High-altitude migration of Psylloidea (Hemiptera) over England

Some species of psyllid (Hemiptera: Psylloidea) are known to make high-altitude windborne migrations, but compared with their sister superfamily, the Aphidoidea, our knowledge of these movements is rudimentary and unsystematised. Here we have extracted psyllid capture data from day and night aerial sampling carried out at a height of 200 m above ground at Cardington, Bedfordshire, UK, during summers between 1999 and 2007. These records were consolidated with high-altitude psyllid catches made over England during the 1930s and with some other trapping results from northwest Europe which were indicative of migration. Information on aerial densities, diel flight periodicity, and the sex-ratio of the aerial psyllid populations is presented. We also compared our results with those of a recent study which used the Rothamsted Insect Survey network of suction traps (sampling at a height of 12.2 m); this provided confirmative evidence that the suction-traps were indeed detecting migrating psyllids. Finally, both aerial netting and suction trap data were used to tentatively interpret the seasonal timing of migrations in terms of the breeding/overwintering cycles of some common psyllid species.

Complexity and diversity of motion amplification and control strategies in motile carnivorous plant traps

Similar to animals, plants have evolved mechanisms for elastic energy storage and release to power and control rapid motion, yet both groups have been largely studied in isolation. This is exacerbated by the lack of consistent terminology and conceptual frameworks describing elastically powered motion in both groups. Iconic examples of fast movements can be found in carnivorous plants, which have become important models to study biomechanics, developmental processes, evolution and ecology. Trapping structures and processes vary considerably between different carnivorous plant groups. Using snap traps, suction traps and springboard-pitfall traps as examples, we illustrate how traps mix and match various mechanisms to power, trigger and actuate motions that contribute to prey capture, retention and digestion. We highlight a fundamental trade-off between energetic investment and movement control and discuss it in a functional-ecological context.

Aerial psyllid (Hemiptera: Psylloidea) detection and monitoring using suction traps in Britain: population observations, new species found and a revised British checklist

The Psylloidea contains species that can transmit pathogens to plants, including important agricultural crops e.g. the proteobacterium 'Candidatus Liberibacter solanacearum' (CaLsol) to potatoes. To obtain a better understanding of British psyllid populations, a study was conducted over two years to determine their aerial incidence and diversity using an existing network of 12.2 m suction traps. In total, 42 species were detected in the traps. In 2015 in England, the most common species was the grouping of Cacopsylla melanoneura and C. affinis followed by Trioza remota (the latter being most prevalent in autumn). In contrast, in Scotland Cacopsylla species (melanoneura, affinis, pulchra and brunneipennis) accounted for 81% of the population in spring and summer. The yearly sampling in England in 2015 revealed that the aerial movement of the most common species differed in their phenology. The grouping of Cacopsylla melanoneura and C. affinis, as well as T. urticae were most common in summer whereas T. remota was most prevalent in late autumn. Three species new to Britain: Cacopsylla alaterni, Trioza anthrisci and Ctenarytaina spatulata were caught during sampling, in addition to Trioza apicalis which transmits CaLsol. Following our study, the British psyllid checklist was revised and is presented here. The potential of suction traps for monitoring and detecting

Influence of Moonlight on Male Mating Aggregations of Nyssomyia whitmani, a Vector of American Cutaneous Leishmaniasis in Brazil

Nyssomyia whitmani (Antunes & Coutinho) is the sandfly vector of causative agents of American cutaneous leishmaniasis in South and Central America. It is widely spread throughout Brazil, in a close association with domestic animals. Almost nothing is known about male mating aggregations in N. whitmani, let alone the influence of moonlight on this behavior. Thus, the influence of moonlight on male N. whitmani aggregations was investigated by using non-attractant suction traps deployed in chicken cages under full moon and new moon nights. In this 18-night study, 2,160 specimens and seven species were collected. The most frequent species was N. whitmani accounting for 91.48% of the total sample. The abundance of males of N. whitmani was significantly higher in the presence than in the absence of moon. The sex ratio on new moon nights was 1:1 (M:F) and on full moon nights was male-biased (1.7:1). Based on this study, an influence of moonlight on male mating aggregations of N. whitmani was verified. The extent of this influence on increasing sandfly aggregation at hosts, the moonlight influence on the early flight activity of male sandflies and the use of chickens as aggregation sites for males of N. whitmani, are all discussed.

Predicting aphid abundance on winter wheat using suction trap catches

The relationship between the number of cereal aphids in flight (recorded by a national grid of suction traps in the Czech Republic) and their occurrence on winter wheat (in Prague) was established between 1999–2015. The flight of all the species was bimodal. Except for Rhopalosiphum padi, whose flight activity peaked in autumn, > 80% of individuals were trapped during April to mid-August. The species frequency was different between the winter wheat and aerial populations. R. padi, the dominant species in the trap catches, formed a small proportion of the aphids on the winter wheat, while Sitobion avenae and Metopolophium dirhodum, which were underrepresented in the suction traps, alternately dominated the populations on the wheat. The aphid abundance in the wheat stands was correlated with the suction trap catches in the “spring” peak (April to mid-August), and the maximum flight activity occurred 4–10 days after the peak in the number of aphids on the wheat. In contrast, the prediction of the aphid abundance in the wheat stands using the total suction trap catches until the 15th of June (the final date for the application of crop protection actions) was reliable only for M. dirhodum. Its maximum abundance on the wheat exceeded 40 aphids per tiller if the total suction trap catch until the 15th of June was ≥ 60 individuals per trap. The prediction of R. padi and S. avenae abundance using the suction trap catches was not reliable.

Thermodynamics of the Bladderwort Feeding Strike—Suction Power from Elastic Energy Storage

The carnivorous plant bladderwort exemplifies the use of accumulated elastic energy to power motion: respiration-driven pumps slowly load the walls of its suction traps with elastic energy (∼1 h). During a feeding strike, this energy is released suddenly to accelerate water (∼1 ms). However, due to the traps’ small size and concomitant low Reynolds number, a significant fraction of the stored energy may be dissipated as viscous friction. Such losses and the mechanical reversibility of Stokes flow are thought to degrade the feeding success of other suction feeders in this size range, such as larval fish. In contrast, triggered bladderwort traps are generally successful. By mapping the energy budget of a bladderwort feeding strike, we illustrate how this smallest of suction feeders can perform like an adult fish.

Relative abundance and geographical variation of Culex pipiens and Culex torrentium (Diptera: Culicidae) in CO2-baited traps in Denmark

European Culex pipiens and Culex torrentium are morphological fairly similar mosquito species with potentially different vector competences for pathogenic viruses. The relative abundance of the two species is therefore important for quantifying the potential for disease transmission in Denmark. Mosquitoes were sampled from 74 different sites in Denmark with CO2 and octenol-baited suction traps. A total of 285 Culex specimens were identified to species using a restriction enzyme assay. Culex pipiens was the dominating species with 220 (77%) specimens caught at 22 different sites, while 65 (23%) specimens were identified as C. torrentium and only caught at 4 sites. The ratio of the two species differed significantly between sites with C. torrentium dominating in just a single location. Both mosquito species were predominantly caught late in the Danish mosquito season, from mid-August and onwards.