Dima assoi Pérez Arcas 1872 (Coleoptera: Elateridae): from montane to hypogean life. An example of exaptations to the subterranean environment?

Summary

The mesovoid shallow substratum (MSS) of two areas in the Moncayo Massif (Zaragoza, Spain) was sampled for a year with subterranean pitfall traps installed at one meter depth in stony debris. Throughout this period, a large contingent of imagoes of Dima assoi Pérez Arcas 1872 (Elateridae) was found; this is a species whose genus is disjunctively distributed at high altitudes, in the Himalayas and Europe. It frequently appeared in the four subterranean traps located in one of the two areas (a bare scree), as well as in some surface pitfall traps, but less frequently in the other area (a beech forest). This fact contrasts with the knowledge about this species, given its nocturnal nature and its sublapidicolous behavior, but seems to agree with its morphological features. Nevertheless, apart from anecdotal information, almost all other aspects of the biology of this species remain unknown. In this work we provide both biotic and abiotic data about the subterranean habitat where this species has been found. The implications of these findings are discussed in relation to its biology and to the significance of its possible exaptations to the subterranean environment as a result of adaptation to montane habitats.

Résumé

Le milieu souterrain superficiel (MSS) de deux aires dans le massif de Moncayo (Saragosse, Espagne) a été échantillonné pendant une année au moyen de pièges à fosse installés à un mètre de profondeur dans des débris rocheux. Durant toute cette période, un fort effectif de Dima assoi Pérez Arcas 1872 (Elateridae) a été trouvé. Cette espèce appartient à un genre dont la distribution est disjointe aux hautes altitudes de l’Himalaya et de l’Europe. Il est fréquemment apparu dans quatre pièges souterrains dans une des deux aires (un ébouli dénudé) ainsi que dans quelques pièges à fosse de surface, mais moins fréquement dans l’autre aire (une forêt de hêtre). Ceci contraste avec les connaissances actuelles de l’espèce, son mode de vie nocturne et sublapidicole, mais c’est cohérent avec ses caractéristiques morphologiques. Néanmoins, en dehors d’informations anecdotiques, presque tous les autres aspects de la biologie de cette espèce restent inconnus. Dans ce travail, nous fournissons des données biotiques et abiotiques sur l’habitat souterrain de l’espèce. Les implications de ces découvertes sont discutées en relation avec sa biologie et avec la signification de ses exaptations possibles à l’environnement souterrain comme résultat de ses habitats montagnards.

Keywords:

• hypogean habitats
• MSS
• troglobiomorphism
• Moncayo massif
• rare species
• rocky debris
• scree

Acknowledgments

We would like to express our gratitude to all the staff of the Moncayo Natural Park, both the technical team and the crew, for their collaboration in the installation of the SSDs and the samplings. We also thank Raquel Colado, Lucía Veguillas, Tamara Acosta and Pilar Fernández for their help in the fieldwork, and Fernando Prieto, for his diligence when providing us a necessary bibliographical reference. We would also like to thank Dr. Eugen Nitzu for providing us information about the presence of Dima elateroides in the MSS. We are grateful too to Dr. Rainer Schimmel and the other two anonymous referees, for their comments helping us to improve our manuscript. This work has been financed by the I3 program of “Incentivation of the Incorporation and Intensification on Research Activity of the Ministry of Education and Science of Spain” (V. M. Ortuño is the beneficiary).