Description of fossil amber with ant syninclusions

Introduction The close relationships and interactions between multiple species can have important impacts on ecosystems. Fossil amber syninclusions (when multiple organisms are preserved together within the same fossil amber piece) sometimes preserves such interactions. Studying fossil interactions may thus give us hints of the ecosystems of the past. Methods In this study, we describe six cases in fossil amber (Case 1, Baltic amber, Paleocene, Eocene, 55.8 – 33.9 Mya; Cases 2-4 and 6, Burmese amber, Cretaceous, ca. 99 Mya; Case 5, Dominican amber, Oligocene, 33.9 – 23.03 Mya) with ant syninclusions. Results Ants are eusocial insects of the family Formicidae considered an ecologically important species with diversity since their origin in late Mesozoic and eusociality in the Early Cretaceous (120 Mya). Morphologically identified organisms in fossil amber with Stem†, Hell† or Crown ant syninclusions included mites, wasp, plants (Case 1), spider (Case 2), land snail, millipede, unclassified insects (Case 3), mite, plants (Case 4), termites, mosquitoes, mite, unclassified insects (Case 5), and Neuroptera larva, spider, wasp, unclassified insects (Case 6). Discussion However, does syninclusions reflect a random process or biological interactions between different organisms? To address this question, we characterized syninclusions with ants and multiple organisms in fossil amber. This implies the coexistence and evolution since Cretaceous with possible relationships with commensalism, phoresis and parasitism between ants and other organisms.