## 3 Discussion
### Environmental Influence on Floral VOCs and Pollinator Climate  
Environmental variables that contributed the most to the ENMs of the two _Jabrosa_ clades provide candidate factors to explain the differences observed in scent profiles and pollination modes. One challenge inherent to niche modeling approaches is the need for caution when using current climatic or physiological phenomena to interpret historical or paleo-ecological inferences emerging from such models. For example, it is known that drought may affect total VOCs released per flower and its chemical composition as a plastic response in real (ecological) time, and that the magnitude of the response is species-specific [102; 37; 103]. It is less well understood whether plants adapted to drought (or other environmental stressors) tend to produce different blends of volatile compounds constitutively, for reasons ranging from water balance to pleiotropic responses to plant stress (e.g., anthocyanin pigments). For example, one study [36] showed that exposure to different levels of ozone decreased the relative concentrations of monoterpenes and anisaldehyde, but increased the release of benzaldehyde from flowers of _Brassica nigra_ ([PERSON]. Such changes in blend ratios are likely to impact visitation by both mutualists and antagonists [9; 104]. Similarly, higher temperatures generally increase floral VOC emissions due to biosynthetic enzyme kinetics [105; 106], suggesting a general enhancement of floral scent under warmer and/or drier conditions. We speculate that plants expanding into habitats in which heat, desiccation, UV irradiance, wind and changes in relative humidity represent novel selective pressures, might respond in ways that either directly or indirectly alter their potential for volatile biosynthesis and emissions. _Jabrosa_ species in the Andean clade include plants whose entire surfaces (leaf, stem and flower) are covered with several classes of glandular trichomes, whose primary functions may be to protect against desiccation, UV damage and/or herbivore attack. Such trichomes may represent exaptations for shifts in volatile emission and blend composition in Andean _Jabrosa_ species. Our findings suggest that diversification in floral scent could have occurred in concert with shifts in environmental suitability accompanied by geographical differences in pollinator availability, specifically, the reduced abundance of hawkmoths. Diurnal range variation of temperature, the most important variable explaining the environmental suitability of Andean clade species, is also known to affect insect locomotion and physiology [107]. Temperature also contributes to diel differences in floral scent emission profiles [40], thus directly influencing the floral signals that attract both flies and hawkmoths [71; 108]. The harsh environmental conditions in high elevation Andean habitats (low temperatures, short growing seasons, and strong winds) place constraints on potential visitation by nocturnal hawkmoths because they are endothermic insects that rarely fly above 1300 m in Subtropical Argentina [109]. Hawkmoth diversity is higher in subtropical lowland areas where ambient temperatures at dusk are moderate [43; 81; 110]. The oxygenated sesquiterpenes or aromatic VOCs identified from the hawkmoth-pollinated Subtropical Lowland clade species of _Jaborosa_ were previously shown to be targets of phenotypic selection in lowland but not in mountain habitats for _Gymnadenia odoratssima_, a European orchid species [33]. Altitude may be indirectly affecting scent emissions through its effect on the occurrence of hawkmoths, pollinators that are globally constrained to lowland areas. Pollination by saprophilous flies becomes substantial in the high-mountain Andes, where pollinator limitation strongly constrains the reproductive success of self-incompatible plant species [111; 112]. In particular, species of the flesh-fly genus _Microcerella_ Macquart, recorded as pollinators of the Patagonian species _J. magellanica_ and _J.