Convergent setal morphology in sand-covering spiders suggests a design principle for particle capture

Sicarius and Homalonychus are unrelated, desert-dwelling spiders that independently evolved the ability to cover themselves in fine sand particles, making them cryptic against their background. Observations that particles associate with these spiders' setae inspired us to investigate the role of setal microstructure in particle capture and retention. Here we report that Sicarius and Homalonychus convergently evolved numerous high aspect ratio, flexible fibres that we call ‘hairlettes’ protruding from the setal shaft. We demonstrate that particles attach more densely to regions of Homalonychus with hairlettes than to other regions of the same animal where hairlettes are absent, and document close contact of hairlettes to sand particles that persists after applying force. Mathematical models further suggest that adhesion of hairlettes to sand particles is a sufficient mechanism of particle capture and retention. Together, these data provide the first evidence that hairlettes facilitate sand retention through intermolecular adhesion to particles. Their independent evolutionary origins in Sicarius and Homalonychus suggest that the unique setal structure is adaptive and represents a general biomechanical mechanism for sand capture to cuticle. This discovery has implications for the design of inventions inspired by this system, from camouflage to the management of granular systems

Understanding aspirations and expectations of international students in Australian higher education

The aspirations and expectations of the growing international student cohort in Australia are implicitly incorporated into recruitment and internationalization strategies but have received little academic analysis. To address this gap in the literature, this paper develops a conceptual model built upon earlier research by Tim Mazzarol and Geoffrey Soutar, which focuses on the push and pull factors relating to home country and country of destination, respectively, in relation to students’ decisions to seek international study. Focusing predominantly on Chinese and Indian students, we conceptualize, extend and place the push and pull factors within a social psychological framework in relation to students’ aspirations and expectations of international education, indicating factors that can be influenced by higher education (HE) institutions and their programmes, and those which cannot. We then interrogate the model and its applicability in Australian HE through the case study of an Indian international Study Tour conducted in our Australian HE institution in 2009. In the present context of decreased international student enrolments in Australia in 2010, where we seek to better understand our international students, the proposed model provides a basis for identifying international students’ expectations and aspirations and developing prospective international relations