How to escape from insect egg parasitoids: a review of potential factors explaining parasitoid absence across the Insecta.

The egg is the first life stage directly exposed to the environment in oviparous animals, including many vertebrates and most arthropods. Eggs are vulnerable and prone to mortality risks. In arthropods, one of the most common egg mortality factors is attack from parasitoids. Yet, parasitoids that attack the egg stage are absent in more than half of all insect (sub)orders. In this review, we explore possible causes explaining why eggs of some insect taxa are not parasitized. Many insect (sub)orders that are not attacked by egg parasitoids lack herbivorous species, with some notable exceptions. Factors we consider to have led to escape from egg parasitism are parental egg care, rapid egg development, small egg size, hiding eggs, by e.g. placing them into the soil, applying egg coatings or having thick chorions preventing egg penetration, eusociality, and egg cannibalism. A quantitative network analysis of host-parasitoid associations shows that the five most-speciose genera of egg parasitoids display patterns of specificity with respect to certain insect orders, especially Lepidoptera and Hemiptera, largely including herbivorous species that deposit their eggs on plants. Finally, we discuss the many counteradaptations that particularly herbivorous species have developed to lower the risk of attack by egg parasitoids.

Magnetic resonance evaluation of the pediatric knee after arthroscopic fixation of osteochondral lesions with biodegradable nails.

PURPOSE: To use magnetic resonance imaging (MRI) to investigate the knee joint of children following arthroscopic fixation of osteochondral lesions using bioabsorbable nails and to correlate these imaging findings with time from arthroscopic treatment and with risk factors at the time of imaging. MATERIALS AND METHODS: Our study included postarthroscopic MRI studies from 58 children (mean age at arthroscopy, 13.8 + 2.1 years) who have undergone bioabsorbable nail fixation of unstable osteochondral lesions between February 1, 2011 and September 30, 2017. All studies were retrospectively reviewed for broken nails, intra-articular debris, and internal knee derangement. Demographic information and information pertaining to active symptoms was obtained from both MRI questionnaire that was completed at the time of the study and clinical note that preceded the study. Marginal logistic regression models estimated using generalized estimating equations (GEE) were used to identify factors associated with a broken nail and joint effusion. RESULTS: A total of 104 postoperative studies were reviewed, which included 60 with symptoms and 44 without symptoms. Nail breakage was present in 38 (36.6%) studies and associated with presence of symptoms (OR 2.43, p = 0.036) and effusion (OR 2.76, p = 0.025). An effusion was present in 40 (38.5%) studies which decreased with increasing time from treatment (OR 0.89, p = 0.007) and increased with symptoms (OR 10.87, p < 0.001). Meniscal tear was present on 8 (7.7%) and chondral irregularity on 14 (13.5%) studies. CONCLUSION: Broken nail, effusion, and less commonly, meniscal tears and chondral irregularity, are all complications that can arise following fixation of osteochondral lesions with bioabsorbable nails. MRI can serve as a valuable tool in assessing these complications.

Short-range allelochemicals from a plant-herbivore association: a singular case of oviposition-induced synomone for an egg parasitoid.

Oviposition-induced plant synomones are semiochemical cues used by egg parasitoids during host selection, and are therefore considered important elements of plant defence. In this paper we show that, in the tritrophic system Brassica oleracea-Murgantia histrionica-Trissolcus brochymenae, the latter responded in a closed arena and in a static olfactometer to induced chemicals that are perceived from a very short range and after parasitoid contact with the leaf surface opposite the treated surface. An additive or synergistic effect due to (1) egg deposition, (2) feeding punctures and (3) chemical footprints of M. histrionica was observed. When all three phases were present, the parasitoid reacted to the induced synomone locally on the treated leaf area, at a close distance to the treated area, and on the leaf above the treated one, showing that there is also a systemic effect. When plants with host footprints combined with feeding punctures or with oviposition were tested, responses were obtained both locally and at a close distance, whereas in the remaining assays only local responses were observed. Induction time was less than 24 h, whereas signal duration was apparently related to the suitability of the host eggs, as parasitoids did not respond to plants carrying old or hatched eggs. These oviposition-induced short-range plant synomones might have an important role in the host location process after parasitoid landing on the plant, in different combinations with the host kairomones involved in the system studied here.

Source of the host marking pheromone in the egg parasitoid Trissolcus basalis (Hymenoptera: Scelionidae).

After oviposition, Trissolcus basalis females always mark the host's surface, depositing host marking substances for herself and to warn other ovipositing females. The perception of these host marking substances, probably through the antennae, can induce the female to leave and seek healthy hosts. Parasitoid females exposed to conspecific parasitized egg masses left the host egg masses significantly more often than when exposed to non-parasitized egg masses. More egg mass leaving behavior also was observed when the egg masses were treated with Dufour's gland secretion but not when treated with secretion from the common oviducts. The common oviduct has a secretory epithelium that produces electron-dense vesicles, probably containing proteinaceous substances. The secretory cells of the accessory gland, Dufour's gland, contain electron-lucid vesicles, whose secretion appears to be a lipid similarly to that found in pheromone secreting glands. Ultrastructural and behavioral evidence suggests that Dufour's gland is the host marking pheromone source.

Native Lygus spp. (Heteroptera: Miridae) damaging introduced Hibiscus cannabinus in Italy.

Kenaf, Hibiscus cannabinus L, an introduced tropical fiber crop, is attacked in central Italy by the native mirid bugs Lygus rugulipennis Poppius and L. pratensis (L.), thus establishing novel insect-plant associations. Feeding by Lygus bugs damages the apical meristem, with consequent development of secondary stems and leaf tattering. In a laboratory experiment, both species caused apical meristem damage on potted kenaf. In a field experiment with caged plots, the percentage of damaged plants was significantly higher in plots artificially infested with multiple releases of Lygus spp. compared with a single release and with the protected control without Lygus spp. In naturally infested control plots, the percentage of damaged plants was intermediate. Plant height decreased as a function of the number of damaged meristems. Mean plant height was significantly lower in the multiple-release treatment compared with the single-release treatment and the protected control. Dry biomass was significantly lower in the multiple-release plots compared with the protected control, and intermediate in the single-release plots. In a field experiment with three kenaf cultivars naturally infested by Lygus spp., plant height and stem diameter were significantly lower in damaged plants compared with healthy plants. Dry weights of plants, stems, and basts were also lower, depending on the cultivar, whereas the bast/core ratio was not affected. Stem lesions developed due to feeding or incisions made by ovipositing females. Lesions and eggs were significantly more abundant on plants with damaged apical meristems compared with healthy plants. Damage mechanisms by Lygus spp. and consequences of new crop introductions are discussed.

Antennal multiporous sensilla: their gustatory features for host recognition in female parasitic wasps (insecta, Hymenoptera: Platygastroidea).

In parasitic wasps, various kinds of antennal plates have been interpreted as olfactory organs due to the presence of numerous pores. However, on the basis of ultrastructural investigations, some of these multiporous plates were revealed as being release sites of exocrine glands while others were postulated to have a gustatory function. Such sensilla, present only on female antennae, show unique features, found exclusively in Platygastroidea, with some differences between Scelionidae and Platygastridae. The cuticular apparatus consists of a short basiconic shaft with an apical multiporous area, the pores of which are covered by movable structures. The cellular components are made up of a remarkable number of sensory neurons, from 200 to 220, and an undefined number of sheath cells. These multiporous sensilla have tubular accessory glands that release their secretion through the socket sensillum only in scelionids. These morphological characters, combined with behavioral observations, strongly suggest a gustatory function, although electrophysiological studies are still needed to confirm this. A new terminology for antennal multiporous plates is discussed in relation to their different functions.

Sexual attitudes and associated psychiatric features among youths in a community sample.

OBJECTIVE: Using an epidemiological sample of adolescents, this study examined associations between the acceptability of potential sex partners and psychiatric status. METHOD: Subjects aged 14 to 17 years (N = 161) from the Columbia site of the National Institute of Mental Health (NIMH) Methods for the Epidemiology of Child and Adolescent Mental Disorders (MECA) Study were grouped according to their responses about the acceptability of youths their age having sex with partners of (1) the opposite sex, (2) neither sex, and (3) either sex. Youths endorsing either sex were compared with youths endorsing the other two types of partners according to psychiatric indicators obtained from the Diagnostic Interview Schedule for Children Version 2.3. RESULTS: Higher-than-expected proportions of male and female youths endorsed sex partners of either sex as potentially acceptable for peers. Youths who did so abused substances and used mental health services more than peers but did not differ in rates of suicidal ideation or attempts. Males endorsing either sex also had higher rates of mood disorders and, compared with males endorsing only the opposite sex, a higher intelligence level. CONCLUSIONS: Attitudes about the potential acceptability of sex partners for peers are associated with psychiatric morbidity and mental health service use in the respondent as well as with intelligence level in males. Youths who endorsed potential sex partners of either sex, especially males, appear to be at higher risk for multiple psychiatric problems.

Behavioral correlates for minor volatile compounds from stink bugs (Heteroptera: Pentatomidae).

Many terrestrial Heteroptera have small, but functional, dorsal abdominal glands as adults. The chemistry, and associated intra- and inter-specific behavior, for dorsal abdominal gland secretions from 10 species representing four genera of Pentatomidae was investigated. Eighteen volatile compounds were identified in species-specific blends from the dorsal abdominal gland secretions ofEuschistus, Acrosternum, andEurydema adults, including aliphatic, aromatic, and terpenoid constituents. Evidence from bioassays is presented that parasitic Tachinidae (Diptera) and Scelionidae (Hymenoptera) use these secretions as kairomones. A field experiment was performed to test the hypothesis that minor volatiles increase the specificity of the main pheromone component from NearcticEuschistus species, methyl (2E,4Z)-decadienoate. However, significantly fewer individuals ofE. tristigmus were captured in traps baited with the complete blend for this species than in traps baited with methyl (2E,4Z)-decadienoate alone. Thus, at the concentrations tested, these kinds of dorsal abdominal gland secretions may be epideictic, promoting spacing in the natural habitat.

A long-range attractant kairomone for egg parasitoidTrissolcus basalis, isolated from defensive secretion of its host,Nezara viridula.

A short-chain α,ß-unsaturated aldehyde, (E)-2-decenal, present in the defensive metathoracic gland ofNezara viridula (L.) (Heteroptera: Pentatomidae), stimulates a behavioral response in the egg parasitoidTrissolcus basalis (Woll.) (Hymenoptera: Scelionidae). Preliminary studies showed thatT. basalis are attracted to an area containing adultN. viridula, but we also found that femaleT. basalis would examine and probe glass beads coated with an acetone extract of the metathoracic gland from males or females. Using this bioassay, the kairomone was isolated by bioassay directed by preparative gas chromatography and identified by NMR and mass spectrometry as (E)-2-decenal. The biological activity of the identified aldehyde was compared with analogs to determine specificity. An unstable Z isomer was found to be more active but not present in detectable or behaviorly relevant levels in the host, based on the bell-shaped dose-response curve of the two isomers. An investigation was also designed to determine if theE isomer was also responsible for the egg recognition kairomone activity previously reported. However, no 2-decenal isomers were detected in host egg extracts and the chemical characteristics of the 2-decenal isomers differ from the unidentified egg recognition kairomone. The role of the (E)-2-decenal in attracting femaleT. basalts toN. viridula was demonstrated in a Y-tube olfactometer; this alk-2-enal appears to act as a long-range kairomone orientingT. basalis toNezara populations.

[The noninvasive diagnosis of cerebral arteriovenous aneurysms by transcranial dopplerography]. / Neinvazivnaia diagnostika arteriovenoznykh anevrizm golovnogo mozga metodom trankranial'noi doplerografii.

An absolute increase of blood velocity in the arteries of brain arteriovenous aneurysms is of the greatest importance in their diagnosis by transcranial Doppler ultrasonography. If the branches of brain great vessels are involved in blood supply of arteriovenous aneurysms, there is an increase in blood velocity only in the initial portions of the great vessels up to the origin of these branches. A relative increase in brain great vasculature blood velocity is of great diagnostic value. Arteriovenous aneurysms whose blood supply is provided by the anterior cerebral artery are typified by higher blood velocity in the anterior cerebral artery than that in the middle cerebral artery, whereas the reverse is true for health.