Marine Isopoda of The Snares islands,New Zealand — 1. Gnathiidea,Valvifera, Anthuridea,and Flabellifera

Abstract

Twenty-four species of shallow-water marine non-asellote isopods are described or noted from collections made by University of Canterbury workers at The Snares islands (asterisks denote new records): Gnathia akaroensis* (Gnathiidae); Neastacilla antipadea n.sp., N. tuberculata* (Arcturidae); Crabyzos elongatus*, Euidotea peronii*, Idotea metallica* (ldoteidae); Mesanthura sp. (Anthuridae); Colanthura rima n.sp., Paranthura flagellata* (Paranthuridae); Cirolana rossi*, Cirolana sp. (Cirolanidae); Lironeca raynaudii* (Cymothoidae); Limnoria quadripunctata* (Limnoriidae); Plakarthrium typicum* (Plakarthriidae); Amphoroidea falcifer, A. longipes*, Dynamenella condita, D. huttoni, Scutuloidea maculata, Ciliacaea caniculata, Cymodoce allegra, Exosphaeroma obtusum, Isocladus calcareus, and Pseudosphaeroma campbellensis (Sphaeromatidae). Cymodoce australis has been recorded from The Snares but was not represented in the material examined. The genus Paradynamenopsis from Chile is made a junior synonym of Pseudosphaeroma.     

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.     

Skink predation by hedgehogs at Macraes Flat, Otago, New?Zealand

The stomach contents of 158 hedgehogs captured at Macraes Flat, Otago, New Zealand, over two summers in 2000 and 2001 were examined for the occurrence of lizards. The remains of at least 43 skinks (both Oligosoma nigriplantare polychroma and O.?maccanni) and one gecko (Hoplodactylus sp.) were found. Twenty-one percent (n?=?33; 8 males and 25 females) of the examined hedgehogs had fed on skinks. Female hedgehogs ate significantly more skinks than did males. Our results suggest that the presence of large numbers of hedgehogs can have a high impact on native reptile populations in New Zealand and therefore they should be targeted in future trapping programmes.     

Travelling seeds? Examples from New Zealand

New Zealand is an archipelago isolated in time and space. Flowering plants have evolved in the almost-complete absence of terrestrial mammals, some of the most prolific seed-dispersers from the rest of the world, and fascinating mechanisms for spreading seeds have developed.