First observations on the life cycle and mass eclosion events in a mantis fly (Family Mantispidae) in the subfamily Drepanicinae

Abstract

BackgroundThe Mantispidae are a distinctive group of Neuroptera known for the adults’ possession of raptorial forelegs. There are four recognised, extant subfamilies of Mantispidae: the Mantispinae, Symphrasinae, Calomantispinae and Drepanicinae. The life history and larval behaviour of the subfamily Mantispinae is best known: the immatures are spider egg predators. Among the three remaining subfamilies, larval Symphrasinae and Calomantispinae most likely predate on other small arthropods, while the immature life history of Drepanicinae, until now, remained completely unknown.New informationHere we provide observations of annual, near-synchronised, mass emergences of adults of the drepanicine, Ditaxis biseriata (Westwood), within a well-established Macadamia orchard in northern New South Wales, Australia. A female deposited fertile eggs, allowing this first report of egg batch and first instar morphology. The mass emergence of mobile pharate adults from the ground was observed in the same month in two consecutive years. The pharates climbed tree-trunks for a distance before undergoing eclosion. The newly-hatched first instar larvae are campodeiform and prognathous; a typical morphology among Mantispidae. After hatching, they drop to the ground and burrow into soil. They are unpigmented and appear to lack stemmata. Together, the observations infer that the immature component of the life cycle takes place underground in forested habitats. If this feature is common among the Drepanicinae, it might explain why so little is known of the biology of the immature stages.

The ride of the parasite: a 100-million-year old mantis lacewing larva captured while mounting its spider host

“…A more difficult character is the structure of the mandibular-maxillary stylets: they are inward curved in the fossil, but straight in most modern forms [5, 8]. Yet there are also some less well-known cases in which modern mantis lacewing larvae possess curved mandibular-maxillary stylets ([15]; simplified in Fig.…”

“…In the latter case, curved larval mandibles may well represent a plesiomorphic character. Our knowledge of larval morphology and biology of most mantis lacewings is still very incomplete [8]. We will need a denser sampling of larvae before being able to resolve character evolution of larval characters.…”

“…At least one species of Symphrasinae appears to be a parasitoid of crabronid wasps [7]. Other species of Symphrasinae, Drepanicinae and Calomantispinae appear to have a broader food spectrum and may indeed be predators ([8] and references therein).…”

An unusual 100-million-year old holometabolan larva with a piercing mouth cone

“…5D; Rice & Peck, 1991, their fig. 2;Hoffman & Brushwein, 1992;Dorey & Merritt, 2017, their fig. 4C).…”

“…(C) Larva of the beetle group Drilus(Baalbergen, Schelfhorst & Schilthuizen, 2016); no scale available, but estimated length about 18 mm based on similar specimens. (D) Head of larval mantis lacewing(Dorey & Merritt, 2017); note how the piercing-stylets are positioned close to each other almost appearing as forming a single mouth cone; no scale available, but estimated length about 450 µm based on similar specimens.Full-size  DOI: 10.7717/peerj.8661/fig-5…”