Monarchs across the Pacific: the Columbus hypothesis revisited

The 'Columbus hypothesis' suggests that the annual north-south return migration of Danaus plexippus in North America is a very recently evolved behaviour, less than 200 years old. This hypothesis rests, in part, on an analysis of the 19th century spread of the monarch across the Pacific that assumes a continuous east to west movement and is based predominantly on one publication. We review all the contemporary literature and present new analysis of the data. The movement of the monarch across the Pacific in the second half of the 19th century is best explained by a model which involves no more than three spot introductions, directly or indirectly aided by human movement, followed by natural spread of the monarch across island groups. Contemporary records refer to 'boom' and 'bust' population cycles on newly settled islands, which may have led to high rates of monarch movement. We see no evidence in the records to suggest an east to west sweep by monarch populations as suggested by the Columbus hypothesis. (C) 2004 The Linnean Society of London.

Monarchs in Australia: On the winds of a storm?

The monarch butterfly, Danaus plexippus, is one of Australia's best-known exotic butterflies, being first recorded here in the spring/summer of 1870/1871. However, the source of the original population is unknown. Using historical records we suggest that the most likely source of the founder population was from Vanuatu and/or New Caledonia. Many almost simultaneous 'first records' for the butterfly in Australia suggest that a large, well-distributed population was present when first noticed. While such a population may have developed from a limited number of individuals flying across the Coral Sea, the well documented, very dramatic appearance of large monarch populations in Australia does not appear to fit this model. Rather, we hypothesise that large numbers of monarchs were carried to Australia on cyclonic winds: no fewer that 3 cyclones hit the Queensland coast in early 1870. If one or more of these cyclones tracked from the Vanuatu/New Caledonia chain, then they may have transported monarchs. Once established on the central/northern Queensland coast, natural migration would account for the appearance of butterflies further south.

Phylogeny, molecular and fossil dating, and biogeographic history of Annonaceae and Myristicaceae (Magnoliales)

Annonaceae and Myristicaceae, the two largest families of Magnoliales, are pantropical groups of uncertain geographic history. The most recent morphological and molecular phylogenetic analyses identify the Asian-American genus Anaxagorea as sister to all other Annonaceae and the ambavioids, consisting of small genera endemic to South America, Africa, Madagascar, and Asia, as a second branch. However, most genera form a large clade in which the basal lines are African, and South American and Asian taxa are more deeply nested. Although it has been suggested that Anaxagorea was an ancient Laurasian line, present data indicate that this genus is basically South American. These considerations may mean that the family as a whole began its radiation in Africa and South America in the Late Cretaceous, when the South Atlantic was narrower, and several lines dispersed from Africa-Madagascar into Laurasia as the Tethys closed in the Tertiary. This scenario is consistent with the occurrence of annonaceous seeds in the latest Cretaceous of Nigeria and the Eocene of England and with molecular dating of the family. Based on distribution of putatively primitive taxa in Madagascar and derived taxa in Asia, it has been suggested that Myristicaceae had a similar history. Phylogenetic analyses of Myristicaceae, using morphology and several plastid regions, confirm that the ancestral area was Africa-Madagascar and that Asian taxa are derived. However, Myristicaceae as a whole show strikingly lower molecular divergence than Annonaceae, indicating either a much younger age or a marked slowdown in molecular evolution. The fact that the oldest diagnostic fossils of Myristicaceae are Miocene seeds might be taken as evidence that Myristicaceae are much younger than Annonaceae, but this is implausible in requiring transoceanic dispersal of their large, animal-dispersed seeds.

Variation in body size and sexual dimorphism across geographical and environmental space in the frogs Limnodynastes tasmaniensis and L. peronii

This study aimed to identify potential factors responsible for geographically structured morphological variation within the widespread Australian frogs Limnodynastes tasmaniensis Gunther and L. peronii Dumeril & Bibron. There was support for James's rule, and both latitude and present climate explained large amounts of the variation in body size and shape (particularly in L. peronii). There was also some support for the influence of several biogeographical barriers. Finally, both species were sexually dimorphic for body size and the degree of sexual size dimorphism (SSD) varied geographically. Climate was an important explanation for SSD variation in L. peronii, while latitude was most important for L. tasmaniensis. Geographical variations in sexual selection via male-male physical competition and climate-related resources are suggested as potential explanations for SSD variation in L. peronii. (C) 2004 The Linnean Society of London.

Tracking the Mesozoic distribution of Gunnera: comparison with the fossil pollen species Tricolpites reticulatus Cookson

The morphology of the exine of Late Cretaceous and Tertiary specimens of Tricolpites reticulatus previously documented from Kerguelen, the Antarctic Peninsula, and the Otway Basin of southeastern Australia has been re-examined and compared with the three pollen types identified in the genus Gunnera. An Antarctic specimen of T reticulatus (Maastrichtian) has a uniform reticulum with elongated lumina, similar to that characterising pollen type 3a of Gunnera macrophylla (subgenus Pseudogunnera). Late Cretaceous (Maastrichtian) Australian specimens of T reticulatus differ; specimens from McNamara resemble pollen of subgenera Pseudogunnera and Milligania of type 3a or type 3b, while specimens of T reticulatus from Princes show more rounded and equidimensional lumina and are therefore tentatively attributed to pollen type 2 found in subgenera Gunnera, Misandra and Panke. Kerguelen Island T reticulatus (Miocene) are distinct from Vega Island specimens: a closer resemblance of Kerguelen T reticulatus and pollen type 2 of extant Gunnera is hypothesised. A comparison between specimens of the North American Tricolpites reticulatus/microreticulatus and pollen of Gunnera is also made. The clear similarity of the North American specimens of Tricolpites microreticulatus and pollen of Gunnera in shape and in the exine surface features of pollen suggests that this taxon should not be separated from T reticulatus but should be treated as a synonym of this species. (C) 2004 Elsevier B.V. All rights reserved.

Biogeographic analysis of jurassic-early cretaceous wood assemblages from Gondwana

The terrestrial biogeography of Gondwana during Jurassic-Early Cretaceous times is poorly resolved, and the flora is usually considered to have been rather uniform. This is surprising given the size of Gondwana, which extended from the equator to the South Pole. Documenting Gondwanan terrestrial floristic provincialism in the Jurassic-Early Cretaceous times is important because it provides a historical biogeographic context in which to understand the tremendous evolutionary radiations that occurred during the mid-Cretaceous. In this paper, the distribution of Jurassic-Early Cretaceous fossil wood is analysed at generic level across the entire supercontinent. Specifically, wood assemblages are analyzed in terms of five climatic zones (summer wet, desert, winter wet, warm temperate, cool temperate) established on the basis of independent data. Results demonstrate that araucarian-like conifer wood was a dominant, cosmopolitan element, whereas other taxa showed a greater degree of provincialism. Indeed, several narrowly endemic morphogenera are recognizable from the data. Finally, comparisons with Laurasian wood assemblages indicate strong parallelism between the vegetation of both hemispheres. (C) 2004 Elsevier B.V. All rights reserved.

Distribution of the monarch butterfly, Danaus plexippus (L.) (Lepidoptera : Nymphalidae), in western North America

The standard model for the migration of the monarch butterfly in western North America has hitherto been movement in the autumn to overwintering sites in coastal California, followed by a return inland by most individuals in the spring. This model is based largely on observational and limited tagging and recovery data. In this paper we test the model by plotting many years of museum and collection records on a monthly basis on a map of the region. Our plots suggest a movement of Oregon, Washington and other north-western populations of summer butterflies to California in the autumn, but movement of more north-easterly populations (e.g. from Idaho and Montana) along two pathways through Nevada, Utah and Arizona to Mexico. The more westerly of these two pathways may follow the Colorado River south as indicated by museum records and seasonal temperature data. The eastern pathway may enter northern Utah along the western scarp of the Wasatch Mountains and run south through Utah and Arizona. Further analysis of distributions suggests that monarch butterflies in the American West occur primarily along rivers, and there are observations indicating that autumn migrants often follow riparian corridors. More data are needed to test our new model; we suggest the nature of the data required. (c) 2005 The Linnean Society of London.

Feral goat eradications on islands

Introduced mammals are major drivers of extinction. Feral goats (Capra hircus) are particularly devastating to island ecosystems, causing direct and indirect impacts through overgrazing, which often results in ecosystem degradation and biodiversity loss. Removing goat populations from islands is a powerful conservation tool to prevent extinctions and restore ecosystems. Goats have been eradicated successfully from 120 islands worldwide. With newly developed technology and techniques, island size is perhaps no longer a limiting factor in the successful removal of introduced goat populations. Furthermore,. the use of global positioning systems, geographic information systems, aerial hunting by helicopter specialized bunting dogs, and Judas goats has dramatically increased efficiency and significantly reduced the duration of eradication campaigns. Intensive monitoring programs are also critical for successful eradications. Because of the presence of humans with domestic goat populations on large islands, future island conservation actions will require eradication programs that involve local island inhabitants in a collaborative approach with biologists, sociologists, and educators. Given the clear biodiversity benefits, introduced goat populations should be routinely removed from islands.

Conservation action in the Galapagos: Feral pig (Sus scrofa) eradication from Santiago Island

Introduced mammals are major drivers of extinction and ecosystem change. As omnivores, feral pigs (Sus scrofa) are responsible for wholesale adverse effects on islands. Here, we report on the eradication of feral pigs from Santiago Island in the Galápagos Archipelago, Ecuador, which is the largest insular pig removal to date. Using a combination of ground hunting and poisoning, over 18,000 pigs were removed during this 30-year eradication campaign. A sustained effort, an effective poisoning campaign concurrent with the hunting program, access to animals by cutting more trails, and an intensive monitoring program all proved critical to the successful eradication. While low and fluctuating control efforts may help protect select native species, current eradication methods, limited conservation funds, and the potential negative non-target impacts of sustained control efforts all favor an intense eradication effort, rather than a sustained control program. The successful removal of pigs from Santiago Island sets a new precedent, nearly doubling the current size of a successful eradication, and is leading to more ambitious projects. However, now we must turn toward increasing eradication efficiency. Given limited conservation funds, we can no longer afford to spend decades removing introduced mammals from islands.

Eradicating feral cats to protect Galapagos Land Iguanas: methods and strategies

A three-year programme to eradicate Feral Cats Felis catus from the island of Baltra in the Galapagos archipelago achieved good results by Initially poisoning with sodium monofluoroacetate (compound 1080) then trapping or shooting the remaining cats. The poisoning campaign removed 90% of the cats, its success being attributable to pre-baiting with unpolsoned baits to accustom cats to eating baits and placing enough baits to ensure that all cats encountered several baits within their home range. This, together with the use of metaclopromide (Pileran) as an anti-emetic, overcame a problem associated with poor retention of 1080 in thawed fish baits that limited the dose available to 1 mg 1080lbait, a quality Insufficient to kill large cats. Removal of the remaining cats was delayed by a weather-Induced irruption of Black Rats Rattus rattus and House Mice Mus musculus that enabled recruitment of kittens in 2002, but made cats more susceptible to trapping and shooting in 2003 when rodent populations collapsed. Since July 2003 no sign of a cat has been detected on Baltra despite extensive searching and monitoring throughout 2004. As cat abundance has decreased there have been more locally-bred Juvenile iguanas (Conolophus subcristatus) seen during annual censuses. However, such recruitment may reflect the increasing maturity and higher fecundity of iguanas repatriated from 1991 onwards rather than being a direct result of reduced cat predation alone. More time is necessary to determine the benefits of reduced cat predation on the Iguana population.

The Thelastomatoidea (Nematoda : Oxyurida) of two sympatric Panesthiinae (Insecta : Blattodea) from southeastern Queensland, Australia: taxonomy, species richness and host specificity

The thelastomatoid fauna of two species of wood-burrowing cockroach (Blattodea, Blaberidae), Panesthia cribrata and Panesthia tryoni tryoni, from Lamington National Park, Australia, is described. The following eight new species and three new genera of thelastomatid are proposed: Bilobostoma exerovulva n. g., n. sp.; Cordonicola gibsoni n. sp.; Coronostoma australiae n. sp.; Desmicola ornata n. sp.; Hammerschmidtiella hochi n. sp.; Malaspinanema goateri n. g., n. sp.; Travassosinema jaidenae n. sp.; and Tsuganema cribratum n. g., n. sp. Additional data are given for Blattophila sphaerolaima and Leidynemella fusiformis. Of the 11 species reported, nine were found in P. cribrata and ten in P. tryoni tryoni. Such levels of thelastomatoid species richnessness in single host species are exceptional. Only the mole cricket, Gryllotalpa africana (23), and the domestic cockroach, Periplaneta americana (20), have higher reported richness. Three species, T jaidenae, C. australiae and D. ornata, were found either exclusively or significantly more prevalently in P tryoni tryoni than in R cribrata. Species of Travassosinema, Coronostoma and Desmicola have been found previously only in millipedes (Diplopoda), a fact that suggests that there is a greater degree of niche overlap between R tryoni tryoni and millipedes than for R cribrata.

Genetic diversity and regional identity in the Australian remnant Nothofagus moorei

Nothofagus moorei (F. Muell.) Krasser has a disjunct and narrow distribution in south-eastern Australian cool temperate rainforest. To assess the conservation-genetic priorities for this species, the genetic diversity of 20 populations sampled from the largest remnant patches at northern and southern distributional extremes, the McPherson and Barrington ranges (a total of 146 individuals), was investigated by using inter simple sequence repeats (ISSR). Regeneration in northern regions of N. moorei has been documented to be predominantly by vegetative means, but our results indicate little evidence of clonality outside the multi-stemmed rings of trees. In addition, genetic diversity was considerably higher in the northern (McPherson, h = 0.1613) than in the southern range (Barrington, h = 0.1159), and genetic differentiation was significantly positively correlated with geographic distance in the former region, but not the latter. Total intraspecific variation was moderate, as measured by Shannon's diversity index, I = 0.2719, and Nei's gene diversity, h = 0.1672, and is considered at the high end of spectrum for estimates of narrow endemic species. An analysis of molecular variation indicated that the majority of genetic variation is partitioned among individuals within population (60%; P < 0.001), rather than among populations within regions (10%; P < 0.001). However, a large and significant component of the measured diversity was partitioned between northern and southern regions (29%; P < 0.001). Several hypotheses are outlined to explain these differences and management implications are discussed. However, given the narrow range, poor dispersal mechanism and restriction to cool temperate rainforest, the continued existence of N. moorei is most threatened by environmental instability and habitat loss resulting from global climate change. In this context the northern regions of the species are most at risk and extinction of such populations would lead to a significant loss of genetic variation for the species as a whole.

A short note on starch and xylem of Colocasia esculenta (taro) in archaeological deposits from Pitcairn Island, southeast Polynesia

We present results of starch analysis of archaeological deposits from Pitcairn Island. High concentrations of starch grains preserved in cell membranes, and xylem tracheary elements, consistent with introduced Colocasia esculenta (taro) were found. Because of limited age control, we are uncertain if the microfossils are prehistoric. Problems associated with identifying taxa with small starch grains in extractions from weathered deposits are highlighted. (c) 2006 Elsevier Ltd. All rights reserved.