scholarly journals Are island plants really poorly defended? No support for the loss of defense hypothesis in domatia-bearing plants

2021 ◽  
Author(s):  
Matthew Biddick
Keyword(s):  
New Zealand ◽  
Rapid Evolution ◽  
Leaf Size ◽  
Defensive Mutualism

The loss of defense hypothesis posits that island colonizers experience a release from predation on the mainland and subsequently lose their defensive adaptations. While support for the hypothesis is abundant, it has never been tested in domatia-bearing plants. Leaf domatia are cave-like structures produced on the underside of leaves that facilitate a defensive mutualism with predatory and fungivorous mites. I tested the loss of defense hypothesis in six domatia-bearing taxa inhabiting New Zealand and its offshore islands. No support for the loss of defense hypothesis was found. Changes in domatia investment were instead associated with changes in leaf size; a trait that has been repeatedly observed to undergo rapid evolution on islands. Overall results demonstrate that not all types of defense are lost on islands, suggesting a higher-resolution approach is needed when studying the evolution of defense on islands.

CENOZOIC PLANKTONIC FORAMINIFERAL ZONATIONS OF SOUTHERN AUSTRALIA AND NEW ZEALAND

1975 ◽  
Vol 15 (2) ◽  
pp. 42
Author(s):  
D. Graham Jenkins
Keyword(s):  
New Zealand ◽  
Rapid Development ◽  
Planktonic Foraminifera ◽  
Rapid Evolution ◽  
South Australia ◽  
Research Programme ◽  
Oil Exploration ◽  
Major Step ◽  
Fossil Species ◽  
A Minor

BIOSTRATIGRAPHIC DOCUMENTATION of fossil species of planktonic foraminifera has played a major role in correlating marine Cenozoic rocks because of their relatively high diversity, abundance, rapid evolution and wide geographic distribution. A major step was undertaken in Trinidad in 1945 with the division of the Oligocene-Miocene rocks into three zones based on planktonic foraminifera and with the intensive oil-search on the island, there began an equally intensive research programme and rapid development in the study.Two research projects, independent of each other, were initiated in Gippsland. Victoria in the 1950s which resulted in publications: (1) from surface samples, a faunal unit system was devised for the Upper Eocene-Miocene. and (2) 11 named planktonic foraminiferal zones were established in a four-foot sampled Oligocene-Miocene sequence of the Lakes Entrance oil shaft. The latter scheme was tested and expanded for 3 years during oil exploration on the East Coast of New Zealand during 1959-1962 and a further four years was spent thoroughly testing, and expanding it into 21 zones sub-dividing the whole Cenozoic time of 67my. The zones can be identified in both surface and sub-surface sections and used for direct, accurate correlations of marine rock sequences thus providing the geologist with essential data for the construction of maps and subsurface control.The zonal scheme was re-exported back to South Australia, later to Gippsland and used there with minor local changes in the off-shore oil exploration; in 1973 the zonal scheme was further tested during the Deep Sea Drilling Project Leg 29 in the area south of New Zealand and Australia.Studies of planktonic foraminifera and allied microfossils has resulted in the cheapest and most reliable method for rapid age determinations of Cenozoic marine rocks; in perspective it plays a minor, but essential role in oil-search. The zonal scheme is a dynamic model subject to change and improvement.

scholarly journals The Invasive New Zealand Mudsnail, Potamopyrgus Antipodarum, Reduces Growth of the Native Snail, Fossaria SP.

2005 ◽  
Vol 29 ◽  
pp. 42-48
Author(s):  
Amy Krist ◽  
Mark Dybdahl
Keyword(s):  
Invasive Species ◽  
New Zealand ◽  
Biological Invasions ◽  
Native Species ◽  
Rapid Evolution ◽  
Potamopyrgus Antipodarum ◽  
Ecological Impacts ◽  
Or Gene ◽  
New Zealand Mud Snail ◽  
The Impact

Invasive species are one of the greatest threats to global biodiversity. Hence, understanding the role of invasive species is of grave importance to managing and minimizing the impact of biological invasions. To date, the ecological impacts of biological invasions have received significant attention, but little effort has been made to address the evolutionary impact (Sakai et al. 2001, Cox 2004). This is despite the fact that evolutionary impacts are likely to be widespread; invasive species have been shown to alter patterns of natural selection or gene flow within native populations (Parker et al. 1999), and many of the best examples of rapid evolution involve invasive species interacting with native species (Reznick and Ghalambor 2001, Strauss et al. 2006). We have begun to address some of the evolutionary consequences of the invasion of the New Zealand mud snail, (Potamopyrgus antipodarum) on a species of native snail in the Greater Yellowstone Area (GYA).

scholarly journals Genetic Diversity in Invasive Populations of Argentine Stem Weevil Associated with Adaptation to Biocontrol

Insects ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 441 ◽  
Author(s):  
Thomas W. R. Harrop ◽  
Marissa F. Le Lec ◽  
Ruy Jauregui ◽  
Shannon E. Taylor ◽  
Sarah N. Inwood ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Biological Control ◽  
Genetic Variation ◽  
New Zealand ◽  
Insect Pests ◽  
Rapid Evolution ◽  
Parasitoid Wasp ◽  
Control Agent ◽  
Agricultural Landscapes ◽  
Effective Population

Modified, agricultural landscapes are susceptible to damage by insect pests. Biological control of pests is typically successful once a control agent has established, but this depends on the agent’s capacity to co-evolve with the host. Theoretical studies have shown that different levels of genetic variation between the host and the control agent will lead to rapid evolution of resistance in the host. Although this has been reported in one instance, the underlying genetics have not been studied. To address this, we measured the genetic variation in New Zealand populations of the pasture pest, Argentine stem weevil (Listronotus bonariensis), which is controlled with declining effectiveness by a parasitoid wasp, Microctonus hyperodae. We constructed a draft reference genome of the weevil, collected samples from a geographical survey of 10 sites around New Zealand, and genotyped them using a modified genotyping-by-sequencing approach. New Zealand populations of Argentine stem weevil have high levels of heterozygosity and low population structure, consistent with a large effective population size and frequent gene flow. This implies that Argentine stem weevils were able to evolve more rapidly than their biocontrol agent, which reproduces asexually. These findings show that monitoring genetic diversity in biocontrol agents and their targets is critical for long-term success of biological control.

scholarly journals Trends in the global marketing of white clover cultivars

1996 ◽  
Vol 6 ◽  
pp. 7-14
Author(s):  
R.D.J. Mather ◽  
D.T. Melhuish ◽  
M. Herlihy
Keyword(s):  
New Zealand ◽  
South America ◽  
White Clover ◽  
Trifolium Repens ◽  
Western Europe ◽  
Leaf Size ◽  
Global Market ◽  
Production Region ◽  
Trifolium Repens L ◽  
Clover Seed

White clover (Trifolium repens L.) is the dominant legume of temperate pastures, having been improved by breeding since the 1930s. The 1994 OECD Register lists 93 cultivars, with a further 25-30 cultivars also known to commerce. Therefore, in excess of 100 cultivars are available to fulfil a world annual market of 8500-10,500 MT. Globally, New Zealand is the major white clover production region, providing 50- 55% of the seed. Other key production regions are Denmark, USA and South America. Consumption of white clover has been relatively static for some time, ranging from 8000-10,000 MT per annum. Between 55-60% of the seed is used in the northern hemisphere (approx. 40% by Western Europe - UK, France, Germany). USA, South America and New Zealand all consume similar tonnages annually (approx. 1000-2000 MT each) with smaller tonnages used in Australia. One cultivar, Grasslands Huia, has dominated the world white clover seed market for many years and it still remains the world's major cultivar by volume. However, in the last 10 years its position has come under increasing pressure from New Zealand and international proprietary cultivars. Eventually proprietary cultivars with improved agronomic performance will supersede the consumption of commodity/public white clovers in those countries where national listing is required to obtain release and recommended listing is need to ensure successful marketing. Despite this, Grasslands Huia will continue for many years to play a major role in supplying markets where national listing is not a prerequisite to release and price is a major factor in purchase decisions. Keywords: commodity cultivar, global market, Grasslands Huia, leaf size, market share, production trends, proprietary cultivar, seed industry, Trifolium repens L., white clover

scholarly journals Realised Niche Shifts, Rapid Evolution and Phenotypic Plasticity in Introduced Plants

2021 ◽  
Author(s):  
◽  
Charles Daniel Clark
Keyword(s):  
New Zealand ◽  
Phenotypic Plasticity ◽  
Introduced Species ◽  
Effect Size ◽  
Rapid Evolution ◽  
Niche Shift ◽  
Herbarium Specimens ◽  
Climate Niche ◽  
Niche Shifts ◽  
Glasshouse Experiment

<p>Recent biological invasions provide a unique opportunity to examine how species may adapt to novel conditions over relatively short time frames. Introduced species may respond to novel environmental conditions in the new range via rapid evolution, phenotypic plasticity, or the rapid evolution of phenotypic plasticity. However, the prevalence of these different mechanisms in introduced species remains unclear. In this thesis, I explore how introduced plant species may adjust their phenotype when introduced to a new range.  First, I tested for evidence of phenotypic change through time in key morphological traits (plant height, leaf area, leaf shape, and leaf mass per unit area), using historic herbarium records for 34 plants introduced to Australia and New Zealand. Thirty-two out of 94 trait-species combinations showed evidence for change through time. The rate and direction of trait change was variable across species and the local climate. One possibility is that species introduced to a new range exhibit different trait responses depending on the relative difference in environment between the native and introduced range. To investigate this, I quantified climatic niche shifts in introduced species relative to their native range. I then predicted trait change through time from the magnitude and direction of climate niche shift in a meta-regression. This is the first study to simultaneously assess trait change in multiple introduced species in relation to a shift in their realised niche. Overall, climate niche shifts did not predict trait change through time, suggesting that climate may not be the predominant driver of trait change in plants introduced to Australia and New Zealand. Alternatively, the combined uncertainty and the mismatch in spatial scales that may arise when combining these two methods could mask any underlying patterns in plant trait responses to the new environment.  It has been hypothesised that introduced species may respond to a sudden change in environment, by rapidly selecting for an increase in phenotypic plasticity. I tested for a difference in phenotypic plasticity between the native and introduced ranges of a beach daisy, Arctotheca populifolia. Contrary to my expectations, A. populifolia has shown a loss of phenotypic plasticity in as little as 80 years since its introduction to Australia. When using a meta-analysis to test for an overall difference in plasticity across multiple traits, I found that the current practice of calculating an effect size of an effect size (Hedges’ d) can lead to misleading results. I demonstrate how this issue arises when calculating a difference in Hedges’ d between two populations with different standard deviations. I propose an alternative way to calculate Hedges’ d to give a more accurate reflection of the difference in plasticity between ranges.  Finally, I combine different lines of evidence from the previous chapters in a case study to explore how A. populifolia has changed since its introduction to Australia, and examine any discrepancies between the results. A glasshouse experiment revealed distinct trait differences between native and introduced populations of A. populifolia, which were not reflected in trait change through time inferred from herbarium specimens. Additionally, measured trait differences between ranges in the glasshouse experiment better reflected a niche shift into wetter climate, than the predicted trait change through time from herbarium specimens. This suggests that trait differences determined in glasshouse or common garden experiments, may be a more suitable approach to assess trait change in relation to a realised niche shift than using herbarium specimens.</p>

scholarly journals Intensified agriculture favors evolved resistance to biological control

2017 ◽  
Vol 114 (15) ◽  
pp. 3885-3890 ◽  
Author(s):  
Federico Tomasetto ◽  
Jason M. Tylianakis ◽  
Marco Reale ◽  
Steve Wratten ◽  
Stephen L. Goldson
Keyword(s):  
Biological Control ◽  
New Zealand ◽  
Large Scale ◽  
Lolium Multiflorum ◽  
Rapid Evolution ◽  
Pasture Grass ◽  
Parasitism Rates ◽  
Genetic Barriers ◽  
Evolution Of Resistance ◽  
Listronotus Bonariensis

Increased regulation of chemical pesticides and rapid evolution of pesticide resistance have increased calls for sustainable pest management. Biological control offers sustainable pest suppression, partly because evolution of resistance to predators and parasitoids is prevented by several factors (e.g., spatial or temporal refuges from attacks, reciprocal evolution by control agents, and contrasting selection pressures from other enemy species). However, evolution of resistance may become more probable as agricultural intensification reduces the availability of refuges and diversity of enemy species, or if control agents have genetic barriers to evolution. Here we use 21 y of field data from 196 sites across New Zealand to show that parasitism of a key pasture pest (Listronotus bonariensis; Argentine stem weevil) by an introduced parasitoid (Microctonus hyperodae) was initially nationally successful but then declined by 44% (leading to pasture damage of c. 160 million New Zealand dollars per annum). This decline was not attributable to parasitoid numbers released, elevation, or local climatic variables at sample locations. Rather, in all locations the decline began 7 y (14 host generations) following parasitoid introduction, despite releases being staggered across locations in different years. Finally, we demonstrate experimentally that declining parasitism rates occurred in ryegrass Lolium perenne, which is grown nationwide in high-intensity was significantly less than in adjacent plots of a less-common pasture grass (Lolium multiflorum), indicating that resistance to parasitism is host plant–dependent. We conclude that low plant and enemy biodiversity in intensive large-scale agriculture may facilitate the evolution of host resistance by pests and threaten the long-term viability of biological control.

scholarly journals Phormium Yellow Leaf Phytoplasma Is Associated with Strawberry Lethal Yellows Disease in New Zealand

Plant Disease ◽  
1998 ◽  
Vol 82 (6) ◽  
pp. 606-609 ◽  
Author(s):  
M. T. Andersen ◽  
J. Longmore ◽  
L. W. Liefting ◽  
G. A. Wood ◽  
P. W. Sutherland ◽  
...  
Keyword(s):  
New Zealand ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Leaf Size ◽  
Nucleotide Sequence Analysis ◽  
Rrna Gene ◽  
Yellow Leaf ◽  
Yellow Leaf Disease ◽  
Polymerase Chain ◽  
The 16S Rrna Gene

A yellows disease of strawberry plants was identified in propagation beds in New Zealand. Affected plants were flatter to the ground, showed purpling of older leaves, reduced leaf size, yellowing of younger leaves, and sometimes plant death. A phytoplasma was observed in the phloem of affected plants. The 16S rRNA gene of the phytoplasma was amplified by polymerase chain reaction from symptomatic plants and from one asymptomatic plant, but not from 36 other asymptomatic plants. Nucleotide sequence analysis of the 16S rRNA gene showed that the phytoplasma is closely related or identical to the phytoplasma associated with the yellow leaf disease of New Zealand flax (Phormium tenax).

scholarly journals White clover ecotype germplasm from the USA for development of New Zealand and overseas cultivars

1996 ◽  
Vol 6 ◽  
pp. 149-153
Author(s):  
K.H. Widdup ◽  
J.R. Caradus ◽  
J. Green ◽  
Mueller Pennell
Keyword(s):  
North Carolina ◽  
New Zealand ◽  
White Clover ◽  
Leaf Size ◽  
The North ◽  
Nodal Roots ◽  
Wide Range ◽  
Eastern Usa ◽  
The Usa ◽  
Small Set

An ecotype collection of 98 populations of white clover (Trifolium repens L.) from pastures in the eastern USA together with five USA Ladino and five New Zealand cultivars were grown in grass swards at Raleigh, North Carolina; Palmerston North and Lincoln, New Zealand. The material was compared for leaf size, cyanogenesis, seasonal growth, % clover cover and persistence. When examined as a single group, the USA ecotypes consisted of a wide range of plant types from small-leaved acyanogenic to large-leaved cyanogenic types. This contrasted with the uniformly large-leaved acyanogenic USA Ladino cultivars which have been the principal cultivars sown in eastern USA. Various selection pressures over time together with introgression between Ladino and resident wild clover types has resulted in a wide array of plant types. At the North Carolina site, USA ecotype material generally demonstrated better growth and persistence compared to the USA Ladino and New Zealand cultivars. The best ecotype plots from the Piedmont (inland region) had 55% clover cover by the third spring compared to 12% cover from the USA cultivar, SRVR and 2% cover from the NZ cultivar, Huia. Selective pressures such as hot summers, viruses, root-feeding pests and other stresses on the local clover types have resulted in ecotype material with improved adaptive features. The USA ecotype collection is an important source of germplasm for development of improved white clovers for the eastern USA. At the New Zealand sites, the USA material demonstrated pooraverage yields compared to NZ cultivars. However, a small set of USA ecotypes showed good recovery following the dry 1995 summer at Lincoln and this material warrants closer examination to determine the adaptive mechanisms involved. As the USA ecotypes show a general lack of adaptation to New Zealand pastures, any desirable features such as heat tolerance, deeper nodal roots or virus resistance uncovered in this material will require hybridisation and backcrossing with selected elite New Zealand material to capture the benefits. Keywords: adaptation, eastern USA, ecotype populations,

scholarly journals The positioning of white clover cultivars in New Zealand

1996 ◽  
Vol 6 ◽  
pp. 45-49
Author(s):  
J.R. Caradus ◽  
R.J.M. Hay ◽  
D.R. Woodfield
Keyword(s):  
New Zealand ◽  
White Clover ◽  
Leaf Size ◽  
Agronomic Performance ◽  
Flowering Period ◽  
Disease Tolerance ◽  
Negatively Associated ◽  
Seasonal Performance ◽  
Point Density ◽  
History Of

The breeding history of 10 white clover cultivars bred in New Zealand is described. The cultivars are compared for leaf size, cyanogenesis and stolon growing point density. Leaf size and stolon growing point density were negatively associated although more recent cultivars (Prestige, Demand, Sustain and Challenge) had higher stolon growing point densities than older cultivars of similar leaf size. Both leaf size and peak flowering period, and leaf size and cyanogenesis level were positively associated among the 10 New Zealand cultivars. The agronomic performance of cultivars is summarised on the basis of preferred management, key seasonal performance, disease tolerance, and climatic and edaphic adaptation. Keywords: adaptation, breeding, cultivars, cyanogenesis, flowering, leaf size, white clover

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