Silk Spinning Behavior Varies from Species-Specific to Individualistic in Embioptera: Do Environmental Correlates Account for this Diversity?

Abstract

Abstract String sequence analysis revealed that silk spinning behavior of adult female Embioptera varies from species-specific to individualistic. This analysis included 26 species from ten taxonomic families with a total of 115 individuals. Spin-steps, 28 possible positions of the front feet during spinning, were scored from hour-long DVD recordings produced in the laboratory. Entire transcripts of hundreds to thousands of spin-steps per individual were compared by computing Levenshtein edit distances between all possible pairs of subsequences, with lengths ranging from 5 to 25—intraspecific similarity scores were then computed. Silk gallery characteristics and architecture, body size, climatic variables, and phylogenetic relationships were tested as possible drivers of intraspecific similarity in spinning behavior. Significant differences in intraspecific similarity aligned most strongly with climatic variables such that those species living in regions with high temperature seasonality, low annual precipitation, and high annual temperatures displayed more species-stereotypical spinning sequences than those from other regions, such as tropical forests. Phylogenetic signal was significant but weakly so, suggesting that environmental drivers play a stronger role in shaping the evolution of silk spinning. Body size also appears to play a role in that those of similar size are more like each other, even if not related.