Structural manipulations of a shelter resource reveal underlying preference functions in a shell-dwelling cichlid fish

Many animals can modify the environments in which they live, thereby changing the selection pressures they experience. A common example of such niche construction is the use, creation or modification of environmental resources for use as nests or shelters. Because these resources often have correlated structural elements, it can be difficult to disentangle the relative contribution of these elements to resource choice, and the preference functions underlying niche-construction behaviour remain hidden. Here, we present an experimental paradigm that uses 3D scanning, modelling and printing to create replicas of structures that differ with respect to key structural attributes. We show that a niche-constructing, shell-dwelling cichlid fish, Neolamprologus multifasciatus , has strong open-ended preference functions for exaggerated shell replicas. Fish preferred shells that were fully intact and either enlarged, lengthened or had widened apertures. Shell intactness was the most important structural attribute, followed by shell length, then aperture width. We disentangle the relative roles of different shell attributes, which are tightly correlated in the wild, but nevertheless differentially influence shelter choice and therefore niche construction in this species. We highlight the broad utility of our approach when compared with more traditional methods (e.g. two-choice tasks) for studying animal decision-making in a range of contexts.

An innovative prefabricated building system for the seismic regions

At the end of a decade-long research work at the Moravamont plant in Gnjilane, a new completely prefabricated building system was created from reinforced concrete and prestressed precast elements on the track, which was called Moravamont 2000. Presented in paper final results demonstrates that the construction is well and rationally designed, that the construction behaviour for the maximum expected earthquake effects with a return period of 500 years, according to the criterion of regulation, is resistant and resistant to an earthquake without major damage.

Structural manipulations of a shelter resource reveal underlying preference functions in a shell-dwelling cichlid fish

Many animals can modify the environments in which they live, thereby changing the selection pressures they experience. A common example of such niche-construction is the use, creation, or modification of environmental resources for use as nests or shelters. Because these resources often have correlated structural elements, it can be difficult to disentangle the relative contribution of these elements to resource choice, and the preference functions underlying niche-construction behaviour remain hidden. Here, we present an experimental paradigm that uses 3D-scanning, -modelling, and -printing to create replicas of structures that differ with respect to key structural attributes. We show that a niche-constructing, shelldwelling cichlid fish, Neolamprologus multifasciatus, has strong open-ended preference functions for exaggerated shell replicas. Fish preferred shells that were fully intact and either enlarged, lengthened, or had widened apertures. Shell intactness was the most important structural attribute, followed by shell length, then aperture width. We disentangle the relative roles of different shell attributes, which are tightly correlated in the wild, but nevertheless differentially influence shelter choice and therefore niche construction in this species. We highlight the broad utility of our approach when compared to more traditional methods (e.g. two-choice tasks) for studying animal decision-making in a range of contexts.

Flexible prefabricated system moravamont 2000

At the end of a decade-long research work at the Moravamont plant in Gnjilane, a new completely prefabricated building system was created from reinforced concrete and prestressed precast elements on the track, which was called Moravamont 2000. Presented in paper final results demonstrates that the construction is well and rationally designed, that the construction behaviour for the maximum expected earthquake effects with a return period of 500 years, according to the criterion of regulation, is resistant and resistant to an earthquake without major damage. The idea is to present through new system moravamont 2000 its flexible side along with the possible development using 3D technology.

Modular patterns in behavioural evolution: webs derived from orbs

Imperfect knowledge of ancestral behaviour often hampers tracing behavioural evolution. This limitation is reduced in orb weaving spiders, because spider orb web construction behaviour and the cues used by modern orb-weavers are well-studied and highly conserved. Several species in orb-weaving families build non-orb webs that are clearly derived from orbs, allowing transitions from ancestral to modern behaviours to be described with high confidence. Three major patterns of general evolutionary significance were found in 69 phylogenetically independent transitions in 15 groups in 8 families: ancestral traits were often maintained as units; the most frequent of the eight different types of ancestral trait change was transfer of an ancestral behaviour to a new context; and ‘new’ traits that had no clear homology with ancestral traits were also common. Changes occurred in all major stages of orb construction. This may be the most extensive summary of evolutionary transitions in behaviour yet compiled.

Why do female desert lizards construct burrows to lay eggs?

Many oviparous animals construct well-designed nests to provide relatively favourable conditions for their eggs and hatchlings, but the direct evidence that nest structure can determine their reproductive success is insufficient. In the present study, we explored the structure of nests and its effect on nest environments and reproductive success in the toad-headed agama (Phrynocephalus przewalskii). We observed that female P. przewalskii constructed burrow nest consisting of an inclined tunnel and an expanded chamber. We constructed artificial nests with or without the burrow to determine how burrows influence nest environments, egg survival and successful emergence of hatchlings. Our results indicated that burrow nests had higher and more stable humidity than non-burrow nests. More importantly, egg survival and the emergence success of hatchlings were significantly higher for burrow nests than for non-burrow nests. Therefore, our manipulation experiments provide direct evidence that maternal nest construction behaviour could determine parental reproductive success in reptile.