Parallel adaptations to nectarivory in parrots, key innovations and the diversification of the Loriinae

Specialization to nectarivory is associated with radiations within different bird groups, including parrots. One of them, the Australasian lories, were shown to be unexpectedly species rich. Their shift to nectarivory may have created an ecological opportunity promoting species proliferation. Several morphological specializations of the feeding tract to nectarivory have been described for parrots. However, they have never been assessed in a quantitative framework considering phylogenetic nonindependence. Using a phylogenetic comparative approach with broad taxon sampling and 15 continuous characters of the digestive tract, we demonstrate that nectarivorous parrots differ in several traits from the remaining parrots. These trait-changes indicate phenotype–environment correlations and parallel evolution, and may reflect adaptations to feed effectively on nectar. Moreover, the diet shift was associated with significant trait shifts at the base of the radiation of the lories, as shown by an alternative statistical approach. Their diet shift might be considered as an evolutionary key innovation which promoted significant non-adaptive lineage diversification through allopatric partitioning of the same new niche. The lack of increased rates of cladogenesis in other nectarivorous parrots indicates that evolutionary innovations need not be associated one-to-one with diversification events.

Birds at Eucalyptus and other flowers in Southern Brazil: A review

In southern Brazil, I recorded 14 species of hummingbirds, one woodpecker, three Psittacidae, four Tyrannidae, one mockingbird, and 31 tanagers and relatives at eucalyptus flowers. Others have registered 3 different hummingbirds, another parrotlet, four more tyrannids, a peppershrike, a thrush, and 5 tanagers and related birds, for a total of 69 species. However, commercial plantations rarely flower, so use is local or undependable. Understory Phaethorninae are not recorded at eucalyptus, rarely at other tall and hence multiflowered trees. Bromelias and other flowers are noted in various studies, which add 89 species of flower feeders, including 14 Psittacidae, 17 Trochilidae, and 37 tanagers and relatives. Isolated low flowers and epiphytes are mostly visited by hummingbirds (some by Coereba), but some tall trees (Chorisia) also. As two times as many tanager species visit flowers as hummingbirds, researchers will have to get up early and patiently study treetop and nonpatchy habitats. However, tree plantations can attract artificially, like feeders. Bunch-flowering extrafloral nectar (Mabea, Combretum) is preferred by wandering mixed-flock treetop or edge tanagers and relatives, which often crawl over bunched flowers like parrots or woodpeckers (or marsupials and other mammals) rather than hover at separate flowers like nonflocking Trochilidae or peck from nearby like Nectariniidae and Coereba. Clamberers and petal-pullers, even nectar robbers, can cause evolution of umbels and other bunched flowers, for the bird, mammal or insect receives pollen from nearby flowers. Psittacidae, saltators and others mostly eat flowers, but can pollinate if they touch nearby flowers. Multiflowered trees can also attract hawks, causing waves of tanagers, parrots and others that move on to pollinate trees via fear and nectarivory. Certain groups, notably thrushes and tyrannids, seem to use nectar little, the latter often catching insects.

Floral anatomy of Paepalanthoideae (Eriocaulaceae, Poales) and their nectariferous structures

• Background and Aims: Eriocaulaceae (Poales) is currently divided in two subfamilies: Eriocauloideae, which comprises two genera and Paepalanthoideae, with nine genera. The floral anatomy of Actinocephalus polyanthus, Leiothrix fluitans, Paepalanthus chlorocephalus, P. flaccidus and Rondonanthus roraimae was studied here. The flowers of these species of Paepalanthoideae are unisexual, and form capitulum-type inflorescences. Staminate and pistillate flowers are randomly distributed in the capitulum and develop centripetally. This work aims to establish a floral nomenclature for the Eriocaulaceae to provide more information about the taxonomy and phylogeny of the family. • Methods: Light microscopy, scanning electron microscopy and chemical tests were used to investigate the floral structures. • Key Results: Staminate and pistillate flowers are trimerous (except in P. flaccidus, which presents dimerous flowers), and the perianth of all species is differentiated into sepals and petals. Staminate flowers present an androecium with scale-like staminodes (not in R. roraimae) and fertile stamens, and nectariferous pistillodes. Pistillate flowers present scale-like staminodes (except for R. roraimae, which presents elongated and vascularized staminodes), and a gynoecium with a hollow style, ramified in stigmatic and nectariferous portions. • Conclusions: The scale-like staminodes present in the species of Paepalanthoideae indicate a probable reduction of the outer whorl of stamens present in species of Eriocauloideae. Among the Paepalanthoideae genera, Rondonanthus, which is probably basal, shows vascularized staminodes in their pistillate flowers. The occurrence of nectariferous pistillodes in staminate flowers and that of nectariferous portions of the style in pistillate flowers of Paepalanthoideae are emphasized as nectariferous structures in Eriocaulaceae. © The Author 2006. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved.

Flower mites decrease nectar availability in the rain-forest bromeliad Neoregelia johannis

Nectarivorous flower mites can reduce the volume of nectar available to pollinators. The effects of the flower mite Proctolaelaps sp. on nectar availability in flowers of a melittophilous bromeliad Neoregelia johannis (Bromeliaceae) was evaluated in a coastal rain forest in south-eastern Brazil. In a randomized block experiment utilizing 18 flower pairs, one per bromeliad ramet, pollinators (Bombus morio) and mites were excluded, and then nectar volume, sugar concentration and sugar mass were quantified over the anthesis period. Mites significantly reduced nectar volume early in the morning (6h00-8h00), but not later (10h00-12h00). Mites decreased total volume of nectar available up to 22%. Sugar concentration in nectar was higher earlier in the morning, and decreased between 10h00-12h00. The pronounced consumption of nectar by mites during the period of higher sugar concentration reduced the total amount of sugar available to pollinators by 31%. This is the first study showing that flower mites decrease nectar rewards in a melittophilous plant. Because nectar volume by itself incompletely describes nectar production rates and the effects of nectar removal by flower mites on the availability of sugar, our study highlights the inclusion of sugar content in future studies assessing the effects of thieves on nectar production rates. Copyright © 2010 Cambridge University Press.