The Anatomy of the bill Tip of Kiwi and Associated Somatosensory Regions of the Brain: Comparisons with Shorebirds

Three families of probe-foraging birds, Scolopacidae (sandpipers and snipes), Apterygidae (kiwi), and Threskiornithidae (ibises, including spoonbills) have independently evolved long, narrow bills containing clusters of vibration-sensitive mechanoreceptors (Herbst corpuscles) within pits in the bill-tip. These ‘bill-tip organs’ allow birds to detect buried or submerged prey via substrate-borne vibrations and/or interstitial pressure gradients. Shorebirds, kiwi and ibises are only distantly related, with the phylogenetic divide between kiwi and the other two taxa being particularly deep. We compared the bill-tip structure and associated somatosensory regions in the brains of kiwi and shorebirds to understand the degree of convergence of these systems between the two taxa. For comparison, we also included data from other taxa including waterfowl (Anatidae) and parrots (Psittaculidae and Cacatuidae), non-apterygid ratites, and other probe-foraging and non probe-foraging birds including non-scolopacid shorebirds (Charadriidae, Haematopodidae, Recurvirostridae and Sternidae). We show that the bill-tip organ structure was broadly similar between the Apterygidae and Scolopacidae, however some inter-specific variation was found in the number, shape and orientation of sensory pits between the two groups. Kiwi, scolopacid shorebirds, waterfowl and parrots all shared hypertrophy or near-hypertrophy of the principal sensory trigeminal nucleus. Hypertrophy of the nucleus basorostralis, however, occurred only in waterfowl, kiwi, three of the scolopacid species examined and a species of oystercatcher (Charadriiformes: Haematopodidae). Hypertrophy of the principal sensory trigeminal nucleus in kiwi, Scolopacidae, and other tactile specialists appears to have co-evolved alongside bill-tip specializations, whereas hypertrophy of nucleus basorostralis may be influenced to a greater extent by other sensory inputs. We suggest that similarities between kiwi and scolopacid bill-tip organs and associated somatosensory brain regions are likely a result of similar ecological selective pressures, with inter-specific variations reflecting finer-scale niche differentiation.     

The peculiar structural features of kiwi fruit pectin methylesterase: amino acid sequence, oligosaccharides structure, and modeling of the interaction with its natural proteinaceous inhibitor

Pectin methylesterase (PME) from kiwi fruit (Actinidia deliciosa) is a glycoprotein, showing an apparent molecular mass of 50 kDa upon size exclusion chromatography and SDS-PAGE. The primary structure, elucidated by direct sequencing of the protein, comprises 321 amino acid residues providing a molecular mass of 35 kDa. The protein has an acetylated Thr residue at the amino terminus and five N-glycosylation consensus sequences, four of which are actually glycosylated. A careful investigation of the oligosaccharide structures demonstrated that PME glycans belong to complex type oligosaccharides essentially consisting of xylosylated polyfucosylated biantennary structures. Alignment with known mature plant PME sequences indicates that the postulated active site residues are conserved. Kiwi PME activity is inhibited following the interaction with the proteinaceous inhibitor PMEI, isolated from the same source. Gel-filtration experiments show that kiwi PME/PMEI complex is stable in a large pH range and dissociates only at pH 10.0. Modeling of the interaction with the inhibitor was performed by using the crystal structure of the complex between kiwi PMEI and tomato PME as a template. The model shows that the binding site is the same reported for tomato PME. However, additional salt link interactions are found to connect the external loops of kiwi PME to PMEI. This finding may explain the higher pH stability of the complex formed by the two kiwi proteins respect to that formed by PMEI and tomato PME.     

Characterisation of class II B MHC genes from a ratite bird,the little spotted kiwi (<Emphasis Type="Italic">Apteryx owenii</Emphasis>)

Major histocompatibility complex (MHC) genes are important for vertebrate immune response and typically display high levels of diversity due to balancing selection from exposure to diverse pathogens. An understanding of the structure of the MHC region and diversity among functional MHC genes is critical to understanding the evolution of the MHC and species resilience to disease exposure. In this study, we characterise the structure and diversity of class II MHC genes in little spotted kiwi Apteryx owenii, a ratite bird representing the basal avian lineage (paleognaths). Results indicate that little spotted kiwi have a more complex MHC structure than that of other non-passerine birds, with at least five class II MHC genes, three of which are expressed and likely to be functional. Levels of MHC variation among little spotted kiwi are extremely low, with 13 birds assayed having nearly identical MHC genotypes (only two genotypes containing four alleles, three of which are fixed). These results suggest that recent genetic drift due to a species-wide bottleneck of at most seven birds has overwhelmed past selection for high MHC diversity in little spotted kiwi, potentially leaving the species highly susceptible to disease.     

Molecular and other biological evidence supports the recognition of at least three species of brown kiwi

The presence of morphologically crypticlineages within the threatened brown kiwi ofNew Zealand has confounded their taxonomy. Recent genetic studies (Herbert and Daugherty1994; Baker et al. 1995) revealed that atleast two phylogenetic species exist within thebrown kiwi, and suggested that further researchshould resolve the taxonomic problems. In thispaper we extend genetic analyses to includesequences from 58 brown kiwi representing fivephylogenetic lineages for four mitochondrialloci (control region, cytochrome b,ATPase 6 and ATPase 8). Major lineages ofbrown kiwi are shown to be reciprocallymonophyletic, and align with other biologicaldifferences in the ecology, behavior,morphology and parasites of kiwi. BecausemtDNA sequences of major lineages of kiwi arenot evolving in a clocklike manner, we used anew penalized likelihood method withrate-smoothing to date the divergence of NorthIsland brown kiwi and the geographicallyisolated Okarito population (rowi) at about 6.2Mya. These lineages diverged about 8.2 Myafrom the brown kiwi in Fiordland and Haast inthe southern part of the South Island, and arethus older than the species of spotted kiwi(5.8 Mya). Given their distinctness, long-termgeographical isolation, lack of hybridizationin introduced populations, and accumulation ofnew biological characters within theselineages, we hypothesize that reproductiveincompatibilities have probably arisen as well. We therefore recommend that these divergentlineages be formally recognized as fullspecies; Apteryx mantelli should bere-instated for the North Island brown kiwi,A. australis should be restricted to thetokoeka, and a new species A. rowiishould be erected to describe the rowi atOkarito. Tokoeka should be split into at leastthree conservation management units (Haast,Fiordland and Stewart Island [Rakiura]), butfurther research is required to determine theexact relationships and status of theselineages. Further investigation is alsorequired into the genetic structuring of theNorth Island brown kiwi to confirm conservationmanagement units on the North Island.     

Vocal cooperation between the sexes in Little Spotted Kiwi Apteryx owenii

Sexual call dimorphism in birds is usually associated with sexual size dimorphism. Departures from this relationship can be used to infer call function, but research into inter‐sexual call differences, as with song function in general, has been restricted by a bias towards male passerines. The nocturnal and flightless New Zealand kiwi (Apterygidae) are acoustically similar but taxonomically and ecologically very different from other birds, so provide a contrast in exploring avian call function and evolution. However, kiwi acoustic ecology is poorly understood, with the calls of only one of the five kiwi species spectrally described, and acoustic differences between the sexes virtually unknown. We conducted the first bioacoustic study of Little Spotted Kiwi Apteryx owenii, and assessed sexual call dimorphism in this species. There were significant inter‐sexual differences in call temporal and frequency characteristics that were not related to size dimorphism. Contribution to duets and variation in temporal structure with call context also differed between the sexes. We suggest that these differences indicate divergent call function, with male calls more suited for territory defence, and female calls for pair contact. There was a striking lack of overlap in the frequency spectrum distributions of male and female calls, which was also unrelated to size and was further emphasized by the presence of formants in female calls. We propose that this provides evidence for inter‐sexual acoustic cooperation in call frequency, of a type which to our knowledge has not previously been described in birds. This may result from selection for enhanced joint resource defence in kiwi.     

Role of predation in the decline of kiwi,

Kiwi have declined markedly in abundance and range since human settlement of New Zealand. Three of the four species are still extant in mainland forests, despite decades of co-existence with various introduced mammals. Little spotted kiwi is now probably confined to offshore islands. The role of introduced mammals in these population declines was evaluated by measuring the survival rates of adults, eggs and chicks of brown kiwi (A. mantelli) and great spotted kiwi (A. haastii) in mainland forests. Mortality rates of adults ranged from 5%-16% and did not differ significantly between species or sexes. Overall, 14 out of 209 adult kiwi died during 159.6 radio-tracking years. Predators definitely caused five of these deaths. Sixty-nine (68%) of 102 eggs from 77 nesting attempts by 48 pairs failed to hatch. Predators probably caused about 10% of egg failures. Only three of 49 chicks probably survived to adulthood, indicating a juvenile mortality rate of about 94%. Predators killed at least 8% of chicks, 45% of juveniles, and possibly as many as 60% of all young kiwi. Ferrets and dogs were the main predators of adult kiwi, possums and mustelids were the main egg predators, while stoats and cats were largely responsible for the deaths of young kiwi. Population models show that northern brown kiwi are currently declining at 5.8% per annum. This decline could be halted by cutting the current predation rates on young kiwi by about 34% to 33%.     

Ancient DNA and conservation: lessons from the endangered kiwi of New Zealand

Conservation genetics typically seeks to map the distribution of contemporary genetic variation across space, and to use the resulting genetic parameters to infer any likely short-term evolutionary consequences for rare and endangered species. Recent developments in the study of ancient DNA now enable the extension of genetic variation studies backwards in time and provide a context by which to interpret contemporary levels of genetic variation, in addition to any patterns of genetic change over time. Ancient DNA research can also help to determine past levels of genetic diversity, identify species' boundaries and reveal former ranges among morphologically cryptic taxa. Ancient DNA sequence data for the New Zealand kiwi (Apteryx spp.) are presented and we show that most ancient populations of rowi and tokoeka exhibited private mitochondrial DNA haplotypes. Moreover, we illustrate that the extinction of these populations has led to the loss of considerable genetic variation. We also use ancient DNA methodology to determine past species distributions for brown kiwi and great spotted kiwi whose bones are morphologically indistinguishable.     

Alicyclobacillus Contamination in the Production Line of Kiwi Products in China

Alicyclobacillus are spoilage microbes of many juice products, but contamination of kiwi products by Alicyclobacillus is seldom reported. This study aims to investigate the whole production line of kiwi products in China to assess the potential risk of their contamination. A total of 401 samples from 18 commercial products, 1 processing plant and 16 raw material orchards were tested, and 76 samples were positive, from which 76 strains of microbes were isolated and identified as 4 species of Alicyclobacillus, including Alicyclobacillus acidoterrestris, Alicyclobacillus contaminans, Alicyclobacillus herbarius and Alicyclobacillus cycloheptanicus, and another 9 strains as 3 species of Bacillus by sequencing of their 16S rDNA. Through phylogenetic tree construction and RAPD-PCR amplification, it was found that there exist genotypic diversities to some extent among these isolates. Four test strains (each from one species of the 4 Alicyclobacillus species isolated in this study) could spoil pH adjusted kiwi fruit juice and some commercial kiwi fruit products with producing guaiacol (11–34 ppb).     

Focusing and accommodation in the brown kiwi (Apteryx australis)

Summary Brown kiwis are an endangered species of nocturnal, flightless birds which are native to New Zealand. The resting focus of two specimens has previously been studied by retinoscopy in a zoo while the birds were restrained by their keeper (Sivak and Howland 1987). Those birds appeared to be hyperopic (farsighted) by 2–7 D. In this study, examination with infrared photorefraction of the focusing of two unrestrained, feeding birds showed that they could focus objects at infinity and objects in their immediate environment and that they had modest powers of accommodation. Measurements on two 6 month old kiwi chicks showed their corneal radius of curvature to be between 2.90 and 3.00 mm (117 D and 101 D in power).     

Size matters: predation risk and juvenile growth in North Island brown kiwi (

This study investigated how predation risk in North Island brown kiwi changes as the birds grow and develop. Over a 10-year period, 53 adult and 126 young kiwi were radio-tagged at Lake Waikaremoana and studied to determine survival rates, causes of death, and rates of growth. Predation loss amongst adults was low (2.49% year^-1) and caused mainly by ferrets. Young kiwi suffered intense predation from stoats during their first four months of life, but thereafter became too large (> 800 g) for stoats to kill. Juveniles took at least 880 days to attain adult size, about four times longer than expected for a 2–3 kg bird. Growth rates peaked at about the point of hatch, rather than later on in development as in other birds. We suggest that a long evolutionary history dominated by resource limitation rather than predation may account for slow rates of development in kiwi, and that differences among kiwi species in their ability to persist in the presence of stoats are explained by differences in the time that they take to reach safe-size.     

Ancient DNA Analyses Reveal Contrasting Phylogeographic Patterns amongst Kiwi (Apteryx spp.) and a Recently Extinct Lineage of Spotted Kiwi

The little spotted kiwi (Apteryx owenii) is a flightless ratite formerly found throughout New Zealand but now greatly reduced in distribution. Previous phylogeographic studies of the related brown kiwi (A. mantelli, A. rowi and A. australis), with which little spotted kiwi was once sympatric, revealed extremely high levels of genetic structuring, with mitochondrial DNA haplotypes often restricted to populations. We surveyed genetic variation throughout the present and pre-human range of little spotted kiwi by obtaining mitochondrial DNA sequences from contemporary and ancient samples. Little spotted kiwi and great spotted kiwi (A. haastii) formed a monophyletic clade sister to brown kiwi. Ancient samples of little spotted kiwi from the northern North Island, where it is now extinct, formed a lineage that was distinct from remaining little spotted kiwi and great spotted kiwi lineages, potentially indicating unrecognized taxonomic diversity. Overall, little spotted kiwi exhibited much lower levels of genetic diversity and structuring than brown kiwi, particularly through the South Island. Our results also indicate that little spotted kiwi (or at least hybrids involving this species) survived on the South Island mainland until more recently than previously thought.     

Kiwellin, a Novel Protein from Kiwi Fruit. Purification, Biochemical Characterization and Identification as an Allergen*

Kiwellin is a novel protein of 28 kDa isolated from kiwi (Actinidia chinensis) fruit. It is one of the three most abundant proteins present in the edible part of this fruit. Kiwellin has been purified by ion exchange chromatography. Its N-terminal amino acid sequence revealed high identity with that previously reported for a 28 kDa protein described as one of the most important kiwi allergens. This observation prompted us to fully characterize this protein. The complete primary structure, elucidated by direct sequencing, indicated that kiwellin is a cysteine-rich protein. Serological tests and Western Blotting analysis showed that kiwellin is specifically recognized by IgE of patients allergic to kiwi fruit. *The protein sequence data reported in this paper will appear in the Swiss-Prot and TrEMBL knowledgebase under the accessionnumber P84527.     

Effect of Yeast Cell Morphology,Cell Wall Physical Structure and Chemical Composition on Patulin Adsorption

The capability of yeast to adsorb patulin in fruit juice can aid in substantially reducing the patulin toxic effect on human health. This study aimed to investigate the capability of yeast cell morphology and cell wall internal structure and composition to adsorb patulin. To compare different yeast cell morphologies, cell wall internal structure and composition, scanning electron microscope, transmission electron microscope and ion chromatography were used. The results indicated that patulin adsorption capability of yeast was influenced by cell surface areas, volume, and cell wall thickness, as well as 1,3-β-glucan content. Among these factors, cell wall thickness and 1,3-β-glucan content serve significant functions. The investigation revealed that patulin adsorption capability was mainly affected by the three-dimensional network structure of the cell wall composed of 1,3-β-glucan. Finally, patulin adsorption in commercial kiwi fruit juice was investigated, and the results indicated that yeast cells could adsorb patulin from commercial kiwi fruit juice efficiently. This study can potentially simulate in vitro cell walls to enhance patulin adsorption capability and successfully apply to fruit juice industry.     

A preliminary method for estimating the age of brown kiwi (Apteryx mantelli) embryos

Morphological features of a collection of unknown-age wild kiwi (Apteryx mantelli) embryos from early development to point of hatch are described. Using these features, we assign developmental stages to each embryo and compare the progress of development to similar-staged ostrich (Struthio camelus) and chicken (Gallus gallus) embryos. Two ageing schemes for the kiwi embryos are developed by comparing measurements of their hindlimb segments, bills and crown–rump lengths with those of ostrich and chicken embryos at various stages of development. One of the 20 kiwi embryos was of known age. Both the ostrich model and the chicken model gave identical predictions for the marker and four other embryos. Developmental timing of some features differed between all three species, most markedly in the bill, with growth in the kiwi bill being relatively faster to achieve its larger relative and absolute size at hatch.     

Protected areas for kiwi in mainland forests of New Zealand: how large should they be?

This paper examines, theoretically, how dispersal affects the viability of brown kiwi populations in protected areas of different size. Brown kiwi are threatened by introduced mammalian predators in mainland forests and are likely to persist only in managed forests where predators are controlled. In each protected area, the kiwi population will function as a net source, with an outflow of juveniles into the adjoining forest and minimal backflow into the reserve. Computer simulations show the minimum area of forest required for population viability increases non-linearly as the mean dispersal distance of juveniles increases. Preliminary measurements of the mean dispersal distance of brown kiwi in the wild suggest kiwi populations are unlikely to be viable in protected areas of less than 10 000 ha. Our estimate of the forest area requirement for viable populations of brown kiwi agrees with those derived by earlier workers using biogeographic techniques.     

Temporal and environmental influences on the vocal behaviour of a nocturnal bird

Temporal and environmental variation in vocal activity can provide information on avian behaviour and call function not available to short‐term experimental studies. Inter‐sexual differences in this variation can provide insight into selection effects. Yet factors influencing vocal behaviour have not been assessed in many birds, even those monitored by acoustic methods. This applies to the New Zealand kiwi (Apterygidae), for which call censuses are used extensively in conservation monitoring, yet which have poorly understood acoustic ecology. We investigated little spotted kiwi Apteryx owenii vocal behaviour over 3 yr, measuring influences on vocal activity in both sexes from time of night, season, weather conditions and lunar cycle. We tested hypotheses that call rate variation reflects call function, foraging efficiency, historic predation risk and variability in sound transmission, and that there are inter‐sexual differences in call function. Significant seasonal variation showed that vocalisations were important in kiwi reproduction, and inter‐sexual synchronisation of call rates indicated that contact, pair‐bonding or resource defence were key functions. All weather variables significantly affected call rates, with elevated calling during increased humidity and ground moisture indicating a relation between vocal activity and foraging conditions. A significant decrease in calling activity on cloudy nights, combined with no moonlight effect, suggests an impact of light pollution in this species. These influences on vocal activity provide insight into kiwi call function, have direct consequences for conservation monitoring of kiwi, and have wider implications in understanding vocal behaviour in a range of nocturnal birds.     

The breeding season of three species of kiwi (Apteryx) in captivity as determined from egg-laying dates

Records from kiwi ( Apteryx spp.) breeding centres were used to obtain laying dates of 403 North Island brown kiwi ( Apteryx australis mantelli ) eggs, 24 great spotted kiwi ( Apteryx haastii ) eggs and 25 little spotted kiwi ( Apteryx owenii ) eggs. North Island brown kiwi outdoors had an annual cycle of egg-laying with 88.5% of eggs laid from June to January. Eggs were laid in every month of the year, with fewest eggs in April (2.1 % of all eggs). The greatest number of eggs was laid in July (15.6% of all eggs), with a second peak of laying in October (13.5% of all eggs). Both the great spotted kiwi and little spotted kiwi had annual cycles of egg-laying, with the main egg-laying seasons being August-January (87.5% of eggs) for the former and July-December (96.0% of eggs) for the latter. The highest peaks of laying were in October and August, respectively. Kiwi eggs were considered to belong to the same clutch if they were laid no more than 40 days apart. Clutch size in the North Island brown and little spotted kiwi was most commonly one or two eggs. In the great spotted kiwi only clutches of one egg were found. The mean clutch size of North Island brown kiwi outdoors (1.51±0.05) did not differ from that of free-living North Island brown kiwi (1.33±0.09). Similarly, there was no difference in the mean clutch size of captive and free-living little spotted kiwi (1.39±0.14 and 1.10±0.07). The mean interval between eggs for kiwi outdoors did not differ between North Island brown kiwi and little spotted kiwi (27.4±0.5 and 30.7±1.8 days). The results indicate that all three species of kiwi maintain annual cycles of egg-laying in captivity, with the main egg-laying season being longer than in free-living birds.