Identification of Factors Affecting Predation Risk for Juvenile Turtles Using 3D Printed Models

Abstract

Simple Summary: Turtles are one of the most threatened vertebrate groups. High rates of juvenile predation may contribute to population declines for many species, but predator identities and factors contributing to predation risk for juveniles are largely unknown due to their highly secretive nature. Alternatives to studying live juveniles are needed. By monitoring three-dimensional printed models resembling juvenile box turtles (Terrapene carolina) with motion-triggered cameras in the Midwestern USA, we found raccoons (Procyon lotor) were the dominant predator that interacted with models, followed by rodents (Sciuridae). Mesopredator interactions with models were less likely in habitats with higher vegetative ground cover. However, availability of sensory cues (visual or olfactory) provided by models did not influence mesopredator interactions, suggesting they used multiple senses to detect models. Rodents interacted with models that were closer to woody structure, likely because they commonly utilize such small-scale habitat features. Rodents interacted with exposed models more than concealed models, reflecting their predominantly visual foraging behavior. Overall, our results suggest juvenile turtle habitat selection could affect predator-specific predation risk but behavioral differences between particular predators are also important determinants of risk. These findings have implications for management efforts aimed at reducing encounters between juvenile turtles and their major predators.Abstract: Although it is widely accepted that juvenile turtles experience high levels of predation, such events are rarely observed, providing limited evidence regarding predator identities and how juvenile habitat selection and availability of sensory cues to predators affects predation risk. We placed three-dimensional printed models resembling juvenile box turtles (Terrapene carolina) across habitats commonly utilized by the species at three sites within their geographical range and monitored models with motion-triggered cameras. To explore how the presence or absence of visual and olfactory cues affected predator interactions with models, we employed a factorial design where models were either exposed or concealed and either did or did not have juvenile box turtle scent applied on them. Predators interacted with 18% of models during field trials. Nearly all interactions were by mesopredators (57%) and rodents (37%). Mesopredators were more likely to attack models than rodents; most (76%) attacks occurred by raccoons (Procyon lotor). Interactions by mesopredators were more likely to occur in wetlands than edges, and greater in edges than grasslands. Mesopredators were less likely to interact with models as surrounding vegetation height increased. Rodents were more likely to interact with models that were closer to woody structure and interacted with exposed models more than concealed ones, but model exposure had no effect on interactions by mesopredators. Scent treatment appeared to have no influence on interactions by e...

Using eDNA and SCUBA surveys for detection and monitoring of a threatened marine cryptic fish

“…The use of 3D‐printed animal models in the ecological literature appears to be limited ( see Behm et al, 2018), with the few aquatic examples being applied to behavioural research in turtles (Bulté et al, 2018; Tetzlaff et al, 2020) and zebrafish (Cianca et al, 2013; Bartolini et al, 2016; Ruberto, Polverino & Porfiri, 2017). The demonstrated novel application of 3D printed models of red handfish could, however, be used for both training of divers to ensure they have an adequate capability of detecting the species of interest and assessing the robustness of population monitoring programmes for other marine species.…”

Peer Review #1 of "Creation of a prototype biomimetic fish to better understand impact trauma caused by hydropower turbine blade strikes (v0.1)"

“…To our knowledge, this is first use of high-fidelity laser and computed tomography scans to design and produce a mold of an entire organism from which to cast a biomimetic model. To date, use of additive manufacturing for creation of high biofidelic models has mostly centered around 3D printing the desired animal model directly from scanned data (Rhyne et al, 2017;Walker et al, 2019;Tetzla et al, 2020). The cost of printing multiple fish models directly is far greater than multiple models cast from just one mold; consequently, the additive manufacturing industry has focused on printing molds which are less labor intensive, cheaper to produce, and of comparable durability to traditional sand-cast molds (Hassen et al, 2016(Hassen et al, , 2020Hawaldar & Zhang, 2018).…”

Creation of a prototype biomimetic fish to better understand impact trauma caused by hydropower turbine blade strikes

“…To our knowledge, this is first use of high-fidelity laser and computed tomography scans to design and produce a mold of an entire organism from which to cast a biomimetic model. To date, use of additive manufacturing for creation of biofidelic models has mostly centered around 3D printing the desired animal model directly from scanned data (Rhyne et al, 2017;Walker et al, 2019;Tetzla et al, 2020). The cost of printing multiple fish models directly is far greater than multiple models cast from just one mold; consequently, the additive manufacturing industry has focused on printing molds which are less labor intensive, cheaper to produce, and of comparable durability to traditional sand-cast molds (Hassen et al, 2016;Hassen et al, 2020;Hawaldar & Zhang, 2018).…”