An ecological study of the relationship between two living fossils in Malawi: the Mulanje Tiger Moth (Callioratis grandis) and the Mulanje Cycad (Encephalartos gratus) Julian Bayliss 1,2,3,4 *, Camilla Burrow 3 , Sara Martell 3 and Hermann Staude 4 1 Mulanje Mountain Conservation Trust (MMCT), PO Box 139, Mulanje, Malawi, 2 Wildlife Conservation Society (WCS), International Programs, 2300 Southern Boulevard, Bronx, NY 10460-1090, U.S.A., 3 Spatial Ecology and Landuse Unit (SELU), School of Life Sciences, Gipsy Lane Campus, Oxford Brookes University, Headington, Oxford, OX3 0BP, U.K. and 4 Lepidopterists’ Society of Africa, PO Box 398, Magaliesburg, Gauteng 1791, South Africa Abstract The Mulanje tiger moth (Callioratis grandis) has recently been discovered feeding solely on the Mulanje Cycad, Encephalartos gratus. In its type locality Encephalartos gratus is severely threatened through habitat destruction and human population growth. As a result the first detailed demographic survey of Encephalartos gratus on Mount Mulanje was undertaken with particular emphasis on the relationship between E. gratus and Callioratis grandis. What is unusual about C. grandis is that the males exhibit lekking behaviour, for which aposematism may be a prerequisite. Cycads were surveyed in a systematic manner. Both the biotic and abiotic parameters were recorded from 532 wild Encephalartos gratus. Results showed the morphological range of measurements differed from that of previously published literature on this species. Results also showed that the incidence of Callioratis larval damage was related to the maturity of the wild cycads – moth damage was greater on more mature plants. Approximately 50% of surveyed cycads showed evidence of Callioratis moth damage, however, there was no apparent preference from the moth to select either male or female cycads as food plants for the larvae. In some cases there was severe damage to cycad fronds, but this did not seem to affect the production of reproductive cones or even the survival of individual cycads. Key words: Callioratis, cycads, diptychinae, Encephalartos, lekking, Mulanje Re ´sume ´ On a de ´couvert re ´cemment que le papillon du Mulanje (Callioratis grandis) ne se nourrit que sur le cycadale Mulanje Encephalartos gratus. Dans son milieu type, Encephalartos gratus est gravement menace ´ dans la nature a ` cause de la destruction de l’habitat et de la croissance de la population humaine. Par conse ´quent, la premie `re e ´tude de ´mographique de ´taille ´e d’Encephalartos gratus re ´alise ´e sur le mont Mulanje fut entreprise en insistant particulie `re- ment sur la relation entre Encephalartos gratus et Callioratis grandis. Ce qui est inhabituel chez C. grandis, c’est que les ma ˆles pre ´sentent un comportement territorial (lek). Les cycadales ont e ´te ´ syste ´matiquement surveille ´es. On a enregistre ´ les parame `tres biotiques et abiotiques pour 532 Encephalartos gratus poussant dans la nature. Les re ´sultats ont montre ´ que l’amplitude des mesures morphologiques diffe ´rait de ce que la litte ´rature existante de ´crit sur cette espe `ce. Ils ont aussi montre ´ que l’incidence des dommages cause ´s par les larves de Callioratis e ´tait lie ´e a ` la maturite ´ des cycadales sauvages – les de ´ga ˆts cause ´s par les papillons e ´taient plus graves sur les plants plus matures. Environ 50% des cycadales suivis montraient des traces de dom- mages cause ´s par ce papillon, mais il n’y avait pas de preuve qui aurait pu montrer que le papillon se ´lectionnait des cycadales ma ˆles ou femelles pour en nourrir ses larves. Dans certains cas, il y avait des de ´ga ˆts se ´rieux dans les feuilles de cycadales; cependant, cela ne semblait pas af- fecter la production de co ˆ nes reproducteurs, pas plus que la survie des individus. *Correspondence: E-mail: jlbayliss@yahoo.co.uk 472 Ó 2009 The Authors. Journal compilation Ó 2009 Blackwell Publishing Ltd, Afr. J. Ecol., 48, 472–480