On latches in biological systems: a comparative morphological and functional study of the retinaculum and the dens lock in Collembola

Abstract Background Springtails have the ability to jump using morphological structures consisting of a catapult, the furca, and a latching system constructed with interaction of the retinaculum and the dens lock. The retinaculum engages in the furca at the dens lock in order to form a spring mechan...

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Main Authors: Birk Rillich, Fábio G. L. Oliveira
Format: Article
Language:English
Published: BMC 2023-05-01
Series:Frontiers in Zoology
Subjects:
Online Access:https://doi.org/10.1186/s12983-023-00491-2
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author Birk Rillich
Fábio G. L. Oliveira
author_facet Birk Rillich
Fábio G. L. Oliveira
author_sort Birk Rillich
collection DOAJ
description Abstract Background Springtails have the ability to jump using morphological structures consisting of a catapult, the furca, and a latching system constructed with interaction of the retinaculum and the dens lock. The retinaculum engages in the furca at the dens lock in order to form a spring mechanism. They exhibit diversified morphological traits that serve as adaptations to a variety of terrestrial strata and aquatic surface environments. This comparative morphofunctional study centered on the retinaculum and the furcular region of the dens lock aims to describe the morphological variation between taxa and provide insights into the functional dynamics of the latching mechanism at work in the jumping apparatus. Using SEM, µCT and cLSM, we compared representatives of Collembola taxa, Poduromorpha (Neanura muscorum and Podura aquatica), Symphypleona (Dicyrtomina ornata) and Neelipleona (Megalothorax minimus), and examined extracts of the environment in which they were collected. Results A retinaculum is absent in N. muscorum, although vestigial muscles were found. Abdominal musculature varies significantly, being more abundant in springtails with clear segmentation (N. muscorum and P. aquatica), and reduced in springtails with fused segmentation (D. ornata and M. minimus). The M.a-ret varies as regards architecture and point of connection with the ramus, which is lateral in P. aquatica and median in the other species studied. The number of teeth in the retinaculum ramus also varies between three in M. minimus and four in the other species. The dens lock of all species studied has two locks and two furrows. Conclusions The retinaculum and dens lock interact in a key-lock relationship. The latching and unlatching mechanism from the retinaculum and dens lock appear to be similar in all the taxa examined, occurring by muscle force. This leads us to question the hypothesis that hemolymph pressure may be a force generator in jumping. We offer a reconstruction of the ground pattern of the retinaculum and dens lock and, in addition, an explanation of their functioning and the interaction between them. Finally, we frame the interaction between the retinaculum and the dens lock as a latch in a biological system, a mechanism which functions by force of physical contact.
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spelling doaj.art-2eb320cc0a2f4db8a253d8deecd0974d2023-05-14T11:23:18ZengBMCFrontiers in Zoology1742-99942023-05-0120112210.1186/s12983-023-00491-2On latches in biological systems: a comparative morphological and functional study of the retinaculum and the dens lock in CollembolaBirk Rillich0Fábio G. L. Oliveira1Institut Für Biowissenschaften, Universität Rostock, Allgemeine Und Spezielle ZoologieInstitut Für Biowissenschaften, Universität Rostock, Allgemeine Und Spezielle ZoologieAbstract Background Springtails have the ability to jump using morphological structures consisting of a catapult, the furca, and a latching system constructed with interaction of the retinaculum and the dens lock. The retinaculum engages in the furca at the dens lock in order to form a spring mechanism. They exhibit diversified morphological traits that serve as adaptations to a variety of terrestrial strata and aquatic surface environments. This comparative morphofunctional study centered on the retinaculum and the furcular region of the dens lock aims to describe the morphological variation between taxa and provide insights into the functional dynamics of the latching mechanism at work in the jumping apparatus. Using SEM, µCT and cLSM, we compared representatives of Collembola taxa, Poduromorpha (Neanura muscorum and Podura aquatica), Symphypleona (Dicyrtomina ornata) and Neelipleona (Megalothorax minimus), and examined extracts of the environment in which they were collected. Results A retinaculum is absent in N. muscorum, although vestigial muscles were found. Abdominal musculature varies significantly, being more abundant in springtails with clear segmentation (N. muscorum and P. aquatica), and reduced in springtails with fused segmentation (D. ornata and M. minimus). The M.a-ret varies as regards architecture and point of connection with the ramus, which is lateral in P. aquatica and median in the other species studied. The number of teeth in the retinaculum ramus also varies between three in M. minimus and four in the other species. The dens lock of all species studied has two locks and two furrows. Conclusions The retinaculum and dens lock interact in a key-lock relationship. The latching and unlatching mechanism from the retinaculum and dens lock appear to be similar in all the taxa examined, occurring by muscle force. This leads us to question the hypothesis that hemolymph pressure may be a force generator in jumping. We offer a reconstruction of the ground pattern of the retinaculum and dens lock and, in addition, an explanation of their functioning and the interaction between them. Finally, we frame the interaction between the retinaculum and the dens lock as a latch in a biological system, a mechanism which functions by force of physical contact.https://doi.org/10.1186/s12983-023-00491-2BiomaterialsBiomechanicsResilinSpring mechanismSpringtails
spellingShingle Birk Rillich
Fábio G. L. Oliveira
On latches in biological systems: a comparative morphological and functional study of the retinaculum and the dens lock in Collembola
Frontiers in Zoology
Biomaterials
Biomechanics
Resilin
Spring mechanism
Springtails
title On latches in biological systems: a comparative morphological and functional study of the retinaculum and the dens lock in Collembola
title_full On latches in biological systems: a comparative morphological and functional study of the retinaculum and the dens lock in Collembola
title_fullStr On latches in biological systems: a comparative morphological and functional study of the retinaculum and the dens lock in Collembola
title_full_unstemmed On latches in biological systems: a comparative morphological and functional study of the retinaculum and the dens lock in Collembola
title_short On latches in biological systems: a comparative morphological and functional study of the retinaculum and the dens lock in Collembola
title_sort on latches in biological systems a comparative morphological and functional study of the retinaculum and the dens lock in collembola
topic Biomaterials
Biomechanics
Resilin
Spring mechanism
Springtails
url https://doi.org/10.1186/s12983-023-00491-2
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