Epizoochory in Parrots as an Overlooked Yet Widespread Plant-Animal Mutualism.

Plant-animal interactions are key to sustaining whole communities and ecosystem function. However, their complexity may limit our understanding of the underlying mechanisms and the species involved. The ecological effects of epizoochory remain little known compared to other seed dispersal mechanisms given the few vectors identified. In addition, epizoochory is mostly considered non-mutualistic since dispersers do not obtain nutritional rewards. Here, we show a widespread but unknown mutualistic interaction between parrots and plants through epizoochory. Combining our observations with photos from web-sources, we recorded nearly 2000 epizoochory events in 48 countries across five continents, involving 116 parrot species and nearly 100 plant species from 35 families, including both native and non-native species. The viscid pulp of fleshy fruits and anemochorous structures facilitate the adherence of tiny seeds (mean 3.7 × 2.56 mm) on the surface of parrots while feeding, allowing the dispersion of these seeds over long distances (mean = 118.5 m). This parrot-plant mutualism could be important in ecosystem functioning across a wide diversity of environments, also facilitating the spread of exotic plants. Future studies should include parrots for a better understanding of plant dispersal processes and for developing effective conservation actions against habitat loss and biological invasions.

Isolation and characterization of 15 new microsatellite markers for the globally endangered Lear's macaw Anodorhynchus leari.

A set of 16 microsatellite markers was characterized for Lear's macaw (Anodorhynchus leari) using DNA samples from captive individuals. Extending this molecular toolkit, including the use of samples from wild individuals, is expected to provide the required power of resolution for pedigree inference of both wild and captive individuals, and could support research on the genetic structure of wild populations. We characterize a set of 15 microsatellite markers optimized for the Lear's macaw, developed from a microsatellite-enriched library in a three-step procedure. Primer pairs were initially designed for 62 microsatellites with > 7 tandem repetitions. After amplification of DNA of five wild individuals from different localities, 22 loci seemed to be polymorphic and were further tested on 12 wild nestling samples. Fifteen unlinked loci showed unambiguous peaks and low to moderate polymorphism levels. The combination of the four most polymorphic markers allowed individual identification even of putative sibs.These markers complement previously described microsatellites developed for A. leari and constitute a fundamental genetic toolkit for the investigation of the genetics of both wild and captive populations, thus assisting integrated management plans for the conservation of this globally endangered species.

Experimental removal of invasive Africanized honey bees increased breeding population size of the endangered Lear's macaw.

BACKGROUND: Invasive Africanized honey bees potentially compete with cavity-nesting birds in South America. However, the impacts of this competition and its conservation consequences to threatened species are poorly known. We quantified the presence of these bees and assessed their competition for cliff cavities used by nesting Lear's macaws Anodorhynchus leari, a globally endangered parrot endemic to the Caatinga biome of Brazil. We treated beehives with permethrin by shooting them with a crossbow bolt that distributed the compound upon impact. When feasible, we removed the comb and applied an insecticide (fipronil) to deter bee recolonization. We subsequently surveyed the macaw breeding population to verify whether our treatment allowed for nest recruitment in cavities previously occupied by bees. RESULTS: We recorded > 100 beehives in the nesting cliffs. Hives outnumbered macaw nests tenfold in two areas recently recolonized by macaws. Cavities occupied by bees were significantly higher than those occupied by macaws, suggesting that macaws may be forced to breed in lower cavities. None of the untreated cavities (n = 50) were occupied by nesting macaws, whereas 15% of treated cavities (n = 52) were occupied within 2 years post treatment. Treated cavities occupied by macaws were significantly higher than those not occupied. Hive management increased macaw breeding population by 71% of the macaw breeding population increase. CONCLUSION: Experimental hive treatments were effective in restoring nesting resources lost due to bee infestation. An intensive and continued eradication program is recommended to enhance macaw habitat restoration, facilitating its expansion into historical areas. © 2020 Society of Chemical Industry.

The extent, frequency and ecological functions of food wasting by parrots.

Anecdotic citations of food wasting have been described for parrots, but we lack a comprehensive knowledge about the extent of this behaviour, and its ecological and evolutionary implications. Here, we combine experimental and observational approaches to evaluate the spatial, temporal, typological and taxonomic extent of food wasting by parrots, to identify the ecological and evolutionary factors driving food wasting, and to assess the incidence of two ecological functions derived from food wasting, such as food facilitation to other animal species and secondary seed dispersal. We found that food wasting is a widespread behaviour found in all the studied parrot species. However, the proportion of food wasted differed among species and throughout the year. Parrots wasted more food during the non-breeding season, when they relied on exotic plants and on unripe fruits or seeds. We also recorded 86 animal species feeding on the food wasted by parrots, 27 of which potentially acted as secondary seed dispersers. Overall, our study emphasizes the universality of food wasting among parrots, and the important implications that this behaviour may have for the species involved (i.e., the parrot, the plant, the other species feeding on wasted food), and for the functioning of the whole ecosystem.

Internal seed dispersal by parrots: an overview of a neglected mutualism.

Despite the fact that parrots (Psitacifformes) are generalist apex frugivores, they have largely been considered plant antagonists and thus neglected as seed dispersers of their food plants. Internal dispersal was investigated by searching for seeds in faeces opportunistically collected at communal roosts, foraging sites and nests of eleven parrot species in different habitats and biomes in the Neotropics. Multiple intact seeds of seven plant species of five families were found in a variable proportion of faeces from four parrot species. The mean number of seeds of each plant species per dropping ranged between one and about sixty, with a maximum of almost five hundred seeds from the cacti Pilosocereus pachycladus in a single dropping of Lear's Macaw (Anodorhynchus leari). All seeds retrieved were small (<3 mm) and corresponded to herbs and relatively large, multiple-seeded fleshy berries and infrutescences from shrubs, trees and columnar cacti, often also dispersed by stomatochory. An overview of the potential constraints driving seed dispersal suggest that, despite the obvious size difference between seeds dispersed by endozoochory and stomatochory, there is no clear difference in fruit size depending on the dispersal mode. Regardless of the enhanced or limited germination capability after gut transit, a relatively large proportion of cacti seeds frequently found in the faeces of two parrot species were viable according to the tetrazolium test and germination experiments. The conservative results of our exploratory sampling and a literature review clearly indicate that the importance of parrots as endozoochorous dispersers has been largely under-appreciated due to the lack of research systematically searching for seeds in their faeces. We encourage the evaluation of seed dispersal and other mutualistic interactions mediated by parrots before their generalized population declines contribute to the collapse of key ecosystem processes.