Controlling Lygus plant bugs (Heteroptera: Miridae) with European Peristenus relictus (Hymenoptera: Braconidae) in Canada--risky or not?

The European Peristenus relictus Loan (syn. P. stygicus) has been considered for biological control of Lygus plant bugs native to Canada. Laboratory and field studies were conducted in the area of origin to evaluate the host specificity of P. relictus. Laboratory choice and no-choice tests demonstrated that P. relictus attacked all non-target species offered (fundamental host range). However, closely related non-target mirids (tribe Mirini) were generally well accepted by P. relictus, while hosts from the tribe Stenodemini were less frequently attacked and less suitable for parasitoid development. To validate the laboratory results, a thorough examination of the parasitoid complex of common mirids in Europe was conducted to determine which non-target species may serve as alternative hosts for P. relictus in a natural situation (ecological host range). When comparing both approaches, the fundamental host range of P. relictus matched its ecological host range. In addition to three Lygus species, the ecological host range of P. relictus in the area of Schleswig-Holstein, northern Germany, contains at least 16 non-target species, including hosts belonging to the subfamilies Mirinae, Phylinae and Bryocorinae. A broad ecological and fundamental host range suggests that P. relictus is a generalist; however, P. relictus was not the primary contributor to parasitism of most non-target hosts studied. Although P. relictus is assumed to be of minor importance for regulating non-target populations in the area of investigation, the results of the present study indicate that P. relictus has the potential to use non-target host populations for reproduction.     

Spatial pattern of water bugs (Nepomorpha,Gerromorpha) at different scales in the Szigetköz (Hungary)

In 2003, 26 Heteroptera species (16 aquatic and 10 semiaquatic) were collected from 53 sampling sites in the Szigetköz region in Hungary. Hyocoris cimicoides and Gerris argentatus were the most frequent aquatic and semiaquatic species, respectively. Large differences both in the species number and species composition were observed among the different flood-prevention areas, arm systems and habitats. Strong negative correlation was found between the average number of aquatic species and current velocity, and a strong positive correlation between the average number of aquatic and semiaquatic species and macrophyte density. From a faunistic point of view, the marsh at Arak is the most interesting and valuable site.     

When did the ancestor of true bugs become stinky? Disentangling the phylogenomics of Hemiptera–Heteroptera

The phylogeny of true bugs (Hemiptera: Heteroptera), one of the most diverse insect groups in terms of morphology and ecology, has been the focus of attention for decades with respect to several deep nodes between the suborders of Hemiptera and the infraorders of Heteroptera. Here, we assembled a phylogenomic data set of 53 taxa and 3102 orthologous genes to investigate the phylogeny of Hemiptera–Heteroptera, and both concatenation and coalescent methods were used. A binode-control approach for data filtering was introduced to reduce the incongruence between different genes, which can improve the performance of phylogenetic reconstruction. Both hypotheses (Coleorrhyncha + Heteroptera) and (Coleorrhyncha + Auchenorrhyncha) received support from various analyses, in which the former is more consistent with the morphological evidence. Based on a divergence time estimation performed on genes with a strong phylogenetic signal, the origin of true bugs was dated to 290–268 Ma in the Permian, the time in Earth's history with the highest concentration of atmospheric oxygen. During this time interval, at least 1007 apomorphic amino acids were retained in the common ancestor of the extant true bugs. These molecular apomorphies are located in 553 orthologous genes, which suggests the common ancestor of the extant true bugs may have experienced large-scale evolution at the genome level.     

Are mitochondria a permanent source of reactive oxygen species?

The observation that in isolated mitochondria electrons may leak out of the respiratory chain to form superoxide radicals (O(2)(radical-)) has prompted the assumption that O(2)(radical-) formation is a compulsory by-product of respiration. Since mitochondrial O(2)(radical-) formation under homeostatic conditions could not be demonstrated in situ so far, conclusions drawn from isolated mitochondria must be considered with precaution. The present study reveals a link between electron deviation from the respiratory chain to oxygen and the coupling state in the presence of antimycin A. Another important factor is the analytical system applied for the detection of activated oxygen species. Due to the presence of superoxide dismutase in mitochondria, O(2)(radical-) release cannot be realistically determined in intact mitochondria. We therefore followed the release of the stable dismutation product H(2)O(2) by comparing most frequently used H(2)O(2) detection methods. The possible interaction of the detection systems with the respiratory chain was avoided by a recently developed method, which was compared with conventional methods. Irrespective of the methods applied, the substrates used for respiration and the state of respiration established, intact mitochondria could not be made to release H(2)O(2) from dismutating O(2)(radical-). Although regular mitochondrial respiration is unlikely to supply single electrons for O(2)(radical-) formation our study does not exclude the possibility of the respiratory chain becoming a radical source under certain conditions.     

Are Chironomidae (Diptera) good indicators of water scarcity? Dryland streams as a case study

Water scarcity is becoming one of the greatest challenges that human societies will face during this century. Monitoring water availability is expensive and technically challenging. In this regard, biological communities (e.g. aquatic insects) offer a cost-effective alternative, since they integrate temporal and spatial hydrological variability.Here we explore the potential of Chironomidae (Diptera), which have been usually neglected due to their complex taxonomy, as indicators of both local habitat condition and water scarcity. The study took place in 28 sites across seven dryland streams distributed within a 400 km² section of the Upper San Pedro River basin, southeastern Arizona. The selected streams covered a wide range of hydrological variability, which was continuously measured through the deployment of 15 electrical resistance (ER) sensors. Chironomidae taxa with no drought-resistance strategies were rarely found in streams that experienced frequent drying events (i.e. intermittent and ephemeral streams), suggesting that droughts have the potential to reduce species richness due to local extinctions of drought-intolerant taxa. Intermittent and ephemeral streams registered low canopy cover and a significantly higher abundance of scrapers (which mainly feed on algae) and shredders (feeding on poorly decomposed coarse organic material). This suggests that structural changes associated to drought (e.g. reduced canopy cover and decomposition rates) might lead to changes in the functional composition of the Chironomidae assemblages. We conclude that Chironomidae species can be used as indicators of hydrological variability and the impacts of drought on streams in the absence of flow gauges.     

The Nabidae (Insecta,Hemiptera, Heteroptera) of?Argentina

In Argentina, five genera and 14 species are recorded in the subfamilies Prostemmatinae and Nabinae: Hoplistoscelis sordidus Reuter, Lasiomerus constrictus Champion, Metatropiphorus alvarengai Reuter, Nabis argentinus Meyer-Dür, Nabis (Tropiconabis) capsiformis Germar, Nabis faminei Stål, Nabis paranensis Harris, Nabis punctipennis Blanchard, Nabis roripes Stål, Nabis setricus Harris, Nabis tandilensis Berg, Pagasa (Pagasa) costalis Reuter, Pagasa (Lampropagasa) fuscipennis Reuter and Pagasa (Pagasa) signatipennis Reuter.     

Flight potential of Lygus lucorum (Meyer-Dür) (Heteroptera: Miridae)

Lygus lucorum (Meyer-Dür) is a key pest of Bt cotton in China. This study reports on its flight potential examined by a flight-mill system. We found that 10-d-old mated females engaged in flight over the greatest distance (40.1 +/- 5.2 km) and duration (7.7 +/- 1.0 h) in 24-h flight assays in relation to age, sex, and mating status. Optimum temperature for flight was 20 degrees C, and optimum relative humidity was 75% RH. Flight potential of 10-d-old mated females under the optimum conditions (20 degrees C and 75% RH) was tested continuously for 48 h. Results showed that the flight distance amounted to 67.3 +/- 9.7 km, with a maximum distance of 151.3 km. This study shows that L. lucorum has the potential to undertake long-distance flight. The information will help in the development of the forecast and management of L. lucorum.     

Are red wood ants (Formica rufa-group) tectonic indicators? A statistical approach

Recent research in seismically active areas indicated that the spatial distributions of geochemical soil gas anomalies and nests of red wood ants (RWA; Formica rufa-group) are strongly correlated. Here we applied a modified Hough Transform (mHT) and an Iterative Mode Detection (IMD) to RWA nest positions, which we mapped in two Southwest German study areas (Black Forest and Bodanrück), to test for statistical significance of correlation with tectonic features. RWA densities in the seismically active study areas reaching up to 1600 nests/100 ha are about 100× higher than overall values for Northern and Southern Germany. Since the shape of edges of the study area was found to strongly influence the selection of distribution patterns, all subsequent analyses were carried out for circular study areas. Results of the mHT applied on the RWA nests in both study areas clearly showed several modes which correspond to preferred directions. Centres of the modes further processed by IMD transferred into a GIS as RWA prototype lines showed very dominant directions of RWA nest distributions in right lateral strike-slip mode in WNW-ESE resp. NW-SE direction but also in extension direction caused by the recent main stress field in NW-SE resp. NNW-SSE direction. It could thus be clearly shown that the large scale spatial distribution of RWA nests directly reflects significant components of the present day stress field and its accompanying conjugated shear systems: Linear alignments of RWA nests indicate the course of active degassing faults zones and nest clusters indicate area-wide geochemical anomalies respectively crosscut zones of different fault systems. Furthermore, directions of re-activated shear systems, e.g. from Eocene-Oligocene but also from Late Jurassic that had been modified by overprinting due to changes of the main stress field could be identified. Therefore, RWA prototype lines complement and clarify the shear sense and the tectonic regime identified in previous tectonic studies. The high degree of statistical significance of these results will also allow a rating with former contrasting interpretations as to the drivers of RWA distributions.     

Are mitochondria a spontaneous and permanent source of reactive oxygen species?

The bioenergetic properties of mitochondria in combination with the high turnover rate of dioxygen qualify these organelles for the formation of reactive oxygen species (ROS). The assumption that mitochondria are the major intracellular source of ROS was essentially based on in vitro experiments with isolated mitochondria. The transfer of these data to the living cell may, however, be incorrect. Artefacts due to the preparation procedure or inadequate detection methods of ROS may lead to false positive results. Inhomogeneous results were found to be due to an interaction of the detection system with components of the respiratory chain which could be avoided by a recently developed non-invasive method. One of the most critical electron transfer steps in the respiratory chain is the electron bifurcation from ubiquinol to the cytochrome bc(1) complex. This electron bifurcation requires the free mobility of the head domain of the Rieske iron-sulfur protein. Inhibition of electron bifurcation by antimycin A causes leakage of single electrons to oxygen which results in the release of ROS. Hindrance of electron bifurcation was also observed following alterations of the physical state of membrane phospholipids in which the cytochrome bc(1) complex is inserted. Irrespective of whether the fluidity of the membrane was elevated or decreased, electron flow rates to the Rieske iron-sulfur protein were drastically reduced. Concomitantly superoxide radicals were released from these mitochondria, strongly suggesting the involvement of the ubiquinol/cytochrome bc(1) redox couple in this process.     

Heterochrony in Tingidae (Insecta: Heteroptera): paedomorphosis and/or peramorphosis?

Tingidae (Heteroptera: Insecta) exhibit cephalic tubercles that present a very diverse shape in larvae but that are much simpler in adults. A phylogeny based on adult and last instar characters showed that these tubercles evolved independently from simple to complex states in two clades, and reversed from complex to simple in some taxa. These homoplasies are analysed in the light of ontogenetic sequences and interpreted as heterochronic events. The general trend of evolution of the cephalic tubercles in Tingidae is in mosaic, and could be generally peramorphic, with some isolated cases of paedomorphosis.  Journal compilation © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 93 , 71–80. No claim to original French government works.     

Phylogeny of ladybirds (Coleoptera: Coccinellidae): Are the subfamilies monophyletic?

The Coccinellidae (ladybirds) is a highly speciose family of the Coleoptera. Ladybirds are well known because of their use as biocontrol agents, and are the subject of many ecological studies. However, little is known about phylogenetic relationships of the Coccinellidae, and a precise evolutionary framework is needed for the family. This paper provides the first phylogenetic reconstruction of the relationships within the Coccinellidae based on analysis of five genes: the 18S and 28S rRNA nuclear genes and the mitochondrial 12S, 16S rRNA and cytochrome oxidase subunit I (COI) genes. The phylogenetic relationships of 67 terminal taxa, representative of all the subfamilies of the Coccinellidae (61 species, 37 genera), and relevant outgroups, were reconstructed using multiple approaches, including Bayesian inference with partitioning strategies. The recovered phylogenies are congruent and show that the Coccinellinae is monophyletic but the Coccidulinae, Epilachninae, Scymninae and Chilocorinae are paraphyletic. The tribe Chilocorini is identified as the sister-group of the Coccinellinae for the first time.     

Are extraversion and openness indicators of a slow life history strategy?

Theory and data generally concur that a slower Life History Strategy (LHS) is associated with higher Conscientiousness, Agreeableness and Emotional Stability. Whether Extraversion and Openness are indicators of a slow LH, or whether they include both fast and slow LH components, remains unresolved. I addressed these questions in two studies: one of university students observed via periodic brief audio recordings during 72 h of their daily lives, and the second a re-analysis of data from Block and Block's (2006) longitudinal study. In both studies, I operationalized LHS as the correlation between an individual's California Q-Sort (CAQ) profile and the slow Life History (SLH) CAQ template created by Sherman et al. (2013) and Dunkel et al. (2015). I calculated Five Factor Model dimension scores using McCrae et al's (1986) method. In both samples, individuals whose CAQ profile more closely resembled the SLH template were higher in Conscientiousness, Agreeableness, and Emotional Stability than those pursuing a faster LHS. Extraversion was unrelated to LHS, while Openness in the Block and Block data set was actually associated with a faster LHS. Analysis of individual CAQ items revealed some differences between the studies. Generally, Extraversion-loading items tapping excitement-seeking and self-dramatization, and Openness-loading items tapping nonconformity, were associated with a faster LHS. Participants in the audio recording study also completed a HEXACO personality inventory and the Arizona Life History Battery. LHS as measured by the ALHB was uncorrelated with LHS as measured by the CAQ. Controlling for Extraversion yielded a significant positive relationship between the two LHS measures, suggesting that their poor convergent validity resulted from differences in their coverage of Extraversion-related content.     

Quality assessment of the predatory bugs Podisus maculiventris (Say) and Podisus sagitta (Fab.) (Heteroptera: Pentatomidae) after prolonged rearing on a meat—based artificial diet

The predatory stinkbugs Podisus maculiventris and Podisus sagitta were reared for more than 15 consecutive generations on a meat—based artificial diet. When they were returned to a diet of live prey (larvae of the pyralid Galleria mellonella) after different generations on the artificial diet, developmental and reproductive traits were similar to those of bugs continuously reared on live prey. Under laboratory conditions, predation rates for nymphs and adults of both pentatomids on larvae of the noctuid Spodoptera exigua were found to be unaffected by the previous diet. The results suggest that long—term rearing of P. maculiventris and P. sagitta on the meat—based artificial diet did not substantially affect the quality of the predators.     

Reindeer antlers: visual indicators of individual quality?

Fluctuating asymmetry (FA) in ornamental characters may reflect developmental stability in the translation from genotype to phenotype. Antlers of reindeer show FA, are visually conspicuous ornaments and are important in intraspecific assessment. We show that there is a negative relationship between size and asymmetry in visual antler characteristics (i.e., antler length and number of tines) among free-ranging male reindeer in rut. This indicates that individuals that develop large ornaments are better able to buffer developmental stress than individuals that develop small ornaments. There is no relationship between asymmetry in antler length and asymmetry in jaw length, suggesting that symmetry in antlers does not reflect overall body symmetry. This difference may be caused by trait-specific sensitivity to developmental stress. Such stress may partly be caused by parasites, which show a positive association with asymmetry in antlers, but no relationship to asymmetry in jaws. Our results indicate that antlers may be exposed to directional selection in a visual signaler-receiver system and that information about parasite burden may be obtained from evaluation of asymmetry in antlers developed under exposure to a multitude of environmental stresses. Received: 8 October 1996 / Accepted: 13 January 1997     

Are morphometric indices accurate indicators of stored energy in herring Clupea harengus?

The accuracy of the morphometric indices Fulton's K, somatic K and relative condition factor, K_n, as measures of individual North Sea herring Clupea harengus muscle fat content was investigated using the Distell Fish Fat meter. The accuracy of fat‐meter readings from an individual fish was validated by comparison with Soxhlet extraction analysis. The studies conducted demonstrated that Fulton's K is not consistently or strongly correlated with individual C. harengus muscle fat content, as defined by the fat‐meter estimates. The study shows that somatic K and K_n may be better indices of individual North Sea C. harengus muscle fat content than Fulton's K. These morphometric indices, however, should only be used after prior validation against a more direct measure of fat content.     

Are hippos Africa's most influential megaherbivore? A review of ecosystem engineering by the semi-aquatic common hippopotamus

Megaherbivores perform vital ecosystem engineering roles, and have their last remaining stronghold in Africa. Of Africa's remaining megaherbivores, the common hippopotamus (Hippopotamus amphibius) has received the least scientific and conservation attention, despite how influential their ecosystem engineering activities appear to be. Given the potentially crucial ecosystem engineering influence of hippos, as well as mounting conservation concerns threatening their long-term persistence, a review of the evidence for hippos being ecosystem engineers, and the effects of their engineering, is both timely and necessary. In this review, we assess, (i) aspects of hippo biology that underlie their unique ecosystem engineering potential; (ii) evaluate hippo ecological impacts in terrestrial and aquatic environments; (iii) compare the ecosystem engineering influence of hippos to other extant African megaherbivores; (iv) evaluate factors most critical to hippo conservation and ecosystem engineering; and (v) highlight future research directions and challenges that may yield new insights into the ecological role of hippos, and of megaherbivores more broadly. We find that a variety of key life-history traits determine the hippo's unique influence, including their semi-aquatic lifestyle, large body size, specialised gut anatomy, muzzle structure, small and partially webbed feet, and highly gregarious nature. On land, hippos create grazing lawns that contain distinct plant communities and alter fire spatial extent, which shapes woody plant demographics and might assist in maintaining fire-sensitive riverine vegetation. In water, hippos deposit nutrient-rich dung, stimulating aquatic food chains and altering water chemistry and quality, impacting a host of different organisms. Hippo trampling and wallowing alters geomorphological processes, widening riverbanks, creating new river channels, and forming gullies along well-utilised hippo paths. Taken together, we propose that these myriad impacts combine to make hippos Africa's most influential megaherbivore, specifically because of the high diversity and intensity of their ecological impacts compared with other megaherbivores, and because of their unique capacity to transfer nutrients across ecosystem boundaries, enriching both terrestrial and aquatic ecosystems. Nonetheless, water pollution and extraction for agriculture and industry, erratic rainfall patterns and human–hippo conflict, threaten hippo ecosystem engineering and persistence. Therefore, we encourage greater consideration of the unique role of hippos as ecosystem engineers when considering the functional importance of megafauna in African ecosystems, and increased attention to declining hippo habitat and populations, which if unchecked could change the way in which many African ecosystems function.     

Are there costs in the repeated mating activities of female Southern stink bugs Nezara viridula?

Mating is an energy demanding process, imposing risks to physical injuries, pathogen infection and predation. Nevertheless, repeated and multiple mating are widespread even in insect species where nuptial gifts are not involved. The effects of repeated mating, by the same male, are examined on the reproductive performance of female Southern green stink bug Nezara viridula (L.). Fecundity is reduced in females mated three or four times, although there is increased longevity. Females mated once or twice produce more egg clusters and concentrate egg‐laying activity in the early part of adult life, whereas those mating more often lay eggs throughout the life span, with fewer egg clusters. Although fecundity is negatively affected by the number of matings, egg fertility remains unaffected.     

Parasites of the superorganism: are they indicators of ecosystem health?

The concept of ecosystem health is derived from analogies with human health, which subsequently leads to the implication that the ecosystem has organismal properties, a 'superorganism' in the Clementsian sense. Its application and usefulness has been the subject of a contentious debate; yet, the term 'ecosystem health' has captured the public's imagination and woven its way into the current lexicon, even incorporated into public policy. However, the application of parasites as bioindicators of ecosystem health poses a curious conundrum. Perceptions of parasites range from mild distaste to sheer disgust among the general public, the media, environmental managers and non-parasitologists in the scientific community. Nevertheless, the biological nature of parasitism incorporates natural characteristics that are informative and useful for environmental management. The helminths in particular have evolved elegant means to ensure their transmission, often relying on complex life cycle interactions that include a variety of invertebrate and vertebrate hosts. The assemblage of these diverse parasites within a host organism potentially reflect that host's trophic position within the food web as well as the presence in the ecosystem of any other organisms that participate in the various parasite life cycles. Perturbations in ecosystem structure and function that affect food web topology will also impact upon parasite transmission, thus affecting parasite species abundance and composition. As such, parasite populations and communities are useful indicators of environmental stress, food web structure and biodiversity. In addition, there may be useful other means to utilise parasitic organisms based on their biology and life histories such as suites or guilds that may be effective bioindicators of particular forms of environmental degradation. The challenge for parasitology is to convince resource managers and fellow scientists that parasites are a natural part of all ecosystems, each species being a potentially useful information unit, and that healthy ecosystems have healthy parasites.