 restriction fragments, with the most common being in 63% of the boars and the least common appearing in only one boar. Hampshire boars had an average of 12 restriction fragments, with the most common appearing in 73% of the boars and the least common appearing in only one boar. Least squares procedures and stepwise regression methods were used to examine the association between DNA restriction fragments and the selection index (INDEX), average daily gain (ADG), average backfat thickness (BF), loin muscle area (LEA), and age at 104kg (DAY104). In the Duroc breed one DNA restriction fragment was associated with decreased INDEX ( P < 0.05) and decreased ADG ( P < 0.05) whereas two other fragments were associated with increased BF ( P < 0.05). In the Hampshire breed two restriction fragments were associated with an increase in INDEX ( P < 0.05). Cluster analyses were used to group pigs of each breed on the basis of similar RFLP patterns. One cluster group in the Duroc breed was associated with lower average INDEX values ( P < 0.05), greater average DAY104 ( P < 0.05), and a larger mean LEA ( P < 0.05). In the Hampshire breed one cluster group was associated with lower INDEX ( P < 0.05). These results suggest there may be an association between swine MHC class I genes and performance traits in swine. The use of SLA class I restriction fragments, as genetic markers, may have potential in the future for improving pig performance.