The Angiosperm Terrestrial Revolution and the origins of modern biodiversity

Changes in white oak ( Quercus alba ) phytochemistry in response to periodical cicadas: Before, during, and after an emergence

Periodical cicadas have mass emergences once every 13 or 17 years. Plants may need to upregulate defense production in response to an emergence. Defense production is energetically expensive, so plants may downregulate their production after periodical cicada populations dissipate. We examined the defensive responses in leaves, branches, and roots of a common host, white oak (Quercus alba), prior to, during, and after a 17-year periodical cicada (Magicicada spp.) emergence in western Pennsylvania, United States. During the emergence, total tannins and condensed tannins increased in foliar tissue, while simultaneously decreasing in root tissue compared to the prior and subsequent years. Non-structural carbohydrates were low prior to the mass emergence but were re-allocated to belowground storage during the emergence year and dropped thereafter. In the year after the emergence, there was a relaxation of foliar defenses, and root defenses returned to pre-emergence concentrations. We also tested for differences in damaged and undamaged branches on the same tree during (2019) and the year after the emergence (2020). Both damaged and undamaged branches had significantly greater chemical defenses (polyphenols, total tannins, and condensed tannins) during the emergence than in the following year when there was no emergence. We propose that re-allocation of resources may help maximize oak tree fitness by moving resources away from areas that are not in immediate threat to areas that are under immediate threat. Changes in aboveground and belowground phytochemistry in response to periodical cicada mass emergences may help us better understand which resource re-allocation strategies are used by plants to minimize the effects of insect emergencies.

The oldest fossil record of Pseudopsinae from the Lower Cretaceous Yixian Formation of northeastern China (Coleoptera: Staphylinidae: Pseudopsinae)

The Cretaceous witnessed a radiation of rove beetles (Staphylinidae), the most species-rich beetle family. Although most staphylinid subfamilies have been documented from Cretaceous strata over the world, there has been no fossil record of the subfamily Pseudopsinae until a recently reported fossil from the 99-Ma-old Myanmar amber. Here we describe a new compression fossil from the Lower Cretaceous Yixian Formation of northeastern China. It is described as Cretaceonanobius fossilis. gen. et sp. nov. and assigned to the extant subfamily Pseudopsinae, based on the well-preserved carinae on the pronotum, a carina on ventrites II and III, and distinctly separated mesocoxae. The discovery of Cretaceonanobius fossilis gen. et sp. nov. backdates the earliest fossils record of Pseudopsinae to 125 Ma in the Northern Hemisphere and sheds new lights on the evolution history and paleobiogeography of this subfamily.