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Drilling into solid substrates with slender beam-like structures is a mechanical challenge, but is regularly done by female parasitic wasps. The wasp inserts her ovipositor into solid substrates to deposit eggs in hosts, and even seems capable of steering the ovipositor while drilling. The ovipositor generally consists of three longitudinally connected valves that can slide along each other. Alternative valve movements have been hypothesized to be involved in ovipositor damage avoidance and steering during drilling. However, none of the hypotheses have been tested in vivo. We used 3D and 2D motion analysis to quantify the probing behavior of the fruit-fly parasitoid Diachasmimorpha longicaudata (Braconidae) at the levels of the ovipositor and its individual valves. We show that the wasps can steer and curve their ovipositors in any direction relative to their body axis. In a soft substrate, the ovipositors can be inserted without reciprocal motion of the valves. In a stiff substrate, such motions were always observed. This is in agreement with the damage avoidance hypothesis of insertion, as they presumably limit the overall net pushing force. Steering can be achieved by varying the asymmetry of the distal part of the ovipositor by protracting one valve set with respect to the other. Tip asymmetry is enhanced by curving of ventral elements in the absence of an opposing force, possibly due to pretension. Our findings deepen the knowledge of the functioning and evolution of the ovipositor in hymenopterans and may help to improve man-made steerable probes.

Antennae are often considered to be the nostrils of insects. Here, we sequenced the transcriptome of the pheromone gland-ovipositor complex of Helicoverpa assulta and discovered that an odorant receptor (OR) gene, HassOR31, had much higher expression in the ovipositor than in antennae or other tissues. To determine whether the ovipositor was involved in odorant detection, we co-expressed HassOR31 and its co-receptor, HassORco, in a Xenopus oocyte model system, and demonstrated that the OR was responsive to 12 plant odorants, especially Z-3-hexenyl butyrate. These odorants elicited electrophysiological responses of some sensilla in the ovipositor, and HassOR31 and HassORco were co-expressed within ovipositor sensilla. Two oviposition preference experiments showed that female moths lacking antennae still preferentially selected oviposition sites containing plant volatiles. We suggest that the expression of HassOR31 in the ovipositor of H. assulta helps females to determine precise egg-laying sites in host plants. When most insects reproduce they lay eggs that hatch into juveniles known as larvae. To provide good sources of food for the larvae, the adult insects have to carefully select where to lay the eggs. Host plants produce specific sets of chemicals known as odorants that the adult insects are able to smell using proteins called odorant receptors. It is generally thought that odorant receptors in the antennae on the head are responsible for guiding adult insects to good egg-laying sites. However, recent studies have reported that odorant receptors are also present in the egg-laying organs of several different species of moth. It remains unclear what role these odorant receptors may play in egg-laying. The oriental tobacco budworm (Helicoverpa assulta) is considered a serious pest in agriculture. The adult moths lay their eggs on a narrow range of plants in the nightshade family including tobacco and hot pepper. Li et al. have now investigated the odorant receptors of H. assulta and found that one gene for an odorant receptor called HassOR31 was expressed much more in the egg-laying organs of the moths than in the antennae. Further experiments showed that this receptor was tuned to respond to 12 odorants that also stimulated responses in the egg-laying organ of H. assulta. Together these findings suggest that this odorant receptor in the egg-laying organ helps the moths find suitable host plants to lay their eggs on. The work of Li et al. may help us understand how H. assulta evolved to lay its eggs on specific members of the nightshade family and lead to new methods of controlling this pest. An insect’s sense of smell guides many other behaviors including finding food, mates and avoiding enemies. Therefore, these findings may inspire researchers to investigate whether odorant receptors in the antennae or other organs guide these behaviors.

Archaeocercoides puchkovi Simutnik, gen. et sp.nov. , and Rovnopositor voblenkoi Simutnik, gen. et sp.nov. , are described and illustrated based on female specimens from late Eocene Rovno amber. Like most previously described Eocene Encyrtidae, the new taxa differ from the majority of extant encyrtids by the apical or nearly apical position of the cerci, the short radicle, and the long marginal vein of the forewing. Both new genera are characterized by a strongly reduced ovipositor sheaths but long and upwardly bent ovipositor stylets (in the “ovipositing position”), a stigmal vein with a long uncus, and the absence of a filum spinosum. The new genera differ from each other in the width of frontovertex, the location of the cerci, and the lengths of funicular segments and marginal vein. A. puchkovi was fossilized near a Coccoidea crawler.

Abstract In this study, 5 species of Trichogramma Westwood were evaluated for the biological control of Spodoptera frugiperda (JE Smith), concerning the physical characteristics of female Trichogramma. The results showed that Trichogramma chilonis Ishii, Trichogramma dendrolimi Matsumura, and Trichogramma ostriniae Pang et Chen exhibited high parasitism rates, emergence rates, and offspring numbers, with the highest values observed for T. ostriniae. The ovipositor length of Trichogramma japonicum Ashmead and T. dendrolimi were longer than those of other species, and the hind tibia length was the shortest in Trichogramma cacoeciae Marchal. We further evaluated relationships between the parasitism ability of Trichogramma and various morphological indexes based on Spearman’s rank correlation coefficients. A positive correlation was found between the parasitism rate and hind tibia length of T. cacoeciae. In T. dendrolimi, the parasitism rate was negatively correlated with ovipositor width and positively correlated with the length-width ratio of the ovipositor. A significant positive correlation was observed between the proportion of female offspring and the mother’s ovipositor length in T. japonicum. However, there were no significant correlations between morphological indexes and indexes of parasitism in T. ostriniae. Overall, the parasitic abilities of T. chilonis on S. frugiperda eggs were significantly correlated with the morphology of the female ovipositors. Graphical Abstract Graphical Abstract

Fig wasps (pollinators and non-pollinators) develop in the same fig of a fig tree. This study was conducted to compare the body size and ovipositor length of the fig wasps developing inside the figs of a dioecious fig tree, Ficus hispida L. D-phase figs were sampled from F. hispida male trees grown naturally in Lam Kruet Village, Lhoknga, Aceh Besar. Upon emergence, fig wasps’ body size and ovipositor length were measured at the Biological Control Laboratory, Faculty of Agriculture, Syiah Kuala University. The results showed that the pollinator Ceratosolen solmsi marchali accounted for 70.82% of all fig wasps in F. hispida. The non-pollinators: Apocrypta bakeri, Philotrypesis pilosa , and Philotrypesis sp. accounted for 13.47%, 11.47%, and 4.24%, respectively. The average body size of pollinators was 1.92 ± 0.01 mm, while the body sizes of non-pollinators ranged from 2.07 ± 0.01 mm to 2.09 ± 0.01 mm. The ovipositor length of pollinators was 0.84 ± 0.00 mm. The ovipositor length of non-pollinators was significantly longer than that of pollinators, with the average length of A. bakeri being 5.77 ± 0.03 mm, P. pilosa being 7.64 ± 0.07 mm, and Philotrypesis sp. being 7.48 ± 0.08 mm. The ovipositor length of non-pollinators was four times longer than their body size. The difference in ovipositor length was related to the different egg-laying methods. The female pollinators enter the fig through the ostiole and lay eggs directly into the female flowers. In contrast, non-pollinators lay their eggs by injecting their ovipositor through the fig wall.

In percutaneous interventions, long and thin needles are used to reach deep target locations within the body. However, inserting a long and thin needle into the tissue can cause needle buckling, resulting in poor control of the needle’s trajectory and reduced targeting accuracy. In nature, the female parasitic wasp prevents the buckling of her long and slender ovipositor through a self-propelled motion. This study presents a stationary actuation system that can advance a wasp-inspired self-propelled needle consisting of seven 0.3-mm stainless steel rods with a theoretically unlimited insertion length. Based on the pencil lead advance mechanism in mechanical pencils that advances the pencil lead at a fixed increment when the pencil button is pushed, our actuation system advances the seven needle segments that comprise our needle by locking, advancing, releasing, and retracting the advance mechanisms. Experimental evaluation demonstrated that the actuation system successfully executes these actions, enabling step-by-step propulsion of the needle segments in gelatin-based tissue-mimicking phantoms. Moreover, the needle achieved mean motion efficiencies of 98 ± 2%, 68 ± 5%, and 57 ± 7% in air, 5-wt% gelatin, and 10-wt% gelatin, respectively, over 15 actuation cycles. This actuation system prototype, which is based on a mechanical pencil, is a step forward in developing self-propelled needles for targeting deep tissue structures.

Background While the communities constituted by phytophageous insects and their parasites may represent half of all terrestrial animal species, understanding their diversification remains a major challenge. A neglected idea is that geographic phenotypic variation in a host plant may lead to heterogeneous evolutionary responses of the different members of the associated communities. This could result in diversification on a host plant by ecological speciation in some species, leading to geographic variation in community composition. In this study we investigated geographic variation of inflorescence receptacle size in a plant, Ficus hirta , and how the hymenopteran community feeding in the inflorescences has responded. Our predictions were: Inflorescence size variation affects wasp species differently depending on how they access oviposition sites. In some affected lineages of wasps, we may observe vicariant, parapatric species adapted to different inflorescence sizes. Results We show that fig (the enclosed inflorescence of Ficus ) wall thickness varies geographically. The fig-entering pollinating wasp was not affected, while the parasites ovipositing through the fig wall were. Two parapatric species of Philotrypesis , exhibiting strikingly different ovipositor lengths, were recorded. One species of Sycoscapter was also present, and it was restricted, like the shorter-ovipositor Philotrypesis , to the geographic zone where fig walls were thinner. Conclusions Previous work on fig wasps suggested that parapatric geographic ranges among congenerics were due to adaptation to variation in abiotic factors, complemented by interspecific competition. Our results show that parapatric ranges may also result from adaptation to variation in biotic factors. Within an insect community, differences among species in their response to geographic phenotypic variation of their host plant may result in geographically heterogeneous community structure. Such heterogeneity leads to heterogeneous interaction networks among sites. Our results support the hypothesis that plant geographic phenotypic variation can be a driver of diversification in associated insect communities, and can complement other diversification processes.

Cryptic and pseudocryptic species are common in myrmecophilous insects, making their taxonomic classification complex when based solely on morphology. This is the case for the beetles of the genus Oochrotus Lucas, 1852, a group of small tenebrionids inhabiting ant nests. In 1961, Canzoneri described one new species and eight subspecies based on the morphology of the aedeagus and ovipositor. However, in 2000, Soldati and Soldati synonymised most of these taxa, arguing that the differences found by Canzoneri were not significant. The aim of our study was to test these two competing hypotheses using a molecular approach. For this purpose, partial sequences of the nuclear gene ITS2 and the mitochondrial gene cytb were obtained from individuals from North Africa, Italy, and the Iberian Peninsula, followed by phylogenetic analyses based on Bayesian inference. The results show that specimens from these three territories are in separate lineages corresponding to three different species: 1) O. unicolor Lucas, 1852; 2) O. laurae Canzoneri, 1961, stat. rev. , and 3) O. lusitanicus Canzoneri, 1961, stat. nov. (= O. u. espagnoli Canzoneri, 1961, syn. nov. ; = O. u. hispanus Canzoneri, 1961, syn. nov .; = O. u. meridionalis Canzoneri, 1961, syn. nov. ). This new proposal diverges from both preceding hypotheses, showing an intermediate level of diversity between the two. This reflects that species of the genus Oochrotus are probably pseudocryptic, whose morphological examination may lead to misidentification in the absence of molecular data.

Uzelothrips scabrosus Hood, 1952 is the only recent representative of Uzelothripidae. The species is very important for thrips evolution understanding because it is considered an early offshoot of sub-order Terebrantia, without affinities with any other thrips taxa. The lineage that originated the group is at least 53 million years-old, by judging from it the age of the fossil species Uzelothrips eocenicus, collected from amber in France. Both species share unique morphological traits among Thysanoptera, such as forewing (when present) with no longitudinal veins but with cilia arising from sockets, antennae long and slender with circular sensorium ventrally on the apex of segment III, tentorium well developed and ovipositor membranous and with valves absent, but is tentatively classified in the suborder Terebrantia.

In the course of evolution, animals and particularly insects, have developed efficient and complex mechanisms for survival. Biomimetics aims to find applications for these features of organisms (or organs) in industry, agriculture, and medicine. One of these features is the thin, flexible, and mobile insect ovipositor, which is also capable of carrying substances and drilling various substrates, usually of plant origin. Despite the well-studied structure of the ovipositor, the principles of its operation and real possibilities remain poorly understood. In our study, we first discovered an unusual behavioral pattern of oviposition of the female parasitoid Eupelmus messene Walker (Hymenoptera: Eupelmidae): she drilled with her ovipositor through the wall of a polystyrene Petri dish and laid her egg outside the dish. Due to the transparency of the plastic, we described the technique of ovipositor movement and studied its structure using scanning electron microscopy. Our research may contribute to developing minimally invasive guided probes and various other instruments.