Species delimitation in the crypsis‐defended and polymorphic stick insects of the genusLibethra(Phasmatodea, Diapheromeridae)

Abstract

Species delimitation in the crypsis-defended and polymorphic stick insects of the genus Libethra (Phasmatodea, Diapheromeridae). -Zoologica Scripta, 46, 693-705. Crypsis is a widespread defensive mechanism for prey ambushed by visually oriented predators. One well-documented consequence of this interaction is the formation of search images by the predator that leads to the coexistence of multiple morphs in the prey population. Libethra is a genus of stick insects whose ornamentation and coloration are decidedly protective and exhibit exuberant intraspecific variation. Despite this fact, these traits have been extensively used to support the boundaries between the species it includes. This is the case in the north Andean species Libethra rabdota and Libethra rabdotula, delimited on the basis of a specific arrangement of ornamental characters. To state whether such taxonomical practice is meaningful and convenient, we evaluated the grouping of specimens of both species by means of the independent inference of phylogenies obtained with mitochondrial DNA sequences and ootaxonomy. This article synonymizes L. rabdota and L. rabdotula, redescribes the adults and describes the egg of the species. Additionally, we demonstrate that the characters related to crypsis used for the diagnosis of L. rabdota are not exclusive to this species by describing Libethra rioblanco sp. n. and Libethra ucumariensis sp. n. Our findings suggest that this genus requires extensive revision, but also provide support for the usage of different tools that might produce more accurate and stable classification. Evolutionary scenarios for both the extreme morphological variation and possible homoplastic state of camouflage-related traits are discussed herein.

Arumatia, a new genus of Diapheromerinae stick insects (Insecta, Phasmatodea) from Brazil, with description of five new species and reassessment of species misplaced in Australian genera

“…More specific studies must be conducted to attend to these questions. Nevertheless, this is one more of recent recurring examples of the benefits of an integrative taxonomy in Phasmatodea (Gutiérrez-Valencia et al 2017;Crispino et al 2020;Chiquetto-Machado & Cancello 2021;Ghirotto 2021;Chiquetto-Machado et al 2022).…”

“…Neotropical stick insects are generally poorly studied: many species are known only from their original descriptions and relatively few have been covered in recent taxonomic works (see, e.g., Gutiérrez-Valencia et al 2017;Conle et al 2020;Crispino et al 2020;Madeira-Ott et al 2020;Chiquetto-Machado & Cancello 2021;Ghirotto 2021;Chiquetto-Machado et al 2022). Compared to the fauna of other continents, Neotropical phasmids are underrepresented in phylogenetic analyses, reflecting the lack of basic scientific work concerning them (Robertson et al 2018;Simon et al 2019).…”

Integrative taxonomy based on morphometric and molecular data supports recognition of the three cryptic species within the Encyrtus sasakii complex (Hymenoptera, Encyrtidae)

“…A notable one has been inferring gaps in the morphological variation exhibited by closely-related species across their geographical ranges (Zapata and Jiménez, 2011). However, it has been demonstrated that continuous variation may be interrupted by factors that are not necessarily associated with diversification (Viggiani 1999), meaning that discontinuity is not always an evidence for speciation (Gutiérrez-Valencia et al 2017). Another popular approach for cryptic-species delimitation is geometric morphometrics, which is based on statistical analyses of landmark data (Sproul and Maddison 2017).…”

Estudo Morfológico e Caracterização das Espécies de Ceroys Serville, 1838 (Phasmatodea: Heteronemiidae: Heteronemiinae: Pygirhynchini) de Mata Atlântica

“…Antes disso, grande parte dos trabalhos se baseavam em caracteres morfológicos externos, que ainda são amplamente utilizados para caracterização dos táxons (Bacetti, 1987;Tilgner et al, 1999;Bradler, 2003;Grimaldi & Engel, 2005;Friedemann et al 2012, Gutiérrez-Valencia et al 2017 , Hennemann & Gútierrez 2011, Hennemann & Conle 2006, Zompro 2004a, Cumming et al 2020. Diferentes famílias dentro da ordem são consideradas polifiléticas (Bradler 2009, Robertson et al 2018, Simon et al 2019 É nessa situação que grande parte das famílias, gêneros e espécies neotropicais se encontram, principalmente brasileiros: taxonomicamente confusos, mal delimitados e carecendo de urgente estudo (Zompro, 2004a, b Bradler & Buckley 2018.…”

“…Isso apresenta dois problemas: a separação em dois grupos sabidamente artificiais e a validação de Diapheromeridae em seu estado polifilético, englobando duas ou mais famílias de táxons não relacionados (Bradler 2009). Não obstante, há uma sobreposição de espécies, gêneros e famílias descritas ao mesmo tempo para Heteronemiidae, Diapheromeridae e Phasmatidae (Hennemann et al 2016), dada a caracterização superficial dos táxons, convergências morfológicas, polimorfias intraespecíficas e similaridade de nichos (Henneman et al 2016, Gutiérrez-Valencia et al 2017, Crispino et al 2020. A soma destes problemas e a ausência de trabalhos com Heteronemiidae resultam na sub-representação ou ausência da família nos principais estudos filogenéticos recentes (Robertson et al 2018, Simon et al 2019, Tihelka et al 2020, Forni et al 2021 De toda forma, os resultados aqui apresentados são até o momento um dos poucos envolvendo a família Heteronemiidae.…”