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

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.

A new species of the genus Embia Latreille, 1825 (Insecta, Embioptera) from the Madonie Regional Natural Park (Sicily, Italy)

“…Embioptera are insects with gregarious habits, often showing maternal behavior (Edgerly 1987). Neotenic females and individuals of both sexes and all stages are capable of weaving tubular tunnels with the silk secreted by their anterior tarsi (Edgerly et al 2020). The order is widespread in tropical areas and hot climate regions, with approximately 250 known species, but Ross (2000) estimated that at least 2000 species likely exist worldwide.…”

Dispersal Risks and Decisions Shape How Non-kin Groups Form in a Tropical Silk-Sharing Webspinner (Insecta: Embioptera)

“…Between 1982 and the present day, I along with numerous coauthors have conducted experiments and censused field colonies of A. urichi to determine the extent of their silk coverings and number of occupants (Edgerly, 1987a(Edgerly, ,b, 1994, types of trees that support them (Edgerly, 1987c), environmental correlates that predict their presence and abundance (Shenoy et al, 2020), cost of spinning silk (Edgerly et al, 2006), how they spin (Edgerly et al, 2002(Edgerly et al, , 2020Büsse et al, 2015Büsse et al, , 2019McMillan et al, 2016), as well as attributes of their silk and how it acts as waterproofing (Osborn Popp et al, 2016;Stokes et al, 2018;Shenoy et al, 2020;Harper et al, 2021). Related to the occurrence of non-kin groups, the first question posed for my Ph.D. work, under the guidance of the late George Eickwort of Cornell University, was basic: "what type of social behavior do webspinners exhibit?"…”