Extreme suction attachment performance from specialised insects living in mountain streams (Diptera: Blephariceridae).

Suction is widely used by animals for strong controllable underwater adhesion but is less well understood than adhesion of terrestrial climbing animals. Here we investigate the attachment of aquatic insect larvae (Blephariceridae), which cling to rocks in torrential streams using the only known muscle-actuated suction organs in insects. We measured their attachment forces on well-defined rough substrates and found that their adhesion was less reduced by micro-roughness than that of terrestrial climbing insects. In vivo visualisation of the suction organs in contact with microstructured substrates revealed that they can mould around large asperities to form a seal. We have shown that the ventral surface of the suction disc is covered by dense arrays of microtrichia, which are stiff spine-like cuticular structures that only make tip contact. Our results demonstrate the impressive performance and versatility of blepharicerid suction organs and highlight their potential as a study system to explore biological suction mechanisms.

Suction cups are widely used to attach objects to surfaces in bathrooms and kitchens. They work well on tiles and other smooth surfaces, but do not stick well to rougher materials like brick or wood because they are unable to form an air-tight seal. Researchers have been searching for ways to improve these cups by studying how octopuses, remora fish and other sea animals use muscle-powered suction organs to stick to wet and rough surfaces. However, the experiments needed to understand the detailed mechanics of suction organs are difficult to perform on living specimens of these animals. The aquatic larvae of a family of insects known as the net-winged midges also have suction organs that are powered by muscles. These insects survive in fast flowing mountain streams where they use their suction organs to stick to rocks underwater. However, it remained unclear how these suction organs work. Here, Kang et al. found that net-winged midge larvae attach extremely well to a variety of surfaces. The larvae were able to withstand forces over one thousand times their body weight when attached to smooth surfaces. Even on rough materials, where human-made suction cups attach poorly, the larvae were able to withstand forces up to 240-times their body weight. Further experiments using several microscopy approaches revealed that the suction organs of the larvae are covered in multiple spine-like structures called microtrichia that interlock with bumps and dips on a surface to help the organ remain in place. Similar structures have previously been found on the suction organs of remora fish, but are not as tightly packed together. These findings demonstrate that net-winged midge larvae may be useful model systems to study how natural suction organs operate. Furthermore, they provide a new source of inspiration for scientists and engineers to design and manufacture suction cups capable of attaching to a wider variety of surfaces.

Movement Behavior of the Pine Needle Gall Midge (Diptera: Cecidomyiidae).

The movement behavior of the pine needle gall midge (Thecodiplosis japonensis Uchida Et Inouye (Diptera: Cecidomyiidae)), an invasive species in China, was determined by using a tethered flight technique and digital videography in the laboratory. The flight distance, duration, and speed of females were compared at different ages (2-10 h) and ambient temperatures (17, 21, 26, and 30°C). Female flight distance and duration at 26°C were significantly greater than those at 17°C and 21°C. The age of T. japonensis did not significantly affect the three flight characteristics. For females at 2-10 h of age at 26°C and 70% RH, the maximum flight distance was 667.59 m; the longest flight time was 6,222.34 s; and the fastest flight speed was 0.44 m·s-1. For larvae wetted with water, the highest jump was 5.7 cm; the longest jump was 9.6 cm; and the greatest distance moved in 5 min was 27.13 cm, which showed that the active dispersal potential of larvae was very low.

Adhesive latching and legless leaping in small, worm-like insect larvae.

Jumping is often achieved using propulsive legs, yet legless leaping has evolved multiple times. We examined the kinematics, energetics and morphology of long-distance jumps produced by the legless larvae of gall midges (Asphondylia sp.). They store elastic energy by forming their body into a loop and pressurizing part of their body to form a transient 'leg'. They prevent movement during elastic loading by placing two regions covered with microstructures against each other, which likely serve as a newly described adhesive latch. Once the latch releases, the transient 'leg' launches the body into the air. Their average takeoff speeds (mean: 0.85 m s-1; range: 0.39-1.27 m s-1) and horizontal travel distances (up to 36 times body length or 121 mm) rival those of legged insect jumpers and their mass-specific power density (mean: 910 W kg-1; range: 150-2420 W kg-1) indicates the use of elastic energy storage to launch the jump. Based on the forces reported for other microscale adhesive structures, the adhesive latching surfaces are sufficient to oppose the loading forces prior to jumping. Energetic comparisons of insect larval crawling versus jumping indicate that these jumps are orders of magnitude more efficient than would be possible if the animals had crawled an equivalent distance. These discoveries integrate three vibrant areas in engineering and biology - soft robotics, small, high-acceleration systems, and adhesive systems - and point toward a rich, and as-yet untapped area of biological diversity of worm-like, small, legless jumpers.

Neoceroplatus betaryiensis nov. sp. (Diptera: Keroplatidae) is the first record of a bioluminescent fungus-gnat in South America.

Blue shining fungus gnats (Diptera) had been long reported in the Waitomo caves of New Zealand (Arachnocampa luminosa Skuse), in stream banks of the American Appalachian Mountains (Orfelia fultoni Fisher) in 1939 and in true spore eating Eurasiatic Keroplatus Bosc species. This current report observes that similar blue light emitting gnat larvae also occur nearby the Betary river in the buffer zone of High Ribeira River State Park (PETAR) in the Atlantic Forest of Brazil, where the larvae were found when on fallen branches or trunks enveloped in their own secreted silk. The new species is named Neoceroplatus betaryiensis nov. sp. (Diptera: Keroplatidae: Keroplatinae: Keroplatini) based on a morphological analysis. Neoceroplatus betaryiensis nov. sp. larvae emit blue bioluminescence that can be seen from their last abdominal segment and from two photophores located laterally on the first thoracic segment. When touched, the larvae can actively stop its luminescence, which returns when it is no longer being agitated. The in vitro bioluminescence spectrum of N. betaryiensis nov. sp. peaks at 472 nm, and cross-reactivity of hot and cold extracts with the luciferin-luciferase from Orfelia fultoni indicate significant similarity in both enzyme and substrate of the two species, and that the bioluminescence system in the subfamily Keroplatinae is conserved.

A Single Swede Midge (Diptera: Cecidomyiidae) Larva Can Render Cauliflower Unmarketable.

Swede midge, Contarinia nasturtii Kieffer (Diptera: Cecidomyiidae), is an invasive pest causing significant damage on Brassica crops in the Northeastern United States and Eastern Canada. Heading brassicas, like cauliflower, appear to be particularly susceptible. Swede midge is difficult to control because larvae feed concealed inside meristematic tissues of the plant. In order to develop damage and marketability thresholds necessary for integrated pest management, it is important to determine how many larvae render plants unmarketable and whether the timing of infestation affects the severity of damage. We manipulated larval density (0, 1, 3, 5, 10, or 20) per plant and the timing of infestation (30, 55, and 80 d after seeding) on cauliflower in the lab and field to answer the following questions: 1) What is the swede midge damage threshold? 2) How many swede midge larvae can render cauliflower crowns unmarketable? and 3) Does the age of cauliflower at infestation influence the severity of damage and marketability? We found that even a single larva can cause mild twisting and scarring in the crown rendering cauliflower unmarketable 52% of the time, with more larvae causing more severe damage and additional losses, regardless of cauliflower age at infestation.

A New Gall Midge Species of Asphondylia (Diptera: Cecidomyiidae) Inducing Flower Galls on Clinopodium nepeta (Lamiaceae) From Europe, Its Phenology, and Associated Fungi.

A new gall midge, Asphondylia nepetae sp. n. Viggiani (Diptera: Cecidomyiidae), causing flower gall on Clinopodium nepeta (L.) Kuntze (Lamiaceae), is described from Europe. The morphological characteristics of adult, larvae, and pupa are described and illustrated. Molecular approach (by sequencing 28S-D2, ITS2, and COI) confirmed that A. nepetae is a distinct species. The development of the gall is always associated with the presence of the fungus Botryosphaeria dothidea (Moug.: Fr.) Ces. and De Not. (Botryosphaeriales: Botryosphaeriaceae). The new species can complete several generations per year, on the flowers of the same host plant and its adults emerge from late spring to autumn. Pupae overwinter inside peculiar flower galls in a state of quiescence. The impact of the pest is highly variable with a percentage of flowers infested that ranged between 3 and 57.5% in the sampled years. Insect mortality was, at least in part, due to parasitoids that attack the young stages of the midge. Among them, the dominant species was Sigmophora brevicornis (Panzer) (Chalcidoidea: Eulophidae).

Phylogeny of the genus Stephomyia Tavares, 1916 (Diptera: Cecidomyiidae) / Filogenia do gênero Stephomyia Tavares, 1916 (Diptera: Cecidomyiidae)

Abstract Stephomyia Tavares, 1916 comprises seven species, all Neotropical: S. clavata (Tavares, 1920); S. epeugeniae Gagné, 1994; S. espiralis Maia, 1993; S. mina Maia, 1993; S. rotundifoliorum Maia, 1993; S. tetralobae Maia, 1993; and S. eugeniae (Felt, 1913). In the present study, a cladistic analysis based upon adult, pupa, larva and gall morphological characters as well as host plant data is carried out in order to discuss the monophyly of the genus and the relationships among the known species. The Stephomyia monophyly was supported by eight synapomorphies: five homoplastic characters and three non-homoplastic characters. Analyzes showed S. clavata with great instability within the genus, probably due to lack of larva, pupa and female data, so S. clavata was deactivated in analyze. The topology found was (S. mina ((S. eugeniae + S. epeugeniae) (S. tetralobae (S. rotundifoliorum + S. espiralis)))).

Resumo Stephomyia Tavares, 1916 compreende sete espécies, todas neotropicais: S. clavata (Tavares, 1920); S. epeugeniae Gagné, 1994; S. espiralis Maia, 1993; S. mina Maia, 1993; S. rotundifoliorum Maia, 1993; S. tetralobae Maia, 1993 e S. eugeniae (Felt, 1913). Neste estudo, uma análise cladística baseada em caracteres morfológicos dos adultos, pupa, larva e galha, bem como na informação das plantas hospedeiras é realizada e a monofilia do gênero e as relações entre as espécies conhecidas são discutidas. A monofilia de Stephomyia foi suportada por oito sinapomorfias: cinco caracteres homoplásticos e três não homoplásticos. Análises mostraram uma grande instabilidade de S. clavata dentro do gênero, provavelmente devido à falta de informações sobre a larva, a pupa e a fêmea, o que resultou em desativação na análise. A topologia encontrada foi (S. mina ((S. eugeniae + S. epeugeniae) (S. tetralobae (S. rotundifoliorum + S. espiralis)))).

Phylogeny of the genus Stephomyia Tavares, 1916 (Diptera: Cecidomyiidae).

Stephomyia Tavares, 1916 comprises seven species, all Neotropical: S. clavata (Tavares, 1920); S. epeugeniae Gagné, 1994; S. espiralis Maia, 1993; S. mina Maia, 1993; S. rotundifoliorum Maia, 1993; S. tetralobae Maia, 1993; and S. eugeniae (Felt, 1913). In the present study, a cladistic analysis based upon adult, pupa, larva and gall morphological characters as well as host plant data is carried out in order to discuss the monophyly of the genus and the relationships among the known species. The Stephomyia monophyly was supported by eight synapomorphies: five homoplastic characters and three non-homoplastic characters. Analyzes showed S. clavata with great instability within the genus, probably due to lack of larva, pupa and female data, so S. clavata was deactivated in analyze. The topology found was (S. mina ((S. eugeniae + S. epeugeniae) (S. tetralobae (S. rotundifoliorum + S. espiralis)))).

Are midge swarms bound together by an effective velocity-dependent gravity?

Midge swarms are a canonical example of collective animal behaviour where local interactions do not clearly play a major role and yet the animals display group-level cohesion. The midges appear somewhat paradoxically to be tightly bound to the swarm whilst at the same time weakly coupled inside it. The microscopic origins of this behaviour have remained elusive. Models based on Newtonian gravity do, however, agree well with experimental observations of laboratory swarms. They are biologically plausible since gravitational interactions have similitude with long-range acoustic and visual interactions, and they correctly predict that individual attraction to the swarm centre increases linearly with distance from the swarm centre. Here we show that the observed kinematics implies that this attraction also increases with an individual's flight speed. We find clear evidence for such an attractive force in experimental data.