Functional morphology of the raptorial forelegs in Mantispa styriaca (Insecta: Neuroptera)

Abstract

The insect leg is a multifunctional device, varying tremendously in form and function within Insecta: from a common walking leg, to burrowing, swimming or jumping devices, up to spinning apparatuses or tools for prey capturing. Raptorial forelegs, as predatory striking and grasping devices, represent a prominent example for convergent evolution within insects showing strong morphological and behavioural adaptations for a lifestyle as an ambush predator. However, apart from praying mantises (Mantodea)—the most prominent example of this lifestyle—the knowledge on morphology, anatomy, and the functionality of insect raptorial forelegs, in general, is scarce. Here, we show a detailed morphological description of raptorial forelegs of Mantispa styriaca (Neuroptera), including musculature and the material composition in their cuticle; further, we will discuss the mechanism of the predatory strike. We could confirm all 15 muscles previously described for mantis lacewings, regarding extrinsic and intrinsic musculature, expanding it for one important new muscle—M24c. Combining the information from all of our results, we were able to identify a possible catapult mechanism (latch-mediated spring actuation system) as a driving force of the predatory strike, never proposed for mantis lacewings before. Our results lead to a better understanding of the biomechanical aspects of the predatory strike in Mantispidae. This study further represents a starting point for a comprehensive biomechanical investigation of the convergently evolved raptorial forelegs in insects.

Extrinsic and intrinsic musculature of the raptorial forelegs in Mantodea (Insecta) in the light of functionality and sexual dimorphism

“…Additionally, and to cover the most recent studies, terms for extrinsic musculature used by Gray and Mill (1985), and terms and numbering used by Frantsevich (1998) were synonymized with the nomenclature from Friedrich and Beutel (2008) and are listed in Table 2. Our results concerning intrinsic musculature were homologized to the results of the investigations in M. styriaca made by Büsse et al (2021) and in F. rufa workers made by Aibekova et al (2022), and are presented in Table 3.…”

“…Although, the most striking features and key characteristic for Mantodea are the prominent raptorial forelegs, a homologous system can be found in other groups as well, like in the neuropteran Mantispidae (Büsse et al, 2021; Ferris, 1940; Prete et al, 1999; Ullrich, 1965). As shown in the morphological investigation of M. styriaca by Büsse et al (2021), apart from the similar external appearance of the raptorial forelegs, additional analogies can be found concerning their anatomy.…”

“…For the coxa, trochanter and femur, the differing muscle set‐up is most likely related to the different functional morphological requirements for the differing kinematics of the predatory strike (muscle‐driven movement vs. LaMSA‐system). As described by Büsse et al (2021), M. styriaca is fully opening the femur‐tibia joint at the beginning of the strike, representing the loading process of the LaMSA ‐system (Granier, 2019; 1:25‐1:28). Here, a different and reduced set of muscles is likely to be sufficient in Mantispidae to execute the movement.…”

“…More recently, studies focusing on the anatomy of the insect legs are: Büsse et al (2021) on the prehensile raptorial forelegs in Mantispa styriaca (PODA, 1761), while Aibekova et al (2022) focused on the worker ant Formica rufa (LINNAEUS, 1761). Alongside descriptions of the present musculature, Aibekova et al (2022) further proposed a first approach of an updated terminology for intrinsic musculature following the suggestions of Friedrich and Beutel (2008) for the thorax musculature in insects.…”

Material gradients in gastropod radulae and their biomechanical significance: a combined approach on the paludomid Lavigeria grandis

“…Garcia-Castineiras et al 1978 ; Fujimori 1978 ; Gast and Lee 1978 ; Giurginca et al 2015 ). This protocol (Michels and Gorb 2012 ) was applied and enabled to find functional significances of material properties in many studies on arthropod endocuticle (Wang et al 2019 ), wings (Rajabi et al 2018 ; Ma et al 2022 ), foot attachment devices and legs (Peisker et al 2013 ; Rebora et al 2018 ; Petersen et al 2018 ; Friedrich and Kubiak 2018 ; Jandausch et al 2018 ; Beutel et al 2020 ; Büsse et al 2021 ; Li et al 2021 ; Büscher et al 2021 ), thorax structure (Casey et al 2022 ), antennae (Saltin et al 2019 ), mouthparts (Michels et al 2012 ; Michels and Gorb 2015 ; Büsse and Gorb 2018 ; Weihmann and Wipfler 2019 ; Matsumura et al 2021a , b ; Lehnert et al 2021 ; Sun et al 2021 ; Wei et al 2022 ) or genitals (Matsumura et al 2014 , 2017 , 2020a , b , 2021a , b ; Kamimura et al 2021 ). In addition, this protocol was cross-validated by employing AFM-Nanoindentation at least for hair of foot attachment devices in a lady beetle (Peisker et al 2013 ).…”