Notes on New Zealand mammals 6. Second report on the stomach contents of long‐finned pilot whales,Globicephala melas

Abstract

We report data on the stomach contents of the long‐finned pilot whale, Globicephala melas, recovered from a group of whales stranded on Ruakaka Beach, northeastern New Zealand, in November 2006. In nine whales for which identifiable stomach contents were recovered (three that stranded on 10 November and six that stranded on 11 November) prey remains comprised exclusively cephalopod beaks attributed to five squid species. The stomachs of a further two whales contained unidentifiable upper beaks only, while the stomachs of five whales were completely empty. No whale appeared to have been satiated immediately before stranding, given that the maximum biomass of prey recently consumed by any one whale was calculated to be <5 kg. All squids ingested represented oceanic species, found from 50 to 1000 m but more common towards the deeper end of this range. These data both complement and contrast with the only other dietary information available for this species in New Zealand waters, reported from stomach contents of whales stranded on Farewell Spit, South Island in December 2005.     

Stomach contents of long‐finned pilot whales,Globicephala melas,mass‐stranded on Farewell Spit,Golden Bay in 2005 and 2008

Abstract

New data are reported on the diet of the long‐finned pilot whale, Globicephala melas, based on stomach contents recovered from whales involved in a mass stranding on Farewell Spit, Golden Bay, South Island, on 23 January 2008. The stomachs of 11 whales were examined, from which identifiable prey remains were recovered from six, four females and two males (3.1–5.4 m in length). Prey remains comprised exclusively cephalopod beaks (1–46 beaks per whale), attributed to two genera in two orders: arrow squid, Nototodarus spp. (Teuthoidea: Ommastrephidae), and common octopus, Pinnoctopus cordiformis (Octopoda: Octopodidae). The stomachs of eight whales were infested with parasitic nematodes, with two ulcerated; the stomachs of five whales did not contain any prey remains. These data complement and are comparable to the only other information available for this species from this region, reported from whales mass‐stranded at this same location in December 2005. Lower beak rostral length versus mantle length and biomass regression equations for Nototodarus spp. are reviewed, highlighting the importance of the use of species‐specific regression equations for reconstructing both cephalopod mantle length and biomass from lower beak remains in dietary studies.     

Population structure of long‐finned pilot whales in the North Atlantic: a correlation with sea surface temperature?

The long-finned pilot whale, Globicephala melas, is a social, pelagic odontocete distributed widely in the cold temperate waters of the North Atlantic. Despite genetic, morphometric, physiological and observational studies, it remains unclear whether any population substructure exists. We have used eight highly polymorphic microsatellite loci to analyse samples from four disparate sampling sites: USA East Coast (Cape Cod), West Greenland, the Faeroe Islands and the UK. Our results indicate that substructure does exist, and is particularly pronounced between West Greenland and other sites. The magnitudes of the various pairwise comparisons do not support a simple isolation-by-distance model. Instead, the patterns of genetic differentiation suggest that population isolation occurs between areas of the ocean which differ in sea surface temperature. Such a mechanism is supported by the observation that temperature is a primary factor determining the relative distributions of two short-finned pilot whale (G. macrorhynchus) populations off the Pacific coast of Japan.     

Activity patterns of long‐tailed bats (Chalinolobus tuberculatus) in a rural landscape,South Canterbury,New Zealand

Abstract

The temporal and spatial activity patterns of long‐tailed bats (Chalinolobus tuberculatus) were assessed between January and July 1995 by automatic monitoring of echolocation calls, radio‐telemetry and direct observation at Hanging Rock, South Canterbury. Automatic bat detection units recorded 8728 bat passes and 933 feeding buzzes during 272 nights of sampling. In addition, five radio‐tagged post‐lactating female bats were each followed for an average of 13.0 ± 3.2 (SE) days. Home range size averaged 471.4 ± 50.9 ha (95% median minimum convex polygons) but core areas of activity (50% of fixes) were 54.4 ± 5.4 ha (11.6 ± 3.1% of the home range size). Patterns of activity varied in relation to time of year, time of night, temperature, invertebrate activity and habitat. Between January and March, long‐tailed bats consistently emerged from day roosts at sunset and flew throughout the night, with peaks of activity shortly after sunset and before sunrise. After the beginning of April, long‐tailed bats no longer flew throughout the night, but they had one peak of activity between the first and third hour after sunset. Both automatic monitoring and radio‐telemetry showed extensive use by long‐tailed bats of river and riparian habitats. Radio‐tagged bats avoided foraging over open farmland, and repeatedly returned to the same sites on consecutive nights.     

The impact of the ‘New Zealand flatworm’, Arthurdendyus triangulatus, on earthworm populations in the field

The ‘New Zealand flatworm’, Arthurdendyus triangulatus, is a native of the South Island of New Zealand, which has established in the UK, Ireland and the Faroe Islands. In its introduced range, it is a predator of lumbricid earthworms. To assess the impact of A. triangulatus on earthworm species, flatworm distributions were manipulated into ‘high’, control and ‘low’ densities within a replicated field experiment. Earthworm biomass in the ‘high’ flatworm density treatment was significantly lower than the control or ‘low’ treatments. This was due to a reduction in the anecic species Lumbricus terrestris and, to a lesser extent, Aporrectodea longa. There was little evidence of negative effects on other earthworm species, with even a weakly positive relationship between flatworm density and epigeic biomass. Principal components analysis showed a clear separation of anecic species from A. triangulatus, but the epigeic species Lumbricus festivus and Lumbricus rubellus grouped with A. triangulatus, suggesting that they could be benefitting from reduced intraguild competition. Flatworm densities of 0.8 per m², comparable to natural infestations in grassland, were predicted to give a reduction in total earthworm biomass of c. 20 %. The bulk of this was comprised of a reduction in anecic species biomass. In particular, it is considered that A. triangulatus poses a serious risk to L. terrestris populations, with implications for soil functioning and indigenous earthworm-feeding wildlife.     

A new species of Hymenolepis (Cestoda: Hymenolepididae) from the New Zealand long‐tailed bat,Chalinolobus tuberculatus

Hymenolepis chalinolobi n. sp. is described from the small intestine of the New Zealand long‐tailed bat, Chalinolobus tuberculatus (Forster, 1844). The tapeworm is distinguished by its small size (16–19 mm), 23 hooks, and the shape of the ovary and testes.     

Abundance of the rose-grain aphid,Metopolophium dirhodum,on barley in Canterbury,New Zealand, 1984–87

Abstract

Spring populations of Metopolophium dirhodum (Walker) (Hemiptera: Aphididae) on barley, at Lincoln and elsewhere in Canterbury, New Zealand, declined markedly during 1984–87. Spring suction-trap catches of M. dirhodum also declined at the same time. Numbers of immigrant M. dirhodum on young barley, and maximum aphid population density on the crop, were positively correlated with suction-trap catches of M. dirhodum during the preceding week or month, respectively. Egg numbers of the most abundant predator, Micromus tasmaniae Walker (Neuroptera: Hemerobiidae), and mummy numbers of the parasitoid, Aphidius rhopalosiphi De Stefani-Perez (Hymenoptera: Aphidiidae), increased relative to aphid numbers during the study. Entomophagous fungus-disease incidence could not be related to monthly rainfall, and the decline in aphid numbers during the study period was apparently not related to disease incidence. It is suggested that aphid population regulation by predators and parasitoids in the wider habitat of M. dirhodum could reduce the rate of immigration, and hence aphid population growth, in a given crop.     

Evidence of homing following translocation of long‐tailed bats (Chalinolobus tuberculatus) at Grand Canyon Cave,New Zealand

Abstract

Homing behaviour in the New Zealand long‐tailed bat (Chalinolobus tuberculatus), a temperate insectivorous species, was investigated at Grand Canyon Cave, central North Island. A pilot study of nine adult male bats was conducted to determine whether use of the cave was regular enough for a homing study. Eight bats returned to the cave over the 3‐week monitoring period, six on the night following release. Nine additional bats carrying radio transmitters were then released at three sites (three at each site) c. 5, 10 and 20 km due east of the cave; sites estimated to be located within, on the border of, and outside the population's known familiar area respectively. All but one of these nine bats were subsequently detected at the cave. Results suggest that adult long‐tailed bats are able to return home following displacement both inside and outside their familiar area. Implications of these findings for translocations of bats and the possession of a potential long‐distance navigation system by this species are discussed.     

Diet of the opossum Trichosuvus vulpecula (Kerr) in the Orongorongo Valley,Wellington, New Zealand,in relation to food‐plant availability

The food preferences of a population of opossums in 4.4 ha of lowland broadleaf/podocarp forest were studied for 4 years by faecal analysis. A survey and phenological records were made of the vegetation to compare foods eaten with foods available. Metrosideros robusta and Weinmannia racemosa contributed 60% to the leaf diet, and were being defoliated and killed by opossums. Metrosideros fulgens and Ripogonum scandens, both lianes, together contributed 15 % to the leaf diet but were eaten seasonally. About 10 other species contributed small amounts. Flowers, flower buds, fruit, seeds, bark, and petiole made up about 35 % of the total diet. Compared with their status in the same area 30 years ago, Fuchsia excorticata, Alectryon excelsus, Pseudopanax arboreum, Myrsine salicina, and Coriaria arborea are now rare or localised and of much less consequence in the diet.     

Abstracts of papers presented at the 12th Biennial Conference of the Society for Research on Amphibians and Reptiles in New Zealand,University of Otago,Dunedin, New Zealand, 9–11 February 2007

Abstract

This study of customary harvests of sooty shearwater Puffinus griseus chicks by Rakiura Maori compares the utility of Traditional Ecological Knowledge (TEK) and ecological science for understanding patterns in prey availability. We recorded TEK of 28 muttonbirders about emergence patterns and variation in chick size at different aspects of 14 breeding islands and in their coastal fringe compared to inland areas. Spatial and temporal variation of chick availability were measured using the methods of ecological science in the 2001 harvest season across Putauhinu Island, south west of Rakiura, New Zealand. As predicted by TEK, titi emerged earlier from west than east coast locations on Putauhinu. Scientific measures were also consistent with an earlier emergence in coastal compared to inland areas as asserted by TEK, but conclusive inference is potentially confounded by movement of chicks between burrows just before fledging. A TEK construct predicting heavier chicks on the west coast was not supported by scientific measurements. We also measured the characteristics of areas preferred for harvesting so that we could gauge representativeness of the areas “sampled” by the muttonbirders to accumulate their TEK. Within forested habitat, areas harvested by muttonbirders had 62–65% higher chick density than unharvested areas. The muttonbirders concentrated harvesting where there was less ground cover and taller canopy cover and only hunted on nights and times of the season when harvesting was most profitable. Therefore, TEK may be less able to detect wider‐scale variation and harvest impacts on prey in particular. Short runs of scientific information from spatially and temporally stratified sampling will complement and assist inference from longer term TEK. As shown in this case study, TEK and science often agree on pattern, but are likely to disagree on why a pattern exists.     

Population monitoring of the endangered New?Zealand spider,

The endangered New?Zealand widow spider, Latrodectus katipo, is believed to have undergone marked population decline over the last 30 years, but as monitoring methods are time- and labour-intensive, and require observers to have a high level of experience, the current status of many populations is unknown. We investigated the use of artificial cover objects (ACOs) as an alternative monitoring tool for L. katipo at three sites at Himatangi Beach, Manawatu, New?Zealand, from late 2004 through to mid-2005. Occupancy rates of the ACOs were compared with population densities obtained from habitat searches, to assess their efficacy as a monitoring tool. Numbers of the introduced spider, Steatoda capensis, which may be a competitor of L.?katipo, were also recorded during habitat searches. ACOs were reliable monitoring tools, with occupancy rates higher at the site with the highest L.?katipo population density. Latrodectus katipo populations were found to have highly female biased sex-ratios, with a longer breeding season at Himatangi than reported previously at other sites. Steatoda capensis exists at much higher population densities than L.?katipo at Himatangi. However, fluctuations in the populations of the two species appear to be unrelated. ACOs could be used as a non-destructive monitoring tool for many other arachnid species.     

Effect of grazing on ship rat density in forest fragments of lowland Waikato, New?Zealand

Ship rat (Rattus rattus) density was assessed by snap-trapping during summer and autumn in eight indigenous forest fragments (mean 5 ha) in rural landscapes of Waikato, a lowland pastoral farming district of the North Island, New?Zealand. Four of the eight were fenced and four grazed. In each set of four, half were connected with hedgerows, gullies or some other vegetative corridor to nearby forest and half were completely isolated. Summer rat density based on the number trapped in the first six nights was higher in fenced (mean 6.5 rats?ha^?1) than in grazed fragments (mean 0.5 rats?ha^?1; P?=?0.02). Rats were eradicated (no rats caught and no rat footprints recorded for three consecutive nights) from all eight fragments in January?April 2008, but reinvaded within a month; time to eradication averaged 47 nights in fenced and 19 nights in grazed fragments. A second six-night trapping operation in autumn, 1?3 months after eradication, found no effect of fencing (P?=?0.73). Connectedness to an adjacent source of immigrants did not influence rat density within a fragment in either season (summer P?=?0.25, autumn P?=?0.67). An uncalibrated, rapid (one-night) index of ship rat density, using baited tracking tunnels set in a 50 ? 50 m grid, showed a promising relationship with the number of rats killed per hectare over the first six nights, up to tracking index values of c.?30% (corresponding to c.?3?5 rats ha^?1). The index will enable managers to determine if rat abundance is low enough to achieve conservation benefits. Our results confirm a dilemma for conservation in forest fragments. Fencing protects vegetation, litter and associated ecological processes, but also increases number of ship rats, which destroy seeds, invertebrates and nesting birds. Maximising the biodiversity values of forest fragments therefore requires both fencing and control of ship rats.     

Presence of double‐stranded RNAs and virus‐like particles in the entomopathogenic fungus Metarhizium anisopliae

Nucleic acids from 41 strains of Metarhizium anisopliae, obtained from different parts of the world were extracted and examined by electrophoresis. Strong bands of double‐stranded RNA (dsRNA) were detected in two isolates from Brazil, V215 and V291, which had, respectively, 13 and 9 distinct bands ranging in size from ca. 0.75 to 3.5 kb. Icosahedral virus‐like particles (VLPs) (ca. 33 nm in diameter) were observed by transmission electron microscopy in extracts of these isolates. The VLPs and dsRNA were both absent from a clone of the isolate V291 which had been subcultured successively on solid medium. Bioassays against the aphid Myzus persicae showed no detectable difference in virulence between the clone of V291 which contained dsRNA and the clone that did not.     

The First New Zealanders? An Alternative Interpretation of Stable Isotope Data from Wairau Bar,New Zealand

PLOS ONE Volume 8 includes an article “The First New Zealanders: Patterns of Diet and Mobility Revealed through Isotope Analysis”. The paper proposes that burial groups within the settlement phase site of Wairau Bar differ in terms of dietary stable isotopes and ⁸⁷Sr/⁸⁶Sr. The authors argue this difference is probably due to one group being a founding population while the other burials are later. Here we review the work of Kinaston et al. and present an alternative analysis and interpretation of the isotopic data. Treating the isotope data independently from cultural and biological factors we find that sex best explains dietary variation. Our reassessment of ⁸⁷Sr/⁸⁶Sr confirms the authors original finding of high mobility of early New Zealanders but suggests a larger range of individuals should be considered ‘non-local’ on current evidence.     

Effect of codon optimization on the enhancement of the β-carotene contents in rice endosperm

A β-carotene is the most well-known dietary source as provitamin A carotenoids. Among β-carotene-producing Golden Rice varieties, PAC (Psy:2A:CrtI) rice has been previously developed using a bicistronic recombinant gene that linked the Capsicum Psy and Pantoea CrtI genes by a viral 2A sequence. To enhance β-carotene content by improving this PAC gene, its codon was optimized for rice plants (Oryza sativa L.) by minimizing the codon bias between the transgene donor and the host rice and was then artificially synthesized as stPAC (stPsy:2A:stCrtI) gene. The GC content (58.7 from 50.9%) and codon adaptation index (0.85 from 0.77) of the stPAC gene were increased relative to the original PAC gene with 76% DNA identity. Among 67 T₁ seeds of stPAC transformants showing positive correlations between transgene copy numbers (up to three) and carotenoid contents, three stPAC lines with a single intact copy were chosen to minimize unintended insertional effects and compared to the representative line of the PAC transgene with respect to their codon optimization effects. Translation levels were stably increased in all three stPAC lines (3.0-, 2.5-, 2.9-fold). Moreover, a greater intensity of the yellow color of stPAC seeds was correlated with enhanced levels of β-carotene (4-fold, 2.37 μg/g) as well as total carotenoid (2.9-fold, 3.50 μg/g) relative to PAC seeds, suggesting a β-branch preference for the stPAC gene. As a result, the codon optimization of the transgene might be an effective tool in genetic engineering for crop improvement as proven at the enhanced levels of translation and carotenoid production.     

First report on generalized pollination systems in Melastomataceae for the Andean páramos

Melastomataceae is a megadiverse family with records of transitions from specialized to generalized pollination systems for several species. These transitions are associated with the colonization of new, unpredictable and/or impoverished pollinator habitats or habitats where specialized pollinators are scarce (e.g., in highland environments). The bee species diversity is low in highlands. Therefore, autonomous breeding systems such as apomixis and self-pollination emerge in these environments. In this paper, we studied the floral traits associated with the generalization of pollination systems and registered the floral visitors of two species in the Colombian Andes: Miconia cataractae and M. elaeoides. We investigated the breeding system of M. elaeoides. Both species presented small flowers, short anthers of medium pore size, and nectar-producing stomata on the base of the anthers. Miconia cataractae produced an average of 1.62 μl nectar/flower, a sugar concentration of 6.78%, whereas M. elaeoides produced 0.09 μl nectar/flower, a sugar concentration of 6.13%. We recorded a wide diversity of pollinators for both species, mainly insects from the orders Hymenoptera and Diptera. Miconia elaeoides presented a mixed breeding system and was also capable of setting fruits by apomixis. We conclude that flower and anther morphology, combined with nectar production, thus represent convergent traits resulting in a generalist pollination system shared by M. cataractae and M. elaeoides. Here, we presented the first generalist pollination system recorded for Miconia (and the Melastomataceae) in the Andes, the first report for a species from the small-pored section Amblyarrhena, and the first report for a species from the large-pored section Cremanium in Colombia.     

Reproduction and growth of the black shore skink,Leiolopisma suteri (Lacertilia: Scincidae), in north‐eastern New Zealand

Reproduction and growth of a boulder beach population of the nocturnal skink Leiolopisma suteri on Motutapu Island were studied for 19 months. Epididymes contain sperm from April to November, and copulation probably occurs in October or November (spring). Ovulation occurs in late October or early November, and three or four (mean, 3.7) eggs are laid in late December. Incubation takes 3 months. Total development time from ovulation to hatching is 5 months, one of the longest development periods recorded for Scincidae. Growth to sexual maturity is slow, most females depositing their first clutch 33 months after hatching; males mature at 29 months.     

Immature stages of Curculionoidea — the weevils of The Snares islands,New Zealand

Abstract

The following weevil species are known from The Snares islands: Anthribidae — Cacephatus aucklandicus, Lichenobius littoralis; Curculionidae — Exeiratus laqueorum, Pentarthrum spadiceum, Notacalles planidorsis, Lyperobius sp., Hadramphus stilbocarpae, Phrynixus laqueorum, Gromilus laqueorum, Nestrius laqueorum, Catoptes brevicornis australis, Oclandius vestitus. The larvae and pupae are described and figured, and keys for their separation are given.