Diversity, evolutionary specialization and geographic distribution of a mutualistic ant-plant complex: Macaranga and Crematogaster in South East Asia

Abstract

The most conspicuous and species-rich ant-plant mutualism in the Malesian region is found in the important pioneer tree genus Macurungu, yet little is known about the identities or community ecology of the species involved. Our studies have revealed a far more complex system than previously thought. This paper presents the first extensive investigation in the whole distribution area of myrmecophytic Mucarungu. All ant-inhabited species were restricted to the moister parts of SE Asia: Peninsular Malaysia, South and East Thailand, Sumatra and Borneo. We found a rather strict and similar altitudinal zonation of myrmecophytic Macaranga species in all regions. Here we focus on the majority of the 19 Mucaranga species obligatorily associated with ants of the genus Crematogater. We identified a total of 2163 ant queens which belonged to at least eight (morpho)species of the small subgenus Decacraa as well as to one non-Decacrau @robably from Atopogyne). The ant species were not randomly distributed among the Mucuranga species but distinct patterns of associations emerged. Despite common sympatric distribution of Mucurangu species, in most cases a surprisingly high specificity of ant colonization was maintained which was, however, often not species-specific but groups of certain plant species with identical ant partners could be found. These colonization patterns usually but not always mirror existing taxonomic sections within the genus Macaranga. Possible mechanisms of specificity are discussed. The results are compared with other ant-plant mutualisms. 0 1999 The Linnran Socirtv of Ixlndon ADDITIONAL KEY WORDS:-biogeography ~ co-evolution -Decucremuhost specificity~

Timing of butterfly parasitization of a plant–ant–scale symbiosis

“…However, we did not investigate the geographical context of the lycaenid diversification because the lycaenid sampling locations were insufficiently widespread for phylogeographic inferences. Further sampling throughout the distribution area of myrmecophytic Macaranga (Sumatra, the Malay Peninsula, and Borneo; Fiala et al 1999;Davies et al 2001) would be necessary to clarify the postglacial biogeography of the lycaenids.…”

Estimation of dispersal distances of the obligately plant‐associated ant Crematogaster decamera

“…Unlike most other ant-plant associations (Longino, 1989;Fonseca & Ganade, 1996;Fiala et al, 1999;Stanton et al, 2002;Yu et al, 2004;Debout et al, 2009) foundresses only face intraspecific competition. Successional changes in ant-inhabitance do occur though, with foundresses of Crematogaster msp.…”

“…The associations of ants and plants are not strictly speciesspecific. Nonetheless, recurring association patterns between the two groups can be observed over a wide geographical range (Fiala et al, 1999;Feldhaar et al, 2003b).…”

“…These colonies dominate young trees only and for several years. Abandoned trees are colonised by other ant species, mainly Crematogaster (Decacrema) morphospecies 1 (Fiala et al, 1999;Feldhaar et al, 2003a,b). Seedlings often occur clumped in forest gaps and sometimes single individuals are found within gaps (called 'sites' hereafter, Table 1).…”

“…In one of the most species-rich ant-plant symbiotic associations worldwide, approximately 30 species of pioneer trees of the genus Macaranga (Euphorbiaceae) are obligately associated with specific partner ants, mostly by eight species of Crematogaster ants (subgenus Decacrema) (Fiala et al, 1999;Blattner et al, 2001;Davies et al, 2001;Feldhaar et al, 2003a;Bänfer et al, 2004;Quek et al, 2007). The associations of ants and plants are not strictly speciesspecific.…”