Microsatellite markers isolated from polyploid wood‐sorrel Oxalis alpina (Oxalidaceae)

Twelve polymorphic microsatellite loci were isolated from polyploid alpine wood‐sorrel, Oxalis alpina (Oxalidaceae), and optimized for future studies of its breeding system. The loci were screened for variability among 72 individuals from Pinos Altos, New Mexico. The primers amplified loci with allele number ranging from two to 17 per locus and with estimates of Nei's genetic diversity varying from 0.10 to 0.99. These primers provide an opportunity to use polymorphic DNA markers to study the causes of breeding system variability in this species.     

Twelve polymorphic microsatellite loci from the Asian citrus psyllid,Diaphorina citri Kuwayama,the vector for citrus greening disease,huanglongbing

Twelve polymorphic microsatellite markers were developed from microsatellite‐enriched DNA libraries and mined from an expressed sequence tags library of Diaphorina citri, the vector of the citrus greening disease (huanglongbing). Analysis of 288 individuals from Florida, Texas, and Brazil showed that allelic diversity ranged from three to eight alleles per locus and observed and expected heterozygosities ranged from 0.014 to 0.569 and from 0.052 to 0.653, respectively. These variable microsatellite loci can provide means for assessing overall genetic variation and migration patterns for this agriculturally important pest species. This information can be used to aid in developing successful management strategies.     

Mutual mate choice by mountain pine beetles: size‐dependence but not size‐assortative mating

1. Mutual mate choice may be rare, occurring when both sexes invest heavily in reproduction, mating opportunities are abundant, and individuals differ in quality. 2. Mountain pine beetles, Dendroctonus ponderosae (Curculionidae: Scolytinae) appear to meet the conditions for mutual mate choice. We introduced males to females in breeding sites and observed the occurrence and speed of a male entering a female's gallery. We tested for consequences of mutual mate choice, namely condition‐dependent choosiness and assortative mating. 3. Males were more likely to enter a female's gallery when the gallery was in a smaller tree with less resin production and when the gallery was larger. Female body size and condition did not influence the probability of entry. Larger males were less likely to enter a gallery than were smaller males, probably because of size‐dependent choosiness rather than physical limitations. 4. Small males took longer to enter galleries of large females than of small females, whereas large males entered as quickly into galleries of large females as small females. This suggests size‐dependent choosiness by females. 5. No assortative mating by body size was detected, probably because males appeared to choose on the basis of female‐associated resources rather than on female traits.     

Methane production by microbial mats under low sulphate concentrations

Cyanobacterial mats collected in hypersaline salterns were incubated in a greenhouse under low sulphate concentrations ([]) and examined for their primary productivity and emissions of methane and other major carbon species. Atmospheric greenhouse warming by gases such as carbon dioxide and methane must have been greater during the Archean than today in order to account for a record of moderate to warm palaeoclimates, despite a less luminous early sun. It has been suggested that decreased levels of oxygen and sulphate in Archean oceans could have significantly stimulated microbial methanogenesis relative to present marine rates, with a resultant increase in the relative importance of methane in maintaining the early greenhouse. We maintained modern microbial mats, models of ancient coastal marine communities, in artificial brine mixtures containing both modern [] (c. 70 mm ) and ‘Archean’[] (<0.2 mm ). At low [], primary production in the mats was essentially unaffected, while rates of sulphate reduction decreased by a factor of three, and methane fluxes increased by up to 10‐fold. However, remineralization by methanogenesis still amounted to less than 0.4% of the total carbon released by the mats. The relatively low efficiency of conversion of photosynthate to methane is suggested to reflect the particular geometry and chemical microenvironment of hypersaline cyanobacterial mats. Therefore, such mats were probably relatively weak net sources of methane throughout their 3.5 Ga history, even during periods of low environmental levels oxygen and sulphate.     

Long‐distance signals influence assessment of close range mating displays in the field cricket,Gryllus integer

Male sexual displays often include components detected across long distances, and those perceived only at close range. Understanding what information females gain from each component of a complex display and how they use these signals to make decisions are questions of major interest in sexual selection research. We evaluated content‐based hypotheses (‘redundant signals’ and ‘multiple messages’) for the courtship displays of field crickets (Gryllus integer) by measuring female responses to males' long‐distance calling song (calls) and close‐range chemical cues. Females' responses to a male's calls and chemical cues were uncorrelated, supporting the ‘multiple messages’ hypothesis. We also tested the ‘inter‐signal interaction’ hypothesis by investigating how long‐distance calls influence evaluation of close‐range courtship. The relationship between long‐ and close‐range signals was complex and conditional: females accepted close‐range courtship more quickly after exposure to attractive calling song than they did after exposure to either unattractive calling song or silence, and unattractive calls were no more or less effective than silence. This inter‐signal interaction could affect our understanding of mate choice in species with multiple mating signals because it implies that females may save time and energy by not assessing the close‐range signals of attractive long‐distance signalers. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100 , 856–865.     

Limb bone histology and growth in Placerias hesternus (Therapsida: Anomodontia) from the Upper Triassic of North America

Abstract: Patterns of bone deposition are reported and deduced from mid‐shaft sections of 21 limb bones of the dicynodont Placerias hesternus from the Placerias Quarry (Upper Triassic), Arizona, USA. All sampled elements of P. hesternus have a large medullary cavity completely filled with bony trabeculae surrounded by dense cortical bone. Dense Haversian bone extends from the perimedullary region to at least the mid‐cortex in all sampled bones. Primary bone in the outer cortex of limb elements of P. hesternus is generally zonal fibrolamellar with a peripheral layer of parallel‐fibred bone. These data suggest periodic rapid osteogenesis followed by slower growth. Among dicynodonts, this strategy is most similar to growth previously reported in other Triassic (Lystrosaurus, Wadiasaurus) and some Permian taxa (Oudenodon, Tropidostoma). An external fundamental system (EFS), suggesting complete or near complete cessation of appositional growth, is present in the largest tibia. This is the first report of EFS in dicynodonts and may represent the attainment of maximum size in P. hesternus. Slow‐growing peripheral bone was observed in elements of varying size in our sample and may support a differential growth pattern between P. hesternus individuals from this locality. A complete growth series of P. hesternus, analysis of Placerias specimens from other localities, and further sampling of other Upper Triassic dicynodonts are needed to better understand a more complete picture of the growth and remodelling patterns that we have initially investigated.     

Past and present distribution, densities and movements of blue whales Balaenoptera musculus in the Southern Hemisphere and northern Indian Ocean

• 1 Blue whale locations in the Southern Hemisphere and northern Indian Ocean were obtained from catches (303 239), sightings (4383 records of ≥8058 whales), strandings (103), Discovery marks (2191) and recoveries (95), and acoustic recordings.
• 2 Sighting surveys included 7 480 450 km of effort plus 14 676 days with unmeasured effort. Groups usually consisted of solitary whales (65.2%) or pairs (24.6%); larger feeding aggregations of unassociated individuals were only rarely observed. Sighting rates (groups per 1000 km from many platform types) varied by four orders of magnitude and were lowest in the waters of Brazil, South Africa, the eastern tropical Pacific, Antarctica and South Georgia; higher in the Subantarctic and Peru; and highest around Indonesia, Sri Lanka, Chile, southern Australia and south of Madagascar.
• 3 Blue whales avoid the oligotrophic central gyres of the Indian, Pacific and Atlantic Oceans, but are more common where phytoplankton densities are high, and where there are dynamic oceanographic processes like upwelling and frontal meandering.
• 4 Compared with historical catches, the Antarctic (‘true’) subspecies is exceedingly rare and usually concentrated closer to the summer pack ice. In summer they are found throughout the Antarctic; in winter they migrate to southern Africa (although recent sightings there are rare) and to other northerly locations (based on acoustics), although some overwinter in the Antarctic.
• 5 Pygmy blue whales are found around the Indian Ocean and from southern Australia to New Zealand. At least four groupings are evident: northern Indian Ocean, from Madagascar to the Subantarctic, Indonesia to western and southern Australia, and from New Zealand northwards to the equator. Sighting rates are typically much higher than for Antarctic blue whales.
• 6 South‐east Pacific blue whales have a discrete distribution and high sighting rates compared with the Antarctic. Further work is needed to clarify their subspecific status given their distinctive genetics, acoustics and length frequencies.
• 7 Antarctic blue whales numbered 1700 (95% Bayesian interval 860–2900) in 1996 (less than 1% of original levels), but are increasing at 7.3% per annum (95% Bayesian interval 1.4–11.6%). The status of other populations in the Southern Hemisphere and northern Indian Ocean is unknown because few abundance estimates are available, but higher recent sighting rates suggest that they are less depleted than Antarctic blue whales.

     

Molecules,morphology and Mimeoma scarabs: evolutionary and taxonomic implications for a palm‐associated scarab group

Cyclocephaline scarabs, the second largest tribe of rhinoceros beetles, are important pollinators of early‐diverging angiosperm families in the tropics. The evolutionary history of cyclocephaline genera is poorly resolved and several genera are thought to be nonmonophyletic. We assess the monophyly of Mimeoma Casey, a group of Neotropical palm‐feeding scarabs, and its relationship to Cyclocephala with a phylogenetic analysis of 2899 bp of DNA sequence data and 18 morphological characters. All five species of Mimeoma were included in analyses along with species of Cyclocephala Dejean, Dyscinetus Harold and Tomarus Erichson as outgroup taxa. Nearly complete 28S, 12S and CO1 data were collected from 26 of 29 specimens, of which 16 samples were pinned, museum specimens. 28S data strongly support a nonmonophyletic Mimeoma; mitochondrial data (CO1 and 12S) suggest that Mimeoma species are nested within an apical clade of other Cyclocephala species; combined molecular and morphological data identify two strongly supported clades of Mimeoma species but do not support their sister relationship. Combined data show that Mimeoma species are nested within Cyclocephala, thus rendering Cyclocephala paraphyletic. Mimeoma is synonymized within Cyclocephala resulting in the following new combinations: Cyclocephala acuta Arrow n.comb ., Cyclocephala englemani (Ratcliffe) n.comb ., Cyclocephala maculata Burmeister n.comb ., Cyclocephala nigra (Endrödi) n.comb . and Cyclocephala signatoides Höhne n.comb . Our results demonstrate that pinned, museum specimens can be used to obtain DNA sequence data (particularly high‐copy gene regions) for evolutionary studies, and provide the first empirical support that host‐plant associations within cyclocephaline scarab clades are conserved at the plant family‐level.     

Connectivity,small islands and large distances: the Cellana strigilis limpet complex in the Southern Ocean

The Southern Ocean contains some of the most isolated islands on Earth, and fundamental questions remain regarding their colonization and the connectivity of their coastal biotas. Here, we conduct a genetic investigation into the Cellana strigilis (limpet) complex that was originally classified based on morphological characters into six subspecies, five of which are endemic to the New Zealand (NZ) subantarctic and Chatham islands (44–52°S). Previous genetic analyses of C. strigilis from six of the seven island groups revealed two lineages with little or no within‐lineage variation. We analysed C. strigilis samples from all seven island groups using two mitochondrial (COI and 16S), one nuclear (ATPase β) and 58 loci from four randomly amplified polymorphic DNA markers (RAPDs) and confirmed the existence of two distinct lineages. The pronounced genetic structuring within each lineage and the presence of private haplotypes in individual islands are the result of little genetic connectivity and therefore very high self‐recruitment. This study supports the significance of the subantarctic islands as refugia during the last glacial maximum and adds to the knowledge of contemporary population connectivity among coastal populations of remote islands in large oceans and the distance barrier to gene flow that exists in the sea (despite its continuous medium) for most taxa.