The soft scale (Coccidae) associates of Malaysian ant-plants

Abstract

Myrmecophytic species of the Paleotropical plant genus Macaranga (Euphorbiaceae) have hollow stems that are almost always occupied by ants of the genus Crematogaster and scale insects of the family Coccidae (Hemiptera: Coccoidea). The coccids have a cryptic endophytic lifestyle and are confined to this microhabitat. They are much more diverse than previously recognised. First data are presented on the diversity, prevalence, specificity and distribution of the coccids associated with myrmecophytic Macaranga species. Twenty-two species of Coccidae in total, including 15 previously unknown from Macaranga, were discovered from 19 species of Macaranga in Peninsular Malaysia and Borneo. The original describers tentatively assigned the known coccid species to Coccus (Coccinae) but the Macaranga coccids still require taxonomic research to establish their correct placing. The coccids varied in their host-plant specificity from species that occurred in most of the sampled Macaranga to one species that was found almost exclusively only on a single host species. In addition to their occurrence on Macaranga, only three species, C. macarangae and C. secretus and morphospecies C. 214 were found on rare occasions in the stem interior of a few other myrmecophytes and in a non-myrmecophytic liana, but did not regularly colonise these plants. Most of the coccids can be regarded as highly specific at the plant genus level.

How Do Scale Insects Settle into the Nests of Plant-Ants on Macaranga Myrmecophytes? Dispersal by Wind and Selection by Plant-Ants

“…The limited range of symbiotic hemipteran species of Macaranga plant-ants (Heckroth et al 1998;Ueda et al 2008Ueda et al , 2010 can no doubt be maintained by such rejecting behaviors as observed in our system. Selection of scale insects by plant-ants may be adjusted in the evolutionary process on the basis not only of food intake from the honeydew or meat of scale insects but also of the total effects, including herbivory damage caused by the scale insects on the host plants.…”

“…However, partnerships between plant-ants and coccids are not highly species-specific, although several Coccus spp. exclusively inhabit ant nests in Macaranga myrmecophytes (Heckroth et al 1998;Ueda et al 2008Ueda et al , 2010.…”

“…Macaranga myrmecophytes (Euphorbiaceae) harbor scale insects of the genus Coccus (Coccidae) inside hollow stems that are occupied by partner plant-ants (Heckroth et al 1998;Ueda et al 2008Ueda et al , 2010. Some Macaranga species depend on plant-ants for anti-herbivore defense, and they are thought to be unable to survive without symbiotic plant-ants (Fiala et al 1989(Fiala et al , 1994Itioka et al 2000;Heil et al 2001).…”

“…Coccids have never been previously observed being carried by alate foundress queens (Fiala & Maschwitz 1990;Maschwitz et al 1996, and Handa & Itioka personal observation of >30 alate plant-ant queens founding new colonies). In addition, coccids have rarely been observed in early-stage nests of plant-ant colonies, even in several Macaranga myrmecophyte species that almost always harbor symbiotic coccids (Fiala & Maschwitz 1990;Heckroth et al 1998).…”

A new species of ant-tended soft scale of the genus Cryptostigma Ferris (Hemiptera: Coccidae) associated with bamboo in Peru

“…most Cladomyrma ants; Moog et al 2003), whereas a few others only cultivate coccids (e.g. ants of the genus Crematogaster Lund in the hollow stems of Macaranga Thouars; Heckroth et al 1998). In the Neotropics, the coccids most frequently associated with specialist plant-ants, or with other ants nesting inside plant cavities, belong to the genera Akermes Cockerell, Cryptostigma Ferris, Cyclolecanium Morrison, Megasaissetia Cockerell, Neolecanium Parrott and Toumeyella Cockerell of the subfamily Myzolecaniinae (Hodgson 1994.…”