AUTOMATIC FEATURE EXTRACTION AND CLASSIFICATION OF CROSSBILL (LOXIA SPP.) FLIGHT CALLS

ABSTRACT

In this paper a new method for the automatic classification of bird sounds is presented. Our method is based on acoustic parameters (features) taken from the first harmonic component computed from the sound spectrogram. The features are based on a line segment approximation of the first harmonic component. The final feature vectors, consisting of 16 real numbers, are then classified using a self-organizing map (SOM) neural network. Flight calls of four crossbill species (Loxia spp.) are used as a test example. In the first phase, an unsupervised network was trained and tested using common crossbill L. curvirostra flight calls recorded mainly in the Netherlands. The network was tested using two-barred L. leucoptera, Scottish L. scotica and parrot L. pytyopsittacus crossbill flight calls in the second phase. Finally, the results were validated applying the same network to flight calls of common crossbills and parrot crossbills recorded in Finland. The method automatically separated common crossbill flight calls from those of parrot crossbills. The classification accuracy of the Dutch recordings was 58% in the first phase and 54% in the second phase. The Finnish recordings were classified with 54% accuracy.     

Avian predation on a parasitic fly of cervids during winter: can host‐related cues increase the predation risk?

The deer ked (Lipoptena cervi) is an ectoparasitic fly on cervids that has expanded its distribution rapidly in Northern Europe. However, the regulating biotic factors such as predation remain unknown. The host‐independent pupal stage of the fly lasts for several months. Blackish pupae are visible against snow, especially on the bedding sites of hosts, and are thus exposed to predators. To evaluate the role of predation on the invasion dynamics and evolution of L. cervi, we monitored pupal predation on artificial bedding sites in three geographical areas in Finland during winter. We explored: (1) possible predators; (2) magnitude of predation; and (3) whether predation risk is affected by host‐derived cues. We demonstrate that pupae are predated by a number of tit species. Any reddish brown snow discoloration on bedding sites, indicating heavy infestation of the host, serves as an exploitable cue for avian predators, thereby increasing the risk of pupal predation. The ability of tits to use this host‐derived cue seems to be dependent on the prevalence of L. cervi and the period of invasion history, which suggests that it may be a learned behavioural response. Predation by tits may potentially affect the L. cervi population dynamics locally. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 106 , 275–286.     

Genital variation in a dimorphic moth Selenia tetralunaria (Lepidoptera, Geometridae)

Insect genitals vary greatly among species and provide a key tool for species-level taxonomy. Insects differing in the genitalia are often treated as discrete, reproductively isolated species. This principle dates back to the lock-and-key hypothesis, which states that genitalia vary between species in order to provide a mechanical reproductive isolation system. Thus, the hypothesis assumes low within-species variability in genital traits. However, recent studies suggest that sexual selection may be responsible for the evolution of insect genitalia. We studied allometry and genital size and shape variation in a dimorphic moth Selenia tetralunaria . We found that the genitalia showed negative allometry in relation to body size as reported in many insect and spider species. This allometry was stronger in internal genital structures than it was in external genitalia. We also found that there was more variation in internal compared with external genitalia. Finally, we found that the shape of genital structures differed between morphs in all three examined areas. S. tetralunaria is among the first reported cases of genitally dimorphic insect species. Considerable variation in internal genitalia and especially the presence of genital shape differences between morphs were not consistent with the predictions of the lock-and-key hypothesis.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 87 , 297–307.     

Alterations in growth of tissue-cultured tansy (Tanacetum vulgare L.) treated with antibiotics

Effects of three antibiotics (cefotaxime, rifampicin and gentamicin) were tested on in vitro shoots cultures of tansy (Tanacetum vulgare L.)- These antibiotics were selected because endophytic bacteria isolated from the in vitro shoot cultures of tansy showed that all bacteria were Gram-negative and their growth was reduced by these three antibiotics. Five isolates were Enterobacteriaceae, three were fluorescent Pseudomonas, and two were aerobic bacteria. Increased concentrations of antibiotics caused usually linear or quadratic changes on the initiation of shoot growth, shoot number, growth rate, and shoot height. These changes and changes in pH of the culture media were tansy genotype-dependent following treatments with gentamicin. Also, the treatment with rifampicin or cefotaxime showed a genotype-dependent effect, because they resulted in significantly higher percentage of rooted plants in one of the three tansy genotypes tested. The growth rate and length of shoots were reduced in the media containing both gentamicin and rifampicin, but less so than in media containing both gentamicin and cefotaxime.     

A Dynamic Model for Photosynthesis

A dynamic mathematical model of the effect of radiant flux densityand CO₂ concentration on the rate of photosynthesis is proposed.An appropriate dynamic experimental method for ecological studiesof this subject is described. The methodology permits the analysisof numerous problems, including the effect of changes in CO₂concentration on photosynthesis and the effectiveness of energyconversion by a leaf of a plant in different environmental conditions. The dynamic model for photosynthesis is composed of two separateinteracting non-linear parts; one describes the dynamics ofthe complex set of light reactions, and the other describesthe dark reactions. The model explains the dynamics of leafphotosynthesis in a closed circuit flow system, and also explainsthe expressions for the equilibrium states of photosyntheticrate widely used in the literature. photosynthesis, mathematical model, carbon dioxide fixation, light reactions     

Significance of spring migration and flexibility in flight-muscle histolysis in waterstriders (Heteroptera, Gerridae)

Abstract. 1. Individuals of long-winged waterstrider (Gerridae) species were found in spring far from their breeding habitats, which indicates that they fly before reproduction.
2. Field samples and laboratory studies show that once they return to their breeding sites, many individuals of three waterstrider species ( Gerris odontogaster (Zett.), Gerris lacustris (L.) and Limnoporus rufoscutellatus (Lat.)) histolyse wing muscles and lose flight ability during their reproductive period.
3. The extent of flight-muscle histolysis varies with environmental factors. Food scarcity affects flight-muscle histolysis in G.odontogaster females. In G.Lacustris , flight-muscle histolysis was more common in the laboratory than in the field samples. Proportionately more females than males lost their flight ability by the end of the reproductive period.
4. Flight ability had direct costs in reproductive potential with (non-flyer) females, which histolysed their flight muscles, laying more eggs than (flyer) females, which maintained flight ability. This was also the case during food scarcity. Non-flyer males of G.odontogaster survived longer than flyer males.
5. Spring migration was distinguished from dispersal during the reproductive period, because these flights serve different functions. Flight-muscle histolysis of females during reproduction is a qualitative reproductive option, with a trade-off between dispersal ability and reproductive potential. Ability to change reproductive behaviour depending on environmental conditions increases an individual's ability to cope with a large variety of habitats.     

Analysis of Two Rubisco-Deficient Tobacco Mutants, H7 and Sp25; Evidence for the Production of Rubisco Large Subunits in the Sp25 Mutant that Form Clusters and are Inactive

The basis for the lesions in the Sp25 and H7 ribulose-l,5-bisphosphatecarboxylase/oxygenase (Rubisco) mutants of tobacco was studiedin detail because these plants may be suitable hosts for transformationwith the genes for Rubisco enzymes of various origins that havedifferent substrate specificities. We show that the Sp25 mutantlacks active holoenzyme, but contains the large and small subunitpolypeptides, Rubisco activase and the chloroplast chaperonin,Cpn 60. The large subunit polypeptides were not distributeduniformly in the stroma in the Sp25 mutant as they were in thewild-type plants, but had an anomalous distribution being presentonly in aggregated clusters notably in chloroplasts with largestarch grains. Furthermore, these clusters were not uniformlydistributed throughout the photosynthetic cells but were localizedlargely in the mesophyll cells surrounding the vascular tissue.In contrast to the Sp25 mutant, the H7 mutant contained theRubisco holoenzyme, but in this case the enzyme was inactive.It is clear that in both these mutants the Rubisco holoenzymefails to assemble correctly. In the Sp25 mutant assembly islost completely while in the H7 mutant the holoenzyme is formed,but the assembly process fails to produce an active enzyme.We suggest that the flaw in assembly in the Sp25 mutant resultsfrom a defect in chloroplast encoded proteins. Key words: Rubisco, assembly, tobacco, mutants