Species status and conservation issues of New Zealand's endemic Latrodectus spider species (Araneae : Theridiidae)

Abstract

New Zealand has two endemic widow spiders, Latrodectus katipo Powell, 1871 and L. atritus Urquhart, 1890. Both species face many conservation threats and are actively managed. The species status of the Latrodectus spiders of New Zealand was assessed using molecular (COI, ITS1, ITS2) and morphological methods and with cross-breeding experiments. Latrodectus katipo and L. atritus were not found to be reciprocally monophyletic for any of the gene regions or morphological traits. Other than colour, which is variable, there were no morphological characters that separated the two species, which cross-bred in the laboratory and produced fertile eggsacs. Colour variation is clinal over latitude and correlates significantly with mean annual temperature. We conclude that L. atritus is a junior synonym of L. katipo. An example of introgression from the Australian species L. hasseltii Thorell, 1870 was also detected and its conservation implications are discussed.

Biogeography and diversification of hermit spiders on Indian Ocean islands (Nephilidae: Nephilengys)

“…We amplified fragments of two loci that have proven to be useful to separate species and populations in araneoid spiders: the mitochondrial cytochrome c oxidase subunit 1 (COI) (e.g., Agnarsson et al, 2007;Su et al, 2007;Vink et al, 2008) and the nuclear internal transcribed spacer 2 (ITS2) (see Agnarsson, 2010 for review of its utility in spiders). We used the LCO1490 (Folmer et al, 1994), and C1-N-2776 (Hedin and Maddison, 2001) primer pair to amplify COI, and the ITS-5.8S (FITS) and ITS-28S (RITS) primers (White et al, 1990) for ITS2.…”

Redescription and generic placement of the spider Cryptachaea gigantipes (Keyserling, 1890) (Araneae: Theridiidae) and notes on related synanthropic species in Australasia

“…COI genetic diversity in C. gigantipes is quite low (1.9%), but other theridiid species have also been found to have low COI diversity (e.g. Vink et al 2008). The maximum intraspecific variation we observed in New Zealand C. veruculata was as high as 5.0%, which is close to the minimum divergence of 5.7% between C. gigantipes and C. veruculata.…”

The invasive Australian redback spider, Latrodectus hasseltii Thorell 1870 (Araneae: Theridiidae): current and potential distributions, and likely impacts

“…To clarify the distribution of L. hasseltii in New Zealand, we obtained reliable records that had been based on expert identification of specimens using criteria outlined in Vink et al (2008). This was achieved by a thorough search of the published literature, consultation with other arachnologists, examination of arthropod collections and records from the following organisations: MAF Biosecurity New Zealand (MAFBNZ), New Zealand Arthropod Collection (NZAC), Museum of New Zealand Te Papa Tongarewa (MONZ), Auckland Museum (AMNZ) and Otago Museum (OMNZ).…”

“…Vink and Sirvid 2000;Framenau and Vink 2001) and L. hasseltii exhibits behaviours associated with ballooning during early juvenile stages (Forster 1995), but it seems that natural long distance dispersal is rare in L. hasseltii. The genetic distance between L. hasseltii and the closely related L. katipo Powell 1870, a New Zealand endemic species, indicates that the two species have been isolated from each other for hundreds of thousands of years (Griffiths et al 2005;Vink et al 2008). Latrodectus hasseltii were not found in aerial samples of spiders collected over one month in an agricultural area in New South Wales (Greenstone et al 1987).…”

“…by L. hasseltii could occur, as it has in other spiders (Nyffeler et al 1986;Hann 1990;Bednarski et al 2010). Latrodectus geometricus has been accidentally introduced to southern California where it is thought to be displacing L. hesperus (Vincent et al 2009), and in New Zealand there is potential for L. hasseltii to displace L. katipo, a closely related endemic species (Garb et al 2004;Griffiths et al 2005;Vink et al 2008) that is now classified as in ''serious decline'' due to human activities (Patrick 2002;Hitchmough et al 2007). To date, L. hasseltii has not been recorded from sand dunes where L. katipo occurs, and its potential to invade this habitat remains uncertain.…”