A soil-carrying lacewing larva in Early Cretaceous Lebanese amber

Ricardo Pérez-De La Fuente,Dany Azar,Enrique Peñalver,Michael S Engel

doi:10.1038/s41598-018-34870-1

Abstract

Diverse organisms protect and camouflage themselves using varied materials from their environment. This adaptation and associated behaviours (debris-carrying) are well known in modern green lacewing larvae (Neuroptera: Chrysopidae), mostly due to the widespread use of these immature insects in pest control. However, the evolutionary history of this successful strategy and related morphological adaptations in the lineage are still far from being understood. Here we describe a novel green lacewing larva, Tyruschrysa melqart gen. et sp. nov., from Early Cretaceous Lebanese amber, carrying a preserved debris packet composed by soil particles entangled among specialised setae of extremely elongate tubular tubercles. The new morphotype has features related to the debris-carrying habit that are unknown from extant or extinct green lacewings, namely a high number of tubular tubercle pairs on the abdomen and tubular tubercle setae with mushroom-shaped endings that acted as anchoring points for debris. The current finding expands the diversity of exogenous materials used by green lacewing larvae in deep time, and represents the earliest direct evidence of debris-carrying in the lineage described to date. The debris-carrying larval habit likely played a significant role during the initial phases of diversification of green lacewings.

Highlights

Selecting, gathering, and carrying exogenous materials for mechanical protection and camouflage ‒ debris-carrying, trash-carrying, or decoration‒ is a strategy that has evolved independently across a wide diversity of metazoans, including sea urchins, gastropods, and, above all, arthropods
Two morphobehavioural types are distinguished among modern green lacewing larvae: the debris-carrying forms and the so-called “naked” ones
We describe a novel-looking chrysopoid larva with peculiar morphological adaptations for debris-carrying that is associated to debris packet elements interpreted as soil particles

Summary

Introduction

Selecting, gathering, and carrying exogenous materials for mechanical protection and camouflage ‒ debris-carrying, trash-carrying, or decoration‒ is a strategy that has evolved independently across a wide diversity of metazoans, including sea urchins, gastropods, and, above all, arthropods In the latter, debris-carrying (excluding structure-building behaviour) is known in crustaceans (namely decorating crabs), arachnids (some oribatid mites and harvestmen, as well as sand-covering and walking mud spiders), and immature insects (assassin bugs, barklice, beetles, and neuropterans)[1,2,3,4,5,6]. Debris-carrying larvae allocate the packet elements on their backs through a series of stereotyped movements arching the head backward while bowing the thorax and abdomen forward, followed by occasional peristaltic body movements to reallocate said packet elements[13,14] In any case, both debris-carrying and naked forms are known to occur in two of the three subfamilies of Chrysopidae, i.e., Nothochrysinae and Chrysopinae (the latter subdivided into four tribes, Ankylopterygini, Belonopterygini, Chrysopini, and Leucochrysini). Further diversity of Cretaceous chrysopoid larvae but not of the debris-carrying morphotype have been described ‒ an unnamed neonate clutching at the egg from where it hatched in Canadian amber, an extremely long-legged larva interpreted as a spider hunter in Burmese amber, and a larva mimicking liverworts from Burmese amber[16,17,18]

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Conclusion