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Abstract: We tested the applicability of electron transport system (ETS) derived from a single leg as a tool for non-lethal assessment of metabolic activity in freshwater crayfish. ETS activity of the whole body and of a leg was measured in four crayfish (Arthropoda, Crustacea, Decapoda) species: two European (Astacus astacus, Austropotamobius torrentium), and two North American (Orconectes limosus, Pacifastacus leniusculus). Mass scaling of whole body ETS activity (ETSwhole) and leg ETS activity (ETSleg) was not significantly different for the European A. astacus and the American O. limosus. Therefore common models were constructed and tested on the remaining two species. The ratio ETSwhole/ETSleg was significantly positively related to body mass. In the first model (model 1) ETSwhole was calculated from ETSleg multiplied by the ratio estimated from the known body mass. ETSwhole of A. torrentium was underestimated by this model, because they mature at smaller body size than the larger species. A direct relation between ETSleg and ETSwhole was therefore proposed as a general model (model 2), since they are correlated similarly in the studied species. The results show that model 2 is suitable for estimating the whole body ETS activity from leg ETS activity for the four investigated decapods.
Keywords: electron transport system (ETS) activity, crayfish, size scaling, methods (biology)
Published in DiRROS: 12.03.2025; Views: 23; Downloads: 34
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Abstract: Food production is considered to be the main source of human impact on the environment and the concerns about detrimental effects of pesticides on biodiversity and human health are likely to lead to an increasingly restricted use of chemicals in agriculture. Since the first successful field trial, pheromone based mating disruption enabled sustainable insect control, which resulted in reduced levels of pesticide use. Organic farming is one of the fastest growing segments of agriculture and with the continuously growing public concern about use of pesticides, the main remaining challenge in increasing the safety of the global food production is to identify appropriate alternative mating disruption approaches for the numerous insect pests that do not rely on chemical communication. In the present study, we show for the first time that effective mating disruption based on substrate-borne vibrational signals can be achieved in the field. When disruptive vibrational signals were applied to grapevine plants through a supporting wire, mating frequency of the leafhopper pest Scaphoideus titanus dropped to 9 % in semi-field conditions and to 4 % in a mature vineyard. The underlying mechanism of this environmentally friendly pest-control tactic is a masking of the vibrational signals used in mate recognition and location. Because vibrational communication is widespread in insects, mating disruption using substrate vibrations can transform many open field and greenhouse based farming systems.
Keywords: insects, ethology, pest management
Published in DiRROS: 12.03.2025; Views: 43; Downloads: 18
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Abstract: While a plethora of studies have focused on the role of visual, chemical and near-field airborne signals in courtship of Drosophila fruit flies, the existence of substrate-borne vibrational signals has been almost completely overlooked. Here we describe substrate vibrations generated during courtship in three species of the D. melanogaster group, from the allegedly mute species D. suzukii, its sister species D. biarmipes, and from D. melanogaster. In all species, we recorded several types of substrate vibrations which were generated by locomotion, abdominal vibrations and most likely through the activity of thoracic wing muscles. In D. melanogaster and D. suzukii, all substrate vibrations described in intact males were also recorded in males with amputated wings. Evidence suggests that vibrational signalling may be widespread among Drosophila species, and fruit flies may provide an ideal model to study various aspects of this widespread form of animal communication.
Keywords: animal communication, ethology, animal behaviour
Published in DiRROS: 12.03.2025; Views: 42; Downloads: 27
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Abstract: The aim of the study was to compare nest survival of Great Tit between different regions, altitudes and years to discern which has the highest influence. Temperature is known to be prominent for breeding parameters and it changes consistently with altitude. Our hypothesis was that altitude has greater influence on nest survival than the region and year. Breeding parameters were monitored with the use of nestboxes over a three year period at three altitude belts in two regions. The main factor influencing nesting success was modelled using daily survival rate in the program MARK. We gathered data from 104 first nesting attempts of which 26 failed. Although nest failure increased with altitude this was significant only for one region. There was significant difference in nest failure between the regions but not between the years. Modelling showed higher support in data for regions than for altitudes and years thus rejecting the hypothesis. Some possible reasons for such results are discussed.
Keywords: great tit, nest survival, altitude
Published in DiRROS: 12.03.2025; Views: 25; Downloads: 36
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Abstract: : Fledgling mass can have great influence on individual’s life history and reflects the availability and quality of food in the breeding territory. Thus growth curve is used to compare the difference in the quality between different ecological conditions. The aim of the study was to fill the knowledge gap on nestling growth in Great Tit in Slovenia, to determine the influence of altitude on it and to present a tool for estimating age of nestlings and key dates in breeding phenology of Great Tit. Great Tits young were monitored using nest-boxes at three locations between years 2010 and 2012. At two locations nest-boxes were placed on three separate altitudinal belts. Weight growth curve was compared with the curves from other parts of Europe. Growth curve from Slovenia differs in growth parameters from other European populations but falls within their range. Difference in growth parameters between separate populations probably comes from the difference in ecological conditions. When comparing three altitudes weight parameters of hatchlings were similar at lower and middle but different at upper altitudes indicating that weigh growth changes with the altitude. Lower food abundance that comes with rising altitude may be offset by lower competition through lower breeding density (hence similar growth parameters in lower and middle altitude), but not past certain altitude. Weight parameters are useful when comparing different populations, but wing-length is better in determining the age of young in the nest
Keywords: great tit, hatchling growth, altitude
Published in DiRROS: 12.03.2025; Views: 37; Downloads: 23
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