Neat and clear: 700 species of crane flies (Diptera: Tipulomorpha) link southern South America and Australasia

A biogeographical analysis of crane flies (Diptera, Tipulomorpha) in the southern hemisphere is used to test if their distribution patterns provide evidence of biogeographical homology (shared history) in the South Pacific. Crane fly distributions are interpreted in light of patterns of endemism and diversity and published phylogenetic studies. A panbiogeographical approach, assuming that repeating distribution patterns strongly suggest the existence of past connections between the areas (biogeographical homology), is used. A clear pattern is revealed in which crane fly taxa shared between southern South America, New Zealand and Australia are restricted to that region. Thirty genera and subgenera, together comprising about 700 species, occur in both South America and Australasia and only in these areas. This distribution defines the limits of the South Pacific Track, a standard biogeographical pattern displayed by many taxa, including the southern beeches (Nothofagus). Although the distribution of some taxa spans the entire track, others are present in parts of the areas only, forming a nested set of distributions. Within the surveyed genera and subgenera, all individual species are endemic to one single region or continent, suggesting vicariance as the main process behind crane fly disjunctions in this part of the world. The nested set of distribution patterns could be explained by extinctions in areas where taxa were present previously. Alternatively, it may indicate historical absences and the existence of a heterogeneous set of ancestral distributional ranges. ‘Gondwanan’ may not be the best term for the observed disjunctions, which should be labelled as trans‐Pacific instead. Recent molecular estimates of divergence times suggest a Permian origin of the earliest extant Diptera lineages such as the Tipulomorpha, followed by fast radiation in the Triassic. Although the differentiation of some crane fly groups occurring in the region may have been driven by recent Mesozoic and Cenozoic events of continental breakup, as least part of the fauna may have evolved allopatrically in response to older events. This may explain the overlapping distribution of subgenera in large genera such as Gynoplistia.     

Historical biogeography of the Yucatan Peninsula,Mexico: a perspective from ferns (Monilophyta) and lycopods (Lycophyta)

Based on known data sets and maximum entropy distribution data of fern and lycopod species registered in the Yucatán Peninsula, track and parsimony analyses were undertaken to evaluate the contribution of these groups to the establishment of biogeographical relationships of the peninsula with other areas. The resulting generalized tracks clearly agree with the geological origin of the peninsula and the previously recognized relationship with the Greater Antilles is not supported for ferns and lycopods. Instead, a Central American generalized track connects the Yucatán Peninsula with south‐eastern México and Central America. Floristically, the peninsula harbours 66 species of ferns and lycopods. Seven are registered for the first time in the Yucatán Peninsula and one is a new species for México. These species do not follow the latitudinal pattern expected if ecological factors, such as humidity and rainfall, were the most important in determining their distributions. Groups of areas recognized with parsimony analysis of endemicity could not be defined as provinces as a result of the lack of endemic species. Nevertheless, a regionalization scheme based on maximum entropy distribution data and supported by track analyses is proposed. Two separate districts are recognized within the Yucatán Peninsula: arid/dry Yucatán in the north and El Petén (humid) in the south. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98 , 775–786.     

Modelling climate‐change‐induced nonlinear thresholds in cephalopod population dynamics

A significant global challenge lies in our current inability to anticipate, and therefore prepare for, critical ecological thresholds (i.e. tipping points in ecosystems). This deficit stems largely from an inadequate understanding of the many complex interactions between species and the environment at the ecosystem level, and the paucity of mechanistic models relating environment to population dynamics at the species level. In marine ecosystems, abundant, short‐lived and fast‐growing species such as anchovies or squids, consistently function as ‘keystone’ groups whose population dynamics affect entire ecosystems. Increasing exploitation coupled with climate change impacts has the potential to affect these ecological groups and consequently, the entire marine ecosystem. There are currently very few models that predict the impact of climate change on these keystone groups. Here we use a combination of individual‐based bioenergetics and stage‐structured population models to characterize the fundamental capacity of cephalopods to respond to climate change. We demonstrate the potential for, and mechanisms behind, two unfavourable climate‐change‐induced thresholds in future population dynamics. Although one threshold was the direct consequence of a decrease in incubation time caused by ocean warming, the other threshold was linked to survivorship, implying the possibility of management through a modification of fishing mortality. Additional substantive changes in phenology were also predicted, with a possible loss in population resilience. Our results demonstrate the feasibility of predicting complex nonlinear dynamics with a reasonably simplistic mechanistic model, and highlight the necessity of developing such approaches for other species if attempts to moderate the impact of climate change on natural resources are to be effective.     

Bottom‐up effects on a plant‐endophage‐parasitoid system: The role of flower‐head size and chemistry

The effects of water and nutrient addition on a trophic chain were studied in a plant‐endophage‐parasitoid system comprised of insects associated with flower heads of Chromolaena squalida (Asteraceae). Nine species of endophages associated with C. squalida flower heads were found, belonging to two families of Diptera – Tephritidae (Cecidochares sp1, Cecidochares sp2, Xanthaciura biocellata, X. chrysura, X. sp. and Neomyopites sp.) and Agromyzidae (Melanagromyza sp.), and two families of Coleoptera – Apionidae (Apion sp.) and Anthicidae (Anthicidae sp.). A factorial field experiment with water and nutrient addition showed that resource availability can affect the developmental process of flower heads. Fertilization increased flower‐head diameter and nitrogen and alkaloid concentrations. Although nutrient availability affected the size and chemistry of flower heads, endophage species did not respond consistently to the experimental treatments. This is contrary to other studies where endophages showed preference for larger flower heads. Thus, the plant vigour hypothesis was not corroborated for our study system. Our results also showed that coupled responses of plants to resource availability (i.e. tissue nutritional quality and investment in growth of the structure that serves as shelter for endophages) can represent distinct kinds of indirect interactions with opposing effects on the herbivore‐parasitoid interaction.     

Scaling body mass and use of space in three species of marsupials in the Atlantic Forest of Brazil

Abstract Body mass is considered a major determinant of home range size, but usually at a large scale of body mass variation. The exact scale where body size becomes more important than particular adaptations of each species is not clear, and uncertainty in the estimate of home range size is a possible cause of weak intraspecific scaling. We determine the scaling to body mass of two alternative movement measurements, daily home range (DHR) and its intensity of use (IU), in three species of didelphid marsupials, Didelphis aurita, Philander frenatus, and Metachirus nudicaudatus (Didelphimorphia, Didelphidae). The expected scaling exponents DHR ≈ M^0.5 and IU ≈ M^?0.25 were derived from the scaling to body mass of home range and daily movement distance. Animals were tracked in Serra dos Órgãos, Rio de Janeiro, Brazil, using a spool‐and‐line device. Individuals of the three species were compared combining intra and interspecific variation in a single analysis, with species, body mass, and thread tracked as covariates. The model best supported included only body mass as the independent variable, with DHR ≈ M^0.435 and IU ≈ M^?0.218, close to the expected values. The second best supported model included species identity, but with a non‐significant effect. It was surprising that body mass was more important than species identity in a comparison involving only three species, and considering the morphological and locomotory adaptations of the three species. Body mass may become more important than species identity when the scale of variation approaches one order of magnitude.     

Lichens of St Helena and Ascension Island

Lichens are the dominant organisms on most of the South Atlantic island of St Helena. In total, 220 different species were found during a recent survey, most of which have never been reported from the island. Previously, less than 50 lichen species were reported from the island, one half of which are most probably incorrect records. The total number of lichens known from the island now stands at 225. Most species could be identified, but the following, most probably endemic, species are described as new to science: Dolichocarpus seawardii , which is only the second species in this genus, the type being from Chile; Dermatiscum pusillum , which is only the third species in this African genus; Dimelaena triseptata ; Xanthoparmelia beccae ; and four Ramalina species, Ramalina geniculatella , R. ketner‐oostrae , R. rigidella , and R. sanctae‐helenae . The lichen flora has many species in common with that of the geologically much younger Ascension Island, where just under 100 species were recently found by the author, most of which are equally new to that island. Lecanora sanctae‐helenae, previously known as the only endemic lichen of St Helena, was also found to be abundant on Ascension Island. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158 , 147–171.     

Selection for a dominant oncogene and large male size as a risk factor for melanoma in the Xiphophorus animal model

Adult height is a risk factor in numerous human cancers that involve aberrant receptor tyrosine kinase (RTK) signalling. However, its importance is debated due to conflicting epidemiological studies and the lack of useful in vivo models. In Xiphophorus fishes (Platyfishes/Swordtails), a functional RTK, Xiphophorus melanoma receptor kinase (Xmrk), serves as the dominant oncogene and has been maintained for several million years despite being deleterious and in an extremely unstable genomic region. Here we show that the Xmrk genotype is positively correlated with standard length in male and female wild caught Xiphophorus cortezi sampled throughout their phylogeographic distribution. Histopathology confirms the occurrence of malignant melanomas in both sexes; however, melanoma incidence was extremely male biased. Furthermore, males collected with malignant melanomas in the field were significantly larger than both Xmrk males collected without melanomas and wildtype (Xmrk deficient) males. These results not only provide a novel selective mechanism for the persistence of the germline Xmrk oncogene but also create an innovative avenue of melanoma research within the Xiphophorus fishes. Wildlife cancer in natural systems is a growing concern, therefore, future research investigating life history characteristics associated with certain phenotypes and genotypes that predispose an individual to cancer will be fundamental to increasing our understanding of the evolutionary biology of cancer in nature as well as in humans.     

Morphology agrees with molecular data: phylogenetic affinities of Euptychiina butterflies (Nymphalidae: Satyrinae)

Euptychiina is the most species‐rich subtribe of Neotropical Satyrinae, with over 450 known species in 47 genera (14 monotypic). Here, we use morphological characters to examine the phylogenetic relationships within Euptychiina. Taxonomic sampling included 105 species representing the majority of the genera, as well as five outgroups. A total of 103 characters were obtained: 45 from wing pattern, 48 from genitalia and 10 from wing venation. The data matrix was analysed using maximum parsimony under both equal and extended implied weights. Euptychiina was recovered as monophyletic with ten monophyletic genera, contrasting previous DNA sequence‐based phylogenies that did not recover the monophyly of the group. In agreement with sequence‐based hypotheses, however, three main clades were recognized: the ‘Megisto clade’ with six monophyletic and three polyphyletic genera, the ‘Taygetis clade’ with nine genera of which three were monophyletic, and the ‘Pareuptyhia clade’ with four monophyletic and two polyphyletic genera. This is the first morphology‐based phylogenetic hypothesis for Euptychiina and the results will be used to complement molecular data in a combined analysis and to provide critical synapomorphies for clades and genera in this taxonomically confused group.     

Flipper Bands Modify the Short-Term Diving Behavior of Little Penguins

ABSTRACT Flipper banding has long been the primary method to identify individual penguins, despite studies indicating that it may be detrimental to breeding success and survival. Our objectives were to measure the effects that flipper bands may have on diving performance of little penguins to determine whether the bands may be detrimental. We studied short- and long-term direct effects of flipper banding on diving behavior of free-ranging little penguins (Eudyptula minor) by comparing diving behavior before and after banding and by comparing diving performance of unbanded birds to those that had carried flipper bands for several years, respectively. Recently banded birds displayed increases in multiple variables following banding. Long-term banded penguins did not exhibit differences to their unbanded counterparts in most variables examined. Our findings are useful to those considering or reviewing the use of bands in penguin study and management.