Abstract
Today, integrative taxonomy is often considered the gold standard when it comes to species recognition and delimitation. Using the Tetrix bipunctata complex, we here present a case where even integrative taxonomy may reach its limits. The Tetrix bipunctata complex consists of two morphs, bipunctata and kraussi, which are easily distinguished by a single character, the length of the hind wing. Both morphs are widely distributed in Europe and reported to occur over a large area in sympatry, where they occasionally may live also in syntopy. The pattern has led to disparate classifications, as on the one extreme, the morphs were treated merely as forms or subspecies of a single species, on the other, as separate species. For this paper, we re-visited the morphology by using multivariate ratio analysis (MRA) of 17 distance measurements, checked the distributional data based on verified specimens and examined micro-habitat use. We were able to confirm that hind wing length is, indeed, the only morphological difference between bipunctata and kraussi. We were also able to exclude a mere allometric scaling. The morphs are, furthermore, largely sympatrically distributed, with syntopy occurring regularly. However, a microhabitat niche difference can be observed. Ecological measurements in a shared habitat confirm that kraussi prefers a drier and hotter microhabitat, which possibly also explains the generally lower altitudinal distribution. Based on these results, we can exclude classification as subspecies, but the taxonomic classification as species remains unclear. Even with different approaches to classify the Tetrix bipunctata complex, this case is, therefore, not settled. We recommend continuing to record kraussi and bipunctata separately.
Highlights
Species concepts shape the way we see an individual from a given population
Today, integrative taxonomy is often considered the gold standard when it comes to species recognition and delimitation
The Tetrix bipunctata complex consists of two morphs, bipunctata and kraussi, which are distinguished by a single character, the length of the hind wing
Summary
Species concepts shape the way we see an individual from a given population. Species are the fundamental unit in evolutionary biology (Coyne and Orr 2004) and it is, important to apply the species status to the best of our current knowledge (Sites and Marshall 2004). The Tetrix bipunctata complex is an intriguing case: T. bipunctata (Linnaeus, 1758) and T. kraussi Saulcy, 1888 (see Evenhuis 2002 for year of publication) are two widely distributed European Orthoptera of the family Tetrigidae They are considered morphologically very similar, except for a striking hind wing dimorphism. Based on several syntopic occurrences (Schulte 2003), Lehmann (2004) suggested to raise the morphs to species status, a view that has since been widely adopted (Baur et al 2006; Default and Morichon 2015; Sardet et al 2015b; Zuna-Kratky et al 2017; Willemse et al 2018; Cigliano et al 2021), with some exceptions (Wranik et al 2008; Pfeifer et al 2011; Massa et al 2012; Bellmann et al 2019; Fischer et al 2020). To test for differential habitat use, we studied microhabitat niches in a syntopic population discovered in southern Brandenburg (Lehmann and Landeck 2011)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
