Showing posts with label habitat type. Show all posts
Showing posts with label habitat type. Show all posts

Thursday, November 10, 2011

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 Unpublished report.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.

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