Influence of Natal Experience on Nest-Site Selection by Urban-Nesting Cooper's Hawks

Abstract: Exposure to environmental features early in life potentially can influence the kinds of places animals select to live later in life. We examined whether there is evidence that Cooper's hawks (Accipiter cooperii) hatched in an urban environment choose sites with features similar to their natal areas when they nest for the first time. The features we examined were the nest tree species and the level of development surrounding the nest tree. We banded nestling and fledgling Cooper's hawks in Tucson, Arizona, USA, from 1994 to 2004. We then monitored nests in Tucson to identify hawks that had been hatched in the city and eventually secured a breeding site. Percent cover of buildings around first breeding nests was not related to percent cover of buildings around natal nests for either sex. There was some evidence that being hatched in a particular tree species influenced choice of tree species at first breeding sites for males, but the influence was weak. In contrast, tree species in which first-time breeders built their nests, and the sites where the trees were located relative to development, were proportional to what was available in the Tucson metropolitan area. Our data suggest that natal experience played a limited role in nest-site selection by Cooper's hawks in Tucson for the features we examined. If learning occurred, it could have been for the general structure of natal sites. Thus, any small grove of large trees planted in Tucson could be used as a nest site by Cooper's hawks regardless of the level of development surrounding the nest.     

Temporal patterns of territory settlement and detectability in mated and unmated Nightingales Luscinia megarhynchos

In many bird species the sex ratio of adults is male-biased, which is likely to have consequences for the ecology as well as for the conservation of a species. For example, when some males remain unpaired in a population, there should be strong selection on behavioural traits that enhance pairing success. A surplus of males is also likely to have important implications for the interpretation of breeding bird survey data. In our study population of Nightingales Luscinia megarhynchos , about half of the males stayed unpaired, suggesting that the number of males encountered singing was greater than the number of breeding pairs. Furthermore, the detectability (the probability of encountering a male singing) of mated males was only two-thirds that of unmated males when censused in the morning or late in the breeding season. The relative detectability was more similar early in the season and during the twilight periods before sunrise and after sunset. Males that arrived earlier on the breeding grounds were more successful in attracting a mate than males arriving later. Some of the unmated males deserted their territories and prospected areas up to 4000 m distant, whereas others settled on the study site only late in the season and may actually have changed territories. We suggest that adult sex ratios and the time of the census should be taken into account when interpreting the results of breeding bird surveys.     

Revision of the Neotropical Scleropactidae (Crustacea: Oniscidea)

The species of Scleropactidae from America are revised and redescribed. A phylogeny hypothesis based on an analysis of morphological characters is presented. The genera are redefined and the generic placement of several species is corrected. The Neotropical Scleropactidae include Colomboscia , Scleropactes , Circoniscus , Neosanfilippia , Sphaeroniscus , Richardsoniscus , Spherarmadillo , Colomboniscus , Amazoniscus and Protosphaeroniscus . The genus Chileoniscus is excluded from the Scleropactidae. Sphaerobathytropa is excluded from the Scleropactidae and its previous record from Argentina is revealed to be erroneous. Synuropus is revalidated and excluded from the Scleropactidae. The following new genera are introduced: Scleropactoides gen. nov. , Globopactes gen. nov. , Caecopactes gen. nov. , and Troglopactes gen. nov. Thirteen species are described as new: Caecopactes minimus sp. nov. , Colomboscia parva sp. nov. , Globopactes falconensis sp. nov. , Globopactes hispidus sp. nov. , Globopactes meridae sp. nov. , Scleropactes cotopaxii sp. nov. , Scleropactes ecuadoriensis sp. nov. , Scleropactes pululahua sp. nov. , Scleropactoides curvatus sp. nov. , Circoniscus hirsutus sp. nov. , Sphaeroniscus quintus sp. nov. , Spherarmadillo nebulosus sp. nov. , and Chileoniscus armadillidioides sp. nov. Identification keys to all species are provided.  © 2007 The Linnean Society of London, Zoological Journal of the Linnean Society , 2007, 151 (Suppl. 1), 1–339.     

Identification of host‐plant chemical stimuli for the European grape berry moth Eupoecilia ambiguella

Olfaction is of major importance for survival and reproduction in moths. Males possess highly specific and sensitive olfactory receptor neurones to detect female sex pheromones. However, the capacity of male moths to respond to host‐plant volatiles is relatively neglected and the role that such responses could play in the sensory ecology of moths is still not fully understood. The present study aims to identify host‐plant stimuli for the European grape berry moth Eupoecilia ambiguella Hb. (Tortricidae, Lepidoptera), a major pest of vine in Europe. Headspace volatiles from Vitis vinifera L. cv. Pinot Noir, Vitis vinifera subsp. sylvestris and five other host‐plant species comprising five different families are analyzed by gas chromatography linked to electroantennogram (EAG) recording from male E. ambiguella antennae and by gas chromatography‐mass spectrometry. This procedure identifies 32 EAG‐active compounds, among them the aliphatic compounds 1‐hexanol, (Z)‐3‐hexenol, (Z)‐3‐hexenyl acetate and 1‐octen‐3‐ol; the terpenes limonene, β‐caryophyllene and (E)‐4,8‐dimethyl‐1,3,7‐nonatriene; and the aromatic compounds benzaldehyde and methyl salicylate. Male and female E. ambiguella show similar EAG response amplitudes to individual chemical stimuli and also to mixtures of plant volatiles, as represented by essential oils from ten other plant species. This possibly indicates a common role for plant compounds in the sensory ecology of the two sexes of E. ambiguella.     

Multiple Pleistocene refugia and Holocene range expansion of an abundant southwestern American desert plant species (Melampodium leucanthum,Asteraceae)

Pleistocene climatic fluctuations had major impacts on desert biota in southwestern North America. During cooler and wetter periods, drought‐adapted species were isolated into refugia, in contrast to expansion of their ranges during the massive aridification in the Holocene. Here, we use Melampodium leucanthum (Asteraceae), a species of the North American desert and semi‐desert regions, to investigate the impact of major aridification in southwestern North America on phylogeography and evolution in a widespread and abundant drought‐adapted plant species. The evidence for three separate Pleistocene refugia at different time levels suggests that this species responded to the Quaternary climatic oscillations in a cyclic manner. In the Holocene, once differentiated lineages came into secondary contact and intermixed, but these range expansions did not follow the eastwardly progressing aridification, but instead occurred independently out of separate Pleistocene refugia. As found in other desert biota, the Continental Divide has acted as a major migration barrier for M. leucanthum since the Pleistocene. Despite being geographically restricted to the eastern part of the species’ distribution, autotetraploids in M. leucanthum originated multiple times and do not form a genetically cohesive group.     

Local and systemic effects of two herbivores with different feeding mechanisms on primary metabolism of cotton leaves

Caterpillars and spider mites are herbivores with different feeding mechanisms. Spider mites feed on the cell content via stylets, while caterpillars, as chewing herbivores, remove larger amounts of photosynthetically active tissue. We investigated local and systemic effects of short-term caterpillar and spider mite herbivory on cotton in terms of primary metabolism and growth processes. After short-term caterpillar feeding, leaf growth and water content were decreased in damaged leaves. The glutamate/glutamine ratio increased and other free amino acids were also affected. In contrast, mild spider mite infestation did not affect leaf growth or amino acid composition, but led to an increase in total nitrogen and sucrose concentrations. Both herbivores induced locally increased dark respiration, suggesting an increased mobilization of storage compounds potentially available for synthesis of defensive substances, but did not affect assimilation and transpiration. Systemically induced leaves were not significantly affected by the treatments performed in this study. The results show that cotton plants do not compensate the loss of photosynthetic tissue with higher photosynthetic efficiency of the remaining tissue. However, early plant responses to different herbivores leave their signature in primary metabolism, affecting leaf growth. Changes in amino acid concentrations, total nitrogen and sucrose content may affect subsequent herbivore performance.     

Evidence of Alaskan Trumpeter Swan Population Growth Using Bayesian Hierarchical Models

ABSTRACT Alaska (USA) contains a large proportion of the breeding population of trumpeter swans (Cygnus buccinator) in the United States. However, tracking population trends in Alaska trumpeter swans is complicated by variables such as an increase in survey effort over time, periodic surveys (1968 and every 5 yr after 1975), and missing data. We therefore constructed Bayesian hierarchical negative binomial models to account for nuisance variables and to estimate population size of trumpeter swans using aerial survey data from all known breeding habitats in Alaska, 1968–2005. We also performed an augmented analysis, where we entered zeroes for missing data. This approach differed from the standard (nonaugmented) analysis where we generated estimates for missing data through simulation. We estimated that adult swan populations in Alaska increased at an average rate of 5.9% annually (95% credibility interval = 5.2–6.6%) and cygnet production increased at 5.3% annually (95% credibility interval = 2.2–8.0%). We also found evidence that cygnet production exhibited higher rates of increase at higher latitudes in later years, which may be a response to warmer spring temperatures. Augmented analyses always produced higher swan population estimates than the nonaugmented estimates and likely overestimate true population abundance. Our results provide evidence that trumpeter swan populations are increasing in Alaska, especially at northern latitudes. Changes in population size and distribution could negatively affect tundra swans (Cygnus columbianus) breeding in Alaska, and biologists should monitor these interactions. We recommend using nonaugmented Bayesian hierarchical analyses to estimate wildlife populations when missing survey data occur.     

Localization of 5''-Ribonucleotide Phosphohydrolase in Regenerating (and Normal) Limb Tissues of the Adult Newt Notophthalmus viridescens

The regenerating forelimb of the adult newt, Notophthalmus viridescens was investigated for 5'-nucleotidase (5' ribonucleotide phosphohydrolase, 3.1.3.5) acitivity. The newt's humeri were surgically removed, and after a twenty-one-day recovery period, the forelimbs amputated above the elbows. Regenerates were sampled at predetermined times for specific phases in the progress of regeneration, frozen, sectioned in a cryostat, and the sections fixed in 10% cold formol calcium. The Wachstein and Meisel [25] lead procedure at neutral pH was used predominately in these experiments, although tests were also conducted with Gomori's [14] calcium, Allen's [21] highly alkaline procedures. The substrates used to obtain specific enzyme reactions were adenine, cytosine, guanine, uracil and inosine 5'-monophosphate nucleotides. Sodium beta-glycerophosphate served as a non-specific phosphomonoesterase substrate, distilled water replaced substrate, and inhibitors such as zinc and cyanide ions were used as control measures to assist in increasing the precision in interpreting the results obtained. The most reactive 5'-nucleotidase (5'-Nase) loci were in the walls of the blood vascular system, mysial and neural sheaths, dermis, and periosteum: the principal cells involved were macrophages, endothelium of blood vessels, and fibrocytes of connective tissues. A moderate enzyme response was elicited from secretory cells of some of the subcutaneous glands, hypertrophied chondrocytes and osteogenic centers, chondrocytes in the articular regions and within red blood cells and leucocytes. Normal, injured and degenerating, or regenerating striated muscle and nerve fibers were judged unreactive for 5'-Nase. The epidermis and wound epithelium displayed negative responses for 5'-Nase. Cells forming the regeneration blastema were 5'-Nase reactive during the early formative phase, but with growth and development of the blastema into bulb and conic forms, these cells did not respond for this enzyme-activity. One suggestion offered is that the absence of 5'-Nase in cells of the blastema may be related to the lack of an adequate blood-vascular supply. Several functions of 5'-Nase in normal and regenerating tissues are discussed. A basic conclusion reached is that 5'-nucleotidase hydrolyses may be more involved in fundamental anabolic than in catabolic metabolism.