A Cretaceous bug with exaggerated antennae might be a double-edged sword in evolution

Abstract

Sexual selection can favor production of exaggerated features, but the high cost of such features in terms of energy consumption and enemy avoidance makes them go to extinction under the influence of natural selection. However, fossils preserved with specialized features are very rare. Here, we report a new nymph from Burmese amber, Magnusantena wuae Du & Chen gen. et sp. nov., which has exaggerated leaf-like expanded antennae. Such bizarre antennae indicate that sensitive and delicate sensory system and magnificent appearance in Hemiptera have been already established in mid-Cretaceous. Our findings may provide evidence for Darwin's view that sensory organs play an important role in sexual selection. This nymph with the leaf-like antennae may also represents a new camouflage pattern. However, the oversized antennae are costly to develop and maintain, increasing the risks from predators. Such unparalleled expanded antennae might be the key factor for the evolutionary fate of the coreid.

Drawing the Excalibur bug from the stone: adding credibility to the double-edged sword hypothesis of coreid evolution (Hemiptera, Coreidae)

“…Unfortunately, with the fossil record of coreids rather fragmented and often from partial or nymphal specimens this still leaves a great deal of confusion surrounding their evolutionary history. Thankfully with nymphal antennae morphology rather stable into adulthood (Du et al 2021) recent and herein described fossilized nymphs present a unique opportunity to understand the possible origin of elaborate morphological features.…”

“…Illustrations were done by scientific illustrator Liz Sisk (Washington D.C., USA) using either photographs of the holotype, photographs saved from various online sources illustrating non-type specimens or recreated from the photographs/ illustration presented in Du et al (2021) in order to present side-by-side images of a uniform style.…”

“…The Alydidae can be differentiated from Coreidae by the length of the bucculae, with the bucculae shorter, not extending posteriorly beyond the base of the antennae in Alydidae but longer in Coreidae, extending posteriorly beyond the base of the antennae (Swanson 2011). Within Magnusantenna wuae Du et al (2021) clearly state that the bucculae are long extending posteriorly beyond the base of the antennae and therefore due to this feature would fit within Coreidae. Unfortunately, the amber piece that our Ferriantenna gen. nov. is within is too thick to clearly see the ventral surface of the head, but it does appear that the bucculae are longer than the base of the antennae and therefore more likely a Coreidae than an Alydidae.…”

“…The first reported Coreidae species from Cretaceous Burmese amber was the recently described Magnusantenna wuae Du & Chen, 2021 (Fig. 2C), and was only the fifth species of coreid described from the Cretaceous (the others being impression fossils, not amber inclusions; Du et al (2021)). Du et al (2021) presented the first coreid from the Cretaceous with expansions on the antennae, a feature that is also seen in a few extant coreid species (Fig.…”

“…2C), and was only the fifth species of coreid described from the Cretaceous (the others being impression fossils, not amber inclusions; Du et al (2021)). Du et al (2021) presented the first coreid from the Cretaceous with expansions on the antennae, a feature that is also seen in a few extant coreid species (Fig. 1D), but what was notable about their description was that the antennae were far more elaborate than any known extant species.…”