Fossil Friday: Treehopper Nymph in Dominican Amber and the Miracle of Mimicry
This undescribed exuvia of a treehopper nymph of the family Membracidae was embedded 15-20 million years ago in the fossil resin of Miocene amber from the Dominican Republic (Iturralde-Vinent & MacPhee 1996). The hardly developed wing sheaths and the small size of only 2.5 mm prove that it was still an early stage nymph. Along the median line you can see the crack in the cuticle, from which the next nymphal stage had hatched.
The specimen is deposited at the Sauriermuseum Aathal in Switzerland. No membracid nymph was ever reported or described before from Dominican amber; so you see it here first! The first adult membracid from Dominican amber was recently described by Wang et al. (2020), while previously only a few undescribed adult specimens were briefly mentioned or figured from this fossil locality (Schlee 1990: fig. 56, Poinar 1992: fig. 65, Wu 1996, McKamey 1998, Wallace & Deitz 2006).
The cicada family Membracidae is globally distributed, especially in the tropics, and the insects often possess monstrous helmets on the prothorax that mimic thorns or fungi. Developmental studies proposed that these stiff outgrowths have the same genetic basis as the wings (Prud’homme et al. 2011, Fisher et al. 2020, Wu 2019). The researchers commented in a press release (Hood 2011) “That’s probably shocking news if you are an entomologist, and challenges some very basic ideas about what makes an insect an insect.” Indeed! Since the assumed ancestors of treehoppers neither had prothoracic winglets nor such helmets, and wings are only developed on the meso- and metathoracic segments, these results do not really make sense and strongly suggest that the question of homology needs to be reconsidered: Homologous structures can be produced by different genes and tissues, while homologous genes can produce very different non-homologous structures. Such a pattern is not expected under the assumption of the modern evolutionary synthesis (neo-Darwinism), but it is quite compatible with a design explanation.
The distantly related planthopper family Fulgoridae often has similar outgrowths on the head. A prominent example is the South American lantern fly Fulgora laternaria, which was first illustrated by Maria Sybilla Merian in her 1705 book about insects from Suriname. My specimen, featured in this article, is also from the tropical rainforest of Suriname, where I spent two adventurous years of my young adult life.
The peanut-shaped outgrowth is a remarkable case of mimicry. It obviously mimics the head of a baby caiman, complete with teeth, nostrils and eyes. The hind wings have elaborate eye spots that mimic an owl, when spread to startle potential predators. So, this insect indeed mimics two different classes of vertebrate animals.
A wonderful video of a living animal is available on YouTube (below). This miracle of mimicry, for which there are countless other examples in the animal kingdom, represents powerful evidence for design in nature.
- Fisher CR, Wegrzyn JL & Jockusch EL 2020. Co-option of wing-patterning genes underlies the evolution of the treehopper helmet. Nature Ecology & Evolution 4, 250–260. DOI: https://doi.org/10.1038/s41559-019-1054-4.
- Hood M 2011. Evolution in reverse: insects recover lost ‚wings‘. Phys.org May 5, 2011. https://phys.org/news/2011-05-evolution-reverse-insects-recover-lost.html.
- Iturralde-Vinent MA & MacPhee RDE 1996. Age and Paleogeographical Origin of Dominican Amber.
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- McKamey SH 1998. Taxonomic Catalogue of the Membracoidea (exclusive of leafhoppers): Second Supplement to Fascicle 1 — Membracidae of the General Catalogue of the Hemiptera. Memoirs of the American Entomological Institute 60, 1–377.
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- Prud’homme B, Minervino C, Hocine M et al. 2011. Body plan innovation in treehoppers through the evolution of an extra wing-like appendage. Nature 473, 83–86. DOI: https://doi.org/10.1038/nature09977.
- Schlee D 1990. Das Bernstein–Kabinett. Begleitheft zur Bernsteinausstellung im Museum am Löwentor, Stuttgart. Stuttgarter Beiträge zur Naturkunde Serie C 28, 1–100.
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- Wang H, Zhang X, Shih C, Dong R & Yao Y 2020. A new species of Membracidae (Hemiptera: Cicadomorpha: Membracoidea) from Dominican amber. Historical Biology 33(10), 2491–2495. DOI: https://doi.org/10.1080/08912963.2020.1803300.
- Wu RJC 1996. Secrets of a lost world: Dominican amber and its inclusions. Self published, Santo Domingo (Dominican Republic).
- Wu KJ 2019. Treehoppers’ Bizarre, Wondrous Helmets Use Wing Genes to Grow. Smithsonian Magazine December 9, 2019. https://www.smithsonianmag.com/science-nature/treehoppers-bizarre-wondrous-helmets-use-wing-genes-grow-180973713/.