Leisnham: Relationship between male head size & mating opp in Hemideina maori

Leisnham, P. T., & Jamieson, I. G. (2004). Relationship between male head size and mating opportunity in the harem-defence, polygynous tree weta Hemideina maori (Orthoptera: Anostostomatidae). New Zealand Journal of Ecology, 28(1), 49-54. (3 copies)

Objectives of study were to determine whether males with larger heads have access to great #s of females, and whether male head size has an effect on male survival and longevity. Results suggested that small males intermittently retreat to small cracks or cavities within tor columns, where there are unlikely to be large female groups. So, larger males had access to more females than smaller males. Larger males also had no detectable disadvantage in terms of daily survival and longevity. Evidence that larger male tree weta do associate with larger harems in the wild.

Lovei (1997) Harmonic radar

Lovei, G.L., Stringer, I.A.N., Devine, C.D. and Cartellier, M 1997 Harmonic Radar, a method using inexpensive tags to study invertebrate movement on land. New Zealand Journal of Ecology (1997) 21(2): 187-193 (1 copy)

Effects of aerial size and shape, detection range of several types of diodes, potential and limitations of using harmonic radar are discussed. Examples of tracking short term movement of a beetle and long term movement of a snail. Monitoring method, tracking, behavior

Morgan-Richards: Taxonomic status of tree weta from Stephens Is.

Morgan-Richards, M., Daugherty, C.H. and Gibbs, G.W. 1995 Taxonomic status of tree weta from Stephens Island, Mt. Holdsworth and Mt. Arthur, based on allozyme variation. Journal of the Royal Society of New Zealand Vol 25(2) June 1995: 301-312. (3 copies)

Sort of a tedious account of genetic relationships. Researchers undertook an analysis of allozyme variation of tree weta from 13 sites including Stephens Island to find out whether the tree weta on that island should be viewed as a separate species. They came to the conclusion that the population is sufficiently different to warrant taxonomic recognition.

Morgan-Richards (1995): New species of tree weta from North Island

Morgan-Richards, M 1995 A new species of tree weta from the North Island of new Zealand (Hemideina: Stenopelmatidae: Orthoptera). New Zealand Entomologist, 1995, Vol 18: 15-23 (3 copies)

New discovery from Hawkes Bay. Differs from Wellington tree weta only in the colouration of the pronotum (upper surface of the protorax; the foremost section of thorax) – it is light yellow/orange. It also differs in two different allozyme loci and karyotype. I don’t really think this is of much use to Team Weta.

Beakly: Design & use of artificial refuges for monitoring adult tree weta

Beakly, C., Stringer, I., Robertson, A., & Hedderly, D. (2006). Design and use of artificial refuges for monitoring adult tree weta, Hemideina crassidens and H. thoracica. DoC Research and Development Series 233, Department of Conservation, Science and Technical publishing, Wellington. (1 copy)

Artificial refuges were constructed in order to find out tree weta dwelling preferences. Tree weta were found to prefer refuges made of fresh pine, galleries with tapering terminations, holes 16-25mm diameter, et cetera...# of weta positively correlated wth # of weta in natural cavities; no diff in results between refuge locations. This article can give us some pretty decent insight into understanding ideal weta holes.

Trewick: Weta roost proj Mohi Bush Scenic Reserve

Trewick, S.A. 1995 Interim Report on weta roost project at Mohi Bush Scenic Reserve, Hawkes Bay Regional Conservancy. Unpublished report. School of Biological Sciences, Victoria University, Wellington. (1 copy)

Six artificial weta roosts were constructed and occupancy recorded. The researchers speculate on what habitat characteristics are ideal or nonideal for inhabitation. Both tree weta and cave weta appear to have a tendency to use holes that have been previously occupied by a weta. Recommendation to continue the study using larger holes to allow harems.

Lynch...To the Future: Kaorori

Lynch, J.(1995) to the Future: Kaorori- from reservoir to wildlife sanctuary. Forest and Bird

This article outlines how a wildlife sanctuary on the edge of Wellington City was formed starting with an idea and eventually receiving approval.  This deals with the concept of mainland islands which are a secure place for populatins of nature plants and animals, and an easily accessible place for us to experience them.

·         Diplomatic steps that it takes to create a mainland island outlined, especially one that is in the middle of a town like this one.

·         Goes over the strategies of pest eradication, translocation and maintenance of the site as a whole

·         New Zealanders are profoundly unaware of their indigenous flora and fauna but they will not go to the offshore island sanctuaries to find out about it.  This is an educational opportunity in close proximity of the city.

·         Goes over the structure of predator proof fences and the pitfalls of maintenance as well as possible weaknesses.

Tags: mainland island restoration

Atkinson, Simberloff, Towns..Restoration of New Zealand Islands

Atkinson, I., Simberloff, D & Towns, D. (1997). Restoration of New Zealand islands: redressing the effects              of introduced species. Pacific Conservation Biology, 3, 99-123

·         This article is all about the effects of each individual introduced species on native flora and fauna.  This article goes into specific examples of Mangere Island and Chatham Island.

·         Goes over the pitfalls of exotic keystone species introduction

·         Abstract: Ecological restoration of New Zealand islands has potential to replace damaged or lost communities, expand the ranges of relict populations, reduce the selective influence of exotic (keystone) species on indigenous species, help in understanding how the systems are formed, provide opportunities for educational and scientific investigation, and act as a testing ground for new technologies against pests.

·         Goes over the effects of herbivores on native populations, good segment and could pertain to our topic.  Essentially goes over all of the negative ecological effects, predation, habitat modification, harvesting etc.

·         Article is slightly older so you may have to do some research as to if the methods have changed, but the ecological aspects should all be good for use in our presentations.

Tags: introduced species

Burke, S. & Mitchell, N. (2007). People as Ecological Participants in Ecological Restoratin. Restoration

Ecology, 15(2) 348-350.

·         Article analyses  the statement that ecological restoration is ultimate “acid test” of our understanding the functioning ecosystem

•          Abstract conclusion: ecological restoration may not be so much an acid test of our understanding the functioning of ecosystems, but rather, an acid test of our understanding mutually beneficial interactios between humans and ecosystems

Craig. potential for ecological restoration

Craig, J.L. (1990). Potential for ecological restoration of islands for indigenous fauna and flora. Pa              156-165 in Towns, D.R., Daugherty, C.H., &Atkinson, I.A.E. (Eds). (1990). Ecological restoration of  New Zealand islands, Conservation Sciences Publication 2, Department of Conservation, Wellington, New Zealand

·         This article outlines Island restoration policy.  It gives examples of five island groups whose general restoration plans are offered to represent a spectrum of likely public accessibility and participation as well as revenue generation.

·         This article is older so it will give good insight into the development of island ecosystems as nature preserves for introduction.  As far as info pertaining to Weta I think it might be a bit useless.

Tags: island restoration

Gibbs New Zealand Weta

Gibbs, G. (1998). New Zealand Weta .Reed Books (NZ)

·         Weta droppings can be distringuished from possum and rat dropings by their neatly rounded ends, not pointed as in mamals. 

·         There Cerci are accessory sense organs on the rear end of the abdomen.  These detect sound waves and other vibrations that warn the weta of something approaching from behind.  Males have longer Cerci then females.  At dusk tree weta sit with their ass out of the hold monitoring weather it is safe conditions.  Sometimes they will sit there for an hour or two before going outside. 

·         Ground weta have sharp teeth and the small species are very alert and active, certainly more suited to predation then the clumsy tree weta. Ground weta as well as tusked weta are almost entirely carnivorous.

·         Cave weta are omnivorous scavengers.  Those that live inside caves forage for dead insects, spiders, and debris that is washed into the cave by streams.  They can adapt to human modifications of caves by foraging on the mosses and liverworts that grouw around electric lights in the Waitomo caves.

·         Tree and giant weta are described as omnivorous but they are largely vegetarians.

·         Once male tree weta are about half grown they take up residence in holes or galleries.  Weta do not make their own tunnels but rely on finding holes made by large wood-boring insects or formed by some other agency.  They always enter head first and back out.

·         Any number of females will be allowed in the gallery but the dominant male will not allow any other males, they must fight for possession of the gallery if challenged. 

·         Large headed males are the species that fight over gallery occupation.  They are more aggressive

·         Sexually mature adult males will have varying head sizes from enormous “oversized” (roughly 1/3 of a colony)down to smaller then female heads.  Once insects like weta are sexually mature they cannot grow any larger.

·         Males have different instar numbers (molting cycles). Small headed have 8, medium headed have 9 and large headed have 10.  All species have mating success, while large headed individuals are protecting their galleries smaller headed are cruising around looking for chicks. Only in tree and possible tusked but not sure due to lack of research.

·         Weta are tone-deaf, meaning that they caould never enjoy music, but they can hear your approach, especially if you tread on dry stick.

·         Weta call is generated by rubbing tiny pegs (like sandpaper0 over a compb.  Biologists call it stridulation (tree weta).

·         Cave and ground weta do not have ears, cave produce no sound but ground can produce a low intensity sound.

·         Native weta predators: lizards, tuatara, birds and short-tailed bats.  Morepork is most common native predator that attachs weta at nights.  All weta natural predators are rare or nearly extinct today.

·         Invasive predators (rats, stoats, weasels and cats) have a large hunting advantage in that their sense of smell is much sharper than that of birds so they can track down weta by smell.

Tags: tree weta, ground weta, cave weta, giant weta, habitat type/use, behavior, food

Moller H. Tree Wetas

Moller, H. 1984 Tree wetas (Hemideina crassicruris) (Orthoptera: Stenopelmatidae) of Stephens Island, Cook Strait. New Zealand Journal of Zoology: 1985 Vol 12: 55-69.

·         Talks about two separate island restoration projects with tree weta populations, stephens island and

·         Tuataras important native predator of weta on these island reserves and they probably stop the tree weta from moving to the forest floor. Very well outlined in this article

·         This article is good because it is all about another experiment and goes into several monitoring methods as well as results.  However, it is very old (1984) and some of the claims that Mr. Moller makes have been disproven.  If you use something from this article make sure to fact check it with current information.

Tags: tree weta, monitoring method, food, behavior, habitat type, introduced species, island restoration

Rate, S.R. Does rat control...

Rate, S.R. (2009). Does rat control benefit forest invertebrates at Moehau, Coromandel Peninsula? DOC Research & Development Series 316. Department of Conservation, Wellington, New Zealand.

·         This is a scientific research paper put out by DOC: it looks to monitor if invertebrate populations would react positively to rat eradication on Moehau in the corremandel.

·         The conclusions of this study were that rat control had no effect on the relative abundance, diversity andbody length of pitfall-trapped invertebrates, except for a significant reduction in the numbers of ants (Formicidae).

·         They hypothesize that invertebrates that are susceptible to predation by rats were not adequately sampled, the predatory pest mammals were not reduced to low enough levels to elict a measurable invertebrate response.

·         This goes over several recommendation for the improvement of further studies

Tags: Tree weta, mainland restoration, monitoring method

Gibbs, G. Why are some Weta

Gibbs, G. W. (1998). Why are some weta (Orthoptera: Stenopelmatidae) vulnerable yet others are common? Journal of Insect Conservation, 2, 161-166.

·         Examines why some types of weta have thrived in the presence of key predators (rats), while others only exist on predator-free island refuges.  Paper addresses the question of what aspects of their bilology enable some of the “demon grasshoppers” to survive while others became extinct.

·         New Zealand lacked large mammals which made it a paradise for invertebrates, birds and reptiles.  A consequese is the high proportion of large-bodied, flightless forms of birds and insects in the fauna

·         The real impact of mammal invasions came with the Norway rat (Rattus norvegicus), which is active on the ground and the ship rat (Rattus rattus), an agile tree-climbing rate, introduced by European vessels over the last 200 years (King, 1990).

·         Lists 10 reasons why weta are so vulnerable to mammal predation: 1.Their large size 2. Flightlessness 3. They are distinctly “smelly” 4. All species are nocturnally active and relatively slow moving 5.By day they retreat into a sheltered refuge 6. They may be solitary or distinctly gregarious 7. An acoustic communication system is developed and is used also as part of their defense mechanism. 8. Long development (18-36 months) from egg-adult, they are considered K selected species unlike most insects9. Oviposition is in soil or soft rotten wood 10. Omnivores

·          

Ordish, R.G. 1992 Aggregation and communication of the Wellington weta Hemideina crassidens (Blanchard) (Orthoptera: Stenopelmatidae). New Zealand Entomologist 1992 Vol 15:1-8. (2 copies)

• Discusses aggregation of tree weta: their interactions with each other and whether they form clusters

• Also discusses stridulation (noise makin’!) and talks a little about how their morphology contributes to this ability. I

• Stridulation is their principal means of communication and is used primarily for defense, territorial, and eviction calls. The article describes these calls.

Edwards, F. (1997). Conservation management—island-style: from off-shore to the mainland. Forest & Bird, 36-41. (1 copy)

-       An easy to read overview of mainland island restoration in NZ.

Duthie, C., Gibbs, G., & Burns, K. C. (2006). Seed dispersal by weta. Science, 311, 1575. (3 copies)

-       Tested whether weta are legitimate seed-dispersers

-       Found that they are! Seeds pass through the weta intact and are able to germinate. There is evidence that weta disperse seeds in the wild.

Burns, K. C. (2006). Weta and the evolution of fleshy fruits in New Zealand. New Zealand Journal of Ecology, 30(3), 405-406.

• Describes ground weta’s role in mountain snow berry seed dispersal 
• Discusses weta’s possible role in the evolution of NZ fruit form 
• No other insect is known to perform the function of seed dispersal, so that’s pretty tight.

St Clair, J. J. (2011). The impacts of invasive rodents on island invertebrates. Biological Conservation, 144, 68-81.(3 copies)

• Broad, global review--the title says it all

Rufaut, C. G., & Gibbs, G. W. (2003). Responses of a Tree Weta Population (Hemideina crassidens) After Eradication of the Polynesian Rat from a New Zealand Island. Restoration Ecology, 11(1), 13-19. (3 copies)

• Measures changes in a population of tree weta on an offshore island after removal of rats. 
• Found that weta density didn’t change, but proportion of adults changed, and weta spent more time closer to the ground and less time in tree refuges. 
• The study concludes that weta are able to withstand rat predation, but live a more relaxed lifestyle in their absence.

 

Watts, C.H., Armstrong, D.P., Innes, J. and Thornburrow, D. 2011 Dramatic increases in weta (Orthoptera) following mammal eradication on Maungatautari – evidence from pitfalls and tracking tunnels. New Zealand Journal of Ecology (2011) 35(3):261-272 (3 copies)

• Monitored weta populations before and after predator eradication in Maungatautari       
• Compared the effectiveness of two different monitoring methods: lethal pitfall traps and footprint tracking tunnels
• Saw an increase in weta post-eradication, as well as an increase in the proportion of adults

 

Trewick, S.A. and Morgan-Richards, M. 2000 Artificial weta roosts: A technique for ecological study and population monitoring of Tree Weta (Hemideina) and other invertebrates. New Zealand Journal of Ecology (2000) 24(2):201-208 (3 copies)

• Studies the effectiveness of using artifical roosts to monitor tree weta populations.

• Artifical roosts appear affective after weta are allowed sufficient time to establish.

 

Gibbs, G.W. (2009). The end of an 80-million year experiment: a review of evidence describing the impact of introduced rodents on New Zealand’s ‘mammal-free’ invertebrate fauna. Biol Invasions, 11, 1587-1593. (1 copy)

•  Broad review of the impacts of mammalian predators (mainly rats) on NZ insects.

•  Includes a brief discussion of behavioral adaptations of tree weta to rats.

Watts, C., Stringer, I., Sherley, G., Gibbs, G., & Green, C. (2008). History of weta (Orthoptera: Anostostomatidae) translocation in New Zealand: lessons learned, islands as sanctuaries and the future. J Insect Conserv, 12, 359-370. (2 copies)

                         

• A review of weta translocations in NZ. 
• Provides case studies of past successes and failures in weta translocations to both offshore and mainland islands. 
• Also reviews various monitoring and transfer techniques.

Griffin, MJ: the case of weta as small mammals

Griffin, M.J., Trewick, S.A., Wehi, P. M. and Morgan-Richards, M. 2011 Exploring the concept of niche convergence in a land without rodents: the case of weta as small mammals. New Zealand Journal of Ecology (2011) 35(3):0-0 (3 copies)

A discussion of the use of the metaphor of weta as ecologically equivalent to rodents in other countries. This article takes an opposing stance, explaining how they are different in ecology and characteristics. This article shows that the reproductive potential and scale of change in population size differ greatly between mice and tree weta.

Townsend, C: Ecological applications: toward a sust world

Townsend, C. (2008). Ecological Applications: toward a sustainable world. Australia: Blackwell. Chapter 1. (1 copy)

An overview of the biodiversity crisis and humans’ role in it. The scale of the biodiversity problem, ecosystem function and services, drivers of biodiversity loss, habitat loss, invaders, overexploitation, habitat degradation, global climate change, social/political/economic aspects of the situation.

Spellerberg, I.: Monitoring ecological change.

Spellerberg, I. (2005). Monitoring ecological change. 2^nd ed. Cambridge. (2005). (3 copies)

Defines census, surveillance, and monitoring. The bulk of the paper is dedicated to discussing monitoring – what it is exactly, priority areas, long-term ecological monitoring, past and future of monitoring, and why it is relevant.

Saunders; ecological restoration at mainland islands

Saunders, A. & Norton, D. A. (2001). Ecological restoration at mainland islands in New Zealand. Biological Conservation, 99: 109-119. (1 copy)

An exhaustive account of the emergence of mainland islands, how they are doing now, and predictions for the future. Also has a bit about how conservation management could be made more effective.

Mainland islands [fact sheet]

Department of Conservation. (1999). Mainland islands [fact sheet]. (1 copy)

Brief history of human impacts and sanctuaries.

Craig, J.: Conservation issues in New Zealand.

Craig, J. et al. (2000). Conservation issues in New Zealand. Annu. Rev. Ecol. Syst., 31: 61-78. (1 copy)
An overview. Section headings are as follows: History and status of NZ biodiversity, effects of people, introduced pests, preservation vs. sustainable management, representativeness, management of alien species, reintroductions, conservation of functional diversity, Maori & conservation, marine conservation.

Atkinson; introduced mammals & models for conservation.

Atkinson, I. (2001). Introduced mammals and models for restoration. Biological Conservation, 99: 81-96. (1 copy)

Traces the development of ecological restoration in NZ and discusses factors that have inflenced its direction. Factors: (1) The extent to which introduced animals have changed selective forces operating on the native biota, (2) our improved capacity to control or remove introduced mammals, and (3) the growing realization that there are sometimes opportunities to rebuild former trophic guilds even though restoration of the full system is not possible.

Watts, C., Stringer, I., Sherley, G., Gibbs, G., & Green, C. (2008). History of weta (Orthoptera: Anostostomatidae) translocation in New Zealand: lessons learned, islands as sanctuaries and the future. J Insect Conserv, 12, 359-370. (2 copies)

                         

A review of weta translocations in NZ. Provides case studies of past successes and failures in weta translocations to both offshore and mainland islands. Also reviews various monitoring and transfer techniques.