{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/141264"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/141264","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Bridging the gap: Biomechanics of vertical gap-crossing in snakes and cicadas","abstract":"The ability to locomote through arboreal environments is essential for the animals which make those environments their home. An animal's ability to move among branches can depend on both environmental features, such as branch diameter or discontinuities in branch support, as well as the animals' features such as claws, sticky toe pads, or the presence or absence of limbs. Periodical cicadas (Magicada septendecim) are an example of animals which must overcome both discontinuities and changes in branch diameter. After spending 13-17 years of their lives underground, periodical cicadas burrow their way to the surface, climb trees to molt into adults, and then climb to the edges of branches, mate, and oviposit their eggs. Both nymphs and adults must overcome the same surfaces, yet how the environmental factors of these surfaces interact with the age of the subject to influence climbing performance remains unknown. Additionally, the influence of arboreal surface structure on animal locomotion is not limited to insects, or even limbed animals. Limbless animals, such as arboreal snakes, must contend with these same issues. While perch diameter's effects on horizontal locomotor speed and balance have been well explored, its influence on limbless animal's abilities to cross vertical gaps between branches remains relatively understudied. Despite perch diameter's known influence on an animal's ability to prevent toppling, no study has recorded how this influence translates to its influence on vertical gap crossing ability for limbless animals. This dissertation seeks to answer how arboreal surface structures shape locomotor performance across diverse taxa. Chapter 2 presents a study asking how increasing perch diameter and varying surface friction influences adult periodical cicadas ability to navigate cylindrical surfaces, showing that, at smaller diameters, cicadas are able to cross distances which proved difficult to impossible at larger diameters. Chapter 3 expands on this, exploring gap size's relationships with successful climbs but also compares the performance of adult cicadas to those of nymphs. Additionally, a series of trials are introduced within this chapter to explore surface roughness's influence on climbing capability for both age groups, revealing relationships between surface roughness and success for both age groups, as well as age groups and how well they succeed, defined by how quickly they completed the cross. Finally, Chapter 4 explores diameter's influence on vertical gap crossing in arboreal snakes, exploring factors such as the heights they reach, the speed at which they reach these heights, how well they maintain balance in doing so, and the torque the portion of the bodies within the gap experience. My results have found that perch diameter does influence several performance variables in arboreal locomotion for cicadas and snakes. These variables include, but are not limited to, maximum size of gaps possible to cross for the former, and heights reached for the latter. Additionally, I found that age groups influence the performance of periodical cicadas on climbing structures, while the surface conditions of these structures influence their ability to successfully climb.","abstract_html":"The ability to locomote through arboreal environments is essential for the animals which make those environments their home. An animal's ability to move among branches can depend on both environmental features, such as branch diameter or discontinuities in branch support, as well as the animals' features such as claws, sticky toe pads, or the presence or absence of limbs. Periodical cicadas (Magicada septendecim) are an example of animals which must overcome both discontinuities and changes in branch diameter. After spending 13-17 years of their lives underground, periodical cicadas burrow their way to the surface, climb trees to molt into adults, and then climb to the edges of branches, mate, and oviposit their eggs. Both nymphs and adults must overcome the same surfaces, yet how the environmental factors of these surfaces interact with the age of the subject to influence climbing performance remains unknown. Additionally, the influence of arboreal surface structure on animal locomotion is not limited to insects, or even limbed animals. Limbless animals, such as arboreal snakes, must contend with these same issues. While perch diameter's effects on horizontal locomotor speed and balance have been well explored, its influence on limbless animal's abilities to cross vertical gaps between branches remains relatively understudied. Despite perch diameter's known influence on an animal's ability to prevent toppling, no study has recorded how this influence translates to its influence on vertical gap crossing ability for limbless animals. This dissertation seeks to answer how arboreal surface structures shape locomotor performance across diverse taxa. Chapter 2 presents a study asking how increasing perch diameter and varying surface friction influences adult periodical cicadas ability to navigate cylindrical surfaces, showing that, at smaller diameters, cicadas are able to cross distances which proved difficult to impossible at larger diameters. Chapter 3 expands on this, exploring gap size's relationships with successful climbs but also compares the performance of adult cicadas to those of nymphs. Additionally, a series of trials are introduced within this chapter to explore surface roughness's influence on climbing capability for both age groups, revealing relationships between surface roughness and success for both age groups, as well as age groups and how well they succeed, defined by how quickly they completed the cross. Finally, Chapter 4 explores diameter's influence on vertical gap crossing in arboreal snakes, exploring factors such as the heights they reach, the speed at which they reach these heights, how well they maintain balance in doing so, and the torque the portion of the bodies within the gap experience. My results have found that perch diameter does influence several performance variables in arboreal locomotion for cicadas and snakes. These variables include, but are not limited to, maximum size of gaps possible to cross for the former, and heights reached for the latter. Additionally, I found that age groups influence the performance of periodical cicadas on climbing structures, while the surface conditions of these structures influence their ability to successfully climb.","abstract_has_math":false,"creators":["Pulliam, Joshua Nicholas"],"institution":"Virginia Tech","degree_name":"Doctor of Philosophy","degree_level":"doctoral","degree_discipline":"Engineering Mechanics","degree_department":"Engineering Science and Mechanics","school":null,"contributors":[],"advisors":[],"committee_chairs":["Socha, John"],"committee_members":["Ross, Shane David","Rieser, Jennifer","Abaid, Nicole Teresa","Moore, Ignacio T."],"year":2026,"date_issued":"2026-02-13","date_published":"2026-02-13","updated_at":"2026-07-22T22:20:11Z","subjects":[": climbing","balance","gap crossing","gait"],"languages":["en"],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["vt_gsexam:45298"],"render_values":[{"text":"vt_gsexam:45298","href":null,"code":true}]}]},"links":{"outbound_url":"https://hdl.handle.net/10919/141264","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["Socha, John"]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Ross, Shane David","Rieser, Jennifer","Abaid, Nicole Teresa","Moore, Ignacio T."]},{"key":"dc:contributor.department","label":"Department","values":["Engineering Science and Mechanics"]},{"key":"dc:creator","label":"Author","values":["Pulliam, Joshua Nicholas"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2026-02-14T09:00:56Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2026-02-14T09:00:56Z"]},{"key":"dc:date.issued","label":"Date","values":["2026-02-13"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Tech"]},{"key":"dc:type","label":"Dc Type","values":["Dissertation"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Engineering Mechanics"]},{"key":"thesis:degree_level","label":"Degree Level","values":["doctoral"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Doctor of Philosophy"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Virginia Polytechnic Institute and State University"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":[": climbing","balance","gap crossing","gait"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["In Copyright"]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://rightsstatements.org/vocab/InC/1.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["vt_gsexam:45298"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/10919/141264"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["The ability to locomote through arboreal environments is essential for the animals which make those environments their home. An animal's ability to move among branches can depend on both environmental features, such as branch diameter or discontinuities in branch support, as well as the animals' features such as claws, sticky toe pads, or the presence or absence of limbs. Periodical cicadas (Magicada septendecim) are an example of animals which must overcome both discontinuities and changes in branch diameter. After spending 13-17 years of their lives underground, periodical cicadas burrow their way to the surface, climb trees to molt into adults, and then climb to the edges of branches, mate, and oviposit their eggs. Both nymphs and adults must overcome the same surfaces, yet how the environmental factors of these surfaces interact with the age of the subject to influence climbing performance remains unknown. Additionally, the influence of arboreal surface structure on animal locomotion is not limited to insects, or even limbed animals. Limbless animals, such as arboreal snakes, must contend with these same issues. While perch diameter's effects on horizontal locomotor speed and balance have been well explored, its influence on limbless animal's abilities to cross vertical gaps between branches remains relatively understudied. Despite perch diameter's known influence on an animal's ability to prevent toppling, no study has recorded how this influence translates to its influence on vertical gap crossing ability for limbless animals. This dissertation seeks to answer how arboreal surface structures shape locomotor performance across diverse taxa. Chapter 2 presents a study asking how increasing perch diameter and varying surface friction influences adult periodical cicadas ability to navigate cylindrical surfaces, showing that, at smaller diameters, cicadas are able to cross distances which proved difficult to impossible at larger diameters. Chapter 3 expands on this, exploring gap size's relationships with successful climbs but also compares the performance of adult cicadas to those of nymphs. Additionally, a series of trials are introduced within this chapter to explore surface roughness's influence on climbing capability for both age groups, revealing relationships between surface roughness and success for both age groups, as well as age groups and how well they succeed, defined by how quickly they completed the cross. Finally, Chapter 4 explores diameter's influence on vertical gap crossing in arboreal snakes, exploring factors such as the heights they reach, the speed at which they reach these heights, how well they maintain balance in doing so, and the torque the portion of the bodies within the gap experience. My results have found that perch diameter does influence several performance variables in arboreal locomotion for cicadas and snakes. These variables include, but are not limited to, maximum size of gaps possible to cross for the former, and heights reached for the latter. Additionally, I found that age groups influence the performance of periodical cicadas on climbing structures, while the surface conditions of these structures influence their ability to successfully climb."]},{"key":"dc:description.abstractgeneral","label":"General Abstract","values":["Animals that live in trees face many mechanical challenges related locomotion. These can include gripping areas with low friction, balancing on branches of different sizes, and leaping or reaching across gaps from one perch to another. In this dissertation, I explore how specific features of trees such as surface roughness, perch diameter, and gap size shape the movement abilities of two different groups of animals: periodical cicadas and tree snakes. Cicadas climb trees at two different life stages, nymph and adult, which have different body forms. The nymphs end more than a decade of life spent underground by digging upward through the earth and climbing onto trees to molt into adults. The adults, in turn, have to climb trees to mate and lay eggs. Despite different body forms that need to accomplish different tasks, both adults and nymphs face the same climbing challenges. My work tested how the diameter, gap size between high friction areas, surface roughness, and age influence the climbing ability of the cicada. Tree snakes spend most of their lives navigating through trees. While some work has been done on vertical gap crossing ability in different species of snakes (brown tree snakes), no one has created an in depth look at how surface structure influences a snake's ability to vertically cross gaps across multiple species. This study examined how branch diameter affects the snake's ability to cross open-air, vertical gaps between branches. Overall, these projects help us to understand how the variations in substrate influence animals' abilities to successfully navigate their environments."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Doctor of Philosophy"]},{"key":"dc:format.medium","label":"Dc Format Medium","values":["ETD"]},{"key":"dc:title","label":"Title","values":["Bridging the gap: Biomechanics of vertical gap-crossing in snakes and cicadas"]}]}],"canonical_facts":{"dc:contributor.committeechair":["Socha, John"],"dc:contributor.committeemember":["Ross, Shane David","Rieser, Jennifer","Abaid, Nicole Teresa","Moore, Ignacio T."],"dc:contributor.department":["Engineering Science and Mechanics"],"dc:creator":["Pulliam, Joshua Nicholas"],"dc:date.accessioned":["2026-02-14T09:00:56Z"],"dc:date.available":["2026-02-14T09:00:56Z"],"dc:date.issued":["2026-02-13"],"dc:description.abstract":["The ability to locomote through arboreal environments is essential for the animals which make those environments their home. An animal's ability to move among branches can depend on both environmental features, such as branch diameter or discontinuities in branch support, as well as the animals' features such as claws, sticky toe pads, or the presence or absence of limbs. Periodical cicadas (Magicada septendecim) are an example of animals which must overcome both discontinuities and changes in branch diameter. After spending 13-17 years of their lives underground, periodical cicadas burrow their way to the surface, climb trees to molt into adults, and then climb to the edges of branches, mate, and oviposit their eggs. Both nymphs and adults must overcome the same surfaces, yet how the environmental factors of these surfaces interact with the age of the subject to influence climbing performance remains unknown. Additionally, the influence of arboreal surface structure on animal locomotion is not limited to insects, or even limbed animals. Limbless animals, such as arboreal snakes, must contend with these same issues. While perch diameter's effects on horizontal locomotor speed and balance have been well explored, its influence on limbless animal's abilities to cross vertical gaps between branches remains relatively understudied. Despite perch diameter's known influence on an animal's ability to prevent toppling, no study has recorded how this influence translates to its influence on vertical gap crossing ability for limbless animals. This dissertation seeks to answer how arboreal surface structures shape locomotor performance across diverse taxa. Chapter 2 presents a study asking how increasing perch diameter and varying surface friction influences adult periodical cicadas ability to navigate cylindrical surfaces, showing that, at smaller diameters, cicadas are able to cross distances which proved difficult to impossible at larger diameters. Chapter 3 expands on this, exploring gap size's relationships with successful climbs but also compares the performance of adult cicadas to those of nymphs. Additionally, a series of trials are introduced within this chapter to explore surface roughness's influence on climbing capability for both age groups, revealing relationships between surface roughness and success for both age groups, as well as age groups and how well they succeed, defined by how quickly they completed the cross. Finally, Chapter 4 explores diameter's influence on vertical gap crossing in arboreal snakes, exploring factors such as the heights they reach, the speed at which they reach these heights, how well they maintain balance in doing so, and the torque the portion of the bodies within the gap experience. My results have found that perch diameter does influence several performance variables in arboreal locomotion for cicadas and snakes. These variables include, but are not limited to, maximum size of gaps possible to cross for the former, and heights reached for the latter. Additionally, I found that age groups influence the performance of periodical cicadas on climbing structures, while the surface conditions of these structures influence their ability to successfully climb."],"dc:description.abstractgeneral":["Animals that live in trees face many mechanical challenges related locomotion. These can include gripping areas with low friction, balancing on branches of different sizes, and leaping or reaching across gaps from one perch to another. In this dissertation, I explore how specific features of trees such as surface roughness, perch diameter, and gap size shape the movement abilities of two different groups of animals: periodical cicadas and tree snakes. Cicadas climb trees at two different life stages, nymph and adult, which have different body forms. The nymphs end more than a decade of life spent underground by digging upward through the earth and climbing onto trees to molt into adults. The adults, in turn, have to climb trees to mate and lay eggs. Despite different body forms that need to accomplish different tasks, both adults and nymphs face the same climbing challenges. My work tested how the diameter, gap size between high friction areas, surface roughness, and age influence the climbing ability of the cicada. Tree snakes spend most of their lives navigating through trees. While some work has been done on vertical gap crossing ability in different species of snakes (brown tree snakes), no one has created an in depth look at how surface structure influences a snake's ability to vertically cross gaps across multiple species. This study examined how branch diameter affects the snake's ability to cross open-air, vertical gaps between branches. Overall, these projects help us to understand how the variations in substrate influence animals' abilities to successfully navigate their environments."],"dc:description.degree":["Doctor of Philosophy"],"dc:format.medium":["ETD"],"dc:identifier.other":["vt_gsexam:45298"],"dc:identifier.uri":["https://hdl.handle.net/10919/141264"],"dc:language.iso":["en"],"dc:publisher":["Virginia Tech"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:subject":[": climbing","balance","gap crossing","gait"],"dc:title":["Bridging the gap: Biomechanics of vertical gap-crossing in snakes and cicadas"],"dc:type":["Dissertation"],"thesis:degree_discipline":["Engineering Mechanics"],"thesis:degree_level":["doctoral"],"thesis:degree_name":["Doctor of Philosophy"],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:20:11Z"}