Sister species diverge in modality-specific courtship signal form and function

Understanding the relative importance of different sources of selection (e.g., the environment, social/sexual selection) on the divergence or convergence of reproductive communication can shed light on the origin, maintenance, or even disappearance of species boundaries. Using a multistep approach, we tested the hypothesis that two presumed sister species of wolf spider with overlapping ranges and microhabitat use, yet differing degrees of sexual dimorphism, have diverged in their reliance on modality- specific courtship signaling. We predicted that male Schizocosa crassipalpata (no ornamentation) rely predominantly on diet-dependent vibratory signaling for mating success. In contrast, we predicted that male S. bilineata (black foreleg brushes) rely on diet-dependent visual signaling. We first tested and corroborated the sister-species relationship between S. crassipalpata and S. bilineata using phylogenomic scale data. Next, we tested for species-specific, diet-dependent vibratory and visual signaling by manipulating subadult diet and subsequently quantifying adult morphology and mature male courtship signals. As predicted, vibratory signal form was diet-dependent in S. crassipalpata, while visual ornamentation (brush area) was diet-dependent in S. bilineata. We then compared the species-specific reliance on vibratory and visual signaling by recording mating across artificially manipulated signaling environments (presence/absence of each modality in a 2 × 2 full factorial design). In accordance with our diet dependence results for S. crassipalpata, the presence of vibratory signaling was important for mating success. In contrast, the light and vibratory environment interacted to influence mating success in S. bilineata, with vibratory signaling being important only in the absence of light. We found no differences in overall activity patterns. Given that these species overlap in much of their range and microhabitat use, we suggest that competition for signaling space may have led to the divergence and differential use of sensory modalities between these sister species

Incidence of parasitoids and predators on eggs of seven species of Therididae (Araneae)

Although many characteristics of the egg sacs of spiders likely evolved to reduce the effect of parasites and predators that attack their eggs, many parasite and predator insects have become specialized on spider eggs. Eggs of six of the seven species of Theridiidae included in this study were attacked by wasp parasites (Baeus achaearaneus, Idris sp., and Comastichus zopheros), and two by the specialized spider egg predator (Neuroptera: Zeugomantispa minuta). The incidence of parasites in the egg sacs varied across species. Parasites attacked more than 60% of the egg sacs of Tidarren sisyphoides and Parasteatoda tepidariorum, but none of the sacs of Latrodectus geometricus. The incidence of parasites in the egg sacs was higher during the dry season for T. sisyphoides, and during the rainy season for P. tepidariorum. The proportion of the eggs parasitized per egg sac varied from 0.09 (± 0.19) in Nesticodes rufipes to 0.50 (± 0.46) in T. sisyphoides. Differences in the biology of parasites, as well as in the structure of spider webs and hábitat preference of spiders, may influence the incidence of parasitism and proportion of eggs parasitized in each egg sac.Vicerrectoría de InvestigaciónUCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Biologí

Beauty and sustainability - Survey on Liberty heritage in Varese and Ticino area

Since the beginning of XX century the Liberty heritage in Varese and the Ticino area has undergone a slow abandon, due to both the development of new architectural trends and the speculative demolition, and is at great risk of loss. The vital element of the Liberty period is the importance of beauty. Protecting this architecture and landscape system allows to taking care of our identity, finding a thread from the relationship between man and nature, to the most recent findings on sustainability and an "ecological" design. The paper presents the results of a survey carried out on the Liberty architectures of the Varese and Ticino territory, a limited geographical area where nature and architecture are complementary elements that blend into a whole to be preserved in its unity

Architectural and landscape Liberty heritage in Varese area: design for knowledge, conservation and enhancement

A research project aimed at enhancing and networking the architectural and landscape Liberty heritage in the province of Varese has been carried out. The aim of the project is to encourage the preservation of a valuable built complex and its cultural-touristic fruition through the creation of an integrated system, also including the intervention on some specific significant cases. In particular, a design methodology is proposed, which is developed through both system actions and local interventions

L’INTERVENTO DI CONSERVAZIONE E CONSOLIDAMENTO DEI SOLAI LIGNEI DELL’EX CHIESA DELLA TRASFIGURAZIONE A CANTÙ (CO)

The wooden-beam floors of the sixteenth century ex Church of St Ambrogio in Cantù (CO), located in small buildings inside the main one, have been the object of a strongly opposed conservation, because they were not considered suitable for the future museum use. After having identified the main points and the pathologies of degradation and after having worked on the materials in place, loading tests were performed that determined the static compatibility with the planned museum use. As a warranty for the static behavior of the floors two innovative consolidation systems have been designed and implemented, consisting in wing reinforcements made in plexiglass

Progettare per la conservazione del costruito e del paesaggio nella periferia milanese

Le periferie di Milano: un tema approfondito in due interventi che rpesentano le ricerche condott

Proposta di metodo per la raccolta e la gestione dei dati sui materiali da costruzione negli strumenti di pianificazione per i centri storici. il caso di Palazzolo Acreide

Lo studio, pluridisciplinare, fa parte di un progetto Murst indirizzato al progetto di un sistema informativo per la gestione dei piani di recupero di centri antichi. Nello specifico, partendo da uno dei casi campione assunti, il centro storico di Palazzolo Acreide, partendo da rilievi, studi e più specifiche caratterizzazioni, si sono voluti mettere in evidenza alcuni caratteri e denominatori comuni utile alla conoscenza per la gestione e la pianificazione dei lavori nei centri storici