Li S, Shih C, Wang C, Pang H, Ren D (2014) Correction: Forever Love: The Hitherto Earliest Record of Copulating Insects from the Middle Jurassic of China. PLOS ONE 9(1): 10.1371/annotation/54a6126f-eed2-456e-ba80-5a1fd2d78e8e. https://doi.org/10.1371/annotation/54a6126f-eed2-456e-ba80-5a1fd2d78e8e View correction

Abstract Background Mating behaviors have been widely studied for extant insects. However, cases of mating individuals are particularly rare in the fossil record of insects, and most of them involved preservation in amber while only in rare cases found in compression fossils. This considerably limits our knowledge of mating position and genitalia orientation during the Mesozoic, and hinders our understanding of the evolution of mating behaviors in this major component of modern ecosystems. Principal Finding Here we report a pair of copulating froghoppers, Anthoscytina perpetua sp. nov., referable to the Procercopidae, from the Middle Jurassic of northeastern China. They exhibit belly-to-belly mating position as preserved, with male's aedeagus inserting into the female's bursa copulatrix. Abdominal segments 8 to 9 of male are disarticulated suggesting these segments were twisted and flexed during mating. Due to potential taphonomic effect, we cannot rule out that they might have taken side-by-side position, as in extant froghoppers. Genitalia of male and female, based on paratypes, show symmetric structures. Conclusions/Significance Our findings, consistent with those of extant froghoppers, indicate froghoppers' genitalic symmetry and mating position have remained static for over 165 million years.

Citation: Li S, Shih C, Wang C, Pang H, Ren D (2013) Forever Love: The Hitherto Earliest Record of Copulating Insects from the Middle Jurassic of China. PLoS ONE 8(11): e78188. https://doi.org/10.1371/journal.pone.0078188 Editor: Fabio S. Nascimento, Universidade de São Paulo, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Brazil Received: May 16, 2013; Accepted: September 3, 2013; Published: November 6, 2013 Copyright: © 2013 Li et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: This research is supported by the National Basic Research Program of China (973 Program) (grant 2012CB821906), the National Natural Science Foundation of China (grants 31172143, 31230065, 31272352 and 41272006), Project of Great Wall Scholar and KEY project of Beijing Municipal Commission of Education (grants KZ201310028033), and China Geological Survey (grant 1212011120115). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing interests: The authors have declared that no competing interests exist.

Introduction Mating behaviors for extant insects have been studied and documented, for example, for froghoppers[1], scorpionflies[2] and planthoppers[3]. However, fossil records of unequivocal insect mating are fairly sparse. Boucot and Poinar[4] listed 33 instances of fossilized mating insects, such as fireflies, mosquitoes, planthoppers, leafhoppers, water striders, bees and ants, 27 of which are preserved in amber, others on compression fossils. The hitherto oldest example of copulation in fossil insects is a pair of chironomids (Diptera) discovered in Early Cretaceous amber from Lebanon [4], [5]. Herein, we report a pair of well-preserved copulating froghoppers, Anthoscytina perpetua sp. nov., referable to the Procercopidae, from Jiulongshan Formation at the Daohugou Village in northeastern China. Procercopidae is an extinct family in the superfamily of froghoppers, Cercopoidea Leach, 1815. Froghoppers get their name because the adults hop around on plants and shrubs like tiny frogs. The nymphs of froghoppers are called spittlebugs because they cover themselves with foaming spittle, composed of tiny air bubbles trapped in secretions from their Malpighian tubules, which provides protection from predation, parasitism and desiccation[6]. This discovery of the earliest record of copulating insects hitherto sheds light on the evolution of mating behavior in this group of insects. Daohugou Village (N41°18′38″, E119°13′20″) is located in Shantou Township, Ningcheng County, Inner Mongolia Autonomous Region, northeastern China. The Jiulongshan Formation is considered to be of late Middle Jurassic age (Bathonian–Callovian boundary interval, 164–165 Ma), based on Ar-Ar and SHRIMP U-Pb dating results [7]–[10]. Currently, about 19 insect orders have been reported from this locality[11].

Materials and Methods Materials We examined more than 1200 specimens from the locality of Daohugou, Inner Mongolia, China. All fossil materials studied are housed in the fossil insect collection of the Key Laboratory of Insect Evolution and Environmental Changes, College of Life Sciences, Capital Normal University, Beijing, China (CNUB; Dong Ren, Curator). The extant Cosmoscarta heros (Fabricius) specimens are from the Insect Collection of Sun Yat-sen University, Guangzhou, China. Methods The specimens were examined by a LEICA MZ12.5 dissecting microscope and illustrated with the aid of a drawing tube attachment. Fossil photographs were taken by Nikon Digital Camera DXM1200C. We follow the traditional terminologies of Cercopoidea[12] and Nel et al.[13]. Venation abbreviations used in the text and Figures: Cu, Cubitus; CuA, Cubitus Anterior; CuP, Cubitus Posterior; M, Media; MA, Media Anterior; MP, Media Posterior; Pcu, Postcubitus; R, Radius; RA, Radius Anterior; RP, Radius Posterior; ScA, Subcosta Anterior; ScP, Subcosta Posterior; m-cua, veinlet between MP and CuA, r-m; veinlet between R and M; ir, veinlet between RA and RP. Nomenclatural Acts The electronic edition of this article conforms to the requirements of the amended International Code of Zoological Nomenclature, and hence the new names contained herein are available under the Code from the electronic edition of this article. This published work and the nomenclatural acts it contains have been registered in Zoobank, the online registration system for the ICZN. The Zoobank LSIDs (Life Science Identifiers) can be resolved and the associated information viewed through any standard web browser by appending the LSID to the prefix “Http://zoobank.org”. The ISID for this publication is: urn: lsid: zoobank.org: pub: AF664AE6-A000-45B9-B9BC-6759CD0F63EE. The electronic edition of this work was published in a journal with an ISSN, and has been archived and is available from the following digital repositories: PubMed Central and LOCKSS.

Conclusions In summary, our finding of the hitherto earliest record of copulating froghoppers, consistent with those of extant froghoppers, indicate froghoppers' genitalic symmetry and mating position have remained static for 165 million years. The evidence also confirms that symmetric genitalia are plesiomorphic for the taxon and by the Middle Jurassic, froghoppers have adopted the belly-to-belly (or side-by-side) position, which was proposed by Huber et al.[21] as the next step in the process of position changes from the basal female-above.

Acknowledgments We are grateful to Dr. Stuart McKamey of the US Department of Agriculture for his valuable inputs and comments in improving this manuscript.

Author Contributions Conceived and designed the experiments: DR. Performed the experiments: SL CW HP. Analyzed the data: SL CS HP. Wrote the paper: SL CS HP DR. Photographs and line drawings: SL CW.