Floral colour variation of Nicotiana glauca in native and non-native ranges: Testing the role of pollinators' perception and abiotic factors.

Invasive plants displaying disparate pollination environments and abiotic conditions in native and non-native ranges provide ideal systems to test the role of different ecological factors driving flower colour variation. We quantified corolla reflectance of the ornithophilous South American Nicotiana glauca in native populations, where plants are pollinated by hummingbirds, and in populations from two invaded regions: South Africa, where plants are pollinated by sunbirds, and the Balearic island of Mallorca, where plants reproduce by selfing. Using visual modelling we examined how corolla reflectance could be perceived by floral visitors present in each region. Through Mantel tests we assessed a possible association between flower colour and different abiotic factors. Corolla reflectance variation (mainly along medium to long wavelengths, i.e. human green-yellow to red colours) was greater among studied regions than within them. Flower colour was more similar between South America and South Africa, which share birds as pollinators. Within invaded regions, corolla reflectance variation was lower in South Africa, where populations could not be distinguished from each other by sunbirds, than in Spain, where populations could be distinguished from each other by their occasional visitors. Differences in corolla colour among populations were partially associated with differences in temperature. Our findings suggest that shifts in flower colour of N. glauca across native and invaded ranges could be shaped by changes in both pollination environment and climatic factors. This is the first study on plant invasions considering visual perception of different pollinators and abiotic drivers of flower colour variation.

Flower Diversification Across "Pollinator Climates": Sensory Aspects of Corolla Color Evolution in the Florally Diverse South American Genus Jaborosa (Solanaceae).

Flower phenotype may diverge within plant lineages when moving across "pollinator climates" (geographic differences in pollinator abundance or preference). Here we explored the potential importance of pollinators as drivers of floral color diversification in the nightshade genus Jaborosa, taking into account color perception capabilities of the actual pollinators (nocturnal hawkmoths vs. saprophilous flies) under a geographic perspective. We analyzed the association between transitions across environments and perceptual color axes using comparative methods. Our results revealed two major evolutionary themes in Jaborosa: (1) a "warm subtropical sphingophilous clade" composed of three hawkmoth-pollinated species found in humid lowland habitats, with large white flowers that clustered together in the visual space of a model hawkmoth (Manduca sexta) and a "cool-temperate brood-deceptive clade" composed of largely fly-pollinated species with small dark flowers found at high altitudes (Andes) or latitudes (Patagonian Steppe), that clustered together in the visual space of a model blowfly (Lucilia sp.) and a syrphid fly (Eristalis tenax). Our findings suggest that the ability of plants to colonize newly formed environments during Andean orogeny and the ecological changes that followed were concomitant with transitions in flower color as perceived by different pollinator functional groups. Our findings suggest that habitat and pollination mode are inextricably linked in the history of this South American plant lineage.

Revision of "Aemilia" pagana Species-Group (Lepidoptera: Erebidae: Arctiinae), with a Description of a New Endemic Species and Comments on the Conservation Status.

A taxonomical rearrangement of "Aemilia" pagana species-group is proposed: Leucanopsis pagana (Schaus in Proc Zool Soc London 1894:225-243, 1894) comb. nov. and L. ninae (Orfila in Rev Soc Entomol Argent 21:67-70, 1959) comb. nov. A new endemic species from Pampa de Achala, Córdoba, Argentina, closer to both species, is described: Leucanopsis navarroi sp. nov. These three species can be recognized because the color pattern is the darkest among species of Leucanopsis. Characteristics of male genitalia suggest the nomenclatural rearrangement proposed. Leucanopsis pagana comb. nov. has a wide distribution from the center of Brazil to northeastern Argentina, including southern Paraguay. The known distribution and geospatial analysis suggest that this species is not in danger. Leucanopsis ninae comb. nov. is restricted to only one known locality (Villa Gesell, Buenos Aires). The restricted known distribution, the different land use practices, and geospatial analysis suggest that this species could be endangered. Leucanopsis navarroi sp. nov. is endemic to the high plateau present in the center of Argentina called Pampa de Achala. The known distribution and geospatial analysis suggest that this species could be endangered. Further studies are necessary to determine effectively the conservation status of these three species.

Reexamination of the activation of yeast proteinase B at pH 5: loss of inhibition effect of proteinase B inhibitors.

The activation of yeast proteinase B at pH 5 has been suggested to be due to the degradation of a specific inhibitor for the enzyme, IB, by proteinase A. However, we found that when pepstatin, which completely inhibits proteinase A, was included in the pH 5 activation mixture, the same time-dependent activation of proteinase B was observed. Furthermore, proteinase B preparations that were void of proteinase A activity were still activated by incubation at pH 5. We found that the activation of proteinase B at pH 5 was due primarily to the irreversible loss of inhibitory effect of IB, which can be resolved by isoelectrofocusing into four distinct bands with isoelectric points of 4.6, 6.1, 6.8 and 7.6. These four forms of IB showed varying degrees of stability at pH 5, which may explain some of the differing observations reported in the past.