Which factors limited stitchbird population growth on Mokoia Island?

Reintroduction programmes need to be monitored as a way of gauging potential causes of their success or failure. This, in turn, can be used to improve the likelihood of future translocation success. Since the 1990s, stitchbird (or hihi: Notiomystis cincta) translocations have been intensively monitored, with comparisons between two of these projects (Tiritiri Matangi Island ? a successful introduction, and Mokoia Island ? an unsuccessful introduction) often compared and contrasted as a means of identifying factors important in translocation success for this species. A consistently low adult survival rate on Mokoia Island in conjunction with a study showing a high prevalence of aspergillosis (a fungal disease of the respiratory tract caused by Aspergillus fumigatus) in adult stitchbirds led to this disease being commonly discussed as a major factor responsible for the difference in translocation outcomes. However, A. fumigatus infection rates have never been compared between the two stitchbird populations; thus, population differences in adult survival may have resulted from other factors. One possibility is that survival differences between populations were influenced by differing predation pressures from morepork (or ruru: Ninox novaeseelandiae). Evidence of stitchbird predation by moreporks and the fact that morepork density on Mokoia Island was markedly higher than on Tiritiri Matangi Island provides some support for this hypothesis. It is important that all plausible hypotheses for differences in survival be considered so that we can better evaluate future conservation strategies that target the recovery of this species.     

Honeyeaters and the New Zealand forest flora: The utilisation and profitability of small flowers

New Zealand flowers are frequently considered unspecialised allowing easy access to pollen and nectar by a wide range of visitors. Most conform with a syndrome of insect pollination (entomophily). Pollination of forest flowers by birds has been described for a range of species whose flowers are morphologically ornithophilous. On Kapiti Island and Little Barrier Island, all three species of New Zealand honeyeaters have been described feeding on flowers currently assumed to be entomophilous or where the pollination system is unknown. The persistence and regularity of visits suggests that the birds are obtaining suitable rewards in the form of nectar and could be serving as pollinators. We measured the nectar energetic value from flowers of three ornithophilous and five entomophilous species. Nectar production over 24 hours was highest in ornithophilous species, but the standing crop of nectar overlapped—ornithophilous species: Metrosideros fulgens (standing crop 6.6 J), Metrosideros excelsa (22 J), and Fuchsia excorticata (1.8 J); and entomophilous: Pittosporum crassifolium (23 J), Pseudopanax arboreus (1.5 J), Dysoxylum spectabile (3.7 early flowers -6.7 J late flowers), Pittosporum eugenioides (2.7 J) and Geniostoma rupestre (1.8 J). The entomophilous species present the flowers in aggregation and as result birds can visit a large number flowers per minute. We found that the average estimated nectar consumption rate for all the entomophilous species except G. rupestre was enough to sustain the two smaller New Zealand honeyeaters (hihi energy requirements= 0.12 kJ min(-1), median energy obtained: 0.16 kJ min(-1) D. spectabile—0.57 kJ min(-1) P. crassifolium); bellbird energy requirements = 0.10 kJ min(-1), median energy obtained: 0.14 kJ min(-1) D. spectabile—0.68 kJ min(-1) P. crassifolium). However, we estimate that if the birds are able to selectively forage on the flowers with most nectar, the energetic returns of all species may be sufficient for hihi and bellbird (hihi: 0.18 kJ min(-1) G. rupestre—0.93 kJ min(-1); P. crassifolium; bellbird: 0.12 kJ min(-1) G. rupestre 1.11 kJ min(-1) P. crassifolium). If tui (energy requirements: 0.25 kJ min(-1), forages randomly, only P. crassifolium (0.80 kJ min(- 1)) and D. spectabile late in the season (0.30 kJ min(-1)) provide sufficient returns, but if selective, P. arboreus (0.45 kJ min(-1)) may also suffice. We suggest that because (a) the nectar produced by entomophilous flowers provides sufficient energy to sustain the energetic requirements of birds, and (b) these plants flower in the cooler months when insect activity is reduced, birds might have played a wider role in pollination than previously considered. This finding is of particular importance because the abundance of New Zealand honeyeaters on the mainland has decreased considerably since human colonisation and this could be affecting forest regeneration.     

Aspergillus fumigatus Densities in Relation to Forest Succession and Edge Effects: Implications for Wildlife Health in Modified Environments

The hihi (or stitchbird, Notiomystis cincta) is a New Zealand endemic nectivorous forest bird now restricted to one pristine island. Relocation to establish viable hihi populations on other islands has been the main conservation action since the early 1980s. To date, hihi reintroductions to young growth islands have had poor success despite the absence of mammalian predators. It was thought that past failures were due to food limitation, but research suggests that food limitation alone cannot account for their poor survivorship. Post-mortems of dead hihi has shown that aspergillosis caused by Aspergillus fumigatus is a major mortality factor and there is current concern regarding their susceptibility to this fungal disease. In this paper we develop and assess the hypothesis that A. fumigatus limits hihi population viability on modified islands, and suggest that A. fumigatus is a potential indicator species for habitat disturbance. We report that the prevalence of A. fumigatus spores in the soil is much higher in young growth forests and forest edge habitats. Results suggest that hihi mortality rates between islands are potentially due to differential exposure to A. fumigatus spores. We assess relationships between habitat disturbance, A. fumigatus contamination and hihi mortality rates by testing the following predictions: (1) that densities of A. fumigatus spores will be higher on modified islands, (2) that densities of A. fumigatus spores on islands will be correlated with hihi mortality rates and (3) that densities of A. fumigatus spores will be higher at the forest edge than in the interior. We test each of these predictions using soil samples, air samples and samples of nectar from plant species fed on by hihi.     

Estimating impacts of poison operations using mark-recapture analysis: hihi (

Hihi (Notiomystis cincta) were reintroduced to Mokoia Island, Lake Rotorua, New Zealand, in September 1994, and two years later there was an aerial drop of brodifacoum cereal pellets aimed to eradicate mice (Mus musculus). Using Program MARK, we analyzed data from resighting surveys to assess whether hihi had lower than normal survival in the 6-week interval following the drop. The resighting data were collected on a regular basis over a 3-year period, from 1994-97, allowing us to control for yearly and seasonal variation in resighting and survival probabilities. We initially established that the Cormack-Jolly- Seber model had a good fit to the data and could therefore be used as the global model for our analysis. We then compared a range of simpler candidate models, some of which included a poison effect (an unusual survival rate for the interval after the poison drop). Under the best model (that with the lowest AIC), the survival probability was constant over time and there was no poison effect. The estimated survival probability for the 6 weeks after the poison drop was 0.95, which is slightly higher than the value of 0.89 expected based on pre- and post- poison intervals. The approximate 95% confidence interval for the probability of a bird dying due to poison ranged from -0.17 (i.e., a decrease in mortality rate due to the poison) to +0.04. We therefore concluded that the poison caused at most a negligible increase in mortality, and that mark-recapture analysis on resighting data provided a powerful method for assessing the impact of the poison drop. We discuss the relative costs and benefits of radio tagging versus resighting surveys of banded birds for estimating impacts of poison operations. For species with relatively high resighting rates, such as hihi, analysis of resighting surveys is a much more reliable and cost-efficient methodology.     

Plant richness and blooming cover affect abundance of flower visitors and network structure in Colombian orchards

1. Pollination is essential to fruit production. How plant diversity and blooming events in and around orchards affect the pollinator community and the plant-flower-visitor network in neotropical systems remains largely unknown.
2. We surveyed the flower visitors in deciduous fruit trees and alternative blooming resources (other crops, hedgerows and weeds) in Colombia across 6 orchards over 12 months. We evaluated whether plant species richness and blooming cover influenced abundance and richness of flower visitors, as well as network-level connectance and specialization. We also assessed the role of alternative blooming resources for the flower visitors of deciduous fruit trees.
3. Overall, we found 66 taxa of flower visitors, 35 of which visited deciduous fruit trees. There was a greater abundance of flower visitors when there was higher richness of weedy species and greater blooming cover of deciduous fruit trees. Networks were less connected when there was lower crop and weedy species richness. Finally, flower visitor abundance and specialization increased when there were multiple hedgerow species in bloom with a high blooming cover.
4. We highlight the importance of maintaining alternative blooming resources in and around the orchards to support deciduous fruit tree pollinators and diversity in the plant flower-visitor network.

     

Microgeographical, inter-individual, and intra-individual variation in the flower characters of Iberian pear Pyrus bourgaeana (Rosaceae)

Flower characteristics have been traditionally considered relatively constant within species. However, there are an increasing number of examples of variation in flower characteristics. In this study, we examined the variation in attracting and rewarding flower characters at several ecological levels in a metapopulation of Pyrus bourgaeana in the Do?ana area (SW Spain). We answered the following questions: what are the variances of morphological and nectar characters of flowers? How important are intra-individual and inter-individual variance in flower characters? Are there microgeographical differences in flower characters? And if so, are they consistent between years? In 2008 and 2009, we sampled flowers of 72 trees from five localities. For six flower morphological and two nectar characteristics, we calculated coefficients of variation (CV). The partitioning of total variation among-localities, among-individuals, and within-individuals was estimated. To analyze differences among localities and their consistency between years, we conducted generalized linear mixed models. The CVs of nectar characters were always higher than those of morphological characters. As expected, inter-individual variation was the main source of variation of flower morphology, but nectar characters had significant variation at both intra- and inter-individual levels. For most floral traits, there were no differences among localities. Our study documents that variation is a scale-dependent phenomenon and that it is essential to consider intra- and inter-individual variance when investigating the causes and consequences of variation. It also shows that single year studies of floral characters should be viewed with caution.     

Movements,status, access to nectar,and spatial organisation of the tui

Abstract

Movements of tui (Prosthetnadera novaeseelandiae) breeding on Tiritiri Matangi Island were followed and related to changes in nectar access. The island has limited nectar sources and birds must move to gain access to nectar year round. All tui leave the island, although the extent and timing of movement varies for different individuals. Tui return for breeding but again the timing of the return varies for individuals. Nectar sources were typically concentrated in both time and space, and access was related to individual asymmetries such as sex, residential status and age. These same asymmetries also relate to the timing of individuals movements, and where individuals nest relative to nectar sources. At concentrated food sources, access was determined by an absolute social hierarchy. Although tui defend exclusive feeding territories, breeding territories are not exclusive and access to nectar is determined by distance to nest site. Such variability in spatial organisation is related to a continuum concept of social organisation.     

Effect of Extra-Pair Paternity on Effective Population Size in a Reintroduced Population of the Endangered Hihi, and Potential for Behavioural Management

We collected genetic and behavioural data on hihi (Notiomysts cincta, an endangered New Zealand bird) after reintroduction to Mokoia Island to assess the effect of extrapair copulation on effective population size (N _e), and investigate the potential for increasing N _e through behavioural management. DNA fingerprinting revealed that 46% of chicks (n = 188) resulted from extra-pair paternity, and 82% of broods (n = 56) had at least one extra-pair chick. Of the extra-pair young, 34%(n = 89) were from unpaired males, and the remainder were from paired males. Variance in reproductive success (VRS) among individuals changed between years, and the relative variance among males and females depended on the sex ratio. VRS increased when measured over longer time scales, the variance in recruits being three times higher than the variance in the number of hatchlings. Extra-pair copulation increased VRS by 150% in 1 year and decreased it by 30% in another year, but this only caused a 4% decrease and 8% increase, respectively, to N _e/N. Although there is potential to manage VRS in this species through behavioural management, a more important factor is adult lifespan, which is the main correlate of lifetime reproductive success as well as the determinant of generation time. The high annual mortality rate in Mokoia hihi (females = 64%, males = 52%) has prevented the population from growing, so the key factors limiting N and N _e/N are the same.     

The reproductive biology of Sophora fernandeziana (Leguminosae), a vulnerable endemic species from Isla Robinson Crusoe

Sophora fernandeziana is the only legume endemic to Isla Robinson Crusoe (Archipelago Juan Fernández, Chile); it is uncommon and becoming rare. Although its preservation status is listed as "vulnerable," as with many species, little is known of its reproductive biology. Flowering phenology, floral morphology, nectar features, breeding system, and visitors were analyzed in two populations. Flowering is from late winter to early spring. Flowers last 6 d and have a number of ornithophilous features. A floral nectary begins to secrete highly concentrated nectar 48 h after flowers open. Nectar secretion increases as the flower ages but culminates in active nectar reabsorption as the flower senesces. Nectar production is negatively affected by nectar removal. Self-pollen germinates and tubes grow down the style. However, pollen tubes were only observed to enter the ovaries in open pollinated styles, suggesting the possibility of an ovarian self-incompatibility mechanism. Both sexes of the two hummingbird species that inhabit the island are regular visitors. Low fruit and seed set, low genetic diversity, and a shrinking number of populations all contribute to increased concern about the future of this species-and perhaps the hummingbirds that depend on it.     

Functional flower traits and their diversity drive pollinator visitation

Recent studies have shown that the diversity of flowering plants can enhance pollinator richness and visitation frequency and thereby increase the resilience of pollination. It is assumed that flower traits explain these effects, but it is still unclear which flower traits are responsible, and knowing that, if pollinator richness and visitation frequency are more driven by mass‐ratio effects (mean trait values) or by trait diversity. Here, we analyse a three‐year data set of pollinator observations collected in a European grassland plant diversity experiment (The Jena experiment). The data entail comprehensive flower trait measurements, including reward traits (nectar and pollen amount), morphological traits (height, symmetry, area, colour spectra) and chemical traits (nectar‐amino acid and nectar‐sugar concentration). We test if pollinator species richness and visitation frequency of flower communities depend on overall functional diversity combining all flower traits within a community, single trait diversities (within trait variation) and community‐weighted means of the single traits, using Bayesian inference. Overall functional diversity did not affect pollinator species richness, but reduced visitation frequency. When looking at individual flower traits separately, we found that single trait diversity of flower reflectance and flower morphology were important predictors of pollinator visitation frequency. Moreover, independent of total flower abundance, community‐weighted means of flower height, area, reflectance, nectar‐sugar concentration and nectar‐amino acid concentration strongly affected both pollinator species richness and visitation frequency. Our results, challenge the idea that functional diversity always positively affects ecosystem functions. Nonetheless, we demonstrate that both single trait diversity and mass‐ratio effects of flower traits play an important role for diverse and frequent flower visits, which underlines the functionality of flower traits for pollination services.     

The feeding ecology of Stephen's lory and nectar availability in its food plants

Stephen's lory, Vini stepheni , is one of four landbirds which are endemic to Henderson Island and until recently, its habits and ecology were unknown. I studied the diet and feeding ecology of Stephen's lory with particular reference to nectar variation in dominant food plants. Stephen's lory feeds on nectar, pollen and fruits from a variety of plants with lepidopteran larvae also forming a large component of the diet. The two plants which were dominant nectar sources for Stephen's lory produced flowers with very different nectar yields. Scaevola sericea flowers contained larger maximum volumes of more concentrated nectar than Timonius polygamus flowers. However, Scaevola flowers were a less predictable nectar resource, and grew at much lower densities, than Timonius flowers. Lories fed on the two flower types at different frequencies and it was hypothesized that the net rate of energy gained from feeding from a similar sized patch of the two plant species was comparable. Although nectar volumes of Timonius polygamus flowers decreased from the early mornings up until late afternoons, the lories did not show a corresponding daily pattern of foraging behaviour. Nectar yields also increased with the age of Timonius flowers. Stephen's lory has probably been the least affected of its genus by adverse changes to its habitat, and any information gained on the species may be useful when conservation measures of other Vini species are addressed.     

Effects of nectar-robbing on plant reproduction and evolution

The relationship between plant and pollinator is considered as the mutualism because plant benefits from the pollinator's transport of male gametes and pollinator benefits from plant's reward.Nectar robbers are frequently described as cheaters in the plant-pollinator mutualism,because it is assumed that they obtain a reward (nectar) without providing a service (pollination).Nectar robbers are birds,insects,or other flower visitors that remove nectar from flowers through a hole pierced or bitten in the corolla.Nectar robbing represents a complex relationship between animals and plants.Whether plants benefit from the relationship is always a controversial issue in earlier studies.This paper is a review of the recent literatures on nectar robbing and attempts to acquire an expanded understanding of the ecological and evolutionary roles that robbers play.Understanding the effects of nectar robbers on the plants that they visited and other flower visitors is especially important when one considers the high rates of robbing that a plant population may experience and the high percentage of all flower visitors that nectar robbers make to some species.There are two standpoints in explaining why animals forage on flowers and steal nectar in an illegitimate behavior.One is that animals can only get food in illegitimate way because of the mismatch of the morphologies of animals'mouthparts and floral structure.The other point of view argues that nectar robbing is a relatively more efficient,thus more energy-saving way for animals to get nectar from flowers.This is probably associated with the difficulty of changing attitudes that have been held for a long time.In the case of positive effect,the bodies of nectar robbers frequently touch the sex organs of plants during their visiting to the flowers and causing pollination.The neutral effect,nectar robbers' behavior may destruct the corollas of flowers,but they neither touch the sex organs nor destroy the ovules.Their behavior does not affect the fruit sets or seed sets of the hosting plant.Besides the direct impacts on plants,nectar robbers may also have an indirect effect on the behavior of the legitimate pollinators.Under some circumstances,the change in pollinator behavior could result in improved reproductive fitness of plants through increased pollen flow and out-crossing.     

Relationship between floral tube length and nectar robbing in Duranta erecta L. (Verbenaceae)

Although nectar robbing is a common phenomenon in plant species with tubular flowers or flowers with nectar spurs, the potential effect of this illegitimate interaction on plant reproductive success has not received the deserved attention. In the present study, we analysed the functional relationship between flower morphology and nectar robbing, and examined the reproductive consequences of the interaction in a population of Duranta erecta (Verbenaceae) on the island of Cuba. The results show that nectar robbing is conducted by the carpenter bees Xylocopa cubaecola and affects up to 44% of flowers in the studied population. However, not all the flowers have the same probability of being robbed. The chance of flowers being robbed increases with flower length and flower diameter. Moreover, nectar robbing significantly decreases the chance that flowers will set fruit. Also, the impact of nectar robbing on the probability of flowers to set fruits is dependent on the plant. We suggest that nectar robbing may represent an opposite selective force that balances the selection for longer corollas often imposed by pollinators specializing in visiting tubular flowers. Such a relationship with nectar robbers would have obvious implications for the evolution of tubular or closed flowers. This preliminary finding deserves further research in light of the ecological and evolutionary consequences of nectar robbing in tubular flowers.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 96 , 392–398.     

Nectar-feeding bird and bat niches in two worlds: pantropical comparisons of vertebrate pollination systems

Aim We review several aspects of the structure of regional and local assemblages of nectar‐feeding birds and bats and their relationships with food plants to determine the extent to which evolutionary convergence has or has not occurred in the New and Old World tropics. Location Our review is pantropical in extent and also includes the subtropics of South Africa and eastern Australia. Within the tropics, it deals mostly with lowland forest habitats. Methods An extensive literature review was conducted to compile data bases on the regional and local species richness of nectar‐feeding birds and bats, pollinator sizes, morphology, and diets. Coefficients of variation (CVs) were used to quantify the morphospace occupied by the various families of pollinators. The extent to which plants have become evolutionarily specialized for vertebrate pollination was explored using several criteria: number and diversity of growth forms of plant families providing food for all the considered pollinator families; the most common flower morphologies visited by all the considered pollinator families; and the number of plant families that contain genera with both bird‐ and bat‐specialized species. Results Vertebrate pollinator assemblages in the New World tropics differ from those in the Old World in terms of their greater species richness, the greater morphological diversity of their most specialized taxa, and the greater degree of taxonomic and ecological diversity and morphological specialization of their food plants. Within the Old World tropics, Africa contains more specialized nectar‐feeding birds than Asia and Australasia; Old World nectar‐feeding bats are everywhere less specialized than their New World counterparts. Main conclusions We propose that two factors – phylogenetic history and spatio‐temporal predictability (STP) of flower resources – largely account for hemispheric and regional differences in the structure of vertebrate pollinator assemblages. Greater resource diversity and resource STP in the New World have favoured the radiation of small, hovering nectar‐feeding birds and bats into a variety of relatively specialized feeding niches. In contrast, reduced resource diversity and STP in aseasonal parts of Asia as well as in Australasia have favoured the evolution of larger, non‐hovering birds and bats with relatively generalized feeding niches. Tropical Africa more closely resembles the Neotropics than Southeast Asia and Australasia in terms of resource STP and in the niche structure of its nectar‐feeding birds but not its flower‐visiting bats.     

Resource partitioning among flower visitors and evolution of nectar concealment in multi-species communities

The plant community within which flower evolution takes place has largely been ignored. We develop two models for the evolution of nectar concealment when flowers are visited by legitimate pollinators and flower parasites. When there is a single plant species, no level of nectar concealment is evolutionarily stable: any population can be invaded by mutants exhibiting a higher level of nectar concealment. However, the presence of a second flower species with exposed nectar and not subject to evolution breaks the runaway process. In the presence of open flowers, depending on the fitness function there may be an evolutionarily stable level of nectar concealment, or more complex evolutionary dynamics, with nectar concealment fluctuating within a bounded range. Concealment of nectar from flower parasites can evolve even if it implies decreasing the accessibility of nectar to legitimate pollinators.     

Community-dependent foraging habits of flower visitors: cascading indirect interactions among five bumble bee species

Despite the ubiquity and the importance of interspecific interactions among flower visitors, few studies have examined their effects on the realized feeding niches of visitor species in a community context. To evaluate the community-wide effects of interactions among flower visitors, I have examined changes in the flower utilization patterns of each visitor species at several sites where the component of the visitor’s community differed. Specifically, I compared the flower preferences and foraging habits (legitimate foraging vs. primary nectar robbing vs. secondary nectar robbing) of five bumble bee species in flower patches consisting of Trifolium pratense L. (red clover) and T. repens L. (white clover) on Hokkaido Island, Japan. I also examined the nectar production and standing crops of each flower species to evaluate the exploitation competition based on nectar. The bumble bee species exhibited different flower utilization patterns among sites. At sites where the long-tongued Bombus diversus tersatus was common and the exotic short-tongued B. terrestris was rare, B. diversus tersatus visited red clover (long-tubed flowers) exclusively, whereas medium-tongued B. pseudobaicalensis and short-tongued B. hypocrita sapporoensis and B. hypnorum koropokkrus preferentially visited white clover (short-tubed flowers). Conversely, at sites where the long-tongued bee was rare, four other species frequently visited red clover in different modes: B. pseudobaicalensis visited legitimately, B. hypocrita sapporoensis and B. terrestris visited as primary nectar robbers, and B. hypnorum koropokkrus visited as a secondary nectar robber. The presence or absence of resource exploitation by the long-tongued species and the interaction between primary and secondary nectar robbers via robbing holes was the major ecological sources of these differences. Diverse effects of interactions among flower visitors played important roles in shaping pattern of plant and flower visitor interactions.     

Influence of Forest Seasonality on Gibbon Food Choice in the Rain Forests of Barito Ulu,Central Kalimantan

We describe the diet of two hybrid gibbon groups (Hylobates mulleri x H. agilis) in relation to forest seasonality. We collected data over 12 mo in lowland dipterocarp forest in the Barito Ulu research area, Central Kalimantan, Indonesia. Although non-fig fruit was the main dietary item (52–64% of diet), gibbon diet was most strongly influenced by the availability of flowers. During periods when flowers were most abundant and the gibbons increased consumption of them, they also ate figs or young leaves more often. We suggest that although flowers are nutritionally rich sources of food, providing relatively high levels of protein compared to fruit, they are unlikely to satiate gibbon hunger and they seek dietary bulk from figs or young leaves, because they are easily obtained. Rainfall also influenced food choice, and non-fig fruit availability had a weak influence on fruit selection for one group. The group concentrated feeding on the fruit of a few species when fruit was most abundant and ate a greater diversity of species when fruit was scarce. Gibbon diet appeared not to be influenced by changes in availability of figs, young leaves and diversity of fruiting species.     

Flowers, fruits, and the abundance of the yellow-chevroned parakeet (Brotogeris chiriri) at a gallery forest in the South Pantanal (Brazil).

Parakeets usually forage for massive and ephemeral plant resources at forest canopies. Fruit pulp is widely cited as a major food resource for these birds, which often eat seeds and nectar. In this study, I assessed flower and fruit production at a gallery forest in the Pantanal flood plain (Brazil) in order to evaluate the relationship between food resource production and abundance of a common parakeet, Brotogeris chiriri. Also, I evaluated the relationship between food resource production and foraging activity. Parakeet abundance varied markedly along the year, coinciding with massive episodes of flower and fleshy fruit availability. Inga vera nectar, intensely used during the latter part of dry season, was by far the most exploited food item by parakeets when they were very abundant. The nectar comprised 34% of the parakeets' diet (N = 131 feeding records) at the gallery forest, while fleshy fruits made up the rest. Parakeets principally exploited fruits of Cecropia pachystachya and Ficus luschnathiana, besides palm fruits and Inga vera arils. The consistent relationship between foraging activity and parakeet abundance, as well as the coincidence between fluctuations of these parameters and availability of major food resources, suggests that food availability mostly influenced B. chiriri occurrence in the gallery forest. Furthermore, I found no evidence for gallery forest use for roosting and/or breeding, in spite of the fact that such factors usually influence local parakeet abundance.     

Learning in the nectar foraging behaviour of Helicoverpa armigera

Abstract .1. Learning may enable insects to obtain nectar from flowers more efficiently. Learning in nectar foraging has been shown primarily in studies of bees and butterflies. Here, learning is demonstrated in the nectar foraging behaviour of a noctuid moth, Helicoverpa armigera .
2. The present studies show that: (1) previous experience with a flowering host species increases the probability of that species being selected for nectar foraging, and (2) previous experience of a particular flower type (food source at bottom or top of the corolla tube) increases the likelihood of the food source being found when that flower type is being searched.
3. The implications of these findings for understanding the pattern of oviposition observed in wild populations of this important pest species are discussed.     

High genetic diversity in the remnant island population of hihi and the genetic consequences of re-introduction

The maintenance of genetic diversity is thought to be fundamental for the conservation of threatened species. It is therefore important to understand how genetic diversity is affected by the re-introduction of threatened species. We use establishment history and genetic data from the remnant and re-introduced populations of a New Zealand endemic bird, the hihi Notiomystis cincta, to understand genetic diversity loss and quantify the genetic effects of re-introduction. Our data do not support any recent bottleneck events in the remnant population. Furthermore, all genetic diversity measures indicate the remnant hihi population has retained high levels of genetic diversity relative to other New Zealand avifauna with similar histories of decline. Genetic diversity (N(A) , alleles per locus, allelic richness, F(IS) and H(S) ) did not significantly decrease in new hihi populations founded through re-introduction when compared to their source populations, except in the Kapiti Island population (allelic richness and H(S) ) which had very slow post-re-introduction population growth. The N(e) /N(c) ratio in the remnant population was high, but decreased in first-level re-introductions, which together with significant genetic differentiation between populations (F(ST) & Fisher's exact tests) suggest that extant populations are diverging as a result of founder effects and drift. Importantly, simulations of future allele loss predict that the number of alleles lost will be higher in populations with a slow population growth, fewer founding individuals and with nonrandom mating. Interestingly, this species has very high levels of extra-pair paternity which may reduce reproductive variance by allowing social and floater males to reproduce a life history trait that together with a large remnant population size may help maintain higher levels of genetic diversity than expected.