Scanning electron microscope study of the structure of the hypostome of <i>Phityogamasus, Laelaps</i> and <i>Ornithonyssus</i> (Acari: Mesostigmata)

Evans, G. O.; Loots, G. C.

doi:10.1111/j.1469-7998.1975.tb03213.x

Cited by 8 publications

(2 citation statements)

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“…Much as the green, red or dark particulate material observed in the gut of phytoseiids (Flechtmann and McMurtry 1992 ), this must represent partly or unbroken down prey material as well as perhaps opaque precipitated-out products from the initial imbibition of clear fluid. As the granular material P. longicornis was homogeneous on microscopic inspection yet the larval dipteran prey tissues are macroscopically heterogeneous, it suggests a screening/straining mechanism in the mite’s oral apparatus (perhaps by the pre-oral channel spicules under the labrum—see Evans and Loots 1975 ; Flechtmann et al. 1994 ) is used.…”

Section: Discussionmentioning

confidence: 99%

Gut contents, digestive half-lives and feeding state prediction in the soil predatory mite Pergamasus longicornis (Mesostigmata: Parasitidae)

Bowman

2017

Exp Appl Acarol

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Mid- and hind-gut lumenal changes are described in the free-living predatory soil mite Pergamasus longicornis (Berlese) from a time series of histological sections scored during and after feeding on fly larval prey. Three distinct types of tangible material are found in the lumen. Bayesian estimation of the change points in the states of the gut lumenal contents over time is made using a time-homogenous first order Markov model. Exponential processes within the gut exhibit ‘stiff’ dynamics. A lumen is present throughout the midgut from 5 min after the start of feeding as the gut rapidly expands. It peaks at about 21.5 h–1.5 days and persists post-feeding (even when the gut is contracted) up until fasting/starvation commences 10 days post start of feeding. The disappearance of the lumen commences 144 h after the start of feeding. Complete disappearance of the gut lumen may take 5–9 weeks from feeding commencing. Clear watery prey material arrives up to 10 min from the start of feeding, driving gut lumen expansion. Intracellular digestion triggered by maximum gut expansion is indicated. Detectable granular prey material appears in the lumen during the concentrative phase of coxal droplet production and, despite a noticeable collapse around 12 h, lasts in part for 52.5 h. Posterior midgut regions differ slightly from anterior regions in their main prey food dynamics being somewhat faster in processing yet being slightly delayed. Posterior regions are confirmed as Last-In-Last-Out depots, anterior regions confirmed as First-In-First-Out conveyor belt processes. Evidence for differential lability of prey fractions is found. A scheme is presented of granular imbibed prey material being first initially rapidly absorbed ( = 23 min), and also being quickly partly converted to globular material extra-corporeally/extracellularly ( = 36 min)—which then rapidly disappears ( = 1.1 h, from a peak around 4 h). This is then followed by slow intracellular digestion ( = 6.9 h) of the resultant resistant prey residue matching the slow rate of appearance of opaque pre-excretory egestive refractive grains (overall = 4.5 days). The latter confirmed latent ‘catabolic fraction’ (along with Malpighian tubule produced guanine crystals) drives rectal vesicle expansion as ‘faeces’ during the later phases of gut emptying/contraction. Catabolic half-lives are of the order of 6.3–7.8 h. Membraneous material is only present in the lumen of the gut in starving mites. No obvious peritrophic membrane was observed. The total feeding cycle time may be slightly over 52.5 h. Full clearance in the gut system of a single meal including egestive and excretory products may take up to 3 weeks. Independent corroborative photographs are included and with posterior predictive densities confirm the physiological sequence of ingestion/digestion, egestion, excretion, defecation, together with their timings. Visually dark midguts almost certainly indicate egestive refractive grains (xanthine?) production. Nomograms to diagnose the feeding state of P. longicornis ...

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Section: Discussionmentioning

confidence: 99%

Gut contents, digestive half-lives and feeding state prediction in the soil predatory mite Pergamasus longicornis (Mesostigmata: Parasitidae)

Bowman

2017

Exp Appl Acarol

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“…So such cuticular roughness on the sub-labral keel and oral gutter in predatory mites may restrict (not facilitate) prey fluid flow as well as masticate material by their opposing action on labral movement. There is no need to pose a straining function (Evans and Loots 1975 ; Evans 1992 ). It certainly would be a very small mesh to pass through if the latter was its function.…”

Section: Introductionmentioning

confidence: 99%

Looking for future biological control agents: the comparative function of the deutosternal groove in mesostigmatid mites

Bowman

2023

Exp Appl Acarol

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The physics of fluid laminar flow through an idealised deutosternum assembly is used for the first time to review predatory feeding designs over 72 different-sized example species from 16 mesostigmatid families in order to inform the finding of new biological control agents. Gnathosomal data are digitised from published sources. Relevant gnathosomal macro- and micro-features are compared and contrasted in detail which may subtly impact the control of channel- or ‘pipe’-based transport of prey liquids around various gnathosomal locations. Relative deutosternal groove width on the mesostigmatid subcapitulum is important but appears unrelated to the closing velocity ratio of the moveable digit. Big mites are adapted for handling large and watery prey. The repeated regular distance between deutosternal transverse ridges (‘Querleisten’) supports the idea of them enabling a regular fluctuating bulging or pulsing droplet-based fluid wave ‘sticking’ and ‘slipping’ along the groove. Phytoseiids are an outlier functional group with a low deutosternal pipe flow per body size designed for slot-like microchannel transport in low volume fluid threads arising from daintily nibbling nearby prey klinorhynchidly. Deutosternal groove denticles are orientated topographically in order to synergise flow and possible mixing of coxal gland-derived droplets and circumcapitular reservoir fluids across the venter of the gnathosomal base back via the hypostome to the prey being masticated by the chelicerae. As well as working with the tritosternum to mechanically clean the deutosternum, denticles may suppress fluid drag. Shallow grooves may support edge-crawling viscous flow. Lateral features may facilitate handling unusual amounts of fluid arising from opportunistic feeding on atypical prey. Various conjectures for confirmatory follow-up are highlighted. Suggestions as to how to triage non-uropodoid species as candidate plant pest control agents are included.

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Fine structure and functional morphology of the mouthparts of a maleVeigaia sp. (Gamasida: Veigaiidae) with remarks on the spermatodactyl and related sensory structures

et al. 2006

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Mites of the genus Veigaia are common gamasid inhabitants of forest litter. They engage in the peculiar reproductive strategy of podospermy which, along with other morphological and behavioral adaptations, involves modification of the chelicerae of the relatively rare males into gonopods. Each movable digit is provided with an appendage (spermatodactyl) that is involved in sperm transfer. We describe the gross anatomy, fine structure, and functional morphology of the mouthparts of a male Veigaia species and give ultrastructural details for the corniculi, laciniae, preoral cavity, labrum, pharynx, and movable and fixed digits. The fine structure of the spermatodactyl is illustrated here for the first time in detail. A semischematic reconstruction of the gnathosoma and spermatodactyl is provided. The spermatodactyl is totally fused with the movable digit and a sperm transfer duct runs along its entire length. This duct starts at the adaxial base of the movable digit, continues inside the digit into the tube of the spermatodactyl, and finally opens at the distal abaxial surface of the spermatodactyl. Several sensory structures associated with the spermatodactyl probably provide the male with mechanical and chemical clues.

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Scanning electron microscope study of the structure of the hypostome of Phityogamasus, Laelaps and Ornithonyssus (Acari: Mesostigmata)

Cited by 8 publications

References 3 publications

Gut contents, digestive half-lives and feeding state prediction in the soil predatory mite Pergamasus longicornis (Mesostigmata: Parasitidae)

Gut contents, digestive half-lives and feeding state prediction in the soil predatory mite Pergamasus longicornis (Mesostigmata: Parasitidae)

Looking for future biological control agents: the comparative function of the deutosternal groove in mesostigmatid mites

Fine structure and functional morphology of the mouthparts of a maleVeigaia sp. (Gamasida: Veigaiidae) with remarks on the spermatodactyl and related sensory structures

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