New fossil wasp species from the earliest Eocene Fur Formation has its closest relatives in late Eocene ambers (Hymenoptera, Ichneumonidae, Pherhombinae)

Darwin wasps (Ichneumonidae) are one of the most species-rich insect families, but also one of the most understudied ones, both in terms of their extant and extinct diversity. We here use morphometrics of wing veins and an integrative Bayesian analysis to place a new rock fossil species from the Danish Fur Formation (~54 Ma) in the tree of Darwin wasps. The new species, Pherhombus parvulus n. sp., is placed firmly in Pherhombinae, an extinct subfamily so far only known from Baltic and Rovno-Ukranian ambers, which are estimated to be 34-48 Ma and 34-38 Ma, respectively. Our phylogenetic analysis recovers a subfamily clade within the higher Ophioniformes formed by Pherhombinae, Townesitinae and Hybrizontinae, in accordance with previous suggestions. Due to the placement of the new species as sister to the remaining members of Pherhombinae, we argue that our finding is not at odds with a much younger, late Eocene age (~34-41 Ma) of Baltic amber and instead demonstrates that Pherhombus existed over a much longer period than previously thought. Our results also exemplify the power of wing vein morphometrics and integrative phylogenetic analyses in resolving the placement even of poorly preserved fossil specimens.

Morphological and Spatial Diversity of the Discal Spot on the Hindwings of Nymphalid Butterflies: Revision of the Nymphalid Groundplan

Diverse butterfly wing color patterns are understood through the nymphalid groundplan, which mainly consists of central, border, and basal symmetry systems and a discal spot. However, the status of the discal spot remains unexplored. Here, the morphological and spatial diversity of the discal spot was studied in nymphalid hindwings. The discal spot is expressed as a small or narrow spot, a pair of parallel bands, a diamond or oval structure, a large dark spot, a few fragmented spots, or a white structure. In some cases, the discal spot is morphologically similar to and integrated with the central symmetry system (CSS). The discal spot is always located in a distal portion of the discal cell defined by the wing veins, which is sandwiched by the distal and proximal bands of the CSS (dBC and pBC) and is rarely occupied by border ocelli. The CSS occasionally has the central band (cBC), which differs from the discal spot. These results suggest that the discal spot is an independent and diverse miniature symmetry system nested within the CSS and that the locations of the discal spot and the CSS are determined by the wing veins at the early stage of wing development.

Functional Identification of Px-fringe and Px-engrailed Genes under Heat Stress in Chlorpyrifos-Resistant and -Susceptible Plutela xylostella (Lepidoptera: Plutellidae)

In our previous research, the fitness cost of resistance of the diamondback moth (DBM), Plutella xylostella found in insecticide-resistant DBM (Rc-DBM) under heat stress was based on heavier damage to wing veins when compared to insecticide-susceptible DBM (Sm-DBM). To investigate the molecular mechanism of the damage to the veins between Rc- and Sm-DBM, the full-length sequences of two related genes involved in the development of wing veins, fringe (Px-fng) and engrailed (Px-en) of DBM were cloned, and the mRNA expressions of both Px-fng and Px-en were studied. The Px-fng and Px-en cDNA contained 1038 bp and 1152 bp of open reading frames (ORFs), respectively, which encoded a putative protein comprising 345 and 383 amino acids with a calculated molecular weight of 39.59 kDa and 42.69 kDa. Significantly down regulated expressions of Px-fng and Px-en under heat stress were found in pupae and adults of Rc-DBM compared to Sm-DBM, and a result of higher damage to wing veins in Rc-DBM under heat stress. Based on RNAi experiments, significant inhibitions on expressions of Px-fng and Px-en in both Sm-DBM and Rc-DBM were found when the pupae were infected by dsFng or dsEn. Corresponding to these, infections of dsFng or dsEn resulted in significant decrease of eclosion rate and increase malformation rate of DBM. Our results suggest that the higher damage of wing veins in DBM might be related to the heavier inhibitions of Px-fng and Px-en expression, and the Px-fng and Px-en are involved in the development of wings and veins.

Venanides caspius sp. nov. from Iran, the first species of Venanides (Hymenoptera: Braconidae) described from the Palaearctic Region

The genus Venanides Mason, 1981 (Hymenoptera: Braconidae: Microgastrinae) is recorded from Iran for the first time, and a new species, Venanides caspicus Abdoli, Fernandez-Triana & Talebi sp. nov., is described and illustrated. This new species is characterized by its long metasomal tergite 1, that is narrowing towards the posterior end; scutoscutellar sulcus very narrow, obliterated or weakly crenulate; wing veins pale or almost transparent. The newly described taxon is the first representative of Venanides in the Palaearctic Region identified to the species level.

Ghosts from the past: a review of fossil Hepialoidea (Lepidoptera)

We critically re-examine nine of the ten fossil specimens currently assigned to Hepialidae. Three fossils with impressions of wing veins and scales placed in the fossil genus Prohepialus Piton, 1940, and two mummified larvae that show apomorphic characters, have features that support placement in Hepialidae. The other four fossils that we evaluate, Prohepialus incertus Piton, 1940; Oiophassus nycterus Zhang, 1989; Protohepialus comstocki Pierce, 1945; and a fossil scale, lack definitive hepialid characters. One of these, Prohepialus incertus Piton, 1940, appears to represent a symphytan (Hymenoptera), and is excluded from Lepidoptera. The fossilized wings placed in Prohepialus by Jarzembowski display numerous features that indicate a proximate phylogenetic relationship to extant members of the hepialid genus Sthenopis Packard and related genera.

Is †Skleroptera (†Stephanastus) an order in the stemgroup of Coleopterida (Insecta)?

The Carboniferous insect taxon †Stephanastus polinae was assigned to a monotypic new order †Skleroptera, which was postulated as the sister group of the clade Strepsiptera + Coleoptera (= Coleopterida). The placement of †Stephanastus in Holometabola and the proposed relationship with Coleopterida are very likely unjustified. Suggested shared derived features of Skleroptera + Coleopterida are vague, insufficiently documented (characters of proximal leg segments) or likely based on misinterpretation (wing veins). Based on the wing venation we suggest a position in the extinct hemimetabolous order †Protelytroptera.

The first record of parasitism by Forcipomyia (Diptera: Ceratopogonidae) in Cuban odonates

Several species of biting midges of the genus Forcipomyia are frequently found attached to the wings of adult odonates, acting as parasites by sucking haemolymph from the wing veins. Here we report the first finding of F. incubans on odonates in the peninsula of Zapata, Cuba. We found the midge on the wings of Erythrodiplax simplicicollis, E. umbrata, Crocothemis servilia, and in the wings and body of Perithemis domitia, all species belonging to the family Libellulidae. This is the first record of this interaction for the Antilles.

In that vein: inflated wing veins contribute to butterfly hearing

Insects have evolved a diversity of hearing organs specialized to detect sounds critical for survival. We report on a unique structure on butterfly wings that enhances hearing. The Satyrini are a diverse group of butterflies occurring throughout the world. One of their distinguishing features is a conspicuous swelling of their forewing vein, but the functional significance of this structure is unknown. Here, we show that wing vein inflations function in hearing. Using the common wood nymph, Cercyonis pegala , as a model, we show that (i) these butterflies have ears on their forewings that are most sensitive to low frequency sounds (less than 5 kHz); (ii) inflated wing veins are directly connected to the ears; and (iii) when vein inflations are ablated, sensitivity to low frequency sounds is impaired. We propose that inflated veins contribute to low frequency hearing by impedance matching.