Search Results (6)

Holometabolous insects display drastically different morphologies across life stages (i.e., larvae vs. adults). Morphological differences across life stages, such as different sizes and coloration, likely result in differential survival, as predators may find individuals of one life stage more conspicuous and/or more energetically profitable than another. Furthermore, prey conspicuousness may vary temporally because both the sensory environment and predator sensory abilities differ between day and night. Here, we investigated how the interaction between life stage (caterpillar vs. moth) and time of day (day vs. night) influences predation of the white-lined sphinx (Lepidoptera: Hyles lineata). We predicted that caterpillars would be less susceptible to predation than adult moths, as adults are larger and have a more conspicuous shape. After quantifying predation for 72 h during dawn and dusk using 199 plasticine replicas each of adults and caterpillars, predation on adult replicas was twice that of predation on caterpillar replicas. Furthermore, replicas were six times more likely to be predated on during the day than during the night. Lastly, attacks were made mainly by birds, which carried out 86% of the attacks on adult models and 85% of those on caterpillar models. These data support the hypothesis that predation rates differ across life stages in holometabolous insects. This research lays a foundation for further investigation into how specific differences in morphology across life stages affect predation and survival in holometabolous insects. Full article

In the spring and summer of 1906, while visiting the rural village of Gósol in the Spanish Pyrenees, Picasso executed his first woodcut, made two sculptures out of boxwood, and began to focus on the topoi of wood and the forest as avatars of primal matter and of that which lies beyond civilization. In a subsequent series of paintings, he used wooden supports for images that depict male and female heads that look as if they had been chiseled out of wood. Others represent nude figures in forest settings, with explicitly sexual gestures and poses connoting a range of attitudes. These little studied works provide an optic into Picasso’s early exploration of the emergence of sexual identity as an inner psychic state, but one whose signs can be read through the body. Later, responding to the proliferation of cheap, industrially produced materials, including trompe l’oeil woodgrain wallpaper, Picasso began to treat woodgrain as a mere surrogate, one that marks its distance from actual wood through a variety of painterly and mechanical effects. No longer associated with “primitive” authenticity and the primordial forces of the forest, woodgrain now appears as a false sign open to conceptual play and metamorphosis. Full article

The works of Aristotle left an indelible impression on Arabic philosophy after the translation movement. While many philosophers accepted the works of the revered First Teacher (Al-Mu‘allim al-awwal), as Aristotle was designated, others sought to reformulate his ideas in accordance with their own priorities. One such thinker is the hugely influential mystical theorist, Muḥyī al-Dīn ibn ‘Arabī (d. 638/1240), who agrees with Aristotle that all existents are hylomorphic compounds made from the combination of form with matter that comes from prime matter, or hyle (hayūlā), which he frequently uses interchangeably with ‘substance’ (jawhar). He claims that prime matter or substance accepts all forms (ṣuwar), but he theologizes these terms as he believes all things are loci of divine manifestation. Ibn ‘Arabī thus situates Aristotelian hylomorphism within the framework of his own metaphysics. He proceeds to equate the universal hayūlā with the primordial ‘cloud’ (‘amā’), mentioned in prophetic traditions, from which all things in the different levels of existence derive because of the existentiating divine breath. When it comes to the sensible world in particular, Ibn ‘Arabī employs the Qur’anic term of ‘dust’ (habā’) to denote prime matter that serves as the basis of sensible hylomorphic compounds. This study conducts close textual content analysis to demonstrate the way in which Ibn ‘Arabī theologizes Aristotelian hylomorphism to expound his conception of the different realms of existence. Full article

Photoaging is an important extrinsic aging factor leading to altered skin morphology and reduced function. Prior work has revealed a connection between photoaging and loss of subcutaneous fat. Currently, primary models for studying this are in vivo (human samples or animal models) or in vitro models, including human skin equivalents (HSEs). In vivo models are limited by accessibility and cost, while HSEs typically do not include a subcutaneous adipose component. To address this, we developed an “adipose-vascular” HSE (AVHSE) culture method, which includes both hypodermal adipose and vascular cells. Furthermore, we tested AVHSE as a potential model for hypodermal adipose aging via exposure to 0.45 ± 0.15 mW/cm² 385 nm light (UVA). One week of 2 h daily UVA exposure had limited impact on epidermal and vascular components of the AVHSE, but significantly reduced adiposity by approximately 50%. Overall, we have developed a novel method for generating HSE that include vascular and adipose components and demonstrated potential as an aging model using photoaging as an example. Full article

The western Palaearctic species of the hawkmoth genus Hyles (Lepidoptera: Sphingidae) have long been the subject of molecular phylogenetic research. However, much less attention has been paid to the taxa inhabiting the central and eastern Palaearctic, particularly Central Asia, where almost 50% of the species diversity of the genus occurs. Yet, many taxonomic conundrums hinder a proper assessment of the true diversity in these moths. One still unresolved group of species includes Hyles hippophaes and Hyles chamyla. Despite a largely overlapping morphology and ecology, a plethora of infraspecific taxa display some unique divergent characters over a wide geographical area. In this study, we undertook a taxonomic assessment of each population and resolved this species complex using an integrative approach. A combination of new computational techniques (DAISY-II) in comparative morphology and recent advances in DNA extraction methods and sequencing of museum specimens (WISC) alongside more traditional genetic approaches allowed testing of the three main phenotypes—bienerti, chamyla and apocyni—in terms of their morphological, mitochondrial and biogeographical integrity, and to elucidate their evolutionary relationships. Our results support the existence of two closely related species, Hyles chamyla and H. hippophaes, but the former species H. apocyni (here discussed as the ecological form apocyni of H. chamyla) is best regarded as a hybrid between H. chamyla and H. h. bienerti. The results indicate that the evolutionary relationship between H. chamyla and H. hippophaes is one of admixture in the context of ongoing ecological differentiation, which has led to shared morphological characters and a blurring of the species boundaries. These results clarify the evolutionary relationships of this species complex and open future research lines, including the analysis of nuclear markers and denser sampling, particularly of H. hippophaes and H. vespertilio in western Europe. Full article

The spurge hawkmoth Hyles euphorbiae L. (Sphingidae) comprises a remarkable species complex with still not fully resolved taxonomy. Its extensive natural distribution range covers diverse climatic zones. This predestinates particular populations to cope with different local seasonally unfavorable environmental conditions. The ability of the pupae to overcome outer frosty conditions is well known. However, the differences between two main ecotypes (‘euphorbiae’ and ‘tithymali’) in terms of the inherent degree of frost tolerance, its corresponding survival strategy, and underlying mechanism have not been studied in detail so far. The main aim of our study was to test the phenotypic exhibition of pupae (as the relevant life cycle stadia to outlast unfavorable conditions) in response to combined effects of exogenous stimuli, such as daylight length and cooling regime. Namely, we tested the turnout of subitan (with fast development, unadapted to unfavorable conditions) or diapause (paused development, adapted to unfavorable external influences and increased resistance) pupae under different conditions, as well as their mortality, and we measured the super cooling point (SCP) of whole pupae (in vivo) and pupal hemolymph (in vitro) as phenotypic indicators of cold acclimation. Our results show higher cold sensitivity in ‘tithymali’ populations, exhibiting rather opportunistic and short-termed cold hardiness, while ‘euphorbiae’ produces a phenotype of seasonal cold-hardy diapause pupae under a combined effect of short daylight length and continuous cold treatment. Further differences include the variability in duration and mortality of diapause pupae. This suggests different pre-adaptations to seasonal environmental conditions in each ecotype and may indicate a state of incipient speciation within the H. euphorbiae complex. Full article