Species, characters and traits in the (Lep.: Arctiidae)

1 1 2 Michael Boppré , Ottmar W. Fischer & Christoph L. Häuser [email protected] 1 Forstzoologisches Institut, Albert-Ludwigs-Universität, D-79085 Freiburg i.Br., Germany http://www.fzi.uni-freiburg.de contains more information on Amerila, including 2 Staatliches Museum für Naturkunde, Rosenstein1, D-70171 Stuttgart, Germany keys for determination and downloadable PDF files of several p­ublications.

Introduction The diversity of species in Africa Relation of adults to plants containing Pheromonal communication Gaps in knowledge and prospects pyrrolizidine alkaloids (PAs) Female pheromone glands The paleotropic genus Amerila Walker 1855 Although Amerila can in general Strikingly, so far, no pheromone glands The diversity of characters and traits (usually referred to previously as Rho­do­­ easily be recog­nized even in the field by Adult Amerila are pharmacophagous with have been found in females of Amerila – but found in the genus Amerila makes this ta- Amerila s­ynto­mina ­ sp. gas­tria) comprises some sixty species of a characteristic phenotypical appearance, respect to pyrrolizidine alkaloids (PAs), i.e. there is no indication that mate-locating is xon most suitable for morphological, phy- large, robust and aposematically coloured most sp­ecies are difficult to disting­uish by Nyctemera sp. independent of nutritional requirements, they not mediated by female sex pheromones in siological, chemical, behavioural, ecologi- arctiine moths. The majority of species external characters. Male genitalia and are attracted to withered plants containing this genus. However, the females of A. bubo­ cal, genetical, evolutionary and taxonomic occurs in the Afrotropical region including androconial organs, however, show remark­ Early instars these secondary metabolites (as well as to possess elaborate hair brushes laterally to studies. We aim to continue to investigate Madagascar, but in the Indo-Australian re­ able differences. Larval hostplants dishes with pure chemicals) from which they the abdominal tip which are almost indiscri­ this genus thoroughly to eventually come gion some 20 species are distributed from The information in the literature on larval take up these compounds and store them minable to the male scent organs of this up with cladistic analyses considering all India to New Guinea, the Solomon Islands hostplants is very scant and dubious; in for defence. There seems to be no sex-bias species. We have observed that they are kinds of characters. and NE Australia. most cases it is unknown if the caterpillars in PA-related pharmacophagy. displayed at night. However, there are still huge and quite had been found on the respective plants general gaps in knowledge; in particular A. vitrea A. ro­s­eo­marginata and normally utilize them or if they rather data from the field are missing­. Data on only had accepted this food in captivity. larval host plants, adult sources of PAs, The information found in the literature on information on habitat requirements, sea- 9 species covers 15 plant families which sonality, parasitoids, etc., are urgently is hard to believe. However, if it proves Female A. bubo­ displaying abdominal hairbrushes (left) which needed. true, it is most interesting for phylogenetic contain large glandular cells (right). Apparently, we do not yet have a com­ considerations. Several species of Amerila attracted to dishes containing pure plete overview on the African species. In our pyrrolizidine alkaloids. Agavaceae (Dracaena), Apocynaceae Androconial organs recent revision [Häuser & Bop­p­ré (1997) Drawing of an Amerila (18th century). (Beaumon­tia), Asclepiadaceae (Mars­denia), As- Amerila can be Scent organs in male Amerila are more A revision of the Afrotropical taxa of the teraceae (Gynura), Combretaceae (Com­bretum), The genus has received quite little baited with pure diverse than in any other genus of moths. genus Amerila Walker (: Arc- A. catinca A. bubo­ Dioscoreaceae (Dio­s­co­rea), Ebenaceae (Dio­s­pyro­s­), attention in science and the literature Euphorbiaceae (), Moraceae (Ficus­), Myr- PAs as well as with Most peculiar are pneumatically expandable tiidae). System Entomol 22: 1-44] we have is almost entirely restricted to the pure The two colour patterns (white and taceae (Eugenia, Syzegium), Ochnaceae (Ochna), natural sources of coremata originating from the valves, but recognized 35 species (of several males descrip­tion of sp­ecies. Sig­nificant infor- brown) found do not reflect relatedness be- Papilionaceae (), Periplocaceae (Gymnan­ PAs, e.g., dry Helio­­ brushes at certain sternites or the abdomi- only) – in the meantime from several coll- thera), Rubiaceae (Ixo­ra), Sapotaceae (Mimus­o­ps­), mation on their biology is scant. Here, we cause striking sexual dimorphism in several Smilacaceae (Smilax), Solanaceae (So­lanum), Ste- tro­pium (Boragin­ nal tip, tergal scale bands, forewing glands ectors/museums we have received material want to demonstrate that Amerila moths species links both types of patterns. ruliaceae (Theo­bro­ma). aceae) or Cro­talaria and felted patches on hindwings also occur. containing undescribed species. A look at a deserve intense research because of their (Fabaceae). The Some species lack such organs entirely. distribution map also suggests that further interesting combination of features. They Sexual Dimorphism moths gather the species are to be found. exhibit a variety of traits which make them In a few species there is moderate sexual PAs by ap­p­lying­ a fluidvia their proboscides particularly interesting for chemoecological dimorphism, but usually the sexes show onto the dry plant material or pure crystals, studies on chemical defenses, pheromone either no differences at all or they look resp., and imbibe the dissolved PAs. communication and evolutionary aspects completely different (males being brown, 5th-instar larva of ­ and caterpillars of A. affinis of -plant relationships but they also females white – the opposite situation feeding­ on artificial diet. Acoustic communication bear a lot of systematic and biog­eog­rafic does not occur). Then males and females, Larval characters Tymbal and tympanic organs interest. respectively, can hardly be distinguished Larvae have not yet been described, how­ When disturbed, adult Amerila produce his- Our attention to Amerila was drawn by from non-dimorp­hic sp­ecies (cf. fig­ures). Of ever, with the aid of an artificial diet we are sing sounds which are in part detectable to discovering their pharmacophagous relation several species only males are available, able to rear many species (15 so far) and human ears. For Amerila phaedra we have to plants containing pyrrolizidine alkaloids the females remain yet unknown. determine larval characters. In general, we experimental evidence that these acoustic (PAs) (see below), a syndrome Amerila recognize in several species considerable signals facilitate learning of repelling tasting share with several other , e.g., Nyc­ changes of characters between instars. A moths in bats, i.e. there is some prove for Artificiallyp­ rotruded androconial org­ans of Amerila catinca, A. temera, Digama, Ctenuchinae, Danainae, notable behaviour of the caterpillars is that the existence of acoustic aposematism. luteibarba, A. ro­s­eo­marginata and A. vitrea. Ithomiinae, Zo­no­cerus­ grasshoppers, Ga­ they writhe around when disturbed. Tymbal as well as tympanic organs are bo­nia leaf beetles, chlorop­id flies [cf. Bop­p­ré valuable taxonomic characters. Chemistry of androconial secretions M (1999) 'Drug-addicted' insects in Africa. Biology and ecology of Amerila The diverse morp­holog­y is reflected in their Metamorphosis 10: 3-15]. Defensive frothing chemistry. For the human nose only some How intimate are relations of Rhopalo- Apart from their pharmacophagous beha­ species emit an odour which can be pleas­ Examples for strikingly sex-dimorphic species: males (left) and viour towards PAs, there are no field Jointly with hissing sounds, disturbance ant or rep­ulsive. Chemically, we always find cera and Heterocera? females (right) of Amerila phaedra (top) and A. leuco­ptera. We know of two documented cases of court­ records of antagonists, courtship behavi- is responded with the release of large a complex bouquet composed of different Call for help and cooperation ship attempts of a male Amerila bubo­ with a Mimicry? our or any other biologically/ecologically amounts of a repulsive-smelling froth from types of molecules. Lepidopterists interested in this genus are TIC: VITMALE.D Abundance

6500000 male Amauris­ niavius­ (Danainae) .... Amerila s­ynto­mina was previously placed relevant information in the literature prothoratic glands. The froth is made up by 12.67 cordially invited to cooperate with us. With 6000000 in the genus Caryatis­. Indeed, the forewing but laboratory observations as well as haemolymph and, 5500000 the knowledge on attraction of both sexes 5000000 pattern of A. s­ynto­mina is quite exceptional morphological and chemical studies in case, contains 4500000 of Amerila to baits containing PAs, simple 4000000 18.50 22.17 ¨ 15.04 within Amerila and almost indiscriminable show that Amerila possess elaborate PAs. Reimbibing 3500000 10.04 means to collect sp­ecimens in the field 16.47 3000000 froth after an attack 2500000 from Caryatis­, particularly in resting posi- communication systems. Their defensi- 21.77 exist. Also, rearing­ on artificial diet is no 2000000

1500000 likely is to avoide 17.18 tion of the life moths. This also holds true ve means constitute of hissing sounds, 22.9243.37 problem. We can assist you by providing 24.27 1000000 16.93 23.60 26.83 14.24 20.05 22.76 12.59 18.26 19.14 20.2913.30 222.25.982 500000 12.25 14.98 16.23 Note the display of expanded androconia by the A. bubo­ for the (day-active) arctiids of the genus frothing and storage of deterrent-tasting waste of valuable 8.19 15.38 16.87 PA-baits, artificial diet, etc. Time--> 0 6.00 8.00 10.00 12.00 14.00 16.00 18.00 20.00 22.00 24.00 26.00 (arrow). Photos: courtesy of Paul Brakefield. Nyctemera. PAs. Perhaps, ultrasonic signals are also Frothing A. bubo­. proteins and PAs. Gaschromatogram of an extract of scent organs of A. vitrea. P L E A S E, CONTACT US! xi/99