Nepticulidae

Nepticulidae of the Andean Polylepis woodlands

Polylepis Ruiz & Pav. is the only genus with arborescent species that occurs naturally at high elevations of the Andes (Harling 1979; Kessler 2002; Andean Páramo 2016); some species of Polylepis even occur at an altitude of 4850 m (Braun 1997). After the glacial period the highlands of the Andes were open to colonization by Polylepis trees, and Polylepis woodlands constituted the natural vegetation in much of the High Andes (Clapperton 1983; Hooghiemstra & Cleef 1995; Fjeldså & Kessler 1996; Ridbäck 2008). It is interesting to note that this Andean endemic host-plant is phylogenetically related to Acaena (Rosaceae: tribe Sanguisorbeceae, section Elongatae) (Simpson 1986), mainly known from New Zealand, Australia and South Africa.

Until recently, no leaf-mining Nepticulidae associated with Polylepis as a host-plant had been discovered. Only during the last ten years the first records were obtained, in material collected during the Polylepis Expedition (1987), and by later collecting in Peru (2008) and Ecuador (2001, 2005, and 2007). The results have only recently been published (Stonis et al. 2016c). Several discoveries new to science of Polylepis- feeding Nepticulidae species were made in Ecuador (Figs 264, 265) and Peru (Figs 259–263). From the Andes of Peru, a new species Stigmella polylepiella Diškus & Stonis was described (Stonis et al. 2016c); larvae of this morphologically interesting species are leaf-miners in leaves of Polylepis racemosa Ruiz & Pav. and they spin a unique shaped cocoon inside the leafmine (Figs 259, 260). The species was documented as highly abundant in the type locality northwest of Cuzco, with recorded mass mining, literally infesting the host-plant.

A few other discoveries on Polylepis include new, but unnamed species feeding on Polylepis pauta Hieron. in Ecuador (Stigmella species 763, S. species 764) (Figs 264, 265), or merely a documented record of leaf-mines of an unknown Nepticulidae taxon associated with Polylepis racemosa from Peru (Figs 261–263) (Stonis et al. 2016c). Unexpectedly, species feeding on Polylepis are not closely related and display great morphological diversity. They probably represent older evolutionary events rather than very recent speciation so common in the Andean fauna of Nepticulidae (Stonis et al. 2016c).

Finally, although all currently published records of Polylepis -feeding Nepticulidae came from elevations ranging from 2850 to 3400 m, it is expected that these species (or other Polylepis -feeding species) may also occur at elevations above 3700 m.