Abstract. The larvae of the antlion Euroleon nostras are pit‐builders, constructing pitfall traps in loose sand. The number of pits and the pit diameter are recorded when larvae are kept in substrates with different particle sizes. The most convenient pit‐building sand fractions are two fractions with fine sand (≤ 0.23 mm; 0.23–0.54 mm). The largest pits are constructed in sand with a particle size of 0.23–0.54 mm. In this sand fraction, larvae of all three instars most readily build pits. No pits are constructed in sand with a particle size greater than 1.54 mm. First‐ and second‐instar larvae avoid building pits in substrates of particle size 1–1.54 mm, but third‐instar larvae construct pits in this sand fraction. It is assumed that the antlion is capable of distinguishing between substrate types and this hypothesis is tested by giving larvae the choice of building a pit in one of four particle‐size fractions. Larvae of all three instars prefer to build pits in the fraction with a particle size of 0.23–0.54 mm. Only third‐instar larvae build pits in all four fractions, but only occasionally in the coarser fraction.
European pit‐building antlions (Euroleon nostras/ Geoffroy in Fourcroy/) detect their prey by sensing the vibrations that prey generate during locomotory activity. The behavioural reactions and some of the physical properties of substrate vibrations in sand are measured to observe signal transmission through the substrate. The frequency range of the signals of four arthropod species (Tenebrio molitor, Pyrrhocoris apterus, Formica sp. and Trachelipus rathkei) is 0.1–4.5 kHz and acceleration values are in the range 400 μm s−2 to 1.5 mm s−2. Substrate particle size and the frequency of prey signals both influence the propagation properties of vibratory signals. The damping coefficient at a frequency 300 Hz varies from 0.26 to 2.61 dB cm−1 and is inversely proportional to the size of the sand particle. The damping coefficient is positively correlated with the frequency of the pulses. Vibrations in finer sand are attenuated more strongly than in coarser sand and, consequently, an antlion detects its prey only at a short distance. The reaction distance is defined as the distance of the prey from the centre of the pit when the antlion begins tossing sand as a reaction to the presence of prey. The mean reaction distance is 3.3 cm in the finest sand (particle size ≤ 0.23 mm) and 12.3 cm in coarser sand (particle size 1–1.54 mm). The most convenient sands for prey detection are considered to be medium particle‐sized sands.
The shortage of qualified STEM teachers and researchers in these fields can be recognized as an existing and forthcoming problem. The aim of the present study was to explore the influence of the content of STEM subjects Biology, Chemistry, Informatics, Mathematics, Physics, and Technics and Technology and corresponding classroom experiences, as perceived by students, in elementary and general secondary schools on student's career aspirations and ambition to work as researchers or educators as their career choice. The sample comprised 552 upper general school students (ages 17 to 19) in their last two years before entering University. We hypothesized that a combination of general interest in each of the six listed disciplines, together with the content taught in elementary and upper secondary school, together with respective classroom experiences, will influence career aspirations expressed by ranking their wish to work as educators or researchers. With the use of Structural Equation Modeling, we revealed that Biology, Chemistry, and Physics can statistically significantly explain career aspirations to become a researcher. However, Informatics, Mathematics, and Technics and Technology cannot. None of the listed disciplines positively predicts career aspirations to become an educator. From the correlation between ranked aspirations toward a research and an educational career (r 5 -.03; p 5 .964), we can conclude that most of those who considered a career as a researcher as a plausible option do not share the same opinion about a career in education.
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