Preliminary Report / summary (mid-August 2007)
A project aiming to study the community of Ctenuchini (Lep. Arctiidae) at El Bosque Nuevo has been initiated in 2004. Due to the lack of funding, its progress unfortunately is slow, however, research on several key aspects is on a good way.
Details of the research goals and background references have been specified after an initial visit of Tanja Weis in July and August 2004. In her Master Thesis she has done a first survey of moths attracted to sources of pyrrolizidine alkaloids (PAs) (see poster above). Her work was followed up in September/October 2006 by Dinah Esser and Svenja Lorenz who did an internship at EBN, and in August/September 2007 by Annette Majer and Hannes Freitag also doing an internship.
On the way to the long-term goals of the project, so far
- about 90 species of Ctenuchini and ... species of Arctiini have been found at EBN to be pharmacophagous with respect to pyrrolizidine alkaloids, for many it is the first record;
- ... species have been found to possess androconial organs, either inside the abdomen, on the legs or on the wings – morphological and chemical analyses are in progress for a selection of species;
- ... species could be reared from egg to adult, some on our artificial diet
Species attracted to baits containing PAs have, so far, not been found at nectar sources or flying about. It is a great challenge to illucidate their activities. Since in most species PA-pharmacophagy is male-biased, of most species we have not seen females yet and, therefore, rearing and describing the biology of immature stages is still poor. Also, our aim to make certain colourful and day-active species commercial for the mariposario at EBN is less advanced than expected.
Only a small fraction of the species attracted to sources of PAs is also attracted to light, however, at the light we find additional species, not visiting the baits.
Of the few species so far reared, the building of cocoons for pupation was found to be interesting: caterpillars build their cocoons with their own hairs by picking them systematically in small bundles and arrange them to form a shelter for pupation; often certain larval hairs are also used to establish a yard around the cocoon – it probably is a good protection against ants.
In the course of baiting with PA-sources, not only moths have been attracted but also dipteran flies (Chloropidae) – this parallels earlier findings in East Africa (Boppré M, Pitkin BP, 1988).
Androconial organs in Ctenuchini exhibit a great diversity. In addition to 'ordinary' types of androconia at EBN we have found species possessing a novel type of hairs/scales – they do not show the basic structural elements of lepidopteran scales and are filled with sugar. Laboratory studies on these scales are in progress. Also we give special attention to flocculent materials of males of many ctenuchine species which perhaps function like pheromone-transfer-particles.
Mimicry in Ctenuchini is most obvious, however, we are finding few non-Lepidoptera of the presumed mimicry rings.
Most unexpectedly a species has been found which emits an aerosol..
Equally unexpected was the finding that adult moths are parasitized by dipteran maggots.
Parallel to field work at EBN, we are in the process of establishing a database (CtenuIS) including photographs and labels of type material of Ctenuchini from The Natural History Museum (London), ............. which have been taken by Boris Kreusel during his thesis work in 1997-1999.
With respect to plants containing pyrrolizidine alkaloids, so far, at EBN an Emilia sp., Erechtites hieraciifolius and Prestonia portobellensis have been found – they do contain PAs and are attractive for ctenuchines and chloropids. We assume the presence of further natural sources of PAs at EBN.