Range expansion and hybridization in Round Island petrels (Pterodroma spp.): evidence from microsatellite genotypes

Historical records suggest that the petrels of Round Island (near Mauritius, Indian Ocean) represent a recent, long‐distance colonization by species originating from the Atlantic and Pacific Oceans. The majority of petrels on Round Island appear most similar to Pterodroma arminjoniana, a species whose only other breeding locality is Trindade Island in the South Atlantic. Using nine microsatellite loci, patterns of genetic differentiation in petrels from Round and Trindade Islands were analysed. The two populations exhibit low but significant levels of differentiation in allele frequencies and estimates of migration rate between islands using genetic data are also low, supporting the hypothesis that these populations have recently separated but are now isolated from one another. A second population of petrels, most similar in appearance to the Pacific species P. neglecta, is also present on Round Island and observations suggest that the two petrel species are hybridizing. Vocalizations recorded on the island also suggest that hybrid birds may be present within the population. Data from microsatellite genotypes support this hypothesis and indicate that there may have been many generations of hybridization and back‐crossing between P. arminjoniana and P. neglecta on Round Island. Our results provide an insight into the processes of dispersal and the consequences of secondary contact in Procellariiformes.     

Phylogenetic relationships in Pterodroma petrels are obscured by recent secondary contact and hybridization

The classification of petrels (Pterodroma spp.) from Round Island, near Mauritius in the Indian Ocean, has confounded researchers since their discovery in 1948. In this study we investigate the relationships between Round Island petrels and their closest relatives using evidence from mitochondrial DNA sequence data and ectoparasites. Far from providing clear delimitation of species boundaries, our results reveal that hybridization among species on Round Island has led to genetic leakage between populations from different ocean basins. The most common species on the island, Pterodroma arminjoniana, appears to be hybridizing with two rarer species (P. heraldica and P. neglecta), subverting the reproductive isolation of all three and allowing gene flow. P. heraldica and P. neglecta breed sympatrically in the Pacific Ocean, where P. arminjoniana is absent, but no record of hybridization between these two exists and they remain phenotypically distinct. The breakdown of species boundaries in Round Island petrels followed environmental change (deforestation and changes in species composition due to hunting) within their overlapping ranges. Such multi-species interactions have implications not only for conservation, but also for our understanding of the processes of evolutionary diversification and speciation.     

Recently extinct reptile populations from Mauritius and Réunion, Indian Ocean

Previously unreported material of recently extinct reptiles from Mauritius and Reunion is discussed. It confirms the original presence on Mauritius of three species now largely or entirely confined to nearby Round Island: the gecko Cyrtodactylus serpensinsula , the skink, Leiolopisma telfairii and the boa, Casarea dussumieri. Leiolopisma telfairii is also recorded from Reunion for the first time. Leiolopisma telfairii and the extinct giant Dido–saurus mauritianus are shown to be very similar to each other and quite probably derivatives of a single invading species. D. mauritianus is consequently transferred to Leiolopisma. Apparently pathological tooth structure in this form is also reported.     

The Use of Extant Non-Indigenous Tortoises as a Restoration Tool to Replace Extinct Ecosystem Engineers

We argue that the introduction of non-native extant tortoises as ecological replacements for extinct giant tortoises is a realistic restoration management scheme, which is easy to implement. We discuss how the recent extinctions of endemic giant Cylindraspis tortoises on the Mascarene Islands have left a legacy of ecosystem dysfunction threatening the remnants of native biota, focusing on the island of Mauritius because this is where most has been inferred about plant–tortoise interactions. There is a pressing need to restore and preserve several Mauritian habitats and plant communities that suffer from ecosystem dysfunction. We discuss ongoing restoration efforts on the Mauritian offshore Round Island, which provide a case study highlighting how tortoise substitutes are being used in an experimental and hypothesis-driven conservation and restoration project. The immediate conservation concern was to prevent the extinction and further degradation of Round Island's threatened flora and fauna. In the long term, the introduction of tortoises to Round Island will lead to valuable management and restoration insights for subsequent larger-scale mainland restoration projects. This case study further highlights the feasibility, versatility and low-risk nature of using tortoises in restoration programs, with particular reference to their introduction to island ecosystems. Overall, the use of extant tortoises as replacements for extinct ones is a good example of how conservation and restoration biology concepts applied at a smaller scale can be microcosms for more grandiose schemes and addresses more immediate conservation priorities than large-scale ecosystem rewilding projects.     

Nesting biology of Black-shouldered Kite (Elanus caeruleus) in oil palm landscape in Carey Island,Peninsular Malaysia

Black-shouldered Kite (Elanus caeruleus) is a well-known raptor that inhabits open areas such as oil palm plantation or paddy field. To determine preferable habitat and nesting site of Black-shouldered Kite in oil palm landscape, we conducted a study on Black-shouldered Kite’s nesting biology in Carey Island, Selangor, Malaysia. We divided the island into six types of habitat and conducted road-side count of Black-shouldered Kite from April 2009 to February 2011. Whenever the Black-shouldered Kite was detected, we thoroughly searched the surrounding area for their nest. In total, we have recorded forty nests. The nests were built on 15 species of trees but most of the trees shared common physical characteristics. Some novice breeders also used oil palm tree as their nesting site. Structure and building materials of nests constructed on oil palm trees were different from nests built on other trees. Of all breeding attempts, only four nests which were located in residential area adjacent to young oil palm habitat were successful. Among important characteristics of successful nesting site include taller trees with strong branches and good leaf coverage. These trees not only protect nests from predator detection (except from other predatory birds) and physical environment but also facilitate Black-shouldered Kite’s foraging activities by providing good vantage point.     

Characterization of polymorphic microsatellite loci from Round Island Petrels (Pterodroma arminjoniana) and their utility in other seabird species

Six microsatellite loci were isolated from the petrels of Round Island, near Mauritius in the Indian Ocean (Pterodroma arminjoniana). Three loci were monomorphic in P. arminjoniana but were found to be polymorphic in other Procellariiforms. Cross-utility of all six loci was tested in 17 Procellariiform and 1 penguin species. In addition, 53 microsatellite loci developed for other species of birds were tested for cross-species amplification in P. arminjoniana. Six of these loci were found to be polymorphic.     

Widespread gene flow between oceans in a pelagic seabird species complex

Global‐scale gene flow is an important concern in conservation biology as it has the potential to either increase or decrease genetic diversity in species and populations. Although many studies focus on the gene flow between different populations of a single species, the potential for gene flow and introgression between species is understudied, particularly in seabirds. The only well‐studied example of a mixed‐species, hybridizing population of petrels exists on Round Island, in the Indian Ocean. Previous research assumed that Round Island represents a point of secondary contact between Atlantic (Pterodroma arminjoniana) and Pacific species (Pterodroma neglecta and Pterodroma heraldica). This study uses microsatellite genotyping and tracking data to address the possibility of between‐species hybridization occurring outside the Indian Ocean. Dispersal and gene flow spanning three oceans were demonstrated between the species in this complex. Analysis of migration rates estimated using bayesass revealed unidirectional movement of petrels from the Atlantic and Pacific into the Indian Ocean. Conversely, structure analysis revealed gene flow between species of the Atlantic and Pacific oceans, with potential three‐way hybrids occurring outside the Indian Ocean. Additionally, geolocation tracking of Round Island petrels revealed two individuals travelling to the Atlantic and Pacific. These results suggest that interspecific hybrids in Pterodroma petrels are more common than was previously assumed. This study is the first of its kind to investigate gene flow between populations of closely related Procellariiform species on a global scale, demonstrating the need for consideration of widespread migration and hybridization in the conservation of threatened seabirds.     

Use of palm trees as a sleeping site for hamadryas baboons (Papio hamadryas hamadryas) in Ethiopia

Hamadryas baboons sleep on cliffs throughout their range, and this can be attributed to the safety cliffs provide against predators in the absence of tall trees. In this paper, we report the first documented occurrence of hamadryas baboons sleeping in doum palm trees rather than on cliffs. Data derive from a study of hamadryas baboons at the Filoha site in lowland Ethiopia. During all-day follows, data were collected on travel patterns, band activity, and location. Variation in the baboons' home range was characterized using vegetation transects. We discovered that one band in this population, Band 3, occasionally slept in doum palm trees (Hyphaene thebaica). The palm tree sleeping site differed from other palm fragments in the baboons' home range in that it contained a higher density of palm trees. Possible factors influencing this unique use of palm trees as a sleeping site include access to palm fruit, avoiding contact with Afar nomads, avoiding sharing sleeping cliffs with other bands, protection from predators, and the lack of cliffs in a section of the baboons' home range. Evidence from this study suggests that the palm tree sleeping site is used because it affords better protection from predators than other palm fragments in an area of the band's home range that does not contain cliffs.     

Canopy insect herbivores in the Azorean Laurisilva forests: key host plant species in a highly generalist insect community

This article explores patterns of insect herbivore distribution in the canopy of the Laurisilva forests on seven islands in the Azores archipelago. To our knowledge, this is one of the first extensive study of this type in tree or shrub canopies of oceanic island ecosystems. One of the most frequently debated characteristics of such ecosystems is the likely prevalence of vague, ill‐defined niches due to taxonomic disharmony, which may have implications for insect‐plant interactions. For instance, an increase in ecological opportunities for generalist species is expected due to the lack of predator groups and reduced selection for chemical defence in host plants. The following two questions were addressed: 1) Are specialists species rare, and insect herbivore species randomly distributed among host plant species in the Azores? 2) Are the variances in insect herbivore species composition, frequency and richness explained by host plants or by regional island effects? We expect a proportional distribution of herbivore species between host plants, influenced by host frequency and distinct island effects; otherwise, deviation from expectation might suggest habitat preference for specific host tree crowns. Canopy beating tray samples were performed on seven islands, comprising 50 transects with 1 to 3 plant species each (10 replicates per species), giving 1320 samples from ten host species trees or shrubs in total. From a total of 129 insect herbivore species, a greater number of herbivore species was found on Juniperus brevifolia (s=65) and Erica azorica (s=53). However, the number of herbivore species per individual tree crown was higher for E. azorica than for any other host, on all islands, despite the fact that it was only the fourth more abundant plant. In addition, higher insect species richness and greater insect abundance were found on the trees of Santa Maria Island, the oldest in the archipelago. Insect species composition was strongly influenced by the presence of E. azorica, which was the only host plant with a characteristic fauna across the archipelago, whereas the fauna of other plant crowns was grouped by islands. The great insect occurrence on E. azorica reflects strong habitat fidelity, but only four species were clearly specialists. Our findings indicate a broadly generalist fauna. The simplicity of Azorean Laurisilva contributed to the understanding of insect‐plant mechanisms in canopy forest habitats.     

Geographic biotype and host-associated local adaptation in a polyphagous species, Lambdina fiscellaria (Lepidoptera: Geometridae) feeding on balsam fir on Anticosti Island, Canada

The debate about mechanisms underlying the evolution of host specialization by herbivorous insects remains open. Natural selection may act locally and lead to different patterns of geographic variation in life history traits of polyphagous herbivores. The hypothesis of genetically-based trade-offs in offspring performance on different hosts has been proposed but this has rarely been demonstrated. Under laboratory conditions, the biological performance of two populations of the hemlock looper Lambdina fiscellaria (Guenée), a highly polyphagous lepidopteran, was compared when reared on three different tree host species: balsam fir, eastern hemlock and sugar maple. One population originated from Anticosti Island, Québec, Canada, where the insect has evolved without having access to two of the three tree species tested, the other being from the mainland where all tree species are present. When reared on balsam fir foliage, which was naturally available to each population, larvae from Anticosti Island underwent four instars compared with five for the mainland population, indicating the existence of geographic biotypes in L. fiscellaria. When reared on the foliage of non-naturally available host trees, larvae from Anticosti Island had a higher incidence of supernumerary instars. This is a unique example where local adaptation to environmental conditions of an insect herbivore is expressed through a differential number of larval instars. Moreover, the Anticosti Island population showed a higher growth related index on the host available to both populations indicating that a fitness trade-off was the evolutionary process underlying the local adaptation of this population on balsam fir.     

Macro- and microhabitat use of Telfair’s skink (Leiolopisma telfairii) on Round Island, Mauritius: implications for their translocation

The successful eradication of introduced rodents from islets off the coast of Mauritius has led to local conservation bodies investigating the possibility of translocation as a measure of safeguarding endemic reptile populations. The present study was the first to determine the habitat and microhabitat requirements of Telfair's skinks (Leiolopisma telfairii) on Round Island, Mauritius, with a view to aiding future translocation projects to islands within their historic range. Contrasting preferences found for Telfair's skink at macro- and micro- habitat levels underline the importance of sampling at multiple ecological scales in such investigations. Significantly fewer sightings of L. telfairii were recorded in bare rock habitats compared to more vegetated habitats. Conversely, at a microhabitat scale principal component analysis indicated structural characteristics were the primary determinant of microhabitat choice. The first dietary analysis of Telfair's skinks confirmed their status as omnivores. Cockroaches (Blattodea spp.) appeared to be a primary food source. Four exotic plant species were also present in faecal samples and the potential for L. telfairii to aid their dispersal is discussed. Implications for the long-term management and proposed translocation of Telfair's skinks are discussed.     

A new endemic gecko (Reptilia: Gekkonidae) from Mauritius

A previously undescribed gecko, Nactus coindemirensis sp. nov. is reported from Gunner's Quoin, a small island off Mauritius. Nactus coindemirensis is not especially closely related to the other Mauritian member of the genus, N. serpensinsula; thus, it is likely that the precursors of these two species reached Mauritius separately, rather than both being descended from a single colonizer. Unlike other Mauritian reptiles now known only from small off-shore islands, N. coindemirensis coexists with rats, perhaps because it can evade them by taking refuge in small holes and crevices of the basalt it inhabits. This raises the possibility that it may still survive on other islands with rats, including Mauritius itself, but has escaped notice because of its size and cryptic behaviour.     

Distribution and abundance of endemic coelostomidiid scale insects (Hemiptera: Coelostomidiidae) in Auckland forests, New Zealand

Sap-feeding insects can excrete considerable quantities of sugar-rich honeydew. In New Zealand, South Island beech (Nothofagus spp.) forests are shaped by the extensive honeydew resource produced by two endemic coelostomidiid species (Ultracoelostoma assimile and U.?brittini) and geckos on northern islands are known to feed on the honeydew of a third endemic coelostomidiid, Coelostomidia zealandica. There are six other endemic coelostomidiid species in New Zealand that utilise a range of plant hosts but the ecological role of these species is poorly understood. A survey of mainland forests in the Auckland Ecological Region was conducted in February?April 2006 to investigate the distribution and abundance of coelostomidiids in this area. Three coelostomidiid species were detected in the survey (C.?zealandica, C.?pilosa and C.?wairoensis) and five new host?scale insect associations were identified. C.?zealandica was uncommon, C.?pilosa was widespread in broadleaved?podocarp forest but only formed light infestations, and C.?wairoensis was present in all teatree stands examined, often forming heavy infestations on k?nuka (Kunzea ericoides). Infested k?nuka trees had sooty moulds growing on them and exotic wasps were regularly seen feeding on C.?wairoensis honeydew. The extent and intensity of C. wairoensis infestation on k?nuka suggests it will have community-level impacts.     

The intercultural dodo: a drawing from the School of Bundi,Rājasthān

The iconic dodo Raphus cucullatus once occurred on the isolated Mascarene Island of Mauritius, situated in the southwestern Indian Ocean. Mauritius was once a paradise for a unique flora and fauna that evolved in isolation for 8 million years. The dodo was sought after by seafarers who visited the island from the early sixteenth century onwards because we know from remains surviving in collections and a series of artworks that captive dodos were transported to Europe, India and Japan. This article presents a hitherto unpublished image of a dodo, preserved in the collection of the Trustees, Chhatrapati Shivaji Maharaj Vastu Sangrahalaya, Mumbai, the formerly Prince of Wales Museum of Western India. The bird is situated in a non-Mauritian environment together with other animals and it is named in Hindi. We further explore the background of this creation and its implication on the iconography of the dodo.     

The ecology of a scale insect,Aulacaspis tegalensis,on sugar cane in East Africa

• 1 The scale insect, Aulacaspis tegalensis, invaded a sugar estate near Moshi, Tanzania, in 1969.
• 2 The number of fields affected and scale abundance were estimated weekly by weighing eggs sifted from samples scraped from infested cane.
• 3 Abundance increased exponentially with the age of the cane, once mature cane began to develop at the age of six months, and it was also affected by the cane variety.
• 4 The principal source of temporal variation in abundance was weather, especially mean maximum temperature eight weeks before sampling, when the crawlers which gave rise to the females were settling.
• 5 The behaviour of crawlers is affected by temperature, humidity and sunshine.
• 6 Up to 25% of the crop was lost at the height of the infestation.
• 7 Wild natural enemies could not reduce scale numbers to an acceptable level.
• 8 Lindorus lophanthae (Coccinellidae) was introduced from Mauritius in 1971 and may have been responsible for the decline in scales which began after it had become abundant throughout the estate. Since 1972 loss of yield due to scale has been undetectable in the factory.
• 9 The results are discussed in relation to the situation in Mauritius, where L.lophanthae is ineffective and the implications of the studies for the reduction of losses by agronomic methods are detailed.

     

Revising the convergence hypothesis of avian use of honeydew: evidence from Dominican subtropical dry forest

A honeydew-producing scale insect (family Margarodidae, tribe Xylococcini, genus Stigmacoccus ) was found associated with the tree Bursera simaruba in subtropical dry forests at elevations of 100–400 m on the south side of the Sierra de Bahoruco, Pedernales Province, Dominican Republic. At two study sites, 91% of Bursera trees supported locally dense populations of Margarodidae. Fifteen species of birds were observed foraging on the honeydew, but most observations were of the winter resident Cape May warbler ( Dendroica tigrina ) and black-throated blue warbler ( D. caerulescens ), and the permanent resident bananaquit ( Coereba flaveola ) and black-crowned palm tanager ( Phaenicophilus palmarum ). The Cape May warbler actively defended the honeydew resource but frequency of use of honeydew was influenced by the close presence of flowering agave and scale insect density. Data suggest that honeydew may be a critical component of the diet of this species especially during the late winter dry-season. Hymenopteran insects also were observed feeding on honeydew, but rates of consumption did not approach that of avian species. The occurrence of this phenomenon in Dominican dry forest is discussed in light of the convergence hypothesis of bird use and defense of homopteran honeydew in which it is proposed that birds are able to maintain relationships with scale insects in moist, warm temperate forests because it is in these climates where ant abundance is low. We suggest that our observation of a well-developed bird–homopteran system in classic subtropical dry forest supports the proposed mechanism of reduced competition with ants allowing bird use of honeydew, but we suggest that a broader array of especially insular habitats which may be relatively depauperate in terms of ants also can be expected to support bird–homopteran systems.     

Genetic Conservation of Insular Populations of Monterey Pine (Pinus Radiata D. Don)

Monterey pine (Pinus radiata D. Don) has only five extant native populations: three disjunct populations along the coast of California, USA and two on Mexican islands. All populations have been influenced by human activity, but the island populations in particular have been affected by introduced biota. On Guadalupe Island, the pine population has suffered drastically from overgrazing by introduced goats. We visited both island populations and described their status, took measurements, and made seed collections. We counted approximately 200 mature pine trees and virtually no seedlings on Guadalupe Island: a reduction of approximately half the population in the last 50 years. The trees are all large (mean diameter of 144 cm) –considerably larger than trees from the other four populations – and arguably near the end of their natural lifespan. The population on Cedros Island is much more robust, with thousands of trees. None sampled were as large as those on Guadalupe Island (mean diameter of 20 cm) and many groves were young and even-aged – presumably the consequence of natural regeneration after a recent fire. Tissue samples from trees on both islands did not show evidence of infection from the pitch canker pathogen, Fusarium circinatum, that has caused significant mortality in the three mainland populations. Caution is recommended in any restoration activity for the Guadalupe Island pines. Inbreeding levels could indicate the need for some planting or seeding intervention but there are also risks associated with this. Natural regeneration – after goat removal – is preferred.     

Mixed mating strategies and pollination by insects and wind in coconut palm (Cocos nucifera L. (Arecaceae)): importance in production and selection

Abstract 1 Coconut is one of the most important tropical crops. It is threatened by Lethal yellowing disease. Production and selection by breeding require pollination, yet little is known of the pollination requirements and breeding system of this palm. 2 This study was carried out from 1999 to 2001 in coconut plantations represented by five coconut ecotypes commonly found in Mexico. It is the first study in the Neotropics on pollination and the breeding system of this palm. 3 Hymenoptera were the most numerous and diverse visitors to coconut flowers. The greatest period of insect abundance occurred during the rainy season (July to October). Insect abundance on the flowers correlated highly and positively with precipitation. 4 The abundance of visitors to pistillate flowers did not vary with season but there were significant differences between palm ecotypes; the most insect‐visited flowers were of the Atlantic Tall ecotype. 5 The introduced honeybee (Apis mellifera) had the most appropriate foraging behaviour, visiting both pistillate and staminate flowers. These insects were probably the most efficient pollinators as they carry pollen on their ventral surface. Ants were present on flowers day and night but had no effect on pollination. 6 Pollination experiments indicated a mixed mating strategy: self‐pollination by geitenogamy produced almost 19% of the fruit set, but cross‐pollination (xenogamy) was the most important contribution (c. 30%). Anemophilous cross‐pollination only accounted for 10% of fruit set, whereas entomophily became the most important pollination mechanism under Yucatan conditions. 7 As coconut palm grows naturally on the oceanic strand in a wide variety of seasonal conditions of wind and rain, we suggest that they may have evolved pollination, breeding and mating systems that ensure fruit production under a wide variety of conditions, while maximizing the probability of cross‐pollination.     

Using ancient and recent DNA to explore relationships of extinct and endangered Leiolopisma skinks (Reptilia: Scincidae) in the Mascarene islands

Phylogenetic analysis, using 1455 bp of recent mtDNA (cytochrome b 714 bp, 12S rRNA 376 bp) and nuclear (c-mos 365 bp) sequence from 42 species and 33 genera of Scincidae, confirms Leiolopisma telfairii, now confined to Round island off Mauritius, is a member of the mainly Australasian Eugongylus group of the Lygosominae. Ancient mtDNA (cytochrome b 307 bp, 12S rRNA 376 bp) was also extracted from subfossils of two other Mascarene taxa that are now extinct: the giant L. mauritiana from Mauritius and Leiolopisma sp., known only from fragmentary remains from Réunion. Sequence divergences of 4.2-5.7% show that all three forms were distinct and form a clade. There is restricted evidence that L. mauritiana and L. sp. from Réunion were sister species. Monophyly and relationships suggest Leiolopisma arose from a single transmarine invasion of the oceanic Mascarene islands from Australasia, 5600-7000 km away. This origin is similar to that of Cryptoblepharus skinks and Nactus geckos in the archipelago but contrasts with Phelsuma day geckos, which appear to have arrived from Madagascar where Mascarene Cylindraspis tortoises may also have originated. Diversification of the known species of Leiolopisma occurred from about 2.3-3.4 Mya, probably beginning on Mauritius with later invasion of Réunion. The initial coloniser may have had a relatively large body-size, but L. mauritiana is likely to have become gigantic within the Mascarenes. Other relationships supported by this investigation include the following. Scincines: Pamelaescincus+Janetaescincus, and Androngo (Amphiglossus, Paracontias). Lygosomines: Sphenomorphus group--(Sphenomorphus, Lipinia (Ctenotus, Anomalopus (Eulamprus and Gnypetoscincus))): Egernia group--Egernia (Cyclodomorphus, Tiliqua); Eugongylus group--(Oligosoma, Bassiana. (Lampropholis (Niveoscincus, Carlia))).