Surface Coat Movements in Unfertilized Amphibian Eggs

Several features of the surface coat movements displayed by unfertilized, uncleaved amphibian eggs were examined. Those movements were examined in a variety of species, and investigated in detail in Rana eggs. Continuous exposure to a salt solution is a prerequisite for surface coat movements. Various inhibitors were tested for their capacity to inhibit those movements. The possibility was examined that the primary embryonic organizer might be localized in the area which resembles the dorsal lip of normal gastrulae.     

Effects of Road Crossings on Stream and Streamside Salamanders

Abstract: Salamanders are important members of faunal communities in Appalachian Mountain (USA) streams, and the use of salamanders as bioindicators is increasing. Roads are a part of the modern landscape, but effects of roads on stream and streamside salamander diversity and abundance is not clear. We sampled streams in central West Virginia, USA, using quadrats placed along transects in the flowing channel, dry channel, and stream bank to assess salamander diversity, richness, and abundance during 2004. We used Akaike's Information Criterion for model selection at reach (i.e., above and below culverts) and stream scales. Salamander diversity and richness was affected by elevation, stream gradient, canopy cover, and the presence of roads. Overall, stream and riparian habitat quality was the most important factor affecting salamander richness. The presence of roads, stream gradient, and elevation received the most empirical support for predicting species' abundances. Roads benefited disturbance-tolerant species but negatively affected other species. Impacts of roads and culverts on habitat should be considered by federal and state transportation agencies and natural resources agencies during the planning process and addressed through mitigation efforts. Managers should install culverts that are as wide as the stream channel, at grade with the streambed, and dominated by rubble substrate to provide maximum benefit for salamanders. (JOURNAL OF WILDLIFE MANAGEMENT 72(3):760–771; 2008)     

Patterns of morphological variation and correlates of habitat use in Chameleons

The lizard family Chameleonidae is one of the most distinctive taxa of all vertebrates. Nonetheless, despite great intrafamilial diversity, little research has been conducted on morphological variation among chameleons. As a first step in this direction, we took morphological measurements on the head, limbs, spines, and tail of 56 species. Our goals were to investigate whether morphological variation correlates with differences in ecology and to examine whether correlations exist among different aspects of morphology. Based on existing information, species were classified either as arboreal or terrestrial, the latter referring to species that are known to use the ground on a regular basis. This study confirms that considerable intrafamilial variation exists among chameleons and that these traits appear to be evolutionarily quite labile. Once the effects of size are removed, functionally related traits tend to covary; however, few correlations are observed between non-functionally related traits. Many differences in the lengths of the limbs and head elements were detected between terrestrial and arboreal species, but the functional and selective significance of these differences is not clear. Further research on chameleon behaviour and ecology is required to understand the factors contributing to chameleon morphological diversity. © 2002 The Linnean Society of London, Biological Journal of the Linnean Society , 2002, 76 , 91–103.     

Genetic divergence is more tightly related to call variation than landscape features in the Amazonian frogs Physalaemus petersi and P. freibergi

Behavioural isolation from divergence in male advertisement calls and female preferences is hypothesized to cause genetic divergence and speciation in the Amazonian frogs Physalaemus petersi and P. freibergi, yet the importance of call variation and landscape features in genetic divergence is unresolved. We tested for correlations between genetic divergence at microsatellite loci and (1) call variables; and (2) landscape variables among 10 populations of these frogs. Genetic divergence was not correlated with geographical distance, rivers or elevation. There was a strong positive relationship, however, between genetic divergence and inter‐population differences in one call variable, whine dominant frequency. Effective population sizes varied among sites (range = 15–846) and were often small, suggesting that genetic drift could influence call evolution. Evidence for fine‐scale genetic structure within sites was also found. Our results support the hypothesis that behavioural isolation from divergence in male calls and female preferences causes genetic divergence and speciation.     

Interrelationships and diversification of Argynnis Fabricius and Speyeria Scudder butterflies

Diverse radiations of insects are often associated with adaptations to host plants, and well‐resolved phylogenetic relationships are required to fully understand them. Palearctic Argynnis and related subgenera, together with North American Speyeria butterflies make up a radiation whose species hypotheses are confounded by shared wing colour patterns between sympatric populations of closely related recognized species. Previous studies of this group indicate that Speyeria is a lineage within Argynnis, but sampling in these studies has either involved too few Speyeria species or incomplete sampling of Argynnis species. Thus, no comprehensive phylogenetic analysis exists for all members that answers the question of monophyly of Speyeria, or other subgeneric taxa, and their relationship to Argynnis species. We completed a phylogenetic analysis of all North American Speyeria species and all but one species within Argynnis, using one mitochondrial (cytochrome c oxidase I, COI) and four nuclear genes [elongation factor 1 alpha (EF1α), wingless (WG), glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH), and ribosomal protein S5 (RPS5)]. The results indicate three major lineages within Argynnis s.l.: two Palearctic and one containing both Palearctic and Nearctic species. In summary, the phylogenetic analyses suggest the need for reorganization into three natural groups: Argynnis, Fabriciana and Speyeria. Within each of these genera the phylogenetic hypothesis indicates an evolutionary history marked by rapid diversification and potential extinction, followed by ongoing lineage sorting. The position of North American Speyeria is nested within the Palearctic lineages, which indicates that the radiation began in Asia and was fuelled by existing Viola diversity in North America. Dating analyses of Viola and Speyeria corroborate this hypothesis. The current North American Speyeria species are mixed on the tree, indicating a recent and ongoing radiation. These results provide needed clarity on the evolution of this group, which contains species of conservation concern.     

Bombing and Sonoran Pronghorn: A Clear and Present Danger?

ABSTRACT The United States Air Force (USAF) uses part of Sonoran pronghorn (Antilocapra americana sonoriensis) habitat for bombing exercises (i.e., Barry M. Goldwater Air Force Range [BMGR], southwest AZ, USA) that could be detrimental to the endangered subspecies. To minimize injury or death to Sonoran pronghorn, the USAF and United States Fish and Wildlife Service developed a monitoring protocol that would eliminate live ordnance delivery in the vicinity of pronghorn. From 1998 to 2003, we searched for pronghorn on or near military targets prior to ordnance delivery. If we observed pronghorn within 5 km of a target, the target was closed for ≥24 hours. We monitored bombing ranges on BMGR and closed >5,000 targets for >1,000 days due to military activity. To our knowledge, no pronghorn were killed or injured. We recommend that the monitoring program continue as long as military activity occurs in pronghorn habitat.     

Mechanisms for tolerance of very high tissue phosphorus concentrations in Ptilotus polystachyus

Study of plants with unusual phosphorus (P) physiology may assist development of more P‐efficient crops. Ptilotus polystachyus grows well at high P supply, when shoot P concentrations ( [P] ) may exceed 40 mg P g^?1 dry matter (DM). We explored the P physiology of P. polystachyus seedlings grown in nutrient solution with 0–5 mM P. In addition, young leaves and roots of soil‐grown plants were used for cryo‐scanning electron microscopy and X‐ray microanalysis. No P‐toxicity symptoms were observed, even at 5 mM P in solution. Shoot DM was similar at 0.1 and 1.0 mM P in solution, but was ～14% lower at 2 and 5 mM P. At 1 mM P, [P] was 36, 18, 14 and 11 mg P g^?1 DM in mature leaves, young leaves, stems and roots, respectively. Leaf potassium, calcium and magnesium concentrations increased with increasing P supply. Leaf epidermal and palisade mesophyll cells had similar [P]. The root epidermis and most cortical cells had senesced, even in young roots. We conclude that preferential accumulation of P in mature leaves, accumulation of balancing cations and uniform distribution of P across leaf cell types allow P. polystachyus to tolerate very high leaf [P].