Evolutionary and paleobiological implications of Coleoptera (Insecta) from Tethyan-influenced Cretaceous ambers

Abstract

International audienceThe intense study of coleopteran inclusions from Spanish (Albian in age) and French (Albian–Santonian in age) Cretaceous ambers, both of Laurasian origin, has revealed that the majority of samples belong to the Polyphaga suborder and, in contrast to the case of the compression fossils, only one family of Archostemata, one of Adephaga, and no Myxophaga suborders are represented. A total of 30 families from Spain and 16 families from France have been identified (with almost twice bioinclusions identified in Spain than in France); 13 of these families have their most ancient representatives within these ambers. A similar study had previously only been performed on Lebanese ambers (Barremian in age and Gondwanan in origin), recording 36 coleopteran families. Few lists of taxa were available for Myanmar (Burmese) amber (early Cenomanian in age and Laurasian in origin). Coleopteran families found in Cretaceous ambers share with their modern relatives mainly saproxylic and detritivorous habits in the larval or adult stages, rather than wood-boring behavior. Fifteen of the coleopteran families occur in both the Lebanese and Spanish ambers; while only five are present in both Spanish and French. Considering the paleogeographic proximity and similarity of age of the Spanish and French ambers, the small number of taxa found in common at both areas is surprising. The ancient origin for the Lebanese and Spanish ambers, the paleogeography (including some barriers for terrestrial biota) and the local paleohabitats are factors that may explain the dissimilarity with the French specimens. Wildfires are believed to be a more likely cause of resin production during the Cretaceous than infestation by beetles. Current knowledge of the beetle species found in the Cretaceous ambers is introduced

Arthropods in modern resins reveal if amber accurately recorded forest arthropod communities

“…Ground-dwelling beetles are common in resin and amber (Pselaphinae and Scydmaeninae, e.g., ref. 34, our resin samples) because of predatory behavior on small arthropods such as springtails and oribatid mites (35,36). However, arboreal beetles are also well represented in recent and fossil resin and in the yellow sticky traps.…”

“…Although Peris et al (37) speculated that Ptinidae could have promoted resin production by damaging Upper Cretaceous trees, the jaws observed in amber specimens are not strong enough to damage wood and female genitalia are not cutinized for direct deposition into live wood. Thus, they more probably laid eggs on herbaceous plants, or dead or decaying wood (34). The abundance of Ptinidae in the Madagascar yellow sticky traps and in Cenozoic ambers can instead be explained by their high activity on tree trunks.…”

Production and preservation of resins – past and present

“…Regarding older Cretaceous amber deposits, there is no support for resin production in response to insect attacks. A study of coleopteran diversity recorded in Early/middle Cretaceous ambers from France and Spain shows a majority of saproxylic and detritivorous, rather than wood‐boring beetles (Peris et al, ).…”

DNA Barcodes for the Northern European Tachinid Flies (Diptera: Tachinidae)

“…This is in good accordance with our results, since many dipterans, including Tachinids, are strong fliers and are likely characterized with very high metabolic rate. Additionally, when compared to the ancient beetle families [34], Tachinidae are evolutionarily young, having underwent rapid diversification no earlier than the Oligocene [35] and therefore also explaining the large difference between the species divergence in the two groups.…”