Joachim Bresseel

Extreme convergence in egg-laying strategy across insect orders

The eggs of stick and leaf insects (Phasmatodea) bear strong resemblance to plant seeds and are commonly dispersed by females dropping them to the litter. Here we report a novel egg-deposition mode for Phasmatodea performed by an undescribed Vietnamese species of the enigmatic subfamily Korinninae that produces a complex egg case (ootheca), containing numerous eggs in a highly ordered arrangement. This novel egg-deposition mode is most reminiscent of egg cases produced by members of unrelated insect orders, e.g. by praying mantises (Mantodea) and tortoise beetles (Coleoptera: Cassidinae). Ootheca production constitutes a striking convergence and major transition in reproductive strategy among stick insects, viz. a shift from dispersal of individual eggs to elaborate egg concentration. Adaptive advantages of ootheca formation on arboreal substrate are likely related to protection against parasitoids and desiccation and to allocation of specific host plants. Our phylogenetic analysis of nuclear (28S, H3) and mitochondrial (COI, COII) genes recovered Korinninae as a subordinate taxon among the species-rich Necrosciinae with Asceles as sister taxon, thus suggesting that placement of single eggs on leaves by host plant specialists might be the evolutionary precursor of ootheca formation within stick insects.

A black-and-red stick insect from the Philippines - observations on the external anatomy and natural history of a new species of Orthomeria.

Abstract A new stick insect of the genus Orthomeria Kirby, 1904 (Phasmatodea, Aschiphasmatidae) is described from the Philippines. Orthomeria (Orthomeria) kangi sp. n. is readily distinguished from all other congeners by the distinctive blood red colouration of the costal region of the hind wings. Major features of the external morphology of adults, eggs, and first-instar nymphs are illustrated. Locomotory attachment pads are of the smooth type with irregular microgrooves on the contact surface. An unusual condition of male terminalia is the absence of tergal thorn pads on segment 10. The male clasping organs are represented by an elongated vomer terminating in a prominent spine, and by incurved cerci featuring a bilobed apex equipped with a sharp blade-like ridge. Intraspecific variation in body colouration and hind wing length occurs in females. The new species lives at 400-650 m elevation in the surroundings of the Sablang and Tuba regions, in the Benguet Province of Luzon island. Host plants include Ficus spp. (Moraceae), and Pipturus spp. and Leucosyke spp. (Urticaceae). Observations on the mating and defensive behaviour are presented. Orthomeria (Orthomeria) catadromus (Westwood, 1859) is recognised as a junior synonym of Orthomeria (Orthomeria) pandora (Westwood, 1859), syn. n. A lectotype is designated for both species. Finally, an updated identification key to the species of the subgenus Orthomeria is provided.

Morphology of the terminalia of the stick insect Dajaca napolovi from Vietnam (Insecta: Phasmatodea)

Aschiphasmatinae is a small group of stick insects from the Oriental region whose genital morphology has been rarely described in detail. The subfamily is of particular interest, as phylogenetic studies have shown Aschiphasmatinae to be the sister group to the remaining Euphasmatodea. In this paper, the male and female terminalia are described for the first time in Dajaca napolovi Brock, a little known aschiphasmatine species from Vietnam. In the male, the transversally undivided abdominal sternum IX and gently incurved cerci with a conspicuous apical tooth represent apomorphies of Aschiphasmatinae. Thorn pads on the hind margin of abdominal tergum X consist of only a single row of 6–7 ventrally oriented teeth. The simple thorn pad structure of Aschiphasmatinae can represent an ancestral condition for Euphasmatodea. The vomer on venter X is well‐developed and features two unusually large basal apodemes and a strongly developed apical spine showing a specialized streaked surface micropattern. Female terminalia are characterized by an unkeeled abdominal sternum VIII covering the reduced primary ovipositor. Gonapophysis VIII does not extend beyond the tip of gonapophysis IX. An asymmetry concerning the size of the paired gonapophyses is reported for the first time in Phasmatodea.

Phamartes coronatus gen. nov. sp. nov. a new genus and species of stick insect from Bach Ma National Park, central Vietnam (Phasmida, Diapheromeridae, Necrosciinae)

A new genus and species of stick insect Phamartes coronatus gen. nov. sp. nov. from Bach Ma National Park, central Vietnam is described and illustrated from both sexes and the egg. The genus is most closely related to Oxyartes Stål, 1875, but easily distinguishable by the presence of fully developed alae, the head armature and the split and asymmetrical anal segment, a character previously unknown in Necrosciinae.

Fig. 4 In The Oriental Stick Insect Genus Orestes Redtenbacher, 1906: Taxonomical Notes And Six New Species From Vietnam (Phasmida: Heteropterygidae: Dataminae)

Fig. 4. Orestes spp., diagnostic characters of ♀♀ (not to scale). A–D, head, lateral view. A, O. bachmaensis sp. nov. B, O. dittmari sp. nov. C, O. draegeri sp. nov. D, O. subcylindricus (Redtenbacher, 1906) comb. nov. E–H, apex of abdomen, anterolateral view. E, O. botot sp. nov. F, O. dittmari sp. nov. G, O. krijnsi sp. nov. H, O. mouhotii (Bates, 1865). I–J, mesonotum, lateral view. I, O. botot sp. nov. J, O. subcylindricus (Redtenbacher, 1906) comb. nov. K–L, abdomen dorsal view. K, O. draegeri sp. nov. L, O. krijnsi sp. nov. M–N, metafemur, lateral view. M, O. bachmaensis sp. nov. N, O. dittmari sp. nov. C = carina; PmN = posteromedian notch;PlM = posterolateral margin.

Brockphasma spinifemoralis gen. et spec. nov.: a new phasmid genus and new species of Neohiraseini (Phasmida: Necrosciinae) from Vietnam.

A new genus of stick insects, Brockphasma Ho gen. nov., with the type-species, Brockphasma spinifemoralis Ho, Liu, Bresseel & Constant spec. nov., is described and illustrated from Vietnam. Both sexes, the egg and the first instar nymph are described and figured. Data on the habitat and natural foodplants are provided. Brockphasma Ho gen. nov. is differentiated from other genera in Neohiraseini by spinose occiput, anterior region of mesonotum with a spinose hump and spinose anterodorsal and posterodorsal carinae of femora. A key to the genera of Neohiraseini from Vietnam is given.